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Sample records for wave function collapse

  1. Time symmetry in wave-function collapse

    Science.gov (United States)

    Bedingham, D. J.; Maroney, O. J. E.

    2017-04-01

    The notion of a physical collapse of the wave function is embodied in dynamical collapse models. These involve a modification of the unitary evolution of the wave function so as to give a dynamical account of collapse. The resulting dynamics is at first sight time asymmetric for the simple reason that the wave function depends on those collapse events in the past but not those in the future. Here we show that dynamical wave-function collapse models admit a general description that has no built-in direction of time. Given some simple constraints, we show that there exist empirically equivalent pictures of collapsing wave functions in both time directions, each satisfying the same dynamical rules. A preferred direction is singled out only by the asymmetric initial and final time constraints on the state of the universe.

  2. Continuous Observations and the Wave Function Collapse

    CERN Document Server

    Marchewka, A

    2011-01-01

    We propose to modify the collapse axiom of quantum measurement theory by replacing the instantaneous with a continuous collapse of the wave function in finite time $\\tau$. We apply it to coordinate measurement of a free quantum particle that is initially confined to a domain $D\\subset\\rR^d$ and is observed continuously by illuminating $\\rR^d-D$. The continuous collapse axiom (CCA) defines the post-measurement wave function (PMWF)in $D$ after a negative measurement as the solution of Schr\\"odinger's equation at time $\\tau$ with instantaneously collapsed initial condition and homogeneous Dirichlet condition on the boundary of $D$. The CCA applies to all cases that exhibit the Zeno effect. It rids quantum mechanics of the unphysical artifacts caused by instantaneous collapse and introduces no new artifacts.

  3. How fast is the wave function collapse?

    CERN Document Server

    Ignatiev, A Yu

    2012-01-01

    Using complex quantum Hamilton-Jacobi formulation, a new kind of non-linear equations is proposed that have almost classical structure and extend the Schroedinger equation to describe the collapse of the wave function as a finite-time process. Experimental bounds on the collapse time are reported (of order 0.1 ms to 0.1 ps) and its convenient dimensionless measure is introduced. This parameter helps to identify the areas where sensitive probes of the possible collapse dynamics can be done. Examples are experiments with Bose-Einstein condensates, ultracold neutrons or ultrafast optics.

  4. Chameleonic equivalence postulate and wave function collapse

    CERN Document Server

    Zanzi, Andrea

    2014-01-01

    A chameleonic solution to the cosmological constant problem and the non-equivalence of different conformal frames at the quantum level have been recently suggested [Phys. Rev. D82 (2010) 044006]. In this article we further discuss the theoretical grounds of that model and we are led to a chameleonic equivalence postulate (CEP). Whenever a theory satisfies our CEP (and some other additional conditions), a density-dependence of the mass of matter fields is naturally present. Let us summarize the main results of this paper. 1) The CEP can be considered the microscopic counterpart of the Einstein's Equivalence Principle and, hence, a chameleonic description of quantum gravity is obtained: in our model, (quantum) gravitation is equivalent to a conformal anomaly. 2) To illustrate one of the possible applications of the CEP, we point out a connection between chameleon fields and quantum-mechanical wave function collapse. The collapse is induced by the chameleonic nature of the theory. We discuss the collapse for a S...

  5. Primordial gravitational waves and the collapse of the wave function

    CERN Document Server

    Leon, Gabriel; Landau, Susana J

    2015-01-01

    "The self-induced collapse hypothesis'' has been introduced by D. Sudarsky and collaborators to explain the origin of cosmic structure from a perfect isotropic and homogeneous universe during the inflationary regime. In this paper, we calculate the power spectrum for the tensor modes, within the semiclassical gravity approximation, with the additional hypothesis of a generic self-induced collapse of the inflaton's wave function; we also compute an estimate for the tensor-to-scalar ratio. Based on this calculation, we show that the considered proposal exhibits a strong suppression of the tensor modes amplitude; nevertheless, the corresponding amplitude is still consistent with the joint BICEP/KECK and Planck collaborations limit on the tensor-to-scalar ratio.

  6. The realization of the wave function collapse in the linguistic interpretation of quantum mechanics

    CERN Document Server

    Ishikawa, Shiro

    2015-01-01

    Recently I proposed the linguistic interpretation of quantum mechanics, which is characterized as the linguistic turn of the Copenhagen interpretation of quantum mechanics. This turn from physics to language does not only extend quantum theory to classical theory but also yield the quantum mechanical world view. Although the wave function collapse is prohibited in the linguistic interpretation, in this paper I show that the phenomenon like wave function collapse can be realized in the linguistic interpretation. And furthermore, I propose the justification of the von Neumann-L\\"uders projection postulate. After all, I conclude that the wave function collapse should not be adopted in the Copenhagen interpretation.

  7. The argument for an objective wave function collapse: Why spontaneous localization collapse or no-collapse decoherence cannot solve the measurement problem in a subjective fashion

    CERN Document Server

    Thaheld, F H

    2006-01-01

    A more detailed analysis of the measurement problem continues to support the position taken by Shimony and the author that collapse of the wave function takes place in an objective manner in the rhodopsin molecule of the retina. This casts further doubts on the theories involving a spontaneous localization collapse process or a no-collapse decoherence process taking place in the visual cortex in a subjective fashion. The possibility is then raised, as per Anandan, as to whether the solution of the measurement problem in quantum theory allows one to address the problem of quantizing gravitation.

  8. Wave function collapses in a single spin magnetic resonance force microscopy

    CERN Document Server

    Berman, G P; Tsifrinovich, V I

    2004-01-01

    We study the effects of wave function collapses in the oscillating cantilever driven adiabatic reversals (OSCAR) magnetic resonance force microscopy (MRFM) technique. The quantum dynamics of the cantilever tip (CT) and the spin is analyzed and simulated taking into account the magnetic noise on the spin. The deviation of the spin from the direction of the effective magnetic field causes a measurable shift of the frequency of the CT oscillations. We show that the experimental study of this shift can reveal the information about the average time interval between the consecutive collapses of the wave function

  9. Inflation including collapse of the wave function: the quasi-de Sitter case

    Energy Technology Data Exchange (ETDEWEB)

    Leon, Gabriel [Universidad de Buenos Aires, Ciudad Universitaria-PabI, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Landau, Susana J. [Universidad de Buenos Aires y IFIBA, CONICET, Ciudad Universitaria-PabI, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Piccirilli, Maria Pia [Universidad Nacional de La Plata, Grupo de Astrofisica, Relatividad y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, Pcia de Buenos Aires (Argentina)

    2015-08-15

    The precise physical mechanism describing the emergence of the seeds of cosmic structure from a perfect isotropic and homogeneous universe has not been fully explained by the standard version of inflationary models. To handle this shortcoming, D. Sudarsky and collaborators have developed a proposal: the self-induced collapse hypothesis. In this scheme, the objective collapse of the inflaton wave function is responsible for the emergence of inhomogeneity and anisotropy at all scales. In previous papers, the proposal was developed with an almost exact de Sitter space-time approximation for the background that led to a perfect scale-invariant power spectrum. In the present article, we consider a full quasi-de Sitter expansion and calculate the primordial power spectrum for three different choices of the self-induced collapse. The consideration of a quasi-de Sitter background allows us to distinguish departures from an exact scale-invariant power spectrum that are due to the inclusion of the collapse hypothesis. These deviations are also different from the prediction of standard inflationary models with a running spectral index. A comparison with the primordial power spectrum and the CMB temperature fluctuation spectrum preferred by the latest observational data is also discussed. From the analysis performed in this work, it follows that most of the collapse schemes analyzed in this paper are viable candidates to explain the present observations of the CMB fluctuation spectrum. (orig.)

  10. Inflation including collapse of the wave function: The quasi-de Sitter case

    CERN Document Server

    León, Gabriel; Piccirilli, María Pía

    2015-01-01

    The emergence of the seeds of cosmic structure from a perfect isotropic and homogeneous Universe has not been fully explained by the standard version of inflationary models. To handle this shortcoming, D. Sudarsky and collaborators have developed a proposal: "the self-induced collapse hypothesis." In this scheme, the collapse of the inflaton wave function is responsible for the emergence of inhomogeneity and anisotropy at each scale. In previous papers, the proposal was developed with an almost exact de Sitter space-time approximation for the background that lead to a perfect scale-invariant power spectrum. In this paper, we consider a quasi-de Sitter expansion factor and calculate the primordial power spectrum for three different choices of the self-induced collapse. The consideration of a quasi-de Sitter background allow us to distinguish departures from an exact scale-invariant power spectrum that are due to the inclusion of the collapse hypothesis. These deviations are also different from the prediction o...

  11. Unravelling the noise: the discrimination of wave function collapse models under time-continuous measurements

    Science.gov (United States)

    Genoni, Marco G.; Duarte, O. S.; Serafini, Alessio

    2016-10-01

    Inspired by the notion that environmental noise is in principle observable, while fundamental noise due to spontaneous localization would not be, we study the estimation of the diffusion parameter induced by wave function collapse models under continuous monitoring of the environment. We take into account finite measurement efficiencies and, in order to quantify the advantage granted by monitoring, we analyse the quantum Fisher information associated with such a diffusion parameter, identify optimal measurements in limiting cases, and assess the performance of such measurements in more realistic conditions.

  12. Does consciousness really collapse the wave function? A possible objective biophysical resolution of the measurement problem

    CERN Document Server

    Thaheld, F H

    2005-01-01

    An analysis has been performed of the theories and postulates advanced by von Neumann, London and Bauer, and Wigner, concerning the role that consciousness might play in the collapse of the wave function, which has become known as the measurement problem. This reveals that an error may have been made by them in the area of biology and its interface with quantum mechanics, when they called for the reduction of any superposition states in the brain through the mind or consciousness. Many years later Wigner changed his mind to reflect a simpler and more realistic objective position, expanded upon by Shimony, which appears to offer a way to resolve this issue. The argument is therefore made that the wave function of any superposed photon state or states is always objectively changed within the complex architecture of the eye in a continuous linear process initially for most of the superposed photons, followed by a discontinuous nonlinear collapse process later for any remaining superposed photons, thereby guarant...

  13. Gradual collapse of nuclear wave functions regulated by frequency tuned X-ray scattering.

    Science.gov (United States)

    Ignatova, Nina; Cruz, Vinícius V; Couto, Rafael C; Ertan, Emelie; Zimin, Andrey; Guimarães, Freddy F; Polyutov, Sergey; Ågren, Hans; Kimberg, Victor; Odelius, Michael; Gel'mukhanov, Faris

    2017-03-07

    As is well established, the symmetry breaking by isotope substitution in the water molecule results in localisation of the vibrations along one of the two bonds in the ground state. In this study we find that this localisation may be broken in excited electronic states. Contrary to the ground state, the stretching vibrations of HDO are delocalised in the bound core-excited state in spite of the mass difference between hydrogen and deuterium. The reason for this effect can be traced to the narrow "canyon-like" shape of the potential of the state along the symmetric stretching mode, which dominates over the localisation mass-difference effect. In contrast, the localisation of nuclear motion to one of the HDO bonds is preserved in the dissociative core-excited state . The dynamics of the delocalisation of nuclear motion in these core-excited states is studied using resonant inelastic X-ray scattering of the vibrationally excited HDO molecule. The results shed light on the process of a wave function collapse. After core-excitation into the state of HDO the initial wave packet collapses gradually, rather than instantaneously, to a single vibrational eigenstate.

  14. Gravitational waves from gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Fryer, Christopher L [Los Alamos National Laboratory; New, Kimberly C [Los Alamos National Laboratory

    2008-01-01

    Gravitational wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  15. Gravitational Waves from Gravitational Collapse

    Directory of Open Access Journals (Sweden)

    Chris L. Fryer

    2011-01-01

    Full Text Available Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  16. CSL Wave Function Collapse Model as a Mechanism for the Emergence of Cosmological Asymmetries in Inflation

    CERN Document Server

    Cañate, Pedro; Sudarsky, Daniel

    2012-01-01

    As previously discussed in (D. Sudarsky, Int.J.Mod.Phys.D20:509-552, (2011); [arXiv:0906.0315]), the inflationary account for the emergence of the seeds of cosmic structure falls short of actually explaining the generation of primordial anisotropies and inhomogeneities. This description starts from a symmetric background, and invokes symmetric dynamics, so it cannot explain asymmetries. To generate asymmetries, we present an application of the Continuous Spontaneous Localization (CSL) model of wave function collapse (P. Pearle, Phys. Rev. A 39, 2277, (1989); G. C. Ghirardi, P. Pearle and A. Rimini, Phys. Rev. A42, 78 (1990)) in the context of inflation. This modification of quantum dynamics introduces a stochastic non-unitary component to the evolution of the inflaton field perturbations. This leads to passage from a homogeneous and isotropic stage to another, where the quantum uncertainties in the initial state of inflation transmute into the primordial inhomogeneities and anisotropies. We examine requiremen...

  17. The collapse of the wave function in the joint metric-matter quantization for inflation

    CERN Document Server

    Diez-Tejedor, Alberto; Sudarsky, Daniel

    2011-01-01

    It has been argued that the standard inflationary scenario suffers from a serious deficiency as a model for the origin of the seeds of cosmic structure: it can not truly account for the transition from an early homogeneous and isotropic stage to another one lacking such symmetries. The issue has often been thought as a standard instance of the "quantum measurement problem", but as has been recently argued by some of us the situation reaches a critical level in the cosmological context of interest here. This has lead to a proposal in which the standard paradigm is supplemented by a hypothesis concerning the self-induced dynamical collapse of the wave function, as representing the physical mechanism through which such change of symmetry is brought forth. This proposal was formulated within the context of semiclassical gravity. Here we investigate an alternative realization of such idea implemented directly within the standard analysis in terms of a quantum field jointly describing the inflaton and metric pertur...

  18. Continuous spontaneous localization wave function collapse model as a mechanism for the emergence of cosmological asymmetries in inflation

    Science.gov (United States)

    Cañate, Pedro; Pearle, Philip; Sudarsky, Daniel

    2013-05-01

    The inflationary account for the emergence of the seeds of cosmic structure falls short of actually explaining the generation of primordial anisotropies and inhomogeneities. This description starts from a symmetric background, and invokes symmetric dynamics, so it cannot explain asymmetries. To generate asymmetries, we present an application of the continuous spontaneous localization model of wave function collapse in the context of inflation. This modification of quantum dynamics introduces a stochastic nonunitary component to the evolution of the inflaton field perturbations. This leads to passage from a homogeneous and isotropic stage to another, where the quantum uncertainties in the initial state of inflation transmute into the primordial inhomogeneities and anisotropies. We show, by proper choice of the collapse-generating operator, that it is possible to achieve compatibility with the precise observations of the cosmic microwave background radiation.

  19. Inflationary gravitational waves in collapse scheme models

    Energy Technology Data Exchange (ETDEWEB)

    Mariani, Mauro, E-mail: mariani@carina.fcaglp.unlp.edu.ar [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, 1900 La Plata (Argentina); Bengochea, Gabriel R., E-mail: gabriel@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); León, Gabriel, E-mail: gleon@df.uba.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria – Pab. I, 1428 Buenos Aires (Argentina)

    2016-01-10

    The inflationary paradigm is an important cornerstone of the concordance cosmological model. However, standard inflation cannot fully address the transition from an early homogeneous and isotropic stage, to another one lacking such symmetries corresponding to our present universe. In previous works, a self-induced collapse of the wave function has been suggested as the missing ingredient of inflation. Most of the analysis regarding the collapse hypothesis has been solely focused on the characteristics of the spectrum associated to scalar perturbations, and within a semiclassical gravity framework. In this Letter, working in terms of a joint metric-matter quantization for inflation, we calculate, for the first time, the tensor power spectrum and the tensor-to-scalar ratio corresponding to the amplitude of primordial gravitational waves resulting from considering a generic self-induced collapse.

  20. Inflationary gravitational waves in collapse scheme models

    Directory of Open Access Journals (Sweden)

    Mauro Mariani

    2016-01-01

    Full Text Available The inflationary paradigm is an important cornerstone of the concordance cosmological model. However, standard inflation cannot fully address the transition from an early homogeneous and isotropic stage, to another one lacking such symmetries corresponding to our present universe. In previous works, a self-induced collapse of the wave function has been suggested as the missing ingredient of inflation. Most of the analysis regarding the collapse hypothesis has been solely focused on the characteristics of the spectrum associated to scalar perturbations, and within a semiclassical gravity framework. In this Letter, working in terms of a joint metric-matter quantization for inflation, we calculate, for the first time, the tensor power spectrum and the tensor-to-scalar ratio corresponding to the amplitude of primordial gravitational waves resulting from considering a generic self-induced collapse.

  1. Collapse of Electrostatic Waves in Magnetoplasmas

    DEFF Research Database (Denmark)

    Shukla, P. K.; Yu, M. Y.; Juul Rasmussen, Jens

    1984-01-01

    The two-fluid model is employed to investigate the collapse of electrostatic waves in magnetized plasmas. It is found that nonlinear interaction of ion cyclotron, upper-, and lower-hybrid waves with adiabatic particle motion along the external magnetic field can cause wave-field collapse....

  2. Models of Wave-function Collapse, Underlying Theories, and Experimental Tests

    CERN Document Server

    Bassi, Angelo; Satin, Seema; Singh, Tejinder P; Ulbricht, Hendrik

    2012-01-01

    Quantum mechanics is an extremely successful theory that agrees with every experiment. However, the principle of linear superposition, a central tenet of the theory, apparently contradicts a commonplace observation: macroscopic objects are never found in a linear superposition of position states. Moreover, the theory does not really explain as to why during a quantum measurement, deterministic evolution is replaced by probabilistic evolution, whose random outcomes obey the Born probability rule. In this article we review an experimentally falsifiable phenomenological proposal, known as Continuous Spontaneous Collapse: a stochastic non-linear modification of the Schr\\"{o}dinger equation, which resolves these problems, while giving the same experimental results as quantum theory in the microscopic regime. Two underlying theories for this phenomenology are reviewed: Trace Dynamics, and gravity induced collapse. As one approaches the macroscopic scale, the predictions of this proposal begin to differ appreciably ...

  3. Experimental bounds on collapse models from gravitational wave detectors

    Science.gov (United States)

    Carlesso, Matteo; Bassi, Angelo; Falferi, Paolo; Vinante, Andrea

    2016-12-01

    Wave function collapse models postulate a fundamental breakdown of the quantum superposition principle at the macroscale. Therefore, experimental tests of collapse models are also fundamental tests of quantum mechanics. Here, we compute the upper bounds on the collapse parameters, which can be inferred by the gravitational wave detectors LIGO, LISA Pathfinder, and AURIGA. We consider the most widely used collapse model, the continuous spontaneous localization (CSL) model. We show that these experiments exclude a huge portion of the CSL parameter space, the strongest bound being set by the recently launched space mission LISA Pathfinder. We also rule out a proposal for quantum-gravity-induced decoherence.

  4. Cylindrical Collapse and Gravitational Waves

    CERN Document Server

    Herrera, L

    2005-01-01

    We study the matching conditions for a collapsing anisotropic cylindrical perfect fluid, and we show that its radial pressure is non zero on the surface of the cylinder and proportional to the time dependent part of the field produced by the collapsing fluid. This result resembles the one that arises for the radiation - though non-gravitational - in the spherically symmetric collapsing dissipative fluid, in the diffusion approximation.

  5. Sharper criteria for the wave collapse

    DEFF Research Database (Denmark)

    Kuznetsov, E.A.; Juul Rasmussen, J.; Rypdal, K.

    1995-01-01

    Sharper criteria for three-dimensional wave collapse described by the Nonlinear Schrodinger Equation (NLSE) are derived. The collapse threshold corresponds to the ground state soliton which is known to be unstable. Thus, for nonprefocusing distributions this represents the separatrix between...

  6. A Pseudospectral Method for Gravitational Wave Collapse

    CERN Document Server

    Hilditch, David; Bruegmann, Bernd

    2015-01-01

    We present a new pseudospectral code, bamps, for numerical relativity written with the evolution of collapsing gravitational waves in mind. We employ the first order generalized harmonic gauge formulation. The relevant theory is reviewed and the numerical method is critically examined and specialized for the task at hand. In particular we investigate formulation parameters, gauge and constraint preserving boundary conditions well-suited to non-vanishing gauge source functions. Different types of axisymmetric twist-free moment of time symmetry gravitational wave initial data are discussed. A treatment of the axisymmetric apparent horizon condition is presented with careful attention to regularity on axis. Our apparent horizon finder is then evaluated in a number of test cases. Moving on to evolutions, we investigate modifications to the generalized harmonic gauge constraint damping scheme to improve conservation in the strong field regime. We demonstrate strong-scaling of our pseudospectral penalty code. We em...

  7. Gravitational Waves Signals from the Collapse of the First Stars

    CERN Document Server

    Schneider, R; Ciardi, B; Ferrari, V; Matarrese, S

    1999-01-01

    We study the gravitational wave emission from the first stars which are assumed to be Very Massive Objects (VMOs). We take into account various feedback (both radiative and stellar) effects regulating the collapse of objects in the early universe and thus derive the VMO initial mass function and formation rate. If the final fate of VMOs is to collapse, leaving very massive black hole remnants, then the gravitational waves emitted during each collapse would be seen as a stochastic background. The predicted spectral strain amplitude in a critical density Cold Dark Matter universe peaks in the frequency range \\approx 5 \\times 10^{-4}-5 \\times 10^{-3} Hz where it has a value in the range \\approx 10^{-20}-10^{-19} Hz^{-1/2}, and might be detected by LISA. The expected emission rate is roughly 4000 events/yr, resulting in a stationary, discrete sequence of bursts, i.e. a shot--noise signal.

  8. Caldera collapse and the generation of waves

    Science.gov (United States)

    Gray, J. P.; Monaghan, J. J.

    2003-02-01

    The aim of this paper is to begin a study of the waves produced by the collapse of a caldera connected to the sea. An example is the bronze age collapse of the caldera of Santorini (Thera), which is thought to have involved an area of approximately 70 km2 subsiding to a depth close to the present 390 m. In this paper, we concentrate on the purely mechanical aspects of the flow and adopt a simple geometry that replicates some of the features of the pre-bronze age caldera of Santorini. By combining laboratory experiments with computer simulations, we have been able to determine the amplitude of the waves for a wide range of cavity parameters. For cavities with a width comparable to the depth of water entering the cavity, we have determined a scaling relation for the amplitude in terms of the geometry of the system. In the case of wider cavities, the flow begins like a breaking dam flow; it then becomes similar to a classical bore before breaking up into waves. The computer simulations agree well with experiment and will allow us to simulate more complicated geometries.

  9. Electromagnetic wave collapse in a radiation background.

    Science.gov (United States)

    Marklund, Mattias; Brodin, Gert; Stenflo, Lennart

    2003-10-17

    The nonlinear interaction, due to quantum electrodynamical (QED) effects between an electromagnetic pulse and a radiation background, is investigated by combining the methods of radiation hydrodynamics with the QED theory for photon-photon scattering. For the case of a single coherent electromagnetic pulse, we obtain a Zakharov-like system, where the radiation pressure of the pulse acts as a driver of acoustic waves in the photon gas. For a sufficiently intense pulse and/or background energy density, there is focusing and the subsequent collapse of the pulse. The relevance of our results for various astrophysical applications are discussed.

  10. Shock wave emission during the collapse of cavitation bubbles

    Science.gov (United States)

    Garen, W.; Hegedűs, F.; Kai, Y.; Koch, S.; Meyerer, B.; Neu, W.; Teubner, U.

    2016-07-01

    Shock wave emission induced by intense laser pulses is investigated experimentally. The present work focuses on the conditions of shock wave emission in glycerine and distilled water during the first bubble collapse. Experimental investigations are carried out in liquids as a function of temperature and viscosity. Comparison is made with the theoretical work of Poritsky (Proc 1st US Natl Congress Appl Mech 813-821, 1952) and Brennen (Cavitation and bubble dynamics, Oxford University Press 1995). To the best knowledge of the authors, this is the first experimental verification of those theories.

  11. Probing the Core-Collapse Supernova Mechanism with Gravitational Waves

    CERN Document Server

    Ott, C D

    2009-01-01

    The mechanism of core-collapse supernova explosions must draw on the energy provided by gravitational collapse and transfer the necessary fraction to the kinetic and internal energy of the ejecta. Despite many decades of concerted theoretical effort, the detailed mechanism of core-collapse supernova explosions is still unknown, but indications are strong that multi-D processes lie at its heart. This opens up the possibility of probing the supernova mechanism with gravitational waves, carrying direct dynamical information from the supernova engine deep inside a dying massive star. I present a concise overview of the physics and primary multi-D dynamics in neutrino-driven, magnetorotational, and acoustically-driven core-collapse supernova explosion scenarios. Discussing and contrasting estimates for the gravitational-wave emission characteristics of these mechanisms, I argue that their gravitational-wave signatures are clearly distinct and that the observation (or non-observation) of gravitational waves from a ...

  12. Inferring Core-Collapse Supernova Physics with Gravitational Waves

    CERN Document Server

    Logue, J; Heng, I S; Kalmus, P; Scargill, J

    2012-01-01

    Stellar collapse and the subsequent development of a core-collapse supernova explosion emit bursts of gravitational waves (GWs) that might be detected by the advanced generation of laser interferometer gravitational-wave observatories such as Advanced LIGO, Advanced Virgo, and LCGT. GW bursts from core-collapse supernovae encode information on the intricate multi-dimensional dynamics at work at the core of a dying massive star and may provide direct evidence for the yet uncertain mechanism driving supernovae in massive stars. Recent multi-dimensional simulations of core-collapse supernovae exploding via the neutrino, magnetorotational, and acoustic explosion mechanisms have predicted GW signals which have distinct structure in both the time and frequency domains. Motivated by this, we describe a promising method for determining the most likely explosion mechanism underlying a hypothetical GW signal, based on Principal Component Analysis and Bayesian model selection. Using simulated Advanced LIGO noise and ass...

  13. Gravitational Collapse of Gravitational Waves in 3D Numerical Relativity

    CERN Document Server

    Alcubierre, M; Brügmann, B; Lanfermann, G; Seidel, E; Suen, W M; Tobias, M; Alcubierre, Miguel; Allen, Gabrielle; Bruegmann, Bernd; Lanfermann, Gerd; Seidel, Edward; Suen, Wai-Mo; Tobias, Malcolm

    2000-01-01

    We demonstrate that evolutions of three-dimensional, strongly non-linear gravitational waves can be followed in numerical relativity, hence allowing many interesting studies of both fundamental and observational consequences. We study the evolution of time-symmetric, axisymmetric {\\it and} non-axisymmetric Brill waves, including waves so strong that they collapse to form black holes under their own self-gravity. The critical amplitude for black hole formation is determined. The gravitational waves emitted in the black hole formation process are compared to those emitted in the head-on collision of two Misner black holes.

  14. Core-Collapse Supernovae, Neutrinos, and Gravitational Waves

    CERN Document Server

    Ott, C D; Gossan, S; Abdikamalov, E; Gamma, U C T; Drasco, S

    2012-01-01

    Core-collapse supernovae are among the most energetic cosmic cataclysms. They are prodigious emitters of neutrinos and quite likely strong galactic sources of gravitational waves. Observation of both neutrinos and gravitational waves from the next galactic or near extragalactic core-collapse supernova will yield a wealth of information on the explosion mechanism, but also on the structure and angular momentum of the progenitor star, and on aspects of fundamental physics such as the equation of state of nuclear matter at high densities and low entropies. In this contribution to the proceedings of the Neutrino 2012 conference, we summarize recent progress made in the theoretical understanding and modeling of core-collapse supernovae. In this, our emphasis is on multi-dimensional processes involved in the explosion mechanism such as neutrino-driven convection and the standing accretion shock instability. As an example of how supernova neutrinos can be used to probe fundamental physics, we discuss how the rise ti...

  15. Supernova Seismology: Gravitational Wave Signatures of Rapidly Rotating Core Collapse

    CERN Document Server

    Fuller, Jim; Abdikamalov, Ernazar; Ott, Christian

    2015-01-01

    Gravitational waves (GW) generated during a core-collapse supernova open a window into the heart of the explosion. At core bounce, progenitors with rapid core rotation rates exhibit a characteristic GW signal which can be used to constrain the properties of the core of the progenitor star. We investigate the dynamics of rapidly rotating core collapse, focusing on hydrodynamic waves generated by the core bounce and the GW spectrum they produce. The centrifugal distortion of the rapidly rotating proto-neutron star (PNS) leads to the generation of axisymmetric quadrupolar oscillations within the PNS and surrounding envelope. Using linear perturbation theory, we estimate the frequencies, amplitudes, damping times, and GW spectra of the oscillations. Our analysis provides a qualitative explanation for several features of the GW spectrum and shows reasonable agreement with nonlinear hydrodynamic simulations, although a few discrepancies due to non-linear/rotational effects are evident. The dominant early postbounce...

  16. Multivariate Regression Analysis of Gravitational Waves from Rotating Core Collapse

    CERN Document Server

    Engels, William J; Ott, Christian D

    2014-01-01

    We present a new multivariate regression model for analysis and parameter estimation of gravitational waves observed from well but not perfectly modeled sources such as core-collapse supernovae. Our approach is based on a principal component decomposition of simulated waveform catalogs. Instead of reconstructing waveforms by direct linear combination of physically meaningless principal components, we solve via least squares for the relationship that encodes the connection between chosen physical parameters and the principal component basis. Although our approach is linear, the waveforms' parameter dependence may be non-linear. For the case of gravitational waves from rotating core collapse, we show, using statistical hypothesis testing, that our method is capable of identifying the most important physical parameters that govern waveform morphology in the presence of simulated detector noise. We also demonstrate our method's ability to predict waveforms from a principal component basis given a set of physical ...

  17. Transition wave in the collapse of the San Saba bridge

    Science.gov (United States)

    Brun, Michele; Giaccu, Gian Felice; Movchan, Alexander; Slepyan, Leonid

    2014-09-01

    A domino wave is a well-known illustration of a transition wave, which appears to reach a stable regime of propagation. Nature also provides spectacular cases of gravity driven transition waves at large scale, observed in snow avalanches and landslides. On a different scale, the micro-structure level interaction between different constituents of the macro-system may influence critical regimes leading to instabilities in avalanche-like flow systems. Most transition waves observed in systems such as bulletproof vests, racing helmets under impact, shock-wave driven fracture in solids, are transient. For some structured waveguides a transition wave may stabilize to achieve a steady regime. Here we show that the failure of a long bridge is also driven by a transition wave that may allow for steady-state regimes. The recent observation of a failure of the San Saba Bridge in Texas provides experimental evidence supporting an elegant theory based on the notion of transition failure wave. No one would think of an analogy between a snow avalanche and a collapsing bridge. Despite an apparent controversy of such a comparison, these two phenomena can both be described in the framework of a model of the dynamic gravity driven transition fault.

  18. GRAVITATIONAL WAVE SIGNATURES IN BLACK HOLE FORMING CORE COLLAPSE

    Energy Technology Data Exchange (ETDEWEB)

    Cerdá-Durán, Pablo; DeBrye, Nicolas; Aloy, Miguel A.; Font, José A.; Obergaulinger, Martin, E-mail: pablo.cerda@uv.es [Departamento de Astronomia y Astrofísica, Universidad de Valencia, c/Dr. Moliner 50, E-46100-Burjassot (Spain)

    2013-12-20

    We present general relativistic numerical simulations of collapsing stellar cores. Our initial model consists of a low metallicity rapidly-rotating progenitor which is evolved in axisymmetry with the latest version of our general relativistic code CoCoNuT, which allows for black hole formation and includes the effects of a microphysical equation of state (LS220) and a neutrino leakage scheme to account for radiative losses. The motivation of our study is to analyze in detail the emission of gravitational waves in the collapsar scenario of long gamma-ray bursts. Our simulations show that the phase during which the proto-neutron star (PNS) survives before ultimately collapsing to a black hole is particularly optimal for gravitational wave emission. The high-amplitude waves last for several seconds and show a remarkable quasi-periodicity associated with the violent PNS dynamics, namely during the episodes of convection and the subsequent nonlinear development of the standing-accretion shock instability (SASI). By analyzing the spectrogram of our simulations we are able to identify the frequencies associated with the presence of g-modes and with the SASI motions at the PNS surface. We note that the gravitational waves emitted reach large enough amplitudes to be detected with third-generation detectors such as the Einstein Telescope within a Virgo Cluster volume at rates ≲ 0.1 yr{sup –1}.

  19. First targeted search for gravitational-wave bursts from core-collapse supernovae in data of first-generation laser interferometer detectors

    Science.gov (United States)

    Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corpuz, A.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalmus, P.; Kalogera, V.; Kamaretsos, I.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Loew, K.; Logue, J.; Lombardi, A. L.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, K. N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Pereira, R.; Perreca, A.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Santamaria, L.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

    2016-11-01

    We present results from a search for gravitational-wave bursts coincident with two core-collapse supernovae observed optically in 2007 and 2011. We employ data from the Laser Interferometer Gravitational-wave Observatory (LIGO), the Virgo gravitational-wave observatory, and the GEO 600 gravitational-wave observatory. The targeted core-collapse supernovae were selected on the basis of (1) proximity (within approximately 15 Mpc), (2) tightness of observational constraints on the time of core collapse that defines the gravitational-wave search window, and (3) coincident operation of at least two interferometers at the time of core collapse. We find no plausible gravitational-wave candidates. We present the probability of detecting signals from both astrophysically well-motivated and more speculative gravitational-wave emission mechanisms as a function of distance from Earth, and discuss the implications for the detection of gravitational waves from core-collapse supernovae by the upgraded Advanced LIGO and Virgo detectors.

  20. A First Targeted Search for Gravitational-Wave Bursts from Core-Collapse Supernovae in Data of First-Generation Laser Interferometer Detectors

    CERN Document Server

    Abbott, B P; Abbott, T D; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allocca, A; Altin, P A; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Babak, S; Bacon, P; Bader, M K M; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Baune, C; Bavigadda, V; Bazzan, M; Behnke, B; Bejger, M; Bell, A S; Bell, C J; Berger, B K; Bergman, J; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Birney, R; Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bohe, A; Bojtos, P; Bond, C; Bondu, F; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cadonati, L; Cagnoli, G; Cahillane, C; Bustillo, J Calder'on; Callister, T; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Diaz, J Casanueva; Casentini, C; Caudill, S; Cavagli`a, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Baiardi, L Cerboni; Cerretani, G; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chan, M; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, H Y; Chen, Y; Cheng, C; Chincarini, A; Chiummo, A; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, S; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P -F; Colla, A; Collette, C G; Cominsky, L; Constancio, M; Conte, A; Conti, L; Cook, D; Corbitt, T R; Cornish, N; Corpuz, A; Corsi, A; Cortese, S; Costa, C A; Coughlin, M W; Coughlin, S B; Coulon, J -P; Countryman, S T; Couvares, P; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Cripe, J; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Canton, T Dal; Danilishin, S L; D'Antonio, S; Danzmann, K; Darman, N S; Dattilo, V; Dave, I; Daveloza, H P; Davier, M; Davies, G S; Daw, E J; Day, R; DeBra, D; Debreczeni, G; Degallaix, J; De Laurentis, M; Del'eglise, S; Del Pozzo, W; Denker, T; Dent, T; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Dhurandhar, S; D'iaz, M C; Di Fiore, L; Di Giovanni, M; Di Girolamo, T; Di Lieto, A; Di Pace, S; Di Palma, I; Di Virgilio, A; Dojcinoski, G; Dolique, V; Donovan, F; Dooley, K L; Doravari, S; Douglas, R; 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Gosselin, M; Gouaty, R; Grado, A; Graef, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greco, G; Green, A C; Groot, P; Grote, H; Grunewald, S; Guidi, G M; Guo, X; Gupta, A; Gupta, M K; Gushwa, K E; Gustafson, E K; Gustafson, R; Hacker, J J; Hall, B R; Hall, E D; Hammond, G; Haney, M; Hanke, M M; Hanks, J; Hanna, C; Hannam, M D; Hanson, J; Hardwick, T; Harms, J; Harry, G M; Harry, I W; Hart, M J; Hartman, M T; Haster, C -J; Haughian, K; Heidmann, A; Heintze, M C; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Hennig, J; Heptonstall, A W; Heurs, M; Hild, S; Hoak, D; Hodge, K A; Hofman, D; Hollitt, S E; Holt, K; Holz, D E; Hopkins, P; Hosken, D J; Hough, J; Houston, E A; Howell, E J; Hu, Y M; Huang, S; Huerta, E A; Huet, D; Hughey, B; Husa, S; Huttner, S H; Huynh-Dinh, T; Idrisy, A; Indik, N; Ingram, D R; Inta, R; Isa, H N; Isac, J -M; Isi, M; Islas, G; Isogai, T; Iyer, B R; Izumi, K; Jacqmin, T; Jang, H; Jani, K; Jaranowski, P; Jawahar, S; Jim'enez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; K, Haris; Kalaghatgi, C V; Kalmus, P; Kalogera, V; Kamaretsos, I; Kandhasamy, S; Kang, G; Kanner, J B; Karki, S; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, S; Kaur, T; Kawabe, K; Kawazoe, F; K'ef'elian, F; Kehl, M S; Keitel, D; Kelley, D B; Kells, W; Kennedy, R; Key, J S; Khalaidovski, A; Khalili, F Y; Khan, I; Khan, S; Khan, Z; Khazanov, E A; Kijbunchoo, N; Kim, Chunglee; Kim, J; Kim, K; Kim, Nam-Gyu; Kim, Namjun; Kim, Y -M; King, E J; King, P J; Kinzel, D L; Kissel, J S; Kleybolte, L; Klimenko, S; Koehlenbeck, S M; Kokeyama, K; Koley, S; Kondrashov, V; Kontos, A; Korobko, M; Korth, W Z; Kowalska, I; Kozak, D B; Kringel, V; Krishnan, B; Kr'olak, A; Krueger, C; Kuehn, G; Kumar, P; Kuo, L; Kutynia, A; Lackey, B D; Landry, M; Lange, J; Lantz, B; Lasky, P D; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lebigot, E O; Lee, C H; Lee, H K; Lee, H M; Lee, K; Lenon, A; Leonardi, M; Leong, J R; Leroy, N; Letendre, N; Levin, Y; Levine, B M; Li, T G F; Libson, A; Littenberg, T B; Lockerbie, N A; Loew, K; Logue, J; Lombardi, A L; Lord, J E; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J D; L"uck, H; Lundgren, A P; Luo, J; Lynch, R; Ma, Y; MacDonald, T; Machenschalk, B; MacInnis, M; Macleod, D M; na-Sandoval, F Maga; Magee, R M; Mageswaran, M; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Mandel, I; Mandic, V; Mangano, V; Mansell, G L; Manske, M; Mantovani, M; Marchesoni, F; Marion, F; M'arka, S; M'arka, Z; Markosyan, A S; Maros, E; Martelli, F; Martellini, L; Martin, I W; Martin, R M; Martynov, D V; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Masso-Reid, M; Mastrogiovanni, S; Matichard, F; Matone, L; Mavalvala, N; Mazumder, N; Mazzolo, G; McCarthy, R; McClelland, D E; McCormick, S; McGuire, S C; McIntyre, G; McIver, J; McManus, D J; McWilliams, S T; Meacher, D; Meadors, G D; Meidam, J; Melatos, A; Mendell, G; Mendoza-Gandara, D; Mercer, R A; Merilh, E L; Merzougui, M; Meshkov, S; Messenger, C; Messick, C; Metzdorff, R; Meyers, P M; Mezzani, F; Miao, H; Michel, C; Middleton, H; Mikhailov, E E; Milano, L; Miller, A L; Miller, J; Millhouse, M; Minenkov, Y; Ming, J; Mirshekari, S; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moggi, A; Mohan, M; Mohapatra, S R P; Montani, M; Moore, B C; Moore, C J; Moraru, D; Moreno, G; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, C L; Mueller, G; Muir, A W; Mukherjee, Arunava; Mukherjee, D; Mukherjee, S; Mukund, K N; Mullavey, A; Munch, J; Murphy, D J; Murray, P G; Mytidis, A; Nardecchia, I; Naticchioni, L; Nayak, R K; Necula, V; Nedkova, K; Nelemans, G; Neri, M; Neunzert, A; Newton, G; Nguyen, T T; Nielsen, A B; Nissanke, S; Nitz, A; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Oberling, J; Ochsner, E; O'Dell, J; Oelker, E; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Oliver, M; Oppermann, P; Oram, Richard J; O'Reilly, B; O'Shaughnessy, R; Ott, C D; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Pai, A; Pai, S A; Palamos, J R; Palashov, O; Palomba, C; Pal-Singh, A; Pan, H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Paoli, A; Papa, M A; Paris, H R; Parker, W; Pascucci, D; Pasqualetti, A; Passaquieti, R; Passuello, D; Patricelli, B; Patrick, Z; Pearlstone, B L; Pedraza, M; Pedurand, R; Pekowsky, L; Pele, A; Penn, S; Pereira, R; Perreca, A; Phelps, M; Piccinni, O J; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pitkin, M; Poggiani, R; Popolizio, P; Post, A; Powell, J; Prasad, J; Predoi, V; Premachandra, S S; Prestegard, T; Price, L R; Prijatelj, M; Principe, M; Privitera, S; Prix, R; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; P"urrer, M; Qi, H; Qin, J; Quetschke, V; Quintero, E A; Quitzow-James, R; Raab, F J; Rabeling, D S; Radkins, H; Raffai, P; Raja, S; Rakhmanov, M; Rapagnani, P; Raymond, V; Razzano, M; Re, V; Read, J; Reed, C M; Regimbau, T; Rei, L; Reid, S; Reitze, D H; Rew, H; Ricci, F; Riles, K; Robertson, N A; Robie, R; Robinet, F; Rocchi, A; Rolland, L; 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Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stephens, B C; Stone, R; Strain, K A; Straniero, N; Stratta, G; Strauss, N A; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sutton, P J; Swinkels, B L; Szczepa'nczyk, M J; Tacca, M; Talukder, D; Tanner, D B; T'apai, M; Tarabrin, S P; Taracchini, A; Taylor, R; Theeg, T; Thirugnanasambandam, M P; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Tiwari, S; Tiwari, V; Tokmakov, K V; Tomlinson, C; Tonelli, M; Torres, C V; Torrie, C I; T"oyr"a, D; Travasso, F; Traylor, G; Trifir`o, D; Tringali, M C; Trozzo, L; Tse, M; Turconi, M; Tuyenbayev, D; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; van Bakel, N; van Beuzekom, M; Brand, J F J van den; Broeck, C Van Den; Vander-Hyde, D C; van der Schaaf, L; van Heijningen, J V; van Veggel, A A; Vardaro, M; Vass, S; Vas'uth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Vetrano, F; Vicer'e, A; Vinciguerra, S; Vine, D J; Vinet, J -Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Voss, D V; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, M; Wang, X; Wang, Y; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L -W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Wessels, P; Westphal, T; Wette, K; Whelan, J T; Whitcomb, S E; White, D J; Whiting, B F; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Worden, J; Wright, J L; Wu, G; Yablon, J; Yam, W; Yamamoto, H; Yancey, C C; Yap, M J; Yu, H; Yvert, M; zny, A Zadro; Zangrando, L; Zanolin, M; Zendri, J -P; Zevin, M; Zhang, F; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, X J; Zucker, M E; Zuraw, S E; Zweizig, J

    2016-01-01

    We present results from a search for gravitational-wave bursts coincident with a set of two core-collapse supernovae observed between 2007 and 2011. We employ data from the Laser Interferometer Gravitational-wave Observatory (LIGO), the Virgo gravitational-wave observatory, and the GEO 600 gravitational-wave observatory. The targeted core-collapse supernovae were selected on the basis of (1) proximity (within approximately 15 Mpc), (2) tightness of observational constraints on the time of core collapse that defines the gravitational-wave search window, and (3) coincident operation of at least two interferometers at the time of core collapse. We find no plausible gravitational-wave candidates. We present the probability of detecting signals from both astrophysically well-motivated and more speculative gravitational-wave emission mechanisms as a function of distance from Earth, and discuss the implications for the detection of gravitational waves from core-collapse supernovae by the upgraded Advanced LIGO and V...

  1. Gravitational wave signatures in black-hole forming core collapse

    CERN Document Server

    Cerdá-Durán, Pablo; Aloy, Miguel A; Font, José A; Obergaulinger, Martin

    2013-01-01

    We present numerical simulations in general relativity of collapsing stellar cores. Our initial model consists of a low metallicity rapidly-rotating progenitor which is evolved in axisymmetry with the latest version of our general relativistic code CoCoNuT, which allows for black hole formation and includes the effects of a microphysical equation of state (LS220) and a neutrino leakage scheme to account for radiative losses. The motivation of our study is to analyze in detail the emission of gravitational waves in the collapsar scenario of long gamma-ray bursts. Our simulations show that the phase during which the proto-neutron star (PNS) survives before ultimately collapsing to a black hole is particularly optimal for gravitational wave emission. The high-amplitude waves last for several seconds and show a remarkable quasi-periodicity associated with the violent PNS dynamics, namely during the episodes of convection and the subsequent nonlinear development of the standing-accretion shock instability (SASI). ...

  2. Irreversible Behaviour and Collapse of Wave Packets in a Quantum System with Point Interactions

    CERN Document Server

    Guarneri, Italo

    2011-01-01

    A system of a particle and a harmonic oscillator, which have pure point spectrum if uncoupled, is known to acquire absolutely continuous spectrum when the particle and the oscillator are coupled by a sufficiently strong point interaction. Here the simple dynamical mechanism underlying this phenomenon is exposed. The energy of the oscillator is proven to exponentially diverge in time, while the spatial probability distribution of the particle collapses into a delta function in the interaction point. On account of this result, a generalized model with many oscillators which interact with the particle at different points is argued to provide a formal model for approximate measurement of position, and collapse of wave packets.

  3. Irreversible behaviour and collapse of wave packets in a quantum system with point interactions

    Energy Technology Data Exchange (ETDEWEB)

    Guarneri, Italo [Center for Nonlinear and Complex Systems, Universita dell' Insubria, via Valleggio 11, I-22100 Como (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, via Bassi 6, I-27100 Pavia (Italy)

    2011-12-02

    A system of a particle and a harmonic oscillator, which have pure point spectra if uncoupled, is known to acquire an absolutely continuous spectrum when they are coupled by a sufficiently strong point interaction. Here, the dynamical mechanism underlying this spectral phenomenon is exposed. The energy of the oscillator is proven to exponentially diverge in time, while the spatial probability distribution of the particle collapses into a {delta}-function at the interaction point. On account of this result, a generalized model with many oscillators which interact with the particle at different points is argued to provide a formal model for the approximate measurement of position and collapse of wave packets. (paper)

  4. Gravitational Waves from Direct Collapse Black Holes Formation

    CERN Document Server

    Pacucci, Fabio; Marassi, Stefania

    2015-01-01

    The possible formation of Direct Collapse Black Holes (DCBHs) in the first metal-free atomic cooling halos at high redshifts ($z > 10$) is nowadays object of intense study and several methods to prove their existence are currently under development. The abrupt collapse of a massive ($\\sim 10^4 - 10^5 \\, \\mathrm{M_{\\odot}}$) and rotating object is a powerful source of gravitational waves emission. In this work, we employ modern waveforms and the improved knowledge on the DCBHs formation rate to estimate the gravitational signal emitted by these sources at cosmological distances. Their formation rate is very high ($\\sim 10^4 \\, \\mathrm{yr^{-1}}$ up to $z\\sim20$), but due to a short duration of the collapse event ($\\sim 2-30\\, \\mathrm{s}$, depending on the DCBH mass) the integrated signal from these sources is characterized by a very low duty-cycle (${\\cal D}\\sim 10^{-3}$), i.e. a shot-noise signal. Our results show that the estimated signal lies above the foreseen sensitivity of the Ultimate-DECIGO observatory ...

  5. Collapse of nonlinear electron plasma waves in a plasma layer

    Science.gov (United States)

    Grimalsky, V.; Koshevaya, S.; Rapoport, Yu; Kotsarenko, A.

    2016-10-01

    The excitation of nonlinear electron plasma waves in the plasma layer is investigated theoretically. This excitation is realized by means of initial oscillatory perturbations of the volume electron concentration or by initial oscillatory distributions of the longitudinal electron velocity. The amplitudes of the initial perturbations are small and the manifestation of the volume nonlinearity is absent. When the amplitudes of the initial perturbations exceed some thresholds, the values of the electron concentration near the plasma boundary increase catastrophically. The maxima of the electron concentration reach extremely high magnitudes, and sharp peaks in the electron concentration occur, which are localized both in the longitudinal and transverse directions. This effect is interpreted as wave collapse near the plasma boundary.

  6. A possible correspondence between Ricci identities and Dirac equations in the Newman-Penrose formalism: towards an understanding of gravity induced collapse of the wave-function?

    CERN Document Server

    Sharma, Anushrut

    2014-01-01

    It is well-known that in the Newman-Penrose formalism the Riemann tensor can be expressed as a set of eighteen complex first-order equations, in terms of the twelve spin coefficients, known as Ricci identities. The Ricci tensor herein is determined via the Einstein equations. It is also known that the Dirac equation in a curved spacetime can be written in the Newman-Penrose formalism as a set of four first-order coupled equations for the spinor components of the wave-function. In the present article we suggest that it might be possible to think of the Dirac equations in the N-P formalism as a special case of the Ricci identities, after an appropriate identification of the four Dirac spinor components with four of the spin coefficients, provided torsion is included in the connection, and after a suitable generalization of the energy-momentum tensor. We briefly comment on similarities with the Einstein-Cartan-Sciama-Kibble theory. The motivation for this study is to take some very preliminary steps towards deve...

  7. Gravitational waves from dark matter collapse in a star

    CERN Document Server

    Kurita, Yasunari

    2016-01-01

    We investigate the collapse of clusters of weakly interacting massive particles (WIMPs) in the core of a Sun-like star and the possible formation of mini-black holes and the emission of gravity waves. When the number of WIMPs is small, thermal pressure balances the WIMP cluster's self gravity. If the number of WIMPs is larger than a critical number, thermal pressure cannot balance gravity and the cluster contracts. If WIMPs are collisionless and bosonic, the cluster collapses directly to form a mini-black hole. For fermionic WIMPs, the cluster contracts until it is sustained by Fermi pressure, forming a small compact object. If the fermionic WIMP mass is smaller than $4\\times 10^2$ GeV, the radius of the compact object is larger than its Schwarzschild radius and Fermi pressure temporally sustains its self gravity, halting the formation of a black hole. If the fermionic WIMP mass is larger than $4\\times 10^2$ GeV, the radius is smaller than its Schwarzschild radius and the compact object becomes a mini-black h...

  8. Distributional Tests for Gravitational Waves from Core-Collapse Supernovae

    Science.gov (United States)

    Szczepanczyk, Marek; LIGO Collaboration

    2017-01-01

    Core-Collapse Supernovae (CCSN) are spectacular and violent deaths of massive stars. CCSN are some of the most interesting candidates for producing gravitational-waves (GW) transients. Current published results focus on methodologies to detect single GW unmodelled transients. The advantages of these tests are that they do not require a background for which we have an analytical model. Examples of non-parametric tests that will be compared are Kolmogorov-Smirnov, Mann-Whitney, chi squared, and asymmetric chi squared. I will present methodological results using publicly released LIGO-S6 data recolored to the design sensitivity of Advanced LIGO and that will be time lagged between interferometers sites so that the resulting coincident events are not GW.

  9. Developing empirical collapse fragility functions for global building types

    Science.gov (United States)

    Jaiswal, K.; Wald, D.; D'Ayala, D.

    2011-01-01

    Building collapse is the dominant cause of casualties during earthquakes. In order to better predict human fatalities, the U.S. Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER) program requires collapse fragility functions for global building types. The collapse fragility is expressed as the probability of collapse at discrete levels of the input hazard defined in terms of macroseismic intensity. This article provides a simple procedure for quantifying collapse fragility using vulnerability criteria based on the European Macroseismic Scale (1998) for selected European building types. In addition, the collapse fragility functions are developed for global building types by fitting the beta distribution to the multiple experts’ estimates for the same building type (obtained from EERI’s World Housing Encyclopedia (WHE)-PAGER survey). Finally, using the collapse probability distributions at each shaking intensity level as a prior and field-based collapse-rate observations as likelihood, it is possible to update the collapse fragility functions for global building types using the Bayesian procedure.

  10. Field structure of collapsing wave packets in 3D strong Langmuir turbulence

    Science.gov (United States)

    Newman, D. L.; Robinson, P. A.; Goldman, M. V.

    1989-01-01

    A simple model is constructed for the electric fields in the collapsing wave packets found in 3D simulations of driven and damped isotropic strong Langmuir turbulence. This model, based on a spherical-harmonic decomposition of the electrostatic potential, accounts for the distribution of wave-packet shapes observed in the simulations, particularly the predominance of oblate wave packets. In contrast with predictions for undamped and undriven subsonic collapse of scalar fields, oblate vector-field wave packets do not flatten during collapse but, instead, remain approximately self-similar and rigid.

  11. Effect of nonlinear wave collapse on line shapes in a plasma

    Science.gov (United States)

    Hannachi, I.; Stamm, R.; Rosato, J.; Marandet, Y.

    2016-04-01

    The nonlinear interaction of waves can change the structural and radiative properties of plasmas. We describe the main features of a fully ionized unmagnetized plasma affected by strong Langmuir turbulence characterized by nonlinear wave collapse, and propose a simple model for evaluating the changes expected on a hydrogen line shape affected by such conditions. Our model is based on a stochastic renewal model using an exponential waiting time distribution and a half-normal probability density function for the electric-field magnitude of the turbulent wave packet. The first results obtained with a simulation calculation of the hydrogen \\text{L}α line show that strong Langmuir turbulence can provide an additional broadening to a Stark profile.

  12. Does Consciousness Collapse the Wave Function

    CERN Document Server

    Bierman, D J

    2003-01-01

    A conceptual replication of the Hall-experiment to test the 'subjective reduction' interpretation of the measurement problem in Quantum Physics is reported. Two improvements are introduced. First the delay between pre-observation and final observation of the same quantum event is increased from a few microseconds in the original experiment to 1 second in this replication. Second, rather than using the observers conscious response as the dependent variable, we use the early brain responses as measured by EEG. These early responses cover a period where the observer is not yet conscious of the quantum event. Results support the 'subjective reduction' hypothesis because significant differences between the brain responses of the final observer are found dependent upon the pre-observer looking or not looking at the quantum event (exact binomial p < 0.02). Alternative 'normal' explanations are discussed and rejected. It is concluded that the present results do justify further research along these lines.

  13. Spheroidal wave functions

    CERN Document Server

    Flammer, Carson

    2005-01-01

    Intended to facilitate the use and calculation of spheroidal wave functions, this applications-oriented text features a detailed and unified account of the properties of these functions. Addressed to applied mathematicians, mathematical physicists, and mathematical engineers, it presents tables that provide a convenient means for handling wave problems in spheroidal coordinates.Topics include separation of the scalar wave equation in spheroidal coordinates, angle and radial functions, integral representations and relations, and expansions in spherical Bessel function products. Additional subje

  14. Three-dimensional electromagnetic strong turbulence. II. Wave packet collapse and structure of wave packets during strong turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Graham, D. B.; Robinson, P. A.; Cairns, Iver H. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Skjaeraasen, O. [ProsTek, Institute for Energy Technology, P.O. Box 40, N-2027 Kjeller (Norway)

    2011-07-15

    Large-scale simulations of wave packet collapse are performed by numerically solving the three-dimensional (3D) electromagnetic Zakharov equations, focusing on individual wave packet collapses and on wave packets that form in continuously driven strong turbulence. The collapse threshold is shown to decrease as the electron thermal speed {nu}{sub e}/c increases and as the temperature ratio T{sub i}/T{sub e} of ions to electrons decreases. Energy lost during wave packet collapse and dissipation is shown to depend on {nu}{sub e}/c. The dynamics of density perturbations after collapse are studied in 3D electromagnetic strong turbulence for a range of T{sub i}/T{sub e}. The structures of the Langmuir, transverse, and total electric field components of wave packets during strong turbulence are investigated over a range of {nu}{sub e}/c. For {nu}{sub e}/c < or approx. 0.17, strong turbulence is approximately electrostatic and wave packets have very similar structure to purely electrostatic wave packets. For {nu}{sub e}/c > or approx. 0.17, transverse modes become trapped in density wells and contribute significantly to the structure of the total electric field. At all {nu}{sub e}/c, the Langmuir energy density contours of wave packets are predominantly oblate (pancake shaped). The transverse energy density contours of wave packets are predominantly prolate (sausage shaped), with the major axis being perpendicular to the major axes of the Langmuir component. This results in the wave packet becoming more nearly spherical as {nu}{sub e}/c increases, and in turn generates more spherical density wells during collapse. The results obtained are compared with previous 3D electrostatic results and 2D electromagnetic results.

  15. Numerical investigation of wake-collapse internal waves generated by a submerged moving body

    Science.gov (United States)

    Liang, Jianjun; Du, Tao; Huang, Weigen; He, Mingxia

    2016-09-01

    The state-of-the-art OpenFOAM technology is used to develop a numerical model that can be devoted to numerically investigating wake-collapse internal waves generated by a submerged moving body. The model incorporates body geometry, propeller forcing, and stratification magnitude of seawater. The generation mechanism and wave properties are discussed based on model results. It was found that the generation of the wave and its properties depend greatly on the body speed. Only when that speed exceeds some critical value, between 1.5 and 4.5 m/s, can the moving body generate wake-collapse internal waves, and with increases of this speed, the time of generation advances and wave amplitude increases. The generated wake-collapse internal waves are confirmed to have characteristics of the second baroclinic mode. As the body speed increases, wave amplitude and length increase and its waveform tends to take on a regular sinusoidal shape. For three linearly temperature-stratified profiles examined, the weaker the stratification, the stronger the wake-collapse internal wave.

  16. Evidence for Langmuir wave collapse in the interplanetary plasma

    Science.gov (United States)

    Kellogg, Paul J.; Goetz, K.; Howard, R. L.; Monson, S. J.

    1992-01-01

    With the Fast Envelope Sampler part of the URAP experiment on Ulysses, there is observed much rapidly varying structure in plasma waves in the solar wind. Extremely narrow (1 ms) structures observed together with electrostatic Langmuir waves, as well as some broader Langmuir wave packets are discussed.

  17. Measuring the Angular Momentum Distribution in Core-Collapse Supernova Progenitors with Gravitational Waves

    CERN Document Server

    Abdikamalov, Ernazar; DeMaio, Alexandra M; Ott, Christian D

    2013-01-01

    The late collapse, core bounce, and the early postbounce phase of rotating core collapse leads to a characteristic gravitational wave (GW) signal. The precise shape of the signal is governed by the interplay of gravity, rotation, nuclear equation of state (EOS), and electron capture during collapse. We explore the dependence of the signal on total angular momentum and its distribution in the progenitor core by means of a large set of axisymmetric general-relativistic core collapse simulations in which we vary the initial angular momentum distribution in the core. Our simulations include a microphysical finite-temperature EOS, an approximate electron capture treatment during collapse, and a neutrino leakage scheme for the postbounce evolution. We find that the precise distribution of angular momentum is relevant only for very rapidly rotating cores with T/|W|>~8% at bounce. We construct a numerical template bank from our baseline set of simulations, and carry out additional simulations to generate trial wavefo...

  18. Collapse of optical wave arrested by cross-phase modulation in nonlinear metamaterials

    Science.gov (United States)

    Zhang, Jinggui; Li, Ying; Xiang, Yuanjiang; Lei, Dajun; Zhang, Lifu

    2016-03-01

    In this article, we put forward a novel strategy to realize the management of wave collapse through designing probe-pump configuration where probe wave is assumed to propagate in the positive-index region of metamaterials (MMs), while pump wave is assumed to propagate in the negative-index region. We disclose that cross-phase modulation (XPM) in MMs as a new physical mechanism that can be used to arrest the collapse of probe wave in the positive-index region by copropagating it together with pump wave in the negative-index region. Further, we observe that pump wave will evolve into a ring while probe wave will develop a side lob in the wings during the course of coupled waves propagation, different from the corresponding counterpart in the ordinary positive-index materials (OMs) where they simultaneously exhibit the catastrophic self-focusing behavior. Meanwhile, we also discuss how to control the collapse of probe wave by adjusting intensity-detuned pump wave. Our analysis is performed by directly numerically solving the coupled nonlinear Schrödinger equations, as well as using the variational approximation, both showing consistent results. The finding demonstrates XPM as a specific physical mechanism in MMs can provide us unique opportunities unattainable in OMs to manipulate self-focusing of high-power laser.

  19. Gravitational waves from supermassive stars collapsing to a supermassive black hole

    Science.gov (United States)

    Shibata, Masaru; Sekiguchi, Yuichiro; Uchida, Haruki; Umeda, Hideyuki

    2016-07-01

    We derive the gravitational waveform from the collapse of a rapidly rotating supermassive star (SMS) core leading directly to a seed of a supermassive black hole (SMBH) in axisymmetric numerical-relativity simulations. We find that the peak strain amplitude of gravitational waves emitted during the black hole formation is ≈5 ×10-21 at the frequency f ≈5 mHz for an event at the cosmological redshift z =3 , if the collapsing SMS core is in the hydrogen-burning phase. Such gravitational waves will be detectable by space laser interferometric detectors like eLISA with signal-to-noise ratio ≈10 , if the sensitivity is as high as LISA for f =1 - 10 mHz . The detection of the gravitational wave signal will provide a potential opportunity for testing the direct-collapse scenario for the formation of a seed of SMBHs.

  20. Gravitational waves from supermassive stars collapsing to a supermassive black hole

    CERN Document Server

    Shibata, Masaru; Uchida, Haruki; Umeda, Hideyuki

    2016-01-01

    We derive the gravitational waveform from the collapse of a rapidly rotating supermassive star (SMS) core leading directly to a seed of a supermassive black hole (SMBH) in axisymmetric numerical-relativity simulations. We find that the peak strain amplitude of gravitational waves emitted during the black-hole formation is $\\approx 5 \\times 10^{-21}$ at the frequency $f \\approx 5$\\,mHz for an event at the cosmological redshift $z=3$, if the collapsing SMS core is in the hydrogen-burning phase. Such gravitational waves will be detectable by space laser interferometric detectors like eLISA with signal-to-noise ratio $\\approx 10$, if the sensitivity is as high as LISA for $f=1$--10\\,mHz. The detection of the gravitational-wave signal will provide a potential opportunity for testing the direct-collapse scenario for the formation of a seed of SMBHs.

  1. Collapse of Nonlinear Gravitational Waves in Moving-Puncture Coordinates

    CERN Document Server

    Hilditch, David; Weyhausen, Andreas; Dietrich, Tim; Bruegmann, Bernd; Montero, Pedro J; Mueller, Ewald

    2013-01-01

    We study numerical evolutions of nonlinear gravitational waves in moving-puncture coordinates. We adopt two different types of initial data -- Brill and Teukolsky waves -- and evolve them with two independent codes producing consistent results. We find that Brill data fail to produce long-term evolutions for common choices of coordinates and parameters, unless the initial amplitude is small, while Teukolsky wave initial data lead to stable evolutions, at least for amplitudes sufficiently far from criticality. The critical amplitude separates initial data whose evolutions leave behind flat space from those that lead to a black hole. For the latter we follow the interaction of the wave, the formation of a horizon, and the settling down into a time-independent trumpet geometry. We explore the differences between Brill and Teukolsky data and show that for less common choices of the parameters -- in particular negative amplitudes -- Brill data can be evolved with moving-puncture coordinates, and behave similarly t...

  2. Surface ultrasonic envelope solitons and wave collapse in solid film-substrate systems

    Energy Technology Data Exchange (ETDEWEB)

    Grimalsky, V [National Institute for Astrophysics, Optics, and Electronics (INAOE), P.O. 51 and 216, ZP 72000, Puebla, Pue. (Mexico); Koshevaya [Research Center of Applied Sciences and Engineering (CIICAp), Autonomous University of State Morelos (UAEM), Av. Universidad No. 1001, ZP 62210, Cuernavaca, Mor. (Mexico); Gutierrez-D, E [National Institute for Astrophysics, Optics, and Electronics (INAOE), P.O. 51 and 216, ZP 72000, Puebla, Pue. (Mexico); Kolokoltsev, O V [National Autonomous University of Mexico (UNAM), Center of Applied Science and Technological Development (CCADET), P.O. 70-186, ZP 04510, Campus UNAM, Mexico, D.F. (Mexico)

    2005-01-01

    An excitation of ultra-high frequency (100 MHz - 1 GHz) nonlinear envelope solitary acoustic waves, propagating along the interface between a solid film and a solid substrate, is theoretically analyzed. Both the quadratic nonlinearity and the cubic one are important in the case of the envelope waves. When generation of higher harmonics is reduced due to essential waveguide dispersion and the cubic nonlinearity due to the induced zero harmonic is dominating, a possibility of the envelope solitary pulse propagation and the spatial-temporal wave collapse exists, as demonstrated. When the cubic material nonlinearity reduces the associated cubic nonlinear term, there also exists a possibility to observe a wave collapse, if the initial focusing of the input pulse at the first harmonic is applied.

  3. The roads not taken: empty waves, wavefunction collapse and protective measurement in quantum theory

    OpenAIRE

    Holland, Peter

    2014-01-01

    Within the class of ontological interpretations of quantum theory where a physical system comprises a particle and a field (wavefunction) guiding it, an empty wave is a segment of the wavefunction not containing the particle. We examine the impact of this concept on the debate between the epistemological and ontological viewpoints. The theoretical merits of the empty wave in avoiding the wavefunction collapse hypothesis, and in supplying conceptual precision in the application of quantum mech...

  4. Collapse of a nanoscopic void triggered by a spherically symmetric traveling sound wave.

    Science.gov (United States)

    Hołyst, Robert; Litniewski, Marek; Garstecki, Piotr

    2012-05-01

    Molecular-dynamics simulations of the Lennard-Jones fluid (up to 10(7) atoms) are used to analyze the collapse of a nanoscopic bubble. The collapse is triggered by a traveling sound wave that forms a shock wave at the interface. The peak temperature T(max) in the focal point of the collapse is approximately ΣR(0)(a), where Σ is the surface density of energy injected at the boundary of the container of radius R(0) and α ≈ 0.4-0.45. For Σ = 1.6 J/m(2) and R(0) = 51 nm, the shock wave velocity, which is proportional to √Σ, reaches 3400 m/s (4 times the speed of sound in the liquid); the pressure at the interface, which is proportional to Σ, reaches 10 GPa; and T(max) reaches 40,000 K. The Rayleigh-Plesset equation together with the time of the collapse can be used to estimate the pressure at the front of the shock wave.

  5. Circular polarizations of gravitational waves from core-collapse supernovae: a clear indication of rapid rotation

    CERN Document Server

    Hayama, Kazuhiro; Nakamura, Ko; Yamada, Shoichi

    2016-01-01

    We propose to employ the circular polarization of gravitational waves emitted by core-collapse supernovae as an unequivocal indication of rapid rotation deep in their cores. It has been demonstrated by three dimensional simulations that non-axisymmetric accretion flows may develop spontaneously via hydrodynamical instabilities in the post-bounce cores. It is not surprising then that the gravitational waves emitted by such fluid motions are circularly polarized. We show in this letter that a network of the second generation detectors of gravitational waves worldwide may be able to detect such polarizations up to the opposite side of Galaxy as long as the rotation period is shorter than a few seconds prior to collapse.

  6. The Wave Function and Quantum Reality

    CERN Document Server

    Gao, Shan

    2011-01-01

    We investigate the meaning of the wave function by analyzing the mass and charge density distribution of a quantum system. According to protective measurement, a charged quantum system has mass and charge density proportional to the modulus square of its wave function. It is shown that the mass and charge density is not real but effective, and it is formed by the ergodic motion of a localized particle with the total mass and charge of the system. Moreover, it is argued that the ergodic motion is not continuous but discontinuous and random. This result suggests a new interpretation of the wave function, according to which the wave function is a description of random discontinuous motion of particles, and the modulus square of the wave function gives the probability density of the particles being in certain locations. It is shown that the suggested interpretation of the wave function disfavors the de Broglie-Bohm theory and the many-worlds interpretation but favors the dynamical collapse theories, and the rando...

  7. Collapse of the wave field in a one-dimensional system of weakly coupled light guides

    Science.gov (United States)

    Balakin, A. A.; Litvak, A. G.; Mironov, V. A.; Skobelev, S. A.

    2016-12-01

    The analytical and numerical study of the radiation self-action in a system of coupled light guides is fulfilled on the basis of the discrete nonlinear Schrödinger equation (DNSE). We develop a variational method for qualitative study of DNSE and classify self-action modes. We show that the diffraction of narrow (in grating scale) wave beams weakens in discrete media and, consequently, the "collapse" of the one-dimensional wave field with power exceeding the critical value occurs. This results in the ability to self-channel radiation in the central fiber. Qualitative analytical results were confirmed by numerical simulation of DNSE, which also shows the stability of the collapse mode.

  8. Seismic waves generated by aircraft impacts and building collapses at World Trade Center, New York City

    Science.gov (United States)

    Kim, Won-Young; Sykes, L. R.; Armitage, J. H.; Xie, J. K.; Jacob, K. H.; Richards, P. G.; West, M.; Waldhauser, F.; Armbruster, J.; Seeber, L.; Du, W. X.; Lerner-Lam, A.

    Seismologists sometimes do their work of data acquisition and analysis against a tragic background. Usually, the context is fieldwork far from home, in an area subjected to the natural but sometimes devastating effects of an earthquake. But in the present case, we are in our own New York City area; that is, the Lamont-Doherty Earth Observatory of Columbia University, in Palisades, N.Y; and the context is inhuman actions against people and the fabric of our society.As the appalling events of September 11 unfolded, we found that we had recorded numerous seismic signals from two plane impacts and building collapses of the two World Trade Center (WTC) towers, often at times different than those being reported elsewhere. Collapses of the two WTC towers generated large seismic waves, observed in five states and up to 428 km away The north tower collapse was the largest seismic source and had local magnitude ML 2.3. From this, we infer that ground shaking of the WTC towers was not a major contributor to the collapse or damage to surrounding buildings. But unfortunately, we also conclude that from the distance at which our own detections were made (the nearest station is 34 km away at Palisades) it is not possible to infer (with detail sufficient to meet the demands of civil engineers in an emergency situation) just what the near-in ground motions must have been.

  9. Coherent Network Analysis of Gravitational Waves from Three-Dimensional Core-Collapse Supernova Models

    CERN Document Server

    Hayama, Kazuhiro; Kotake, Kei; Takiwaki, Tomoya

    2015-01-01

    Using predictions from three-dimensional (3D) hydrodynamics simulations of core-collapse supernovae (CCSNe), we present a coherent network analysis to detection, reconstruction, and the source localization of the gravitational-wave (GW) signals. By combining with the GW spectrogram analysis, we show that several important hydrodynamics features imprinted in the original waveforms persist in the waveforms of the reconstructed signals. The characteristic excess in the GW spectrograms originates not only from rotating core-collapse and bounce, the subsequent ring down of the proto-neutron star (PNS) as previously identified, but also from the formation of magnetohydrodynamics jets and non-axisymmetric instabilities in the vicinity of the PNS. Regarding the GW signals emitted near at the rotating core bounce, the horizon distance, which we set by a SNR exceeding 8, extends up to $\\sim$ 18 kpc for the most rapidly rotating 3D model among the employed waveform libraries. Following the rotating core bounce, the domi...

  10. NUMERICAL STUDIES OF INTERNAL SOLITARY WAVE GENERATION AND EVOLUTION BY GRAVITY COLLAPSE

    Institute of Scientific and Technical Information of China (English)

    LIN Zhen-hua; SONG Jin-bao

    2012-01-01

    In this study,an analysis on the internal wave generation via the gravity collapse mechanism is carried out based on the theoretical formulation and the numerical simulation.With the linear theoretical model,a rectangle shape wave is generated and propagates back and forth in the domain,while a two-dimensional non-hydrostatic numerical model could reproduce all the observed phenomena in the laboratory experiments conducted by Chen et al.(2007),and the related process realistically.The model results further provide more quantitative information in the whole domain,thus allowing an in depth understanding of the corresponding internal solitary wave generation and propagation.It is shown that the initial type of the internal wave is determined by the relative height between the perturbation and the environmental density interface,while the final wave type is related to the relative height of the upper and lower layers of the environmental fluid.The shape of the internal wave generated is consistent with that predicted by the KdV and EKdV theories if its amplitude is small,as the amplitude becomes larger,the performance of the EKdV becomes better after the wave adjusts itself to the ambient stratification and reaches an equilibrium state between the nonlinear and dispersion effects.The evolution of the mechanical energy is also analyzed.

  11. Nonlinear wave collapse, shock, and breather formation in an electron magnetohydrodynamic plasma.

    Science.gov (United States)

    Ghosh, Samiran; Chakrabarti, Nikhil

    2014-12-01

    Low-frequency nonlinear wave dynamics is investigated in a two-dimensional inhomogeneous electron magnetohydrodynamic (EMHD) plasma in the presence of electron viscosity. In the long-wavelength limit, the dynamics of the wave is found to be governed by a novel nonlinear equation. The result of the moving-frame nonlinear analysis is noteworthy, which shows that this nonlinear equation does have a breather solution and electron viscosity is responsible for the breather. A breather is a nonlinear wave in which energy accumulates in a localized and oscillatory manner. Analytical solution and time-dependent numerical simulation of this novel equation reveal the collapse of a soliton (localized pulse) into a weak noise shelf and formation of shocklike structures.

  12. Gravitational waves from braneworld neutrino oscillations at supernova core-collapse

    Energy Technology Data Exchange (ETDEWEB)

    Mosquera Cuesta, Herman J. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias]. E-mail: hermanjc@cbpfsul.cat.cbpf.br

    2003-07-01

    In braneworld-like solutions of the hierarchy problem gravitons and right-handed (sterile) neutrinos are in principle the unique non-standard model fields allowed to propagate into the bulk, thus their coupling is naturally expected. Since active-to-sterile neutrino oscillations can take place during the core bounce of a supernova collapse, then gravitational waves must be produced over the oscillation length through anisotropic neutrino flow. Because the oscillation feeds mass-energy up into (or takes it out of) the target species, the large mass-squared difference between species makes a huge amount of energy to be given off as gravity waves, which is larger than from neutrino convection and cooling, or quadrupole moments of neutron star matter. The space-time strain from these bursts would turn them the more sure supernova gravitational-wave signal detectable by inferometers, for distances out to the VIRGO cluster of galaxies. (author)

  13. Parametric Study of Flow Patterns behind the Standing Accretion Shock Wave for Core-Collapse Supernovae

    CERN Document Server

    Iwakami, Wakana; Yamada, Shoichi

    2013-01-01

    The systematic research of flow patterns behind the accretion shock wave is conducted using three-dimensional hydrodynamics simulations for core-collapse supernovae in this study. Changing the accretion rate and neutrino luminosity, the steady solutions of the one-dimensional irrotational accretion flow passing through the spherical shock wave are evolved by imposing a random perturbation with 1% amplitude at the onset of the simulations. Depending on the accretion rate and neutrino luminosity, various flow patterns appear behind the shock wave. We classified them into the three fundamental flow patterns: (1) sloshing motion, (2) spiral motion, (3) multiple high-entropy bubbles, and the two anomalous flow patterns: (4) spiral motion with buoyant bubbles, and (5) spiral motion with pulsating rotational velocity. The sloshing and spiral motions tend to be dominant in the higher accretion rate and lower neutrino luminosity, and the generations of multiple buoyant bubbles tend to prevail in the lower accretion ra...

  14. The Role of Waves in the Explosion Mechanism of Core-Collapse Supernovae

    Science.gov (United States)

    Gossan, Sarah; Fuller, Jim; Roberts, Luke

    2017-01-01

    The core-collapse supernova (CCSN) explosion mechanism is not well understood. For garden variety CCSNe, the favored explosion scenario is delayed revival of the stalled shock powered by neutrino-driven convection. Despite huge computational advances, many simulations must use parameterized `light-bulb' models for neutrino heating or mask out inner regions of the proto-neutron star (PNS) for computational efficiency. These approximations can fail to capture hydrodynamical processes in the PNS core where nearly all the binding energy resides, and from which much of the explosion energy may originate. We show that gravity waves excited by core PNS convection may represent a significant heating source for the post-shock region. Using 1D simulations, we calculate the wave heating rate in the post-shock region out to one second after core bounce, showing that wave heating rates in excess of 1051 erg/s may persist for several hundreds of milliseconds, even after neutrino heating rates have decreased. Waves excited by PNS convection may therefore significantly contribute to shock revival and, subsequently, a successful and energetic explosion. We discuss how simulations can miss the effect of waves, and how future simulations can more accurately quantify wave heating rates.

  15. Wave-Packet Collapse Based on Weak Repeatability or Covariant Condition

    Science.gov (United States)

    Wu, Zhao-Qi; Zhu, Chuan-Xi; Wang, Jian-Hui

    2016-02-01

    The conflict between the dynamics postulate (unitary evolution) and the measurement postulate (wave-packet collapse) of quantum mechanics has been reconciled by Zurek from an information transfer perspective [Phys. Rev. A 76 (2007) 052110], and has further been extended to a more general scenario [Phys. Rev. A 87 (2013) 052111]. In this paper, we reconsider Zurek's new derivation by using weak repeatability postulate or covariant condition instead of repeatability postulate. Supported by National Natural Science Foundation of China under Grant Nos. 11461045, 11326099, 11361042, 11265010, and Natural Science Foundation of Jiangxi Province of China under Grant Nos. 20142BAB211016, 20132BAB201001, 20132BAB212009

  16. Inferring the core-collapse supernova explosion mechanism with gravitational waves

    Science.gov (United States)

    Powell, Jade; Gossan, Sarah E.; Logue, Joshua; Heng, Ik Siong

    2016-12-01

    A detection of a core-collapse supernova (CCSN) gravitational-wave (GW) signal with an Advanced LIGO and Virgo detector network may allow us to measure astrophysical parameters of the dying massive star. GWs are emitted from deep inside the core, and, as such, they are direct probes of the CCSN explosion mechanism. In this study, we show how we can determine the CCSN explosion mechanism from a GW supernova detection using a combination of principal component analysis and Bayesian model selection. We use simulations of GW signals from CCSN exploding via neutrino-driven convection and rapidly rotating core collapse. Previous studies have shown that the explosion mechanism can be determined using one LIGO detector and simulated Gaussian noise. As real GW detector noise is both nonstationary and non-Gaussian, we use real detector noise from a network of detectors with a sensitivity altered to match the advanced detectors design sensitivity. For the first time, we carry out a careful selection of the number of principal components to enhance our model selection capabilities. We show that with an advanced detector network we can determine if the CCSN explosion mechanism is driven by neutrino convection for sources in our Galaxy and rapidly-rotating core collapse for sources out to the Large Magellanic Cloud.

  17. Wigner functions of s waves

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Varro, S.; Wolf, A.

    2007-01-01

    We derive explicit expressions for the Wigner function of wave functions in D dimensions which depend on the hyperradius-that is, of s waves. They are based either on the position or the momentum representation of the s wave. The corresponding Wigner function depends on three variables......: the absolute value of the D-dimensional position and momentum vectors and the angle between them. We illustrate these expressions by calculating and discussing the Wigner functions of an elementary s wave and the energy eigenfunction of a free particle....

  18. The Role of Waves in the Explosion Mechanism of Core-Collapse Supernovae

    Science.gov (United States)

    Gossan, Sarah; Fuller, Jim; Roberts, Luke

    2017-01-01

    The core-collapse supernova (CCSN) explosion mechanism is not well understood. For garden variety CCSNe, the favored scenario for explosion is delayed revival of the stalled shock powered by neutrino-driven convection. Despite tremendous computational advances, many simulations must use parameterized ‘light-bulb’ models for neutrino heating or mask out inner regions of the proto-neutron star (PNS) for computational efficiency. These approximations can fail to capture hydrodynamical processes in the core of the PNS where nearly all the binding energy resides, and from which much of the explosion energy may originate. We show that gravity (buoyancy) waves excited by core PNS convection (within the central 20 km of the PNS) may represent a significant heating source for the post-shock region. The gravity waves propagate out of the PNS and transform into acoustic waves before depositing their energy at the shock, converting a small fraction of the PNS binding energy into explosion energy. Using 1D simulations, we calculate the wave heating rate in the post-shock region out to one second after core bounce, showing that wave heating rates in excess of 1051 erg/s may persist for several hundreds of milliseconds, even after neutrino heating rates have declined to smaller values. Waves excited by PNS convection may therefore significantly contribute to shock revival and, subsequently, a successful and energetic explosion. We discuss how simulations can miss the effect of waves (or have not recognized them), and how future simulations can more accurately quantify wave heating rates.

  19. Bayesian parameter estimation of core collapse supernovae using gravitational wave simulations

    CERN Document Server

    Edwards, Matthew C; Christensen, Nelson

    2014-01-01

    Using the latest numerical simulations of rotating stellar core collapse, we present a Bayesian framework to extract the physical information encoded in noisy gravitational wave signals. We fit Bayesian principal component regression models with known and unknown signal arrival times to reconstruct gravitational wave signals, and subsequently fit known astrophysical parameters on the posterior means of the principal component coefficients using a linear model. We predict the ratio of rotational kinetic energy to gravitational energy of the inner core at bounce by sampling from the posterior predictive distribution, and find that these predictions are generally very close to the true parameter values, with $90\\%$ credible intervals $\\sim 0.04$ and $\\sim 0.06$ wide for the known and unknown arrival time models respectively. Two supervised machine learning methods are implemented to classify precollapse differential rotation, and we find that these methods discriminate rapidly rotating progenitors particularly w...

  20. Observational upper limits on the gravitational wave production of core collapse supernovae

    Science.gov (United States)

    Zhu, Xing-Jiang; Howell, E.; Blair, D.

    2010-11-01

    The upper limit on the energy density of a stochastic gravitational wave (GW) background obtained from the 2-yr science run (S5) of the Laser Interferometer Gravitational-Wave Observatory (LIGO) is used to constrain the average GW production of core collapse supernovae (ccSNe). We assume that the ccSNe rate tracks the star formation history of the Universe and show that the stochastic background energy density depends only weakly on the assumed average source spectrum. Using the ccSNe rate for z <= 10, we scale the generic source spectrum to obtain an observation-based upper limit on the average GW emission. We show that the mean energy emitted in GWs can be constrained within < (0.49-1.98)Msolarc2 depending on the average source spectrum. While these results are higher than the total available gravitational energy in a core collapse event, second- and third-generation GW detectors will enable tighter constraints to be set on the GW emission from such systems.

  1. Observational upper limits on the gravitational wave production of core collapse supernovae

    CERN Document Server

    Zhu, Xing-Jiang; Blair, David

    2010-01-01

    The upper limit on the energy density of a stochastic gravitational wave (GW) background obtained from the two-year science run (S5) of the Laser Interferometer Gravitational-wave Observatory (LIGO) is used to constrain the average GW production of core collapse supernovae (ccSNe). We assume that the ccSNe rate tracks the star formation history of the universe and show that the stochastic background energy density depends only weakly on the assumed average source spectrum. Using the ccSNe rate for $z\\leq10$, we scale the generic source spectrum to obtain an observation-based upper limit on the average GW emission. We show that the mean GW production can be constrained within $< (0.49-1.98)\\hspace{1mm} M_{\\odot} c^{2}$ depending on the average source spectrum. While these results are higher than the available energy for explosion in a core collapse event, second and third generation GW detectors will enable tighter constraints to be set on the GW emission from such systems. As experimental limits become str...

  2. Proposed searches for candidate sources of gravitational waves in a nearby core-collapse supernova survey

    CERN Document Server

    Heo, Jeon-Eun; Lee, Dae-Sub; Kong, In-Taek; Lee, Sang-Hoon; van Putten, Maurice H P M; Della Valle, Massimo

    2015-01-01

    Gravitational wave bursts in the formation of neutron stars and black holes in energetic core-collapse supernovae (CC-SNe) are of potential interest to LIGO-Virgo and KAGRA. Events nearby are readily discovered using moderately sized telescopes. CC-SNe are competitive with mergers of neutron stars and black holes, if the fraction producing an energetic output in gravitational waves exceeds about 1\\%. This opportunity motivates the design of a novel Sejong University Core-CollapsE Supernova Survey (SUCCESS), to provide triggers for follow-up searches for gravitational waves. It is based on the 76 cm Sejong University Telescope (SUT) for weekly monitoring of nearby star-forming galaxies, i.e., M51, M81-M82 and Blue Dwarf Galaxies from the Unified Nearby Galaxy Catalog with an expected yield of a few hundred per year. Optical light curves will be resolved for the true time-of-onset for probes of gravitational waves by broadband time-sliced matched filtering.

  3. Inferring the core-collapse supernova explosion mechanism with gravitational waves

    CERN Document Server

    Powell, Jade; Logue, Joshua; Heng, Ik Siong

    2016-01-01

    A detection of a core-collapse supernova (CCSN) gravitational-wave (GW) signal with an Advanced LIGO and Virgo detector network may allow us to measure astrophysical parameters of the dying massive star. GWs are emitted from deep inside the core and, as such, they are direct probes of the CCSN explosion mechanism. In this study we show how we can determine the CCSN explosion mechanism from a GW supernova detection using a combination of principal component analysis and Bayesian model selection. We use simulations of GW signals from CCSN exploding via neutrino-driven convection and rapidly-rotating core collapse. Previous studies have shown that the explosion mechanism can be determined using one LIGO detector and simulated Gaussian noise. As real GW detector noise is both non-stationary and non-Gaussian we use real detector noise from a network of detectors with a sensitivity altered to match the advanced detectors design sensitivity. For the first time we carry out a careful selection of the number of princi...

  4. 第四波“中国崩溃论”之崩溃%The Collapse of the Fourth Wave of “China Collapse Theory”

    Institute of Scientific and Technical Information of China (English)

    陶绍兴

    2016-01-01

    “中国崩溃论”之说由来已久。第四波“中国崩溃论”的鼓吹者们陷入了结论在先的分析陷阱。尽管这种“无视铮铮事实”的论调在实践中一再被证伪,但是鉴于政治正确性、基于西方中心主义的视角和维护西方话语霸权的需要,“中国崩溃论”的噪音是不会自动消失的。第四波“中国崩溃论”之崩溃是一个必然的趋势,中国应增强战略定力,警惕预言的自动实现;努力化危为机,提升话语权。%The“China Collapse Theory” was long-standing. The advocates of the fourth wave for“China collapse” have fallen into the analysis trap that conclusions are first made in advance. Despite the argument of “ignoring the fact” has repeatedly been falsified in practice, the noise of “China collapse theory” will not automatically stop in view of the political correctness, and for the need of maintaining the western centralism and hegemony of the west. The collapse of the fourth wave of “China collapse theory” is an inevitable trend. China should strength strategic concentration, keep a wary eye about automatic realization of the prophecy, make great efforts to transfer danger into opportunity and improve the power of discourse.

  5. Broadband extended emission in gravitational waves from core-collapse supernovae

    CERN Document Server

    Levinson, Amir; Pick, Guy

    2015-01-01

    Black holes in core-collapse of massive stars are expected to surge in mass and angular momentum by hyper-accretion immediately following their formation. We here describe a general framework of extended emission in gravitational waves from non-axisymmetric accretion flows from fallback matter of the progenitor envelope. It shows (a) a maximum efficiency in conversion of accretion energy into gravitational waves at hyper-accretion rates exceeding a critical value set by the ratio of the quadrupole mass inhomogeneity and viscosity with (b) a peak characteristic strain amplitude at the frequency $f_b=\\Omega_b/\\pi$, where $\\Omega_b$ is the Keplerian angular velocity at which viscous torques equal angular momentum loss in gravitational radiation, with $h_{char}\\propto f^{1/6}$ at $ff_b$. Upcoming gravitational wave observations may probe this scaling by extracting broadband spectra using time-sliced matched filtering with chirp templates, recently developed for identifying turbulence in noisy time series.

  6. Prospects for Gravitational Wave Searches for Core-Collapse Supernovae within the Local Universe

    Science.gov (United States)

    Gill, Kiranjyot; Branchesi, Marica; Zanolin, Michele; Szczepanczyk, Marek; LIGO Collaboration

    2017-01-01

    We present an updated estimate of the intrinsic (vs observed) core collapse supernovae (CCSNe) rate within 20 Mpc from Earth, which is roughly the largest distance of interest for the searches for gravitational waves (GWs) from CCSNe with laser interferometers. Recognizing that CCSN galaxy host models are morphologically dependent, we separate the galaxies within 20 Mpc into the local field and Virgo cluster and account for biases, such as galactic plane absorption. The improved estimation of the CCSNe rate within 20 Mpc is 430 +/- 21 CCSNe Century -1 Mpc-1. We also discuss the Feldman-Cousins and GRB methodologies for detecting CCSNe when there are multiple CCSNe optical triggers, as predicted for advanced LIGO data science runs. Illustrative examples of the sensitivity improvement with respect to the single-event current approaches are provided for rapidly rotating semi-analytical models of GW emissions and real (publicly released) LIGO data.

  7. Collapse ratios of buildings due to the 1995 Kobe earthquake and interference between S-wave and the second surface wave at basin edge

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhixin; XU Jiren; Ryuji Kubota; Wakizawa Yasuhiko; Kajikawa Syozo

    2004-01-01

    The distribution characteristics of collapse ratios of buildings in Kobe city due to the 1995 M7.2 Hyogo-ken Nanbu, Japan (Kobe) earthquake and the interferences due to SH or P-SV and the second surface waves propagating in heterogeneous medium are discussed in this paper by using numerical simulation technique of wave equation. The staggered grid real value fast Fourier transform differentiation (SGRFFTD) is used in the pseudospectral method of ground motion simulations because of its speed, high stability and accuracy. The results show that the maximum amplitude of simulated acceleration waveforms on the ground coincides well with the complicated distributions of collapse ratios of buildings. The peak collapse ratio of buildings away from the earthquake fault also coincides well with the peak ground acceleration. The spatial interference process is analyzed by using the snap shots of seismic wave propagation. The peak ground acceleration is probably caused by the interferences due to the second surface wave transmitting from the bedrock to sedimentary basin and the upward body wave. Analyses of the interference process show that seismic velocity structure and geologic structure strongly influence the distribution of the maximum amplitude of acceleration waveforms. Interferences occurring near the basin boundary are probably the cause of the peak collapse ratio of buildings away from the fault. Therefore it is necessary to analyze wave propagations and interference process using numerical simulation strategy for studies on the seismic disasters.

  8. The Application of Bayesian Inference to Gravitational Waves from Core-Collapse Supernovae

    Science.gov (United States)

    Gossan, Sarah; Ott, Christian; Kalmus, Peter; Logue, Joshua; Heng, Siong

    2013-04-01

    The gravitational wave (GW) signature of core-collapse supernovae (CCSNe) encodes important information on the supernova explosion mechanism, the workings of which cannot be explored via observations in the electromagnetic spectrum. Recent research has shown that the CCSNe explosion mechanism can be inferred through the application of Bayesian model selection to gravitational wave signals from supernova explosions powered by the neutrino, magnetorotational and acoustic mechanisms. Extending this work, we apply Principal Component Analysis to the GW spectrograms from CCSNe to take into account also the time-frequency evolution of the emitted signals. We do so in the context of Advanced LIGO, to establish if any improvement on distinguishing between various explosion mechanisms can be obtained. Further to this, we consider a five-detector network of interferometers (comprised of the two Advanced LIGO detectors, Advanced Virgo, LIGO India and KAGRA) and generalize the aforementioned analysis for a source of known position but unknown distance, using realistic, re-colored detector data (as opposed to Gaussian noise), in order to make more reliable statements regarding our ability to distinguish between various explosion mechanisms on the basis of their GW signatures.

  9. Dilatonic Brans-Dicke Anisotropic Collapsing Fluid Sphere And de Broglie Quantum Wave Motion

    CERN Document Server

    Ghaffarnejad, Hossein

    2014-01-01

    Two dimensional analogue of vacuum sector of the Brans Dicke gravity is used to study dynamics of anisotropic spherical symmetric perfect fluid. We solve dynamical equations and obtain internal metric of the fluid describing a stellar collapse with equation of state as $\\rho(p)=2(p-p_0^3/p^3)$ for $\\omega>>1$. We determine time dependence oscillations of particles ensemble, apparent and event horizons location where the particles same as the event horizon are trapped by the apparent horizon and they are located on back of the apparent horizon. We determine radial accelerating velocity of the particles ensemble from the phase part of the corresponding de Broglie quantum wave of the fluid sphere. A good correspondence between our classical and de Broglie quantum wave solutions are obtained by overlapping diagram of the classical solutions of relative distance of the particles, apparent and event horizons with particles ensemble density where finally the particles together with the event horizon located back of ...

  10. High-resolution SH-wave seismic reflection investigations near a coal mine-related roadway collapse feature

    Science.gov (United States)

    Guy, Erich D.; Nolen-Hoeksema, Richard C.; Daniels, Jeffrey J.; Lefchik, Thomas

    2003-11-01

    We acquired crossline-crossline (SH-SH) shear-wave reflection data along a heavily trafficked section of Interstate highway 70 in eastern Ohio where the roadway had collapsed into underground coal-mine workings. We acquired these data to determine whether subsurface subsidence processes had continued at the collapse location after remediation, and to identify additional areas of potential collapse along this section of the roadway. A reflection correlating to the overburden and bedrock interface (above the mine workings) was consistently identified in raw field records, and our data processing and imaging targeted this high impedance contrast. Data quality was high enough to permit resolution of vertical offsets of 3-4 ft (0.91-1.2 m) and horizontal disruptions of about 20 ft (6.1 m) in the otherwise continuous bedrock horizon at two locations close to the previous collapse, suggesting a relatively high risk for future roadway failure in these areas. SH-wave data interpretations were supported by exploratory drilling results which confirmed that bedrock had subsided into underlying coal-mine workings at these two locations. Our results show that high-resolution SH-wave seismic reflection surveys can be effective for diagnosing mine-induced subsidence potential beneath heavily traveled roadways.

  11. Wave function and CKM renormalization

    CERN Document Server

    Espriu, Doménec

    2002-01-01

    In this presentation we clarify some aspects of the LSZ formalism and wave function renormalization for unstable particles in the presence of electroweak interactions when mixing and CP violation are considered. We also analyze the renormalization of the CKM mixing matrix which is closely related to wave function renormalization. The effects due to the electroweak radiative corrections that are described in this work are small, but they will need to be considered when the precision in the measurement of the charged current sector couplings reaches the 1% level. The work presented here is done in collaboration with Julian Manzano and Pere Talavera.

  12. Directed Searches for Broadband Extended Gravitational Wave Emission in Nearby Energetic Core-collapse Supernovae

    Science.gov (United States)

    van Putten, Maurice H. P. M.

    2016-03-01

    Core-collapse supernovae (CC-SNe) are factories of neutron stars and stellar-mass black holes. SNe Ib/c stand out as potentially originating in relatively compact stellar binaries and they have a branching ratio of about 1% into long gamma-ray bursts. The most energetic events probably derive from central engines harboring rapidly rotating black holes, wherein the accretion of fall-back matter down to the innermost stable circular orbit (ISCO) offers a window into broadband extended gravitational wave emission (BEGE). To search for BEGE, we introduce a butterfly filter in time-frequency space by time-sliced matched filtering. To analyze long epochs of data, we propose using coarse-grained searches followed by high-resolution searches on events of interest. We illustrate our proposed coarse-grained search on two weeks of LIGO S6 data prior to SN 2010br (z = 0.002339) using a bank of up to 64,000 templates of one-second duration covering a broad range in chirp frequencies and bandwidth. Correlating events with signal-to-noise ratios > 6 from the LIGO L1 and H1 detectors reduces the total to a few events of interest. Lacking any further properties reflecting a common excitation by broadband gravitational radiation, we disregarded these as spurious. This new pipeline may be used to systematically search for long-duration chirps in nearby CC-SNe from robotic optical transient surveys using embarrassingly parallel computing.

  13. DIRECTED SEARCHES FOR BROADBAND EXTENDED GRAVITATIONAL WAVE EMISSION IN NEARBY ENERGETIC CORE-COLLAPSE SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Van Putten, Maurice H. P. M., E-mail: mvp@sejong.ac.kr [Room 614, Astronomy and Space Science, Sejong University, 98 Gunja-Dong Gwangin-gu, Seoul 143-747 (Korea, Republic of)

    2016-03-10

    Core-collapse supernovae (CC-SNe) are factories of neutron stars and stellar-mass black holes. SNe Ib/c stand out as potentially originating in relatively compact stellar binaries and they have a branching ratio of about 1% into long gamma-ray bursts. The most energetic events probably derive from central engines harboring rapidly rotating black holes, wherein the accretion of fall-back matter down to the innermost stable circular orbit (ISCO) offers a window into broadband extended gravitational wave emission (BEGE). To search for BEGE, we introduce a butterfly filter in time–frequency space by time-sliced matched filtering. To analyze long epochs of data, we propose using coarse-grained searches followed by high-resolution searches on events of interest. We illustrate our proposed coarse-grained search on two weeks of LIGO S6 data prior to SN 2010br (z = 0.002339) using a bank of up to 64,000 templates of one-second duration covering a broad range in chirp frequencies and bandwidth. Correlating events with signal-to-noise ratios > 6 from the LIGO L1 and H1 detectors reduces the total to a few events of interest. Lacking any further properties reflecting a common excitation by broadband gravitational radiation, we disregarded these as spurious. This new pipeline may be used to systematically search for long-duration chirps in nearby CC-SNe from robotic optical transient surveys using embarrassingly parallel computing.

  14. Directed searches for broadband extended gravitational-wave emission in nearby energetic core-collapse supernovae

    CERN Document Server

    Van Putten, Maurice H P M

    2016-01-01

    Core-collapse supernovae are factories of neutron stars and stellar mass black holes. Type Ib/c supernovae stand out as potentially originating in relatively compact stellar binaries and their branching ratio of about 1\\% into long gamma-ray bursts. The most energetic events probably derive from central engines harboring rapidly rotating black holes, wherein accretion of fall-back matter down to the Inner Most Stable Circular Orbit (ISCO) offers a window to {\\em broadband extended gravitational-wave emission} (BEGE). To search for BEGE, we introduce a butterfly filter in time-frequency space by Time Sliced Matched Filtering. To analyze long epochs of data, we propose using coarse grained searches followed by high resolution searches on events of interest. We illustrate our proposed coarse grained search on two weeks of LIGO S6 data prior to SN 2010br $(z=0.002339)$ using a bank of up to 64 thousand templates of one second duration covering a broad range in chirp frequencies and bandwidth. Correlating events w...

  15. Strategies for aggregating gene expression data: The collapseRows R function

    Directory of Open Access Journals (Sweden)

    Miller Jeremy A

    2011-08-01

    Full Text Available Abstract Background Genomic and other high dimensional analyses often require one to summarize multiple related variables by a single representative. This task is also variously referred to as collapsing, combining, reducing, or aggregating variables. Examples include summarizing several probe measurements corresponding to a single gene, representing the expression profiles of a co-expression module by a single expression profile, and aggregating cell-type marker information to de-convolute expression data. Several standard statistical summary techniques can be used, but network methods also provide useful alternative methods to find representatives. Currently few collapsing functions are developed and widely applied. Results We introduce the R function collapseRows that implements several collapsing methods and evaluate its performance in three applications. First, we study a crucial step of the meta-analysis of microarray data: the merging of independent gene expression data sets, which may have been measured on different platforms. Toward this end, we collapse multiple microarray probes for a single gene and then merge the data by gene identifier. We find that choosing the probe with the highest average expression leads to best between-study consistency. Second, we study methods for summarizing the gene expression profiles of a co-expression module. Several gene co-expression network analysis applications show that the optimal collapsing strategy depends on the analysis goal. Third, we study aggregating the information of cell type marker genes when the aim is to predict the abundance of cell types in a tissue sample based on gene expression data ("expression deconvolution". We apply different collapsing methods to predict cell type abundances in peripheral human blood and in mixtures of blood cell lines. Interestingly, the most accurate prediction method involves choosing the most highly connected "hub" marker gene. Finally, to facilitate

  16. Adverse effect of cake collapse on the functional integrity of freeze-dried bull spermatozoa.

    Science.gov (United States)

    Hara, Hiromasa; Tagiri, Miho; Hwang, In-Sul; Takahashi, Masato; Hirabayashi, Masumi; Hochi, Shinichi

    2014-06-01

    Under optimal freeze-drying conditions, solutions exhibit a cake-like porous structure. However, if the solution temperature is higher than the glass transition temperature of the maximally freeze-concentrated phase (Tg') during drying phase, the glassy matrix undergoes viscous flow, resulting in cake collapse. The purpose of the present study was to investigate the effect of cake collapse on the integrity of freeze-dried bull spermatozoa. In a preliminary experiment, factors affecting the Tg' of conventional EGTA buffer (consisting of Tris-HCl, EGTA and NaCl) were investigated in order to establish the main experimental protocol because EGTA buffer Tg' was too low (-45.0°C) to suppress collapse. Modification of the EGTA buffer composition by complete removal of NaCl and addition of trehalose (mEGTA buffer) resulted in an increase of Tg' up to -27.7°C. In the main experiment, blastocyst yields after ooplasmic injection of freeze-dried sperm preserved in collapsed cakes (drying temperature: 0 or -15°C) were significantly lower than those of sperm preserved in non-collapsed cake (drying temperature: -30°C). In conclusion, freeze-dried cake collapse may be undesirable for maintaining sperm functions to support embryonic development, and can be inhibited by controlling both Tg' of freeze-drying buffer and temperature during the drying phase.

  17. Collapsed Shape of Shallow Unlined Tunnels Based on Functional Catastrophe Theory

    Directory of Open Access Journals (Sweden)

    Chengping Zhang

    2015-01-01

    Full Text Available This paper investigates the collapse mechanisms and possible collapsing block shapes of shallow unlined tunnels under conditions of plane strain. The analysis is performed following the framework from a branch of catastrophe theory, functional catastrophe theory. First, the basic principles of functional catastrophe theory are introduced. Then, an analytical solution for the shape curve of the collapsing block of a shallow unlined tunnel is derived using functional catastrophe theory based on the nonlinear Hoek-Brown failure criterion. The effects of the rock mass parameters of the proposed method on the shape and weight of the collapsing block are examined. Moreover, a critical cover depth expression to classify deep and shallow tunnels is proposed. The analytical results are consistent with those obtained by numerical simulation using the particle flow code, demonstrating the validity of the proposed analytical method. The obtained formulas can be used to predict the height and width of the collapsing block of a shallow unlined tunnel and to provide a direct estimate of the overburden on the tunnel lining. The obtained formulas can be easily used by tunnel engineers and researchers due to their simplicity.

  18. Does the polynomial hierarchy collapse if onto functions are invertible?

    NARCIS (Netherlands)

    H. Buhrman; L. Fortnow; M. Koucký; J.D. Rogers; N. Vereshchagin

    2010-01-01

    The class TFNP, defined by Megiddo and Papadimitriou, consists of multivalued functions with values that are polynomially verifiable and guaranteed to exist. Do we have evidence that such functions are hard, for example, if TFNP is computable in polynomial-time does this imply the polynomial-time hi

  19. Functional Catastrophe Analysis of Collapse Mechanism for Shallow Tunnels with Considering Settlement

    Directory of Open Access Journals (Sweden)

    Rui Zhang

    2016-01-01

    Full Text Available Limit analysis is a practical and meaningful method to predict the stability of geomechanical properties. This work investigates the pore water effect on new collapse mechanisms and possible collapsing block shapes of shallow tunnels with considering the effects of surface settlement. The analysis is performed within the framework of upper bound theorem. Furthermore, the NL nonlinear failure criterion is used to examine the influence of different factors on the collapsing shape and the minimum supporting pressure in shallow tunnels. Analytical solutions derived by functional catastrophe theory for the two different shape curves which describe the distinct characteristics of falling blocks up and down the water level are obtained by virtual work equations under the variational principle. By considering that the mechanical properties of soil are not affected by the presence of underground water, the strength parameters in NL failure criterion can be taken to be the same under and above the water table. According to the numerical results in this work, the influences on the size of collapsing block different parameters have are presented in the tables and the upper bounds on the loads required to resist collapse are derived and illustrated in the form of supporting forces graphs that account for the variation of the embedded depth and other factors.

  20. Avoiding coral reef functional collapse requires local and global action.

    Science.gov (United States)

    Kennedy, Emma V; Perry, Chris T; Halloran, Paul R; Iglesias-Prieto, Roberto; Schönberg, Christine H L; Wisshak, Max; Form, Armin U; Carricart-Ganivet, Juan P; Fine, Maoz; Eakin, C Mark; Mumby, Peter J

    2013-05-20

    Coral reefs face multiple anthropogenic threats, from pollution and overfishing to the dual effects of greenhouse gas emissions: rising sea temperature and ocean acidification. While the abundance of coral has declined in recent decades, the implications for humanity are difficult to quantify because they depend on ecosystem function rather than the corals themselves. Most reef functions and ecosystem services are founded on the ability of reefs to maintain their three-dimensional structure through net carbonate accumulation. Coral growth only constitutes part of a reef's carbonate budget; bioerosion processes are influential in determining the balance between net structural growth and disintegration. Here, we combine ecological models with carbonate budgets and drive the dynamics of Caribbean reefs with the latest generation of climate models. Budget reconstructions using documented ecological perturbations drive shallow (6-10 m) Caribbean forereefs toward an increasingly fragile carbonate balance. We then projected carbonate budgets toward 2080 and contrasted the benefits of local conservation and global action on climate change. Local management of fisheries (specifically, no-take marine reserves) and the watershed can delay reef loss by at least a decade under "business-as-usual" rises in greenhouse gas emissions. However, local action must be combined with a low-carbon economy to prevent degradation of reef structures and associated ecosystem services. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Extended phonon collapse in the charge-density-wave compound NbSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Frank [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Materials Science Division, Argonne National Laboratory, Argonne, Illinois (United States); Rosenkranz, Stephan; Castellan, John-Paul; Osborn, Raymond [Materials Science Division, Argonne National Laboratory, Argonne, Illinois (United States); Hott, Roland; Heid, Rolf; Bohnen, Klaus-Peter [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Egami, Takeshi [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee (United States); Said, Ayman [Advanced Photon Source, Argonne National Laboratory, Illinois (United States); Reznik, Dmitry [Karlsruhe Institute of Technology, Institute of Solid State Physics, Karlsruhe (Germany); Department of Physics, University of Colorado at Boulder, Boulder, Colorado (United States)

    2011-07-01

    We investigated the phonon softening in the charge density wave compound NbSe{sub 2} using the high-resolution hard inelastic X-ray scattering beamline 30-ID-C at the Advanced Photon Source, Argonne National Laboratory. The acoustic {sigma}{sub 1} phonon branch was measured from the zone center {gamma} to the M point at temperatures between 250 K and 8 K across the CDW transition at T{sub CDW}=33 K. Density functional theory calculations for the lattice dynamical properties which predict an extended phonon breakdown are used to analyze the detailed nature of the softening phonon branch.

  2. Methodology of the joint search for Gravitational Wave and Low Energy Neutrino signals from Core-Collapse Supernovae

    Science.gov (United States)

    Casentini, Claudio

    2016-05-01

    Core-Collapse Supernovae (CCSNe) have a neutrino (v) signature confirmed by SN 1987A and are potential sources of Gravitational Waves (GWs). vs and GWs coming from these sources will reach the observer almost simultaneously and without significant interaction with interstellar matter. The expected GW signals are in the range of the upcoming advanced detectors for galactic neighborhood events. However, there are still significant uncertainties on the theoretical model of the emission. A joint search of coincident vs and GWs from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent Supernovae. Recently, a project for a joint search involving GW interferometers and v detectors has started. In this paper we discuss about the principal GW theoretical models of emission, and we present a methodological study of the joint search project between GW and v.

  3. Extended phonon collapse and the origin of the charge-density-wave in NbSe{sub 2}.

    Energy Technology Data Exchange (ETDEWEB)

    Weber, F.; Rosenkranz, S.; Castellan, J.-P.; Osborn, R.; Hott, R.; Heid, R.; Bohnen, K.-P.; Egami, T.; Said, A. H.; Reznik, D. (X-Ray Science Division); ( MSD); (Karlsruhe Inst. of Tech.); (Univ. of Tennessee); (Univ. of Colorado at Boulder)

    2011-01-01

    We report inelastic x-ray scattering measurements of the temperature dependence of phonon dispersion in the prototypical charge-density-wave (CDW) compound 2H-NbSe{sub 2}. Surprisingly, acoustic phonons soften to zero frequency and become overdamped over an extended region around the CDW wave vector. This extended phonon collapse is dramatically different from the sharp cusp in the phonon dispersion expected from Fermi surface nesting. Instead, our experiments, combined with ab initio calculations, show that it is the wave vector dependence of the electron-phonon coupling that drives the CDW formation in 2H-NbSe{sub 2} and determines its periodicity. This mechanism explains the so far enigmatic behavior of CDW in 2H-NbSe{sub 2} and may provide a new approach to other strongly correlated systems where electron-phonon coupling is important.

  4. Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. III. Rotating Three Dimensional Cloud Cores

    CERN Document Server

    Boss, Alan P

    2014-01-01

    A key test of the supernova triggering and injection hypothesis for the origin of the solar system's short-lived radioisotopes is to reproduce the inferred initial abundances of these isotopes. We present here the most detailed models to date of the shock wave triggering and injection process, where shock waves with varied properties strike fully three dimensional, rotating, dense cloud cores. The models are calculated with the FLASH adaptive mesh hydrodynamics code. Three different outcomes can result: triggered collapse leading to fragmentation into a multiple protostar system; triggered collapse leading to a single protostar embedded in a protostellar disk; or failure to undergo dynamic collapse. Shock wave material is injected into the collapsing clouds through Rayleigh-Taylor fingers, resulting in initially inhomogeneous distributions in the protostars and protostellar disks. Cloud rotation about an axis aligned with the shock propagation direction does not increase the injection efficiency appreciably, ...

  5. The Wave Function of Quantum de Sitter

    OpenAIRE

    Castro, Alejandra; Maloney, Alexander

    2012-01-01

    We consider quantum general relativity in three dimensions with a positive cosmological constant. The Hartle-Hawking wave function is computed as a function of metric data at asymptotic future infinity. The analytic continuation from Euclidean Anti-de Sitter space provides a natural integration contour in the space of metrics, allowing us -- with certain assumptions -- to compute the wave function exactly, including both perturbative and non-perturbative effects. The resulting wave function i...

  6. Exact Solution for Phenomenon of atomic Collapse and Revival under Rotating Wave and Anti-Rotating Wave Approximation

    Institute of Scientific and Technical Information of China (English)

    DING Bang-Fu; WANG Xiao-Yun; TANG Yan-Fang; MI Xian-Wu; ZHAO He-Ping

    2011-01-01

    An accurate method to solve the Jaynes-Cummings (J-C) Hamiltonian has been investigated here. The phenomenon of atomic collapse and revival predicted by Jaynes-Cummings model is demonstrated. Solutions are consistent with the precious such as using the operator method. Furthermore, the Jaynes-Cummings Hamiltonian including the anti-rotating term is also solved precisely using this accurate way so that results agree with experiments better.Essences of the anti-rotating term are revealed. We discuss the relations of the phenomenon of atonic collapse and revival with the average photons number, the light field phase angle, the resonant frequency, and the size of coupling constant. The discussions may make one select suitable conditions to carry out experiment well and study the virtual light field effect on cavity quantum electrodynamics.

  7. Structure of tracheae and the functional implications for collapse in the American cockroach.

    Science.gov (United States)

    Webster, Matthew R; Socha, John J; Teresi, Luciano; Nardinocchi, Paola; De Vita, Raffaella

    2015-12-01

    The tracheal tubes of insects are complex and heterogeneous composites with a microstructural organization that affects their function as pumps, valves, or static conduits within the respiratory system. In this study, we examined the microstructure of the primary thoracic tracheae of the American cockroach (Periplaneta americana) using a combination of scanning electron microscopy and light microscopy. The organization of the taenidia, which represents the primary source of structural reinforcement of the tracheae, was analyzed. We found that the taenidia were more disorganized in the regions of highest curvature of the tracheal tube. We also used a simple finite element model to explore the effect of cross-sectional shape and distribution of taenidia on the collapsibility of the tracheae. The eccentricity of the tracheal cross-section had a stronger effect on the collapse properties than did the distribution of taenidia. The combination of the macro-scale geometry, meso-scale heterogeneity, and microscale organization likely enables rhythmic tracheal compression during respiration, ultimately driving oxygen-rich air to cells and tissues throughout the insect body. The material design principles of these natural composites could potentially aid in the development of new bio-inspired microfluidic systems based on the differential collapse of tracheae-like networks.

  8. Solitary waves, steepening and initial collapse in the Maxwell-Lorentz system

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Brio, Moysey; Webb, Garry

    2002-01-01

    relation reveals various asymptotic regimes such as Schrödinger and KdV branches. Existence of soliton-type solutions in the Schrödinger regime and light bullets containing few optical cycles together with dark solitons are illustrated numerically. Envelope collapse regimes of the Schrödinger equation......We present a numerical study of Maxwell's equations in nonlinear dispersive optical media describing propagation of pulses in one Cartesian space dimension. Dispersion and nonlinearity are accounted for by a linear Lorentz model and an instantaneous Kerr nonlinearity, respectively. The dispersion...

  9. Spheroidal Wave Functions in Electromagnetic Theory

    Science.gov (United States)

    Li, Le-Wei; Kang, Xiao-Kang; Leong, Mook-Seng

    2001-11-01

    The flagship monograph addressing the spheroidal wave function and its pertinence to computational electromagnetics Spheroidal Wave Functions in Electromagnetic Theory presents in detail the theory of spheroidal wave functions, its applications to the analysis of electromagnetic fields in various spheroidal structures, and provides comprehensive programming codes for those computations. The topics covered in this monograph include: Spheroidal coordinates and wave functions Dyadic Green's functions in spheroidal systems EM scattering by a conducting spheroid EM scattering by a coated dielectric spheroid Spheroid antennas SAR distributions in a spheroidal head model The programming codes and their applications are provided online and are written in Mathematica 3.0 or 4.0. Readers can also develop their own codes according to the theory or routine described in the book to find subsequent solutions of complicated structures. Spheroidal Wave Functions in Electromagnetic Theory is a fundamental reference for scientists, engineers, and graduate students practicing modern computational electromagnetics or applied physics.

  10. Wind wave source functions in opposing seas

    KAUST Repository

    Langodan, Sabique

    2015-08-26

    The Red Sea is a challenge for wave modeling because of its unique two opposed wave systems, forced by opposite winds and converging at its center. We investigate the different physical aspects of wave evolution and propagation in the convergence zone. The two opposing wave systems have similar amplitude and frequency, each driven by the action of its own wind. Wave patterns at the centre of the Red Sea, as derived from extensive tests and intercomparison between model and measured data, suggest that the currently available wave model source functions may not properly represent the evolution of the local fields that appear to be characterized by a less effective wind input and an enhanced white-capping. We propose and test a possible simple solution to improve the wave-model simulation under opposing winds and waves condition. This article is protected by copyright. All rights reserved.

  11. Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-lived Radioisotopes with a Shock Wave. V. Nonisothermal Collapse Regime

    Science.gov (United States)

    Boss, Alan P.

    2017-08-01

    Recent meteoritical analyses support an initial abundance of the short-lived radioisotope (SLRI) 60Fe that may be high enough to require nucleosynthesis in a core-collapse supernova, followed by rapid incorporation into primitive meteoritical components, rather than a scenario where such isotopes were inherited from a well-mixed region of a giant molecular cloud polluted by a variety of supernovae remnants and massive star winds. This paper continues to explore the former scenario, by calculating three-dimensional, adaptive mesh refinement, hydrodynamical code (FLASH 2.5) models of the self-gravitational, dynamical collapse of a molecular cloud core that has been struck by a thin shock front with a speed of 40 km s-1, leading to the injection of shock front matter into the collapsing cloud through the formation of Rayleigh-Taylor fingers at the shock-cloud intersection. These models extend the previous work into the nonisothermal collapse regime using a polytropic approximation to represent compressional heating in the optically thick protostar. The models show that the injection efficiencies of shock front materials are enhanced compared to previous models, which were not carried into the nonisothermal regime, and so did not reach such high densities. The new models, combined with the recent estimates of initial 60Fe abundances, imply that the supernova triggering and injection scenario remains a plausible explanation for the origin of the SLRIs involved in the formation of our solar system.

  12. Sculpturing the Electron Wave Function

    CERN Document Server

    Shiloh, Roy; Lilach, Yigal; Arie, Ady

    2014-01-01

    Coherent electrons such as those in electron microscopes, exhibit wave phenomena and may be described by the paraxial wave equation. In analogy to light-waves, governed by the same equation, these electrons share many of the fundamental traits and dynamics of photons. Today, spatial manipulation of electron beams is achieved mainly using electrostatic and magnetic fields. Other demonstrations include simple phase-plates and holographic masks based on binary diffraction gratings. Altering the spatial profile of the beam may be proven useful in many fields incorporating phase microscopy, electron holography, and electron-matter interactions. These methods, however, are fundamentally limited due to energy distribution to undesired diffraction orders as well as by their binary construction. Here we present a new method in electron-optics for arbitrarily shaping of electron beams, by precisely controlling an engineered pattern of thicknesses on a thin-membrane, thereby molding the spatial phase of the electron wav...

  13. Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. II. Varied Shock Wave and Cloud Core Parameters

    CERN Document Server

    Boss, Alan P

    2013-01-01

    A variety of stellar sources have been proposed for the origin of the short-lived radioisotopes that existed at the time of the formation of the earliest Solar System solids, including Type II supernovae, AGB and super-AGB stars, and Wolf-Rayet star winds. Our previous adaptive mesh hydrodynamics models with the FLASH2.5 code have shown which combinations of shock wave parameters are able to simultaneously trigger the gravitational collapse of a target dense cloud core and inject significant amounts of shock wave gas and dust, showing that thin supernova shocks may be uniquely suited for the task. However, recent meteoritical studies have weakened the case for a direct supernova injection to the presolar cloud, motivating us to re-examine a wider range of shock wave and cloud core parameters, including rotation, in order to better estimate the injection efficiencies for a variety of stellar sources. We find that supernova shocks remain as the most promising stellar source, though planetary nebulae resulting f...

  14. Cosmological Density Distribution Function from the Ellipsoidal Collapse Model in Real Space

    CERN Document Server

    Ohta, Y; Taruya, A; Ohta, Yasuhiro; Kayo, Issha; Taruya, Atsushi

    2004-01-01

    We calculate the one-point probability distribution function (PDF) for cosmic density in non-linear regime of the gravitational evolution. Under the local approximation that the evolution of cosmic fluid fields can be characterized by the Lagrangian local dynamics with finite degrees of freedom, the analytic expressions of PDF are derived taking account of the smoothing effect. The validity and the usefulness of the local approximation are then discussed comparing those results with N-body simulations in a Gaussian initial condition. Adopting the ellipsoidal collapse model (ECM) and the spherical collapse model (SCM) as Lagrangian local dynamics, we found that the PDFs from the local approximation excellently match the simulation results in the case of the cold dark matter initial spectrum. As for the scale-free initial spectra given by $P(k)\\propto k^n$, N-body result suffers from spurious numerical effects, which prevent us to give a detailed comparison. Nevertheless, at the quality of N-body data, the mode...

  15. The evolution of piecewise polynomial wave functions

    Science.gov (United States)

    Andrews, Mark

    2017-01-01

    For a non-relativistic particle, we consider the evolution of wave functions that consist of polynomial segments, usually joined smoothly together. These spline wave functions are compact (that is, they are initially zero outside a finite region), but they immediately extend over all available space as they evolve. The simplest splines are the square and triangular wave functions in one dimension, but very complicated splines have been used in physics. In general the evolution of such spline wave functions can be expressed in terms of antiderivatives of the propagator; in the case of a free particle or an oscillator, all the evolutions are expressed exactly in terms of Fresnel integrals. Some extensions of these methods to two and three dimensions are discussed.

  16. Deuteron wave function and OPE potential

    Science.gov (United States)

    Righi, S.; Rosa-Clot, M.

    1987-06-01

    The deuteron wave function is calculated integrating from outside the Schredinger equation using as input its asymptotic behaviour. Some potentials are tested and the one pion exchange potential (OPEP) is shown to be the main responsible of the wave function structure up to distances of about 1 fm. The relevance of the short range part of the potential is analyzed and it is shown that a substantial enhancement of the OPEP central part is needed in the deuteron channel.

  17. Dilatonic Brans-Dicke Anisotropic Collapsing Fluid Sphere And de Broglie Quantum Wave Motion

    Science.gov (United States)

    Ghaffarnejad, Hossein

    2016-08-01

    Two dimensional (2D) analogue of vacuum sector of the Brans Dicke (BD) gravity [1] is studied to obtain dynamics of anisotropic spherically symmetric perfect fluid. Our obtained static solutions behave as dark matter with state equation but in non-static regimes behave as regular perfect fluid with barotropic index ϒ > 0. Positivity property of total mass of the fluid causes that the BD parameter to be ω >2/3 and/or ω 0 the apparent horizon is covered by event horizon where the cosmic censorship hypothesis is still valid. According to the model [1], we obtain de Broglie pilot wave of our metric solution which describes particles ensemble which become distinguishable via different values of ω. Incident current density of particles ensemble on the horizons is evaluated which describe the ‘Hawking radiation’. The de Brogle-Bohm quantum potential effect is calculated also on the event (apparent) horizon which is independent (dependent) to values of ω.

  18. Species interactions regulate the collapse of biodiversity and ecosystem function in tropical forest fragments.

    Science.gov (United States)

    Bregman, Tom P; Lees, Alexander C; Seddon, Nathalie; Macgregor, Hannah E A; Darski, Bianca; Aleixo, Alexandre; Bonsall, Michael B; Tobias, Joseph A

    2015-10-01

    Competitive interactions among species with similar ecological niches are known to regulate the assembly of biological communities. However, it is not clear whether such forms of competition can predict the collapse of communities and associated shifts in ecosystem function in the face of environmental change. Here, we use phylogenetic and functional trait data to test whether communities of two ecologically important guilds of tropical birds (frugivores and insectivores) are structured by species interactions in a fragmented Amazonian forest landscape. In both guilds, we found that forest patch size, quality, and degree of isolation influence the phylogenetic and functional trait structure of communities, with small, degraded, or isolated forest patches having an increased signature of competition (i.e., phylogenetic and functional trait overdispersion in relation to null models). These results suggest that local extinctions in the context of fragmentation are nonrandom, with a consistent bias toward more densely occupied regions of niche space. We conclude that the loss of biodiversity in fragmented landscapes is mediated by niche-based competitive interactions among species, with potentially far-reaching implications for key ecosystem processes, including seed dispersal and plant damage by phytophagous insects.

  19. The spin rate of pre-collapse stellar cores: wave driven angular momentum transport in massive stars

    CERN Document Server

    Fuller, Jim; Lecoanet, Daniel; Quataert, Eliot

    2015-01-01

    The core rotation rates of massive stars have a substantial impact on the nature of core collapse supernovae and their compact remnants. We demonstrate that internal gravity waves (IGW), excited via envelope convection during a red supergiant phase or during vigorous late time burning phases, can have a significant impact on the rotation rate of the pre-SN core. In typical ($10 \\, M_\\odot \\lesssim M \\lesssim 20 \\, M_\\odot$) supernova progenitors, IGW may substantially spin down the core, leading to iron core rotation periods $P_{\\rm min,Fe} \\gtrsim 50 \\, {\\rm s}$. Angular momentum (AM) conservation during the supernova would entail minimum NS rotation periods of $P_{\\rm min,NS} \\gtrsim 3 \\, {\\rm ms}$. In most cases, the combined effects of magnetic torques and IGW AM transport likely lead to substantially longer rotation periods. However, the stochastic influx of AM delivered by IGW during shell burning phases inevitably spin up a slowly rotating stellar core, leading to a maximum possible core rotation perio...

  20. Meaning of the nuclear wave function

    CERN Document Server

    Terry, John D

    2016-01-01

    Background The intense current experimental interest in studying the structure of the deuteron and using it to enable accurate studies of neutron structure motivate us to examine the four-dimensional space-time nature of the nuclear wave function, and the various approximations used to reduce it to an object that depends only on three spatial variables. Purpose: The aim is to determine if the ability to understand and analyze measured experimental cross sections is compromised by making the reduction from four to three dimensions. Method: Simple, exactly-calculable, covariant models of a bound-state wave state wave function (a scalar boson made of two constituent-scalar bosons) with parameters chosen to represent a deuteron are used to investigate the accuracy of using different approximations to the nuclear wave function to compute the quasi-elastic scattering cross section. Four different versions of the wave function are defined (light-front spectator, light-front, light-front with scaling and non-relativi...

  1. The Wave Function It or Bit?

    CERN Document Server

    Zeh, H D

    2002-01-01

    Schroedinger's wave function shows many aspects of a state of incomplete knowledge or information ("bit"): (1) it is defined on a space of classical configurations, (2) its generic entanglement is, therefore, analogous to statistical correlations, and (3) it determines probabilites of measurement outcomes. Nonetheless, quantum superpositions (such as represented by a wave function) also define individual physical states ("it"). This conceptual dilemma may have its origin in the conventional operational foundation of physical concepts, successful in classical physics, but inappropriate in quantum theory because of the existence of mutually exclusive operations (used for the definition of concepts). In contrast, a hypothetical realism, based on concepts that are justified only by their universal and consistent applicability, favors the wave function as a description of (thus nonlocal) physical reality. The (conceptually local) classical world then appears as an illusion, facilitated by the phenomenon of decoher...

  2. Spontaneous symmetry breaking in correlated wave functions

    Science.gov (United States)

    Kaneko, Ryui; Tocchio, Luca F.; Valentí, Roser; Becca, Federico; Gros, Claudius

    2016-03-01

    We show that Jastrow-Slater wave functions, in which a density-density Jastrow factor is applied onto an uncorrelated fermionic state, may possess long-range order even when all symmetries are preserved in the wave function. This fact is mainly related to the presence of a sufficiently strong Jastrow term (also including the case of full Gutzwiller projection, suitable for describing spin models). Selected examples are reported, including the spawning of Néel order and dimerization in spin systems, and the stabilization of charge and orbital order in itinerant electronic systems.

  3. Constructibility of the Universal Wave Function

    Science.gov (United States)

    Bolotin, Arkady

    2016-10-01

    This paper focuses on a constructive treatment of the mathematical formalism of quantum theory and a possible role of constructivist philosophy in resolving the foundational problems of quantum mechanics, particularly, the controversy over the meaning of the wave function of the universe. As it is demonstrated in the paper, unless the number of the universe's degrees of freedom is fundamentally upper bounded (owing to some unknown physical laws) or hypercomputation is physically realizable, the universal wave function is a non-constructive entity in the sense of constructive recursive mathematics. This means that even if such a function might exist, basic mathematical operations on it would be undefinable and subsequently the only content one would be able to deduce from this function would be pure symbolical.

  4. Critical gravitational collapse with angular momentum: from critical exponents to universal scaling functions

    OpenAIRE

    Gundlach, C

    2001-01-01

    We investigate the threshold of gravitational collapse with angular momentum, under the assumption that the critical solution is spherical and self-similar and has two growing modes, namely one spherical mode and one axial dipole mode (threefold degenerate). This assumption holds for perfect fluid matter with the equation of state p=kappa rho if the constant kappa is in the range 0

  5. Numerical modeling of tsunami waves generated by the flank collapse of the Cumbre Vieja Volcano (La Palma, Canary Islands): Tsunami source and near field effects

    Science.gov (United States)

    Abadie, S. M.; Harris, J. C.; Grilli, S. T.; Fabre, R.

    2012-05-01

    In this work, we study waves generated by the potential collapse of the west flank of the Cumbre Vieja Volcano (CVV; La Palma, Canary Island, Spain) through numerical simulations performed in two stages: (i) the initial slide motion and resulting free surface elevation are first calculated using a 3D Navier-Stokes model; (ii) generated waves are then input into a 2D (horizontal) Boussinesq model to further simulate propagation to the nearby islands. Unlike in earlier work on CVV, besides a similar extreme slide volume scenario of 450 km3, in our simulations: (i) we consider several slide scenarios featuring different volumes (i.e., 20, 40, 80 km3), which partly result from a geotechnical slope stability analysis; (ii) we use a more accurate bathymetry; and (iii) an incompressible version of a multiple-fluid/material Navier-Stokes model. We find wave trains for each scenario share common features in terms of wave directivity, frequency, and time evolution, but maximum elevations near CVV significantly differ, ranging from 600 to 1200 m (for increasing slide volume). Additionally, our computations show that significant energy transfer from slide to waves only lasts for a short duration (order 200 s), which justifies concentrating our best modeling efforts on the early slide motion phase. The anticipated consequences of such wave trains on La Palma and other Canary Islands are assessed in detail in the paper.

  6. Collapse calderas

    Science.gov (United States)

    Aguirre-Diaz, G. J.; Marti, J.

    2007-05-01

    A collapse caldera is a volcanic explosive structure that forms during the collapse of crustal blocks on top of a shallow magma chamber. During this collapse, a large volume of magma is evacuated, first explosively, in the form of pyroclastic fallouts and pyroclastic flows, and then effusively, as lava domes or flows after collapse. The result is a catastrophic explosive volcanic collapse that forms a depression that could end with different shapes, circular, oval, rectangular, or irregular. Three main types of collapse calderas can be defined, 1) summit caldera, 2) classic caldera, and 3) graben caldera. Summit calderas are those formed at the top of large volcanoes and are related to relatively small-volume pyroclastic products that include plinian fallouts and ignimbrites, such as Crater Lake, Las Cañadas, and Somma-Vesuvio. Classic calderas are semi-circular to irregular-shaped large structures, several km in diameter that are related to relatively large-volume pyroclastic products including pumice fallouts and widespread ignimbrites, such as Long-Valley, Campi Flegrei, and Los Humeros. Graben calderas are explosive volcano-tectonic collapse structures from which large-volume, ignimbrite-forming eruptions occurred through several vents along the graben walls and the intra-graben block faults causing the collapse of the graben or of a sector of the graben. The main products of graben calderas are surge-deposits and large-volume widespread ignimbrite sheets. Pumice fallouts are practically absent. Examples include the Sierra Madre Occidental in Mexico, La Pacana (Andes), Catalan Pyrenees, and perhaps Scafell (United Kingdom). Any of the three caldera types mentioned above could have collapsed in three different ways, 1) piston, when the collapse occurs as a single crustal block; 2) trap-door, when collapse occurs unevenly along one side while the opposite side remains with no collapse; 3) piece-meal, when collapse occurs as broken pieces of the crust on top of

  7. Projector augmented wave method: ab initio molecular dynamics with full wave functions

    Indian Academy of Sciences (India)

    Peter E Blöchl; Clemens J Först; Johannes Schimpl

    2003-01-01

    A brief introduction to the projector augmented wave method is given and recent developments are reviewed. The projector augmented wave method is an all-electron method for efficient ab initio molecular dynamics simulations with full wave functions. It extends and combines the traditions of existing augmented wave methods and the pseudopotential approach. Without sacrificing efficiency, the PAW method avoids transferability problems of the pseudopotential approach and it has been valuable to predict properties that depend on the full wave functions.

  8. A Test of Nuclear Wave Functions for Pseudospin Symmetry

    CERN Document Server

    Ginocchio, J N

    2001-01-01

    Using the fact that pseudospin is an approximate symmetry of the Dirac Hamiltonian with realistic scalar and vector mean fields, we derive the wave functions of the pseudospin partners of eigenstates of a realistic Dirac Hamiltonian and compare these wave functions with the wave functions of the Dirac eigenstates.

  9. Test of nuclear wave functions for pseudospin symmetry.

    Science.gov (United States)

    Ginocchio, J N; Leviatan, A

    2001-08-13

    Using the fact that pseudospin is an approximate symmetry of the Dirac Hamiltonian with realistic scalar and vector mean fields, we derive the wave functions of the pseudospin partners of eigenstates of a realistic Dirac Hamiltonian and compare these wave functions with the wave functions of the Dirac eigenstates.

  10. Test of Nuclear Wave Functions for Pseudospin Symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Ginocchio, J. N.; Leviatan, A.

    2001-08-13

    Using the fact that pseudospin is an approximate symmetry of the Dirac Hamiltonian with realistic scalar and vector mean fields, we derive the wave functions of the pseudospin partners of eigenstates of a realistic Dirac Hamiltonian and compare these wave functions with the wave functions of the Dirac eigenstates.

  11. Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. IV. Effects of Rotational Axis Orientation

    CERN Document Server

    Boss, Alan P

    2015-01-01

    Both astronomical observations of the interaction of Type II supernova remnants (SNR) with dense interstellar clouds as well as cosmochemical studies of the abundances of daughter products of short-lived radioisotopes (SLRIs) formed by supernova nucleosynthesis support the hypothesis that the Solar Systems SLRIs may have been derived from a supernova. This paper continues a series devoted to examining whether such a shock wave could have triggered the dynamical collapse of a dense, presolar cloud core and simultaneously injected sufficient abundances of SLRIs to explain the cosmochemical evidence. Here we examine the effects of shock waves striking clouds whose spin axes are oriented perpendicular, rather than parallel, to the direction of propagation of the shock front. The models start with 2.2 solar mass cloud cores and shock speeds of 20 or 40 km/sec. Central protostars and protoplanetary disks form in all models, though with disk spin axes aligned somewhat randomly. The disks derive most of their angular...

  12. Wave function calculations in finite nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, S.C.

    1993-07-01

    One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: (1) specification of the Hamiltonian, and (2) calculation of the ground (or excited) states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependencies. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At Argonne and Urbana, the authors have been following a program of developing realistic NN and NNN interactions and the methods necessary to compute nuclear properties from variational wave functions suitable for these interactions. The wave functions are used to compute energies, density distributions, charge form factors, structure functions, momentum distributions, etc. Most recently they have set up a collaboration with S. Boffi and M. Raduci (University of Pavia) to compute (e,e{prime}p) reactions.

  13. Wave function calculations in finite nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, S.C.

    1993-01-01

    One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: (1) specification of the Hamiltonian, and (2) calculation of the ground (or excited) states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependencies. This structure results in formidable many-body problems in the computation of the ground states of nuclei. At Argonne and Urbana, the authors have been following a program of developing realistic NN and NNN interactions and the methods necessary to compute nuclear properties from variational wave functions suitable for these interactions. The wave functions are used to compute energies, density distributions, charge form factors, structure functions, momentum distributions, etc. Most recently they have set up a collaboration with S. Boffi and M. Raduci (University of Pavia) to compute (e,e[prime]p) reactions.

  14. Lanczos steps to improve variational wave functions

    Science.gov (United States)

    Becca, Federico; Hu, Wen-Jun; Iqbal, Yasir; Parola, Alberto; Poilblanc, Didier; Sorella, Sandro

    2015-09-01

    Gutzwiller-projected fermionic states can be efficiently implemented within quantum Monte Carlo calculations to define extremely accurate variational wave functions for Heisenberg models on frustrated two-dimensional lattices, not only for the ground state but also for low-energy excitations. The application of few Lanczos steps on top of these states further improves their accuracy, allowing calculations on large clusters. In addition, by computing both the energy and its variance, it is possible to obtain reliable estimations of exact results. Here, we report the cases of the frustrated Heisenberg models on square and Kagome lattices.

  15. Bohmian mechanics, collapse models and the emergence of classicality

    Science.gov (United States)

    Toroš, Marko; Donadi, Sandro; Bassi, Angelo

    2016-09-01

    We discuss the emergence of classical trajectories in Bohmian mechanics, when a macroscopic object interacts with an external environment. We show that in such a case the conditional wave function of the system follows a dynamics which, under reasonable assumptions, corresponds to that of the Ghirardi-Rimini-Weber (GRW) collapse model. As a consequence, Bohmian trajectories evolve classically. Our analysis also shows how the GRW (istantaneous) collapse process can be derived by an underlying continuous interaction of a quantum system with an external agent, thus throwing a light on how collapses can emerge from a deeper level theory.

  16. Dancing building prevents collapse

    NARCIS (Netherlands)

    Visscher, R.

    2007-01-01

    In future, anybody caught inside a building during an earthquake need no longer fear the roof collapsing on them. Thanks to the use of composite materials, all the building will do is dance along, riding the waves of the earthquake. At least, according to Professor Ir. Adriaan Beukers of the

  17. Dancing building prevents collapse

    NARCIS (Netherlands)

    Visscher, R.

    2007-01-01

    In future, anybody caught inside a building during an earthquake need no longer fear the roof collapsing on them. Thanks to the use of composite materials, all the building will do is dance along, riding the waves of the earthquake. At least, according to Professor Ir. Adriaan Beukers of the Aerospa

  18. Dancing building prevents collapse

    NARCIS (Netherlands)

    Visscher, R.

    2007-01-01

    In future, anybody caught inside a building during an earthquake need no longer fear the roof collapsing on them. Thanks to the use of composite materials, all the building will do is dance along, riding the waves of the earthquake. At least, according to Professor Ir. Adriaan Beukers of the Aerospa

  19. Comparative study on spreading function for directional wave spectra

    Digital Repository Service at National Institute of Oceanography (India)

    Bhat, S.S.; Anand, N.M.; Nayak, B.U.

    -dimensional wave energy S(f) and the directional spreading function D(f, theta). This paper reviews various spreading functions proposed in the past for estimating the directional wave energy and presents their application to the Indian wave condition. It is found...

  20. A Scheme of Interferometric Measurement of an Atomic Wave Function

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng-Dong; LIN Yu; ZENG Liang; PAN Qin-Min

    2000-01-01

    A new method to measure an atomic wave function is discussed. It effectively solves the problem of an initially random phase of a travelling-wave laser beam. The relationship between the measured data and the atomic wavefunction is presented, and the wave function's reconstruction procedure is also analyzed.PACS: 03.65. Bz, 03. 75. Dg

  1. Boundary conditions at closed edge of bilayer graphene and energy bands of collapsed nanotubes

    Science.gov (United States)

    Nakanishi, Takeshi; Ando, Tsuneya

    2016-10-01

    Band structure is systematically studied in an effective-mass scheme in collapsed armchair and zigzag nanotubes based on the model in which collapsed tubes are regarded as bilayer ribbons with closed edges. Boundary conditions at closed edges, describing the connection of the envelope wave functions between the bottom and top layers, are derived. Among electronic states in bilayers, which change sensitively depending on the relative displacement of two layers, those having wave functions matching well with the obtained boundary conditions, i.e., unaffected by the presence of closed edges, constitute important states near the Fermi level in collapsed nanotubes.

  2. Mariage des maillages: A new 3D general relativistic hydro code for simulation of gravitational waves from core-collapses.

    Science.gov (United States)

    Novak, Jerome; Dimmelmeier, Harrald; Font-Roda, Jose A.

    2004-12-01

    We present a new three-dimensional general relativistic hydrodynamics code which can be applied to study stellar core collapses and the resulting gravitational radiation. This code uses two different numerical techniques to solve partial differential equations arising in the model: high-resolution shock capturing (HRSC) schemes for the evolution of hydrodynamic quantities and spectral methods for the solution of Einstein equations. The equations are written and solved using spherical polar coordinates, best suited to stellar topology. Einstein equations are formulated within the 3+1 formalism and conformal flat condition (CFC) for the 3-metric and gravitational radiation is extracted using Newtonian quadrupole formulation.

  3. Superoscillating electron wave functions with subdiffraction spots

    Science.gov (United States)

    Remez, Roei; Tsur, Yuval; Lu, Peng-Han; Tavabi, Amir H.; Dunin-Borkowski, Rafal E.; Arie, Ady

    2017-03-01

    Almost one and a half centuries ago, Abbe [Arch. Mikrosk. Anat. 9, 413 (1873), 10.1007/BF02956173] and shortly after Lord Rayleigh [Philos. Mag. Ser. 5 8, 261 (1879), 10.1080/14786447908639684] showed that, when an optical lens is illuminated by a plane wave, a diffraction-limited spot with radius 0.61 λ /sinα is obtained, where λ is the wavelength and α is the semiangle of the beam's convergence cone. However, spots with much smaller features can be obtained at the focal plane when the lens is illuminated by an appropriately structured beam. Whereas this concept is known for light beams, here, we show how to realize it for a massive-particle wave function, namely, a free electron. We experimentally demonstrate an electron central spot of radius 106 pm, which is more than two times smaller than the diffraction limit of the experimental setup used. In addition, we demonstrate that this central spot can be structured by adding orbital angular momentum to it. The resulting superoscillating vortex beam has a smaller dark core with respect to a regular vortex beam. This family of electron beams having hot spots with arbitrarily small features and tailored structures could be useful for studying electron-matter interactions with subatomic resolution.

  4. Interpreting the wave function of the Universe.

    Science.gov (United States)

    Tipler, F. J.

    The Many-Worlds Interpretation of quantum mechanics is used to determine the meaning of the universal wave function of quantum cosmology. More precisely, the Many-Worlds Interpretation is used to distinguish those quantities in quantum cosmology which are measureable, and hence physically meaningful, from those which are not. A number of rather surprising conclusions are drawn from the analysis. All conclusions are illustrated with a closed Friedmann universe quantized in conformal time. The author's quantization procedure allows only one solution to Schrödinger's equation, and this solution solves the Flatness Problem. He shows that the ADM quantization method plus the Hartle-Hawking initial foundary condition gives the same result.

  5. Intercellular Ca2+ Waves: Mechanisms and Function

    Science.gov (United States)

    Sanderson, Michael J.

    2012-01-01

    Intercellular calcium (Ca2+) waves (ICWs) represent the propagation of increases in intracellular Ca2+ through a syncytium of cells and appear to be a fundamental mechanism for coordinating multicellular responses. ICWs occur in a wide diversity of cells and have been extensively studied in vitro. More recent studies focus on ICWs in vivo. ICWs are triggered by a variety of stimuli and involve the release of Ca2+ from internal stores. The propagation of ICWs predominately involves cell communication with internal messengers moving via gap junctions or extracellular messengers mediating paracrine signaling. ICWs appear to be important in both normal physiology as well as pathophysiological processes in a variety of organs and tissues including brain, liver, retina, cochlea, and vascular tissue. We review here the mechanisms of initiation and propagation of ICWs, the key intra- and extracellular messengers (inositol 1,4,5-trisphosphate and ATP) mediating ICWs, and the proposed physiological functions of ICWs. PMID:22811430

  6. Tunnelling matrix elements with Gutzwiller wave functions

    Energy Technology Data Exchange (ETDEWEB)

    Di Ciolo, Andrea; Tocchio, Luca F.; Gros, Claudius [Institut fuer Theoretische Physik, Goethe Universitaet Frankfurt, Frankfurt Am Main (Germany)

    2011-07-01

    We use a generalized Gutzwiller approach, in order to study projected particle (hole) excitations for superconducting systems and systems with antiferromagnetic (AFM) order. As in the standard Gutzwiller scheme the effects of the strong electronic correlations are given via the suppression of the site double occupancy; for our computations it is helpful to consider a lattice with a reservoir site unaffected by this suppression of the double occupancy. In this approach we obtain the probabilities for the tunnelling of a particle (hole) into the projected state. Our results are due only to the physical properties of the trial state and not to the choice of a specifical Hamiltonian: in this sense, they are model-independent but not universal, because they rely on the features of the chosen Gutzwiller wave function (projected Fermi Sea, BCS superconductor, AFM..) The accuracy and the reliability of our analytical approximation is tested using the Variational Monte Carlo. Possible comparisons with tunnelling experiments are discussed.

  7. Collapsed Lung

    Science.gov (United States)

    A collapsed lung happens when air enters the pleural space, the area between the lung and the chest wall. If it is a ... is called pneumothorax. If only part of the lung is affected, it is called atelectasis. Causes of ...

  8. Computer network defense through radial wave functions

    Science.gov (United States)

    Malloy, Ian J.

    The purpose of this research is to synthesize basic and fundamental findings in quantum computing, as applied to the attack and defense of conventional computer networks. The concept focuses on uses of radio waves as a shield for, and attack against traditional computers. A logic bomb is analogous to a landmine in a computer network, and if one was to implement it as non-trivial mitigation, it will aid computer network defense. As has been seen in kinetic warfare, the use of landmines has been devastating to geopolitical regions in that they are severely difficult for a civilian to avoid triggering given the unknown position of a landmine. Thus, the importance of understanding a logic bomb is relevant and has corollaries to quantum mechanics as well. The research synthesizes quantum logic phase shifts in certain respects using the Dynamic Data Exchange protocol in software written for this work, as well as a C-NOT gate applied to a virtual quantum circuit environment by implementing a Quantum Fourier Transform. The research focus applies the principles of coherence and entanglement from quantum physics, the concept of expert systems in artificial intelligence, principles of prime number based cryptography with trapdoor functions, and modeling radio wave propagation against an event from unknown parameters. This comes as a program relying on the artificial intelligence concept of an expert system in conjunction with trigger events for a trapdoor function relying on infinite recursion, as well as system mechanics for elliptic curve cryptography along orbital angular momenta. Here trapdoor both denotes the form of cipher, as well as the implied relationship to logic bombs.

  9. The effect of divalent ions on the elasticity and pore collapse of chalk evaluated from compressional wave velocity and low-field Nuclear Magnetic Resonance (NMR)

    DEFF Research Database (Denmark)

    Katika, Konstantina; Addassi, Mouadh; Alam, Mohammad Monzurul

    2015-01-01

    The effects of divalent ions on the elasticity and the pore collapse of chalk were studied through rock-mechanical testing and low-field Nuclear Magnetic Resonance (NMR) measurements. Chalk samples saturated with deionized water and brines containing sodium, magnesium, calcium and sulfate ions were...... subjected to petrophysical experiments, rock mechanical testing and low-field NMR spectroscopy. Petrophysical characterization involving ultrasonic elastic wave velocities in unconfined conditions, porosity and permeability measurements, specific surface and carbonate content determination and backscatter...... electron microscopy of the materials were conducted prior to the experiments. The iso-frame model was used to predict the bulk moduli in dry and saturated conditions from the compressional modulus of water-saturated rocks. The effective stress coefficient, as introduced by Biot, was also determined from...

  10. A New Multi-Dimensional General Relativistic Neutrino Hydrodynamics Code of Core-Collapse Supernovae III. Gravitational Wave Signals from Supernova Explosion Models

    CERN Document Server

    Mueller, Bernhard; Marek, Andreas

    2012-01-01

    We present a detailed theoretical analysis of the gravitational-wave (GW) signal of the post-bounce evolution of core-collapse supernovae (SNe), employing for the first time relativistic, two-dimensional (2D) explosion models with multi-group, three-flavor neutrino transport based on the ray-by-ray-plus approximation. The waveforms reflect the accelerated mass motions associated with the characteristic evolutionary stages that were also identified in previous works: A quasi-periodic modulation by prompt postshock convection is followed by a phase of relative quiescence before growing amplitudes signal violent hydrodynamical activity due to convection and the standing accretion shock instability during the accretion period of the stalled shock. Finally, a high-frequency, low-amplitude variation from proto-neutron star (PNS) convection below the neutrinosphere appears superimposed on the low-frequency trend associated with the aspherical expansion of the SN shock after the onset of the explosion. Relativistic e...

  11. Approximate Stream Function wavemaker theory for highly non-linear waves in wave flumes

    DEFF Research Database (Denmark)

    Zhang, H.W.; Schäffer, Hemming Andreas

    2007-01-01

    An approximate Stream Function wavemaker theory for highly non-linear regular waves in flumes is presented. This theory is based on an ad hoe unified wave-generation method that combines linear fully dispersive wavemaker theory and wave generation for non-linear shallow water waves. This is done...... by applying a dispersion correction to the paddle position obtained for non-linear long waves. The method is validated by a number of wave flume experiments while comparing with results of linear wavemaker theory, second-order wavemaker theory and Cnoidal wavemaker theory within its range of application....

  12. Influence of Generalized (r, q) Distribution Function on Electrostatic Waves

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Non-Maxwellian particle distribution functions possessing high energy tail and shoulder in the profile of distribution function considerably change the damping characteristics of the waves. In the present paper Landau damping ofelectron plasma (Langmuir) waves and ion-acoustic waves in a hot, isotropic, unmagnetized plasma is studied with the generalized (r, q) distribution function. The results show that for the Langmuir oscillations Landau damping becomes severe as the spectral index r or q reduces. However, for the ion-acoustic waves Landau damping is more sensitive to the ion temperature than the spectral indices.

  13. Functional evolution of quantum cylindrical waves

    CERN Document Server

    Cho, D H J; Cho, Demian H.J.; Varadarajan, Madhavan

    2006-01-01

    Kucha{\\v{r}} showed that the quantum dynamics of (1 polarization) cylindrical wave solutions to vacuum general relativity is determined by that of a free axially-symmetric scalar field along arbitrary axially-symmetric foliations of a fixed flat 2+1 dimensional spacetime. We investigate if such a dynamics can be defined {\\em unitarily} within the standard Fock space quantization of the scalar field. Evolution between two arbitrary slices of an arbitrary foliation of the flat spacetime can be built out of a restricted class of evolutions (and their inverses). The restricted evolution is from an initial flat slice to an arbitrary (in general, curved) slice of the flat spacetime and can be decomposed into (i) `time' evolution in which the spatial Minkowskian coordinates serve as spatial coordinates on the initial and the final slice, followed by (ii) the action of a spatial diffeomorphism of the final slice on the data obtained from (i). We show that although the functional evolution of (i) is unitarily implemen...

  14. Wave-function reconstruction in a graded semiconductor superlattice

    DEFF Research Database (Denmark)

    Lyssenko, V. G.; Hvam, Jørn Märcher; Meinhold, D.

    2004-01-01

    We reconstruct a test wave function in a strongly coupled, graded well-width superlattice by resolving the spatial extension of the interband polarisation and deducing the wave function employing non-linear optical spectroscopy. The graded gap superlattice allows us to precisely control the dista...

  15. On quantum mechanical phase-space wave functions

    DEFF Research Database (Denmark)

    Wlodarz, Joachim J.

    1994-01-01

    An approach to quantum mechanics based on the notion of a phase-space wave function is proposed within the Weyl-Wigner-Moyal representation. It is shown that the Schrodinger equation for the phase-space wave function is equivalent to the quantum Liouville equation for the Wigner distribution...

  16. Real no-boundary wave function in Lorentzian quantum cosmology

    Science.gov (United States)

    Dorronsoro, J. Diaz; Halliwell, J. J.; Hartle, J. B.; Hertog, T.; Janssen, O.

    2017-08-01

    It is shown that the standard no-boundary wave function has a natural expression in terms of a Lorentzian path integral with its contour defined by Picard-Lefschetz theory. The wave function is real, satisfies the Wheeler-DeWitt equation and predicts an ensemble of asymptotically classical, inflationary universes with nearly-Gaussian fluctuations and with a smooth semiclassical origin.

  17. Trial wave functions for High-Pressure Metallic Hydrogen

    CERN Document Server

    Pierleoni, Carlo; Morales, Miguel A; Ceperley, David M; Holzmann, Markus

    2007-01-01

    Many body trial wave functions are the key ingredient for accurate Quantum Monte Carlo estimates of total electronic energies in many electron systems. In the Coupled Electron-Ion Monte Carlo method, the accuracy of the trial function must be conjugated with the efficiency of its evaluation. We report recent progress in trial wave functions for metallic hydrogen implemented in the Coupled Electron-Ion Monte Carlo method. We describe and characterize several types of trial functions of increasing complexity in the range of the coupling parameter $1.0 \\leq r_s \\leq1.55$. We report wave function comparisons for disordered protonic configurations and preliminary results for thermal averages.

  18. Collapsing Containers.

    Science.gov (United States)

    Brown, Justina L.; Battino, Rubin

    1994-01-01

    Describes variations on atmospheric pressure demonstrations and some systematic studies. Demonstrations use steam, generated either externally or internally to the container, to sweep out residual air. Preferred vessels collapsed slowly. Demonstrations use plastic milk jugs set in layers of aluminum foil, pop bottles immersed in 4-L beakers…

  19. Flavour Mixing, Gauge Invariance and Wave-function Renormalisation

    CERN Document Server

    Espriu, Doménec; Talavera, P

    2002-01-01

    We clarify some aspects of the LSZ formalism and wave function renormalisation for unstable particles in the presence of electroweak interactions when mixing and CP violation are considered. We also analyse the renormalisation of the CKM mixing matrix which is closely related to wave function renormalisation. We critically review earlier attempts to define a set of "on-shell" wave function renormalisation constants. With the aid of an extensive use of the Nielsen identities complemented by explicit calculations we corroborate that the counter term for the CKM mixing matrix must be explicitly gauge independent and demonstrate that the commonly used prescription for the wave function renormalisation constants leads to gauge parameter dependent amplitudes, even if the CKM counter term is gauge invariant as required. We show that a proper LSZ-compliant prescription leads to gauge independent amplitudes. The resulting wave function renormalisation constants necessarily possess absorptive parts, but we verify that ...

  20. Separation of different wave components in the Bethe–Salpeter wave function

    Indian Academy of Sciences (India)

    Jiao-Kai Chen

    2011-03-01

    The scalar products of polarization tensor and unit vectors are presented explicitly in spherical coordinate system expanded in terms of spherical harmonic functions. By applying the obtained formulae, different wave components in the Salpeter wave function can be shown explicitly, and the results are consistent with the results obtained by - coupling analysis. The cancelation formula is given, by which the terms with pure = + 1 wave components in the Salpeter wave function for the bound state with = (-1) can be obtained by separating the = - 1 wave components from mixing terms. This separation provides the basis for studying higher-order contributions from the coupling of = - 1 and + 1 wave states, and for solving the Salpeter equation exactly without approximation.

  1. Collapse of ordered spatial pattern in neuronal network

    Science.gov (United States)

    Song, Xinlin; Wang, Chunni; Ma, Jun; Ren, Guodong

    2016-06-01

    Spatiotemporal systems can emerge some regular spatial patterns due to self organization or under external periodical pacing while external attack or intrinsic collapse can destroy the regularity in the spatial system. For an example, the electrical activities of neurons in nervous system show regular spatial distribution under appropriate coupling and connection. It is believed that distinct regularity could be induced in the media by appropriate forcing or feedback, while a diffusive collapse induced by continuous destruction can cause breakdown of the media. In this paper, the collapse of ordered spatial distribution is investigated in a regular network of neurons (Morris-Lecar, Hindmarsh-Rose) in two-dimensional array. A stable target wave is developed regular spatial distribution emerges by imposing appropriate external forcing with diversity, or generating heterogeneity (parameter diversity in space). The diffusive invasion could be produced by continuous parameter collapse or switch in local area, e.g, the diffusive poisoning in ion channels of potassium in Morris-Lecar neurons causes breakdown in conductance of channels. It is found that target wave-dominated regularity can be suppressed when the collapsed area is diffused in random. Statistical correlation functions for sampled nodes (neurons) are defined to detect the collapse of ordered state by series analysis.

  2. EVANS FUNCTIONS AND ASYMPTOTIC STABILITY OF TRAVELING WAVE SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper studies the asymptotic stability of traveling wave solutions of nonlinear systems of integral-differential equations. It has been established that linear stability of traveling waves is equivalent to nonlinear stability and some “nice structure” of the spectrum of an associated operator implies the linear stability. By using the method of variation of parameter, the author defines some complex analytic function, called the Evans function. The zeros of the Evans function corresponds to the eigenvalues of the associated linear operator. By calculating the zeros of the Evans function, the asymptotic stability of the travling wave solutions is established.

  3. Density functional calculations of spin-wave dispersion curves.

    Science.gov (United States)

    Kleinman, Leonard; Niu, Qian

    1998-03-01

    Extending the density functional method of Kubler et al( J. Kubler et al, J. Phys. F 18, 469 (1983) and J. Phys. Condens. Matter 1, 8155 (1989). ) for calcuating spin density wave ground states (but not making their atomic sphere approximation which requires a constant spin polarization direction in each WS sphere) we dicuss the calculation of frozen spin-wave eigenfunctions and their total energies. From these and the results of Niu's talk, we describe the calculation of spin-wave frequencies.

  4. Collapsed City

    DEFF Research Database (Denmark)

    Allen, Nacho Ruiz

    2015-01-01

    Currently, when the socio-economic circumstances seem to announce another change of cultural paradigm for the 21st century, the interest in the urban fact seems to have been renewed in architecture. However, this is no longer focused on models of growth and efficiency, as happened in the 70s....... Nowadays the situation is quite different. The enthusiasm for the economic growth which had characterized late capitalism and much of the postmodern cultural production has disappeared, and has given place to some global unease on a possible system collapse. Once the economy does not grow, but threatens...... with its imminent breakdown, the architectural interests have shifted to urban environments like Tokyo, Detroit, Lagos or Rio de Janeiro; places that demonstrate, somehow, an urban culture of collapse....

  5. Modular matrices from universal wave-function overlaps in Gutzwiller-projected parton wave functions

    Science.gov (United States)

    Mei, Jia-Wei; Wen, Xiao-Gang

    2015-03-01

    We implement the universal wave-function overlap (UWFO) method to extract modular S and T matrices for topological orders in Gutzwiller-projected parton wave functions (GPWFs). The modular S and T matrices generate a projective representation of S L (2 ,Z ) on the degenerate-ground-state Hilbert space on a torus and may fully characterize the 2+1D topological orders, i.e., the quasiparticle statistics and chiral central charge (up to E8 bosonic quantum Hall states). We use the variational Monte Carlo method to computed the S and T matrices of the chiral spin liquid (CSL) constructed by the GPWF on the square lattice, and we confirm that the CSL carries the same topological order as the ν =1/2 bosonic Laughlin state. We find that the nonuniversal exponents in the UWFO can be small, and direct numerical computation can be applied on relatively large systems. The UWFO may be a powerful method to calculate the topological order in GPWFs.

  6. Special software for computing the special functions of wave catastrophes

    Directory of Open Access Journals (Sweden)

    Andrey S. Kryukovsky

    2015-01-01

    Full Text Available The method of ordinary differential equations in the context of calculating the special functions of wave catastrophes is considered. Complementary numerical methods and algorithms are described. The paper shows approaches to accelerate such calculations using capabilities of modern computing systems. Methods for calculating the special functions of wave catastrophes are considered in the framework of parallel computing and distributed systems. The paper covers the development process of special software for calculating of special functions, questions of portability, extensibility and interoperability.

  7. On the interpretation of wave function overlaps in quantum dots

    DEFF Research Database (Denmark)

    Stobbe, Søren; Hvam, Jørn Märcher; Lodahl, Peter

    2011-01-01

    that the electron and the hole are located at the same point or region in space, i.e., they must coincide spatially to recombine. Here, we show that this interpretation is not correct even loosely speaking. By general mathematical considerations we compare the envelope wave function overlap, the exchange overlap......The spontaneous emission rate of excitons strongly confined in quantum dots (QDs) is proportional to the overlap integral of electron and hole envelope wave functions. A common and intuitive interpretation of this result is that the spontaneous emission rate is proportional to the probability...... compare our qualitative predictions with recent measurements of the wave function overlap and find good agreement....

  8. Boundary conditions on internal three-body wave functions

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Kevin A.; Littlejohn, Robert G.

    1999-10-01

    For a three-body system, a quantum wave function {Psi}{sub m}{sup {ell}} with definite {ell} and m quantum numbers may be expressed in terms of an internal wave function {chi}{sub k}{sup {ell}} which is a function of three internal coordinates. This article provides necessary and sufficient constraints on {chi}{sub k}{sup {ell}} to ensure that the external wave function {Psi}{sub k}{sup {ell}} is analytic. These constraints effectively amount to boundary conditions on {chi}{sub k}{sup {ell}} and its derivatives at the boundary of the internal space. Such conditions find similarities in the (planar) two-body problem where the wave function (to lowest order) has the form r{sup |m|} at the origin. We expect the boundary conditions to prove useful for constructing singularity free three-body basis sets for the case of nonvanishing angular momentum.

  9. Wave packet construction in three-dimensional quantum billiards: Visualizing the closed orbit, collapse and revival of wave packets in the cubical billiard

    Indian Academy of Sciences (India)

    Maninder Kaur; Bindiya Arora; Mahmood Mian

    2016-01-01

    We examine the dynamical evolution of wave packets in a cubical billiard where three quantum numbers (, , ) determine its energy spectrum and consequently its dynamical behaviour. We have constructed the wave packet in the cubical billiard and have observed its time evolution for various closed orbits. The closed orbits are possible for certain specific values of quantum numbers (, , ) and initial momenta (, , ). We observe that a cubical billiard exhibits degenerate energy levels and the path lengths of the closed orbits for these degenerate energy levels are identical. In spite of the identical path lengths, the shapes of the closed orbits for degenerate levels are different and depend upon angles and which we term as the sweep and the elevation angles, respectively. These degenerate levels owe their origin to the symmetries prevailing in the cubical billiard and these levels disappear completely or partially for a parallelepiped billiard as the symmetry breaks due to commensurate or incommensurate ratio of sides.

  10. The Green-function transform and wave propagation

    Directory of Open Access Journals (Sweden)

    Colin eSheppard

    2014-11-01

    Full Text Available Fourier methods well known in signal processing are applied to three-dimensional wave propagation problems. The Fourier transform of the Green function, when written explicitly in terms of a real-valued spatial frequency, consists of homogeneous and inhomogeneous components. Both parts are necessary to result in a pure out-going wave that satisfies causality. The homogeneous component consists only of propagating waves, but the inhomogeneous component contains both evanescent and propagating terms. Thus we make a distinction between inhomogeneous waves and evanescent waves. The evanescent component is completely contained in the region of the inhomogeneous component outside the k-space sphere. Further, propagating waves in the Weyl expansion contain both homogeneous and inhomogeneous components. The connection between the Whittaker and Weyl expansions is discussed. A list of relevant spherically symmetric Fourier transforms is given.

  11. The Green-function transform and wave propagation

    CERN Document Server

    Sheppard, Colin J R; Lin, Jiao

    2014-01-01

    Fourier methods well known in signal processing are applied to three-dimensional wave propagation problems. The Fourier transform of the Green function, when written explicitly in terms of a real-valued spatial frequency, consists of homogeneous and inhomogeneous components. Both parts are necessary to result in a pure out-going wave that satisfies causality. The homogeneous component consists only of propagating waves, but the inhomogeneous component contains both evanescent and propagating terms. Thus we make a distinction between inhomogenous waves and evanescent waves. The evanescent component is completely contained in the region of the inhomogeneous component outside the k-space sphere. Further, propagating waves in the Weyl expansion contain both homogeneous and inhomogeneous components. The connection between the Whittaker and Weyl expansions is discussed. A list of relevant spherically symmetric Fourier transforms is given.

  12. General Green's function formalism for layered systems: Wave function approach

    Science.gov (United States)

    Zhang, Shu-Hui; Yang, Wen; Chang, Kai

    2017-02-01

    The single-particle Green's function (GF) of mesoscopic structures plays a central role in mesoscopic quantum transport. The recursive GF technique is a standard tool to compute this quantity numerically, but it lacks physical transparency and is limited to relatively small systems. Here we present a numerically efficient and physically transparent GF formalism for a general layered structure. In contrast to the recursive GF that directly calculates the GF through the Dyson equations, our approach converts the calculation of the GF to the generation and subsequent propagation of a scattering wave function emanating from a local excitation. This viewpoint not only allows us to reproduce existing results in a concise and physically intuitive manner, but also provides analytical expressions of the GF in terms of a generalized scattering matrix. This identifies the contributions from each individual scattering channel to the GF and hence allows this information to be extracted quantitatively from dual-probe STM experiments. The simplicity and physical transparency of the formalism further allows us to treat the multiple reflection analytically and derive an analytical rule to construct the GF of a general layered system. This could significantly reduce the computational time and enable quantum transport calculations for large samples. We apply this formalism to perform both analytical analysis and numerical simulation for the two-dimensional conductance map of a realistic graphene p -n junction. The results demonstrate the possibility of observing the spatially resolved interference pattern caused by negative refraction and further reveal a few interesting features, such as the distance-independent conductance and its quadratic dependence on the carrier concentration, as opposed to the linear dependence in uniform graphene.

  13. Improved Wave-vessel Transfer Functions by Uncertainty Modelling

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; Fønss Bach, Kasper; Iseki, Toshio

    2016-01-01

    This paper deals with uncertainty modelling of wave-vessel transfer functions used to calculate or predict wave-induced responses of a ship in a seaway. Although transfer functions, in theory, can be calculated to exactly reflect the behaviour of the ship when exposed to waves, uncertainty in input...... variables, notably speed, draft and relative wave eading, often compromises results. In this study, uncertling is applied to improve theoretically calculated transfer functions, so they better fit the corresponding experimental, full-scale ones. Based on a vast amount of full-scale measurements data......, it is shown that uncertainty modelling can be successfully used to improve accuracy (and reliability) of theoretical transfer functions....

  14. Alignment of wave functions for angular momentum projection

    CERN Document Server

    Taniguchi, Yasutaka

    2016-01-01

    Angular momentum projection is used to obtain eigen states of angular momentum from general wave functions. Multi-configuration mixing calculation with angular momentum projection is an important microscopic method in nuclear physics. For accurate multi-configuration mixing calculation with angular momentum projection, concentrated distribution of $z$ components $K$ of angular momentum in the body-fixed frame ($K$-distribution) is favored. Orientation of wave functions strongly affects $K$-distribution. Minimization of variance of $\\hat{J}_z$ is proposed as an alignment method to obtain wave functions that have concentrated $K$-distribution. Benchmark calculations are performed for $\\alpha$-$^{24}$Mg cluster structure, triaxially superdeformed states in $^{40}$Ar, and Hartree-Fock states of some nuclei. The proposed alignment method is useful and works well for various wave functions to obtain concentrated $K$-distribution.

  15. Road Collapse in Magnum

    NARCIS (Netherlands)

    Wilschut, A.N.; van Zwol, Roelof; Flokstra, Jan; Brasa, Niek; Quak, Wilko

    1998-01-01

    This paper describes the implementation of a triangulation based collapse algorithm in the general-purpose object oriented DBMS Magnum. The contribution of the paper is twofold. First, we show that true integration of complex spatial functionality in a DBMS can be achieved. Second, we worked out a c

  16. Calculation of electron wave functions and refractive index of Ne

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The radial wave functions of inner electron shell and outer electron shell of a Ne atom were obtained by the approximate analytical method and tested by calculating the ground state energy of the Ne atom. The equivalent volume of electron cloud and the refractive index of Ne were calculated. The calculated refractive index agrees well with the experimental result. Relationship between the refractive index and the wave function of Ne was discovered.

  17. Delayed collapses of BECs in relation to AdS gravity

    CERN Document Server

    Biasi, Anxo F; Paredes, Angel

    2016-01-01

    We numerically investigate spherically symmetric collapses in the Gross-Pitaevskii equation with attractive nonlinearity in a harmonic potential. Even below threshold for direct collapse, the wave function bounces off from the origin and may eventually become singular after a number of oscillations in the trapping potential. This is reminiscent of the evolution of Einstein gravity sourced by a scalar field in Anti-de Sitter space where collapse corresponds to black hole formation. We carefully examine the long time evolution of the wave function for continuous families of initial states in order to sharpen out this coincidence which may bring new insights in both directions. On one hand, we comment on possible implications for the so-called Bosenova collapses in cold atom Bose-Einstein condensates. On the other hand, Gross-Pitaevskii provides a toy model to study the relevance of either the resonance conditions or the nonlinearity for the problem of Anti-de Sitter instability.

  18. Do Neutrino Wave Functions Overlap and Does it Matter?

    CERN Document Server

    Li, Cheng-Hsien

    2016-01-01

    Studies of neutrinos commonly ignore anti-symmetrization of their wave functions. This implicitly assumes that either spatial wave functions for neutrinos with approximately the same momentum do not overlap or their overlapping has no measurable consequences. We examine these assumptions by considering the evolution of three-dimensional neutrino wave packets (WPs). We find that it is perfectly adequate to treat accelerator and reactor neutrinos as separate WPs for typical experimental setup. While solar and supernova neutrinos correspond to overlapping WPs, they can be treated effectively as non-overlapping for analyses of their detection.

  19. Wave packet construction in three-dimensional quantum billiards: Visualizing the closed orbit, collapse and revival of wave packets in the cubical billiard

    CERN Document Server

    Kaur, Maninder; Main, M

    2015-01-01

    We examine the dynamical evolution of wave packets in a cubical billiard where three quantum numbers ($n_x,n_y,n_z$) determine its energy spectrum and consequently its dynamical behavior. We have constructed the wave packet in the cubical billiard and have observed its time evolution for various closed orbits. The closed orbits are possible for certain specific values of quantum numbers ($n_x,n_y,n_z$) and initial momenta ($k_x,k_y,k_z$). We observe that a cubical billiard exhibits degenerate energy levels and the path lengths of the closed orbits for these degenerate energy levels are identical. In spite of the identical path lengths, the shapes of the closed orbits for degenerate levels are different and depend upon angles $\\theta$ and $\\phi$ which we term as the sweep and the elevation angle respectively. These degenerate levels owe their origin to the symmetries prevailing in the cubical billiard and degenerate levels disappear completely or partially for a parallelepiped billiard as the symmetry breaks d...

  20. Factorized molecular wave functions: Analysis of the nuclear factor

    Energy Technology Data Exchange (ETDEWEB)

    Lefebvre, R., E-mail: roland.lefebvre@u-psud.fr [Institut des Sciences Moléculaires d’ Orsay, Bâtiment 350, UMR8214, CNRS- Université. Paris-Sud, 91405 Orsay, France and Sorbonne Universités, UPMC Univ Paris 06, UFR925, F-75005 Paris (France)

    2015-06-07

    The exact factorization of molecular wave functions leads to nuclear factors which should be nodeless functions. We reconsider the case of vibrational perturbations in a diatomic species, a situation usually treated by combining Born-Oppenheimer products. It was shown [R. Lefebvre, J. Chem. Phys. 142, 074106 (2015)] that it is possible to derive, from the solutions of coupled equations, the form of the factorized function. By increasing artificially the interstate coupling in the usual approach, the adiabatic regime can be reached, whereby the wave function can be reduced to a single product. The nuclear factor of this product is determined by the lowest of the two potentials obtained by diagonalization of the potential matrix. By comparison with the nuclear wave function of the factorized scheme, it is shown that by a simple rectification, an agreement is obtained between the modified nodeless function and that of the adiabatic scheme.

  1. Ultrarelativistic quasiclassical wave functions in strong laser and atomic fields

    CERN Document Server

    Di Piazza, A

    2014-01-01

    The problem of an ultrarelativistic charge in the presence of an atomic and a plane-wave field is investigated in the quasiclassical regime by including exactly the effects of both background fields. Starting from the quasiclassical Green's function obtained in [Phys. Lett. B \\textbf{717}, 224 (2012)], the corresponding in- and out-wave functions are derived in the experimentally relevant case of the particle initially counterpropagating with respect to the plane wave. The knowledge of these electron wave functions opens the possibility of investigating a variety of problems in strong-field QED, where both the atomic field and the laser field are strong enough to be taken into account exactly from the beginning in the calculations.

  2. Donor wave functions in Si gauged by STM images

    Science.gov (United States)

    Saraiva, A. L.; Salfi, J.; Bocquel, J.; Voisin, B.; Rogge, S.; Capaz, Rodrigo B.; Calderón, M. J.; Koiller, Belita

    2016-01-01

    The triumph of effective mass theory in describing the energy spectrum of dopants does not guarantee that the model wave functions will withstand an experimental test. Such wave functions have recently been probed by scanning tunneling spectroscopy, revealing localized patterns of resonantly enhanced tunneling currents. We show that the shape of the conducting splotches resembles a cut through Kohn-Luttinger (KL) hydrogenic envelopes, which modulate the interfering Bloch states of conduction electrons. All the nonmonotonic features of the current profile are consistent with the charge density fluctuations observed between successive {001 } atomic planes, including a counterintuitive reduction of the symmetry—a heritage of the lowered point group symmetry at these planes. A model-independent analysis of the diffraction figure constrains the value of the electron wave vector to k0=(0.82 ±0.03 ) (2 π /aSi) . Unlike prior measurements, averaged over a sizable density of electrons, this estimate is obtained directly from isolated electrons. We further investigate the model-specific anisotropy of the wave function envelope, related to the effective mass anisotropy. This anisotropy appears in the KL variational wave function envelope as the ratio between Bohr radii b /a . We demonstrate that the central-cell-corrected estimates for this ratio are encouragingly accurate, leading to the conclusion that the KL theory is a valid model not only for energies but for wave functions as well.

  3. Directional Wave Spectra Using Normal Spreading Function

    Science.gov (United States)

    1985-03-01

    energy spectral density function U. g. Army Engineer Waternays Experiment Station. Coastal Engineering Research Center P. 0. lox 631, Vicksburg...Z39-18 D(f,e) = spreading function E (f,(3) = directional spectral density function f = frequency in cycles per second 8 = direction in radians...of this assumption depends on the narrow bandedness of the energy spectral density function . For fairly narrow spectra (e.g., a swell train), the

  4. The effect of meson wave function on heavy-quark fragmentation function

    Energy Technology Data Exchange (ETDEWEB)

    Moosavi Nejad, S.M. [Yazd University, Faculty of Physics (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, Tehran (Iran, Islamic Republic of)

    2016-05-15

    We calculate the process-independent fragmentation functions (FFs) for a heavy quark to fragment into heavy mesons considering the effects of meson wave function. In all previous works, where the FFs of heavy mesons or heavy baryons were calculated, a delta function form was approximated for the wave function of hadrons. Here, for the first time, we consider a typical mesonic wave function which is different from the delta function and is the nonrelativistic limit of the solution of Bethe-Salpeter equation with the QCD kernel. We present our numerical results for the heavy FFs and show how the proposed wave function improves the previous results. As an example, we focus on the fragmentation function for c-quark to split into S-wave D{sup 0} -meson and compare our results with experimental data from BELLE and CLEO. (orig.)

  5. Parametric dependence of ocean wave-radar modulation transfer functions

    Science.gov (United States)

    Plant, W. J.; Keller, W. C.; Cross, A.

    1983-01-01

    Microwave techniques at X and L band were used to determine the dependence of ocean-wave radar modulation transfer functions (MTFs) on various environmental and radar parameters during the Marine Remote Sensing experiment of 1979 (MARSEN 79). These MIF are presented, as are coherence functions between the AM and FM parts of the backscattered microwave signal. It is shown that they both depend on several of these parameters. Besides confirming many of the properties of transfer functions reported by previous authors, indications are found that MTFs decrease with increasing angle between wave propagation and antenna-look directions but are essentially independent of small changes in air-sea temperature difference. However, coherence functions are much smaller when the antennas are pointed perpendicular to long waves. It is found that X band transfer functions measured with horizontally polarized microwave radiation have larger magnitudes than those obtained by using vertical polarization.

  6. Extracting Information from the Atom-Laser Wave Function UsingInterferometric Measurement with a Laser Standing-Wave Grating

    Institute of Scientific and Technical Information of China (English)

    刘正东; 武强; 曾亮; 林宇; 朱诗尧

    2001-01-01

    The reconstruction of the atom-laser wave function is performed using an interferometric measurement with a standing-wave grating, and the results of this scheme are studied. The relations between the measurement data and the atomic wave function are also presented. This scheme is quite applicable and effectively avoids the initial random phase problem of the method that employs the laser running wave. The information which is encoded in the atom-laser wave is extracted.

  7. Rapidity resummation for B-meson wave functions

    Directory of Open Access Journals (Sweden)

    Shen Yue-Long

    2014-01-01

    Full Text Available Transverse-momentum dependent (TMD hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity ζ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for B-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic B-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of B-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive B-meson decays. The phenomenological consequence of rapidity-resummation improved B-meson wave functions is further discussed in the context of B → π transition form factors at large hadronic recoil.

  8. Rossby wave Green's functions in an azimuthal wind

    Science.gov (United States)

    Webb, G. M.; Duba, C. T.; Hu, Q.

    2016-05-01

    Green's functions for Rossby waves in an azimuthal wind are obtained, in which the stream-function $\\psi$ depends on $r$, $\\phi$ and $t$, where $r$ is cylindrical radius and $\\phi$ is the azimuthal angle in the $\\beta$-plane relative to the easterly direction, in which the $x$-axis points east and the $y$-axis points north. The Rossby wave Green's function with no wind is obtained using Fourier transform methods, and is related to the previously known Green's function obtained for this case, which has a different but equivalent form to the Green's function obtained in the present paper. We emphasize the role of the wave eikonal solution, which plays an important role in the form of the solution. The corresponding Green's function for a rotating wind with azimuthal wind velocity ${\\bf u}=\\Omega r{\\bf e}_\\phi$ ($\\Omega=$const.) is also obtained by Fourier methods, in which the advective rotation operator in position space is transformed to a rotation operator in ${\\bf k}$ transform space. The finite Rossby deformation radius is included in the analysis. The physical characteristics of the Green's functions are delineated and applications are discussed. In the limit as $\\Omega\\to 0$, the rotating wind Green's function reduces to the Rossby wave Green function with no wind.

  9. New approach to folding with the Coulomb wave function

    Energy Technology Data Exchange (ETDEWEB)

    Blokhintsev, L. D.; Savin, D. A. [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Kadyrov, A. S. [Department of Physics, Astronomy and Medical Radiation Sciences, Curtin University, GPO Box U1987, Perth 6845 (Australia); Mukhamedzhanov, A. M. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States)

    2015-05-15

    Due to the long-range character of the Coulomb interaction theoretical description of low-energy nuclear reactions with charged particles still remains a formidable task. One way of dealing with the problem in an integral-equation approach is to employ a screened Coulomb potential. A general approach without screening requires folding of kernels of the integral equations with the Coulomb wave. A new method of folding a function with the Coulomb partial waves is presented. The partial-wave Coulomb function both in the configuration and momentum representations is written in the form of separable series. Each term of the series is represented as a product of a factor depending only on the Coulomb parameter and a function depending on the spatial variable in the configuration space and the momentum variable if the momentum representation is used. Using a trial function, the method is demonstrated to be efficient and reliable.

  10. Efficient wave-function matching approach for quantum transport calculations

    DEFF Research Database (Denmark)

    Sørensen, Hans Henrik Brandenborg; Hansen, Per Christian; Petersen, Dan Erik;

    2009-01-01

    The wave-function matching (WFM) technique has recently been developed for the calculation of electronic transport in quantum two-probe systems. In terms of efficiency it is comparable to the widely used Green's function approach. The WFM formalism presented so far requires the evaluation of all ...

  11. Achieving a Collapsible, Strong, and Highly Thermally Conductive Film Based on Oriented Functionalized Boron Nitride Nanosheets and Cellulose Nanofiber.

    Science.gov (United States)

    Wu, Kai; Fang, Jinchao; Ma, Jinrui; Huang, Rui; Chai, Songgang; Chen, Feng; Fu, Qiang

    2017-09-06

    Boron nitride nanosheet (BNNS) films receive wide attention in both academia and industry because of their high thermal conductivity (TC) and good electrical insulation capability. However, the brittleness and low strength of the BNNS film largely limit its application. Herein, functionalized BNNSs (f-BNNSs) with a well-maintained in-plane crystalline structure were first prepared utilizing urea in the aqueous solution via ball-milling for the purpose of improving their stability in water and enhancing the interaction with the polymer matrix. Then, a biodegradable and highly thermally conductive film with an orderly oriented structure based on cellulose nanofibers (CNFs) and f-BNNSs was prepared just by simple vacuum-assisted filtration. The modification of the BNNS and the introduction of the CNF result in a better orientation of the f-BNNS, sufficient connection between f-BNNS themselves, and strong interaction between f-BNNS and CNF, which not only make the prepared composite film strong and tough but also possess higher in-plane TC. An increase of 70% in-plane TC, 63.2% tensile strength, and 77.8% elongation could be achieved for CNF/f-BNNS films, compared with that for CNF/BNNS films at the filler content of 70%. Although at such a high f-BNNS content, this composite film can be bended and folded. It is even more interesting to find that the in-plane TC could be greatly enhanced with the decrease of the thickness of the film, and a value of 30.25 W/m K can be achieved at the thickness of ∼30 μm for the film containing 70 wt % f-BNNS. We believe that this highly thermally conductive film with good strength and toughness could have potential applications in next-generation highly powerful and collapsible electronic devices.

  12. The role of the wave function in the GRW matter density theory

    Energy Technology Data Exchange (ETDEWEB)

    Egg, Matthias [University of Lausanne (Switzerland)

    2014-07-01

    Every approach to quantum mechanics postulating some kind of primitive ontology (e.g., Bohmian particles, a mass density field or flash-like collapse events) faces the challenge of clarifying the ontological status of the wave function. More precisely, one needs to spell out in what sense the wave function ''governs'' the behaviour of the primitive ontology, such that the empirical predictions of standard quantum mechanics are recovered. For Bohmian mechanics, this challenge has been addressed in recent papers by Belot and Esfeld et al. In my talk, I do the same for the matter density version of the Ghirardi-Rimini-Weber theory (GRWm). Doing so will highlight relevant similarities and differences between Bohmian mechanics and GRWm. The differences are a crucial element in the evaluation of the relative strengths and weaknesses of the two approaches, while the similarities can shed light on general characteristics of the primitive ontology approach, as opposed to other interpretative approaches to quantum mechanics.

  13. Niels Bohr on the wave function and the classical/quantum divide

    CERN Document Server

    Zinkernagel, Henrik

    2016-01-01

    It is well known that Niels Bohr insisted on the necessity of classical concepts in the account of quantum phenomena. But there is little consensus concerning his reasons, and what he exactly meant by this. In this paper, I re-examine Bohr's interpretation of quantum mechanics, and argue that the necessity of the classical can be seen as part of his response to the measurement problem. More generally, I attempt to clarify Bohr's view on the classical/quantum divide, arguing that the relation between the two theories is that of mutual dependence. An important element in this clarification consists in distinguishing Bohr's idea of the wave function as symbolic from both a purely epistemic and an ontological interpretation. Together with new evidence concerning Bohr's conception of the wave function collapse, this sets his interpretation apart from both standard versions of the Copenhagen interpretation, and from some of the reconstructions of his view found in the literature. I conclude with a few remarks on ho...

  14. Niels Bohr on the wave function and the classical/quantum divide

    Science.gov (United States)

    Zinkernagel, Henrik

    2016-02-01

    It is well known that Niels Bohr insisted on the necessity of classical concepts in the account of quantum phenomena. But there is little consensus concerning his reasons, and what he exactly meant by this. In this paper, I re-examine Bohr's interpretation of quantum mechanics, and argue that the necessity of the classical can be seen as part of his response to the measurement problem. More generally, I attempt to clarify Bohr's view on the classical/quantum divide, arguing that the relation between the two theories is that of mutual dependence. An important element in this clarification consists in distinguishing Bohr's idea of the wave function as symbolic from both a purely epistemic and an ontological interpretation. Together with new evidence concerning Bohr's conception of the wave function collapse, this sets his interpretation apart from both standard versions of the Copenhagen interpretation, and from some of the reconstructions of his view found in the literature. I conclude with a few remarks on how Bohr's ideas make much sense also when modern developments in quantum gravity and early universe cosmology are taken into account.

  15. Analytic Beyond-Mean-Field BEC Wave Functions

    Science.gov (United States)

    Dunn, Martin; Laing, W. Blake; Watson, Deborah K.; Loeser, John G.

    2006-05-01

    We present analytic N-body beyond-mean-field wave functions for Bose-Einstein condensates. This extends our previous beyond-mean-field energy calculations to the substantially more difficult problem of determining correlated N-body wave functions for a confined system. The tools used to achieve this have been carefully chosen to maximize the use of symmetry and minimize the dependence on numerical computation. We handle the huge number of interactions when N is large (˜N^2/2 two-body interactions) by bringing together three theoretical methods. These are dimensional perturbation theory, the FG method of Wilson et al, and the group theory of the symmetric group. The wave function is then used to derive the density profile of a condensate in a cylindrical trap.This method makes no assumptions regarding the form or strength of the interactions and is applicable to both small-N and large-N systems.

  16. Laws of Nature and the Reality of the Wave Function

    CERN Document Server

    Dorato, Mauro

    2015-01-01

    In this paper I review three different positions on the wave function, namely: nomological realism, dispositionalism, and configuration space realism by regarding as essential their capacity to account for the world of our experience. I conclude that the first two positions are committed to regard the wave function as an abstract entity. The third position will be shown to be a merely speculative attempt to derive a primitive ontology from a reified mathematical space. Without entering any discussion about nominalism, I conclude that an elimination of abstract entities from one's ontology commits one to instrumentalism about the wave function, a position that therefore is not as unmotivated as it has seemed to be to many philosophers.

  17. Propagation of Vortex Electron Wave Functions in a Magnetic Field

    CERN Document Server

    Gallatin, Gregg M

    2012-01-01

    The physics of coherent beams of photons carrying axial orbital angular momentum (OAM) is well understood and such beams, sometimes known as vortex beams, have found applications in optics and microscopy. Recently electron beams carrying very large values of axial OAM have been generated. In the absence of coupling to an external electromagnetic field the propagation of such vortex electron beams is virtually identical mathematically to that of vortex photon beams propagating in a medium with a homogeneous index of refraction. But when coupled to an external electromagnetic field the propagation of vortex electron beams is distinctly different from photons. Here we use the exact path integral solution to Schrodingers equation to examine the time evolution of an electron wave function carrying axial OAM. Interestingly we find that the nonzero OAM wave function can be obtained from the zero OAM wave function, in the case considered here, simply by multipling it by an appropriate time and position dependent pref...

  18. The nucleon wave function in light-front dynamics

    CERN Document Server

    Karmanov, V A

    1998-01-01

    The general spin structure of the relativistic nucleon wave function in the $3q$-model is found. It contains 16 spin components, in contrast to 8 ones known previously, since in a many-body system the parity conservation does not reduce the number of the components. The explicitly covariant form of the wave function automatically takes into account the relativistic spin rotations, without introducing any Melosh rotation matrices. It also reduces the calculations to the standard routine of the Dirac matrices and of the trace techniques. In examples of the proton magnetic moment and of the axial nucleon form factor, with a particular wave function, we reproduce the results of the standard approach. Calculations beyond the standard assumptions give different results.

  19. A unified intrinsic functional expansion theory for solitary waves

    Institute of Scientific and Technical Information of China (English)

    Theodore Yaotsu Wu; John Kao; Jin E. Zhang

    2005-01-01

    A new theory is developed here for evaluating solitary waves on water, with results of high accuracy uniformly valid for waves of all heights, from the highest wave with a corner crest of 120° down to very low ones of diminishing height. Solutions are sought for the Euler model by employing a unified expansion of the logarithmic hodograph in terms of a set of intrinsic component functions analytically determined to represent all the intrinsic properties of the wave entity from the wave crest to its outskirts. The unknown coefficients in the expansion are determined by minimization of the mean-square error of the solution, with the minimization optimized so as to take as few terms as needed to attain results as high in accuracy as attainable. In this regard, Stokes's formula, F2μπ = tanμπ, relating the wave speed (the Froude number F) and the logarithmic decrement μ of its wave field in the outskirt, is generalized to establish a new criterion requiring (for minimizing solution error) the functional expansion to contain a finite power series in M terms of Stokes's basic term (singular inμ), such that 2Mμ is just somewhat beyond unity, i.e. 2Mμ (~-) 1. This fundamental criterion is fully validated by solutions for waves Dedicated to Zhemin Zheng for celebration of his Eightieth Anniversary It gives us a great pleasure to dedicate this study to Prof. Zhemin Zheng and join our distinguished colleagues and friends for the jubilant celebration of his Eightieth Anniversary. Warmest tribute is due from us, as from many others unlimited by borders and boundaries, for his contributions of great significance to science, engineering science and engineering, his tremendous influence as a source of inspiration and unerring guide to countless workers in the field, his admirable leadership in fostering the Institute of Mechanics of world renown, as well as for his untiring endeavor in promoting international interaction and cooperation between academies of various nations

  20. Observing atomic collapse resonances in artificial nuclei on graphene.

    Science.gov (United States)

    Wang, Yang; Wong, Dillon; Shytov, Andrey V; Brar, Victor W; Choi, Sangkook; Wu, Qiong; Tsai, Hsin-Zon; Regan, William; Zettl, Alex; Kawakami, Roland K; Louie, Steven G; Levitov, Leonid S; Crommie, Michael F

    2013-05-10

    Relativistic quantum mechanics predicts that when the charge of a superheavy atomic nucleus surpasses a certain threshold, the resulting strong Coulomb field causes an unusual atomic collapse state; this state exhibits an electron wave function component that falls toward the nucleus, as well as a positron component that escapes to infinity. In graphene, where charge carriers behave as massless relativistic particles, it has been predicted that highly charged impurities should exhibit resonances corresponding to these atomic collapse states. We have observed the formation of such resonances around artificial nuclei (clusters of charged calcium dimers) fabricated on gated graphene devices via atomic manipulation with a scanning tunneling microscope. The energy and spatial dependence of the atomic collapse state measured with scanning tunneling microscopy revealed unexpected behavior when occupied by electrons.

  1. Period functions for Maass wave forms and cohomology

    CERN Document Server

    Bruggeman, R; Zagier, D; Bruggeman, R W; Zagier, D

    2015-01-01

    The authors construct explicit isomorphisms between spaces of Maass wave forms and cohomology groups for discrete cofinite groups \\Gamma\\subset\\mathrm{PSL}_2({\\mathbb{R}}). In the case that \\Gamma is the modular group \\mathrm{PSL}_2({\\mathbb{Z}}) this gives a cohomological framework for the results in Period functions for Maass wave forms. I, of J. Lewis and D. Zagier in Ann. Math. 153 (2001), 191-258, where a bijection was given between cuspidal Maass forms and period functions. The authors introduce the concepts of mixed parabolic cohomology group and semi-analytic vectors in principal serie

  2. Topics in General Relativity theory: Gravitational-wave measurements of black-hole parameters; gravitational collapse of a cylindrical body; and classical-particle evolution in the presence of closed, timelike curves

    Science.gov (United States)

    Echeverria, Fernando

    I study three different topics in general relativity. The first study investigates the accuracy with which the mass and angular momentum of a black hole can be determined by measurements of gravitational waves from the hole, using a gravitational-wave detector. The black hole is assumed to have been strongly perturbed and the detector measures the waves produced by its resulting vibration and ring-down. The uncertainties in the measured parameters arise from the noise present in the detector. It is found that the faster the hole rotates, the more accurate the measurements will be, with the uncertainty in the angular momentum decreasing rapidly with increasing rotation speed. The second study is an analysis of the gravitational collapse of an infinitely long, cylindrical dust shell, an idealization of more realistic, finite-length bodies. It is found that the collapse evolves into a naked singularity in finite time. Analytical expressions for the variables describing the collapse are found at late times, near the singularity. The collapse is also followed, with a numerical simulation, from the start until very close to the singularity. The singularity is found to be strong, in the sense that an observer riding on the shell will be infinitely stretched in one direction and infinitely compressed in another. The gravitational waves emitted from the collapse are also analyzed. The last study focuses on the consequences of the existence of closed time like curves in a worm hole space time. One might expect that such curves might cause a system with apparently well-posed initial conditions to have no self-consistent evolution. We study the case of a classical particle with a hard-sphere potential, focusing attention on initial conditions for which the evolution, if followed naively, is self-inconsistent: the ball travels to the past through the worm hole colliding with its younger self, preventing itself from entering the worm hole. We find, surprisingly, that for all

  3. Inhomogeneous electromagnetic gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Stein-Schabes, J.A.

    1985-04-15

    The collapse of an inhomogeneous dust cloud in the presence of an electromagnetic field is investigated in detail. The possibility of a naked singularity arising is studied using some known solutions for a spherical charged inhomogeneous dust cloud. It is found that locally naked singularities may develop when the arbitrary functions in the solution are chosen in a special way, but that a global naked singularity will not form. Also the role of the electromagnetic pressure is discussed.

  4. P wave dispersion and maximum P wave duration are independently associated with rapid renal function decline.

    Directory of Open Access Journals (Sweden)

    Ho-Ming Su

    Full Text Available The P wave parameters measured by 12-lead electrocardiogram (ECG are commonly used as noninvasive tools to assess for left atrial enlargement. There are limited studies to evaluate whether P wave parameters are independently associated with decline in renal function. Accordingly, the aim of this study is to assess whether P wave parameters are independently associated with progression to renal end point of ≥25% decline in estimated glomerular filtration rate (eGFR. This longitudinal study included 166 patients. The renal end point was defined as ≥25% decline in eGFR. We measured two ECG P wave parameters corrected by heart rate, i.e. corrected P wave dispersion (PWdisperC and corrected P wave maximum duration (PWdurMaxC. Heart function and structure were measured from echocardiography. Clinical data, P wave parameters, and echocardiographic measurements were compared and analyzed. Forty-three patients (25.9% reached renal end point. Kaplan-Meier curves for renal end point-free survival showed PWdisperC > median (63.0 ms (log-rank P = 0.004 and PWdurMaxC > median (117.9 ms (log-rank P<0.001 were associated with progression to renal end point. Multivariate forward Cox-regression analysis identified increased PWdisperC (hazard ratio [HR], 1.024; P = 0.001 and PWdurMaxC (HR, 1.029; P = 0.001 were independently associated with progression to renal end point. Our results demonstrate that increased PWdisperC and PWdurMaxC were independently associated with progression to renal end point. Screening patients by means of PWdisperC and PWdurMaxC on 12 lead ECG may help identify a high risk group of rapid renal function decline.

  5. On the asymptotic evolution of finite energy Airy wave functions.

    Science.gov (United States)

    Chamorro-Posada, P; Sánchez-Curto, J; Aceves, A B; McDonald, G S

    2015-06-15

    In general, there is an inverse relation between the degree of localization of a wave function of a certain class and its transform representation dictated by the scaling property of the Fourier transform. We report that in the case of finite energy Airy wave packets a simultaneous increase in their localization in the direct and transform domains can be obtained as the apodization parameter is varied. One consequence of this is that the far-field diffraction rate of a finite energy Airy beam decreases as the beam localization at the launch plane increases. We analyze the asymptotic properties of finite energy Airy wave functions using the stationary phase method. We obtain one dominant contribution to the long-term evolution that admits a Gaussian-like approximation, which displays the expected reduction of its broadening rate as the input localization is increased.

  6. How close can we get waves to wave functions, including potential?

    Science.gov (United States)

    Faletič, Sergej

    2016-05-01

    In the following article we show that mechanical waves on a braced string can have the same shapes as important wave functions in introductory quantum mechanics. A braced string is a string with additional transversal springs that serve as external "potential". The aim is not to suggest teaching quantum mechanics with these analogies. Instead, the aim is to provide students with some additional relevant experience in wave mechanics before they are introduced to quantum mechanics. We show how this experience can be used in a constructivist sense as the basis for building quantum concepts. We consider energy transfer along such string and show that penetration of a wave into a region with high "potential" is not unexpected. We also consider energy transfer between two such strings and show that it can appear point-like even though the wave is an extended object. We also suggest that applying quantization of energy transfer to wave phenomena can explain some of the more difficult to accept features of quantum mechanics.

  7. A Green's function method for surface acoustic waves in functionally graded materials.

    Science.gov (United States)

    Matsuda, Osamu; Glorieux, Christ

    2007-06-01

    Acoustic wave propagation in anisotropic media with one-dimensional inhomogeneity is discussed. Using a Green's function approach, the wave equation with inhomogeneous variation of elastic property and mass density is transformed into an integral equation, which is then solved numerically. The method is applied to find the dispersion relation of surface acoustic waves for a medium with continuously or discontinuously varying elastic property and mass density profiles.

  8. Dark energy and normalization of the cosmological wave function

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Peng [Sun Yat-Sen University, School of Astronomy and Space Science, Guangzhou (China); Huang, Yue; Li, Nan [Institute of Theoretical Physics, Chinese Academy of Sciences, State Key Laboratory of Theoretical Physics, Beijing (China); Kavli Institute for Theoretical Physics China, Chinese Academy of Sciences, Beijing (China); Li, Miao [Sun Yat-Sen University, School of Astronomy and Space Science, Guangzhou (China); Institute of Theoretical Physics, Chinese Academy of Sciences, State Key Laboratory of Theoretical Physics, Beijing (China)

    2016-08-15

    Dark energy is investigated from the perspective of quantum cosmology. It is found that, together with an appropriate normal ordering factor q, only when there is dark energy can the cosmological wave function be normalized. This interesting observation may require further attention. (orig.)

  9. Wave function of the de Sitter-Schwarzchild universe

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Hiroyuki (Kyushu Industrial Univ., Fukuoka (Japan))

    1989-08-01

    The wave function of the universe with an O(3) invariant inhomogeneous 3-space metric, called the de Sitter-Schwarzschild metric, is calculated under an appropriate boundary condition in the semi-classical approximation. The calculated result suggests that the quantum birth of the inhomogeneous universe cannot be disregarded. (author).

  10. On the Ground State Wave Function of Matrix Theory

    CERN Document Server

    Lin, Ying-Hsuan

    2014-01-01

    We propose an explicit construction of the leading terms in the asymptotic expansion of the ground state wave function of BFSS SU(N) matrix quantum mechanics. Our proposal is consistent with the expected factorization property in various limits of the Coulomb branch, and involves a different scaling behavior from previous suggestions. We comment on some possible physical implications.

  11. On the ground state wave function of matrix theory

    Science.gov (United States)

    Lin, Ying-Hsuan; Yin, Xi

    2015-11-01

    We propose an explicit construction of the leading terms in the asymptotic expansion of the ground state wave function of BFSS SU( N ) matrix quantum mechanics. Our proposal is consistent with the expected factorization property in various limits of the Coulomb branch, and involves a different scaling behavior from previous suggestions. We comment on some possible physical implications.

  12. Precanonical Quantization and the Schr\\"odinger Wave Functional Revisited

    CERN Document Server

    Kanatchikov, I V

    2011-01-01

    We address the long-standing issue of the relation between the Schr\\"odinger functional representation in quantum field theory and the approach of precanonical field quantization which requires neither a distinguished time variable nor infinite-dimensional spaces of field configurations. The functional Schr\\"odinger equation is derived in the limiting case \\varkappa \\rightarrow \\delta(0) from the Dirac-like covariant generalization of the Schr\\"odinger equation within the precanonical quantization approach, where the constant \\varkappa of the dimension of the inverse spatial volume naturally appears on dimensional grounds. An explicit expression of the Schr\\"odinger wave functional as a continuous product of precanonical wave functions on the finite-dimensional covariant configuration space of the field and space-time variables is obtained.

  13. Linear density response function in the projector augmented wave method

    DEFF Research Database (Denmark)

    Yan, Jun; Mortensen, Jens Jørgen; Jacobsen, Karsten Wedel;

    2011-01-01

    We present an implementation of the linear density response function within the projector-augmented wave method with applications to the linear optical and dielectric properties of both solids, surfaces, and interfaces. The response function is represented in plane waves while the single......-particle eigenstates can be expanded on a real space grid or in atomic-orbital basis for increased efficiency. The exchange-correlation kernel is treated at the level of the adiabatic local density approximation (ALDA) and crystal local field effects are included. The calculated static and dynamical dielectric...... functions of Si, C, SiC, AlP, and GaAs compare well with previous calculations. While optical properties of semiconductors, in particular excitonic effects, are generally not well described by ALDA, we obtain excellent agreement with experiments for the surface loss function of graphene and the Mg(0001...

  14. Microstructure Functional Devices-Effectively Manipulate Terahertz Waves

    Institute of Scientific and Technical Information of China (English)

    Fei Fan; Ji-Ning Li; Sai Chen; Sheng-Jiang Chang

    2014-01-01

    Terahertz (THz) technology promises important applications including imaging, spectroscopy, and communications. However, one of limitations at present for advancing THz applications is the lack of efficient devices to manipulate THz waves. Here, our recent important progresses in THz functional devices based on artificial microstructures, such as photonic crystal, metamaterial, and plasmonic structures, have been reviewed in this paper, involving the THz modulator, isolator, and sensor. These THz microstructure functional devices exhibit great promising potential in THz application systems.

  15. Explicitly correlated wave function for a boron atom

    CERN Document Server

    Puchalski, Mariusz; Pachucki, Krzysztof

    2015-01-01

    We present results of high-precision calculations for a boron atom's properties using wave functions expanded in the explicitly correlated Gaussian basis. We demonstrate that the well-optimized 8192 basis functions enable a determination of energy levels, ionization potential, and fine and hyperfine splittings in atomic transitions with nearly parts per million precision. The results open a window to a spectroscopic determination of nuclear properties of boron including the charge radius of the proton halo in the $^8$B nucleus.

  16. Rossby Wave Green's Functions in an Azimuthal Wind

    CERN Document Server

    Webb, G M; Hu, Q

    2015-01-01

    Green's functions for Rossby waves in an azimuthal wind are obtained, in which the stream-function $\\psi$ depends on $r$, $\\phi$ and $t$, where $r$ is cylindrical radius and $\\phi$ is the azimuthal angle in the $\\beta$-plane relative to the easterly direction, in which the $x$-axis points east and the $y$-axis points north. The Rossby wave Green's function with no wind is obtained using Fourier transform methods, and is related to the previously known Green's function obtained for this case, which has a different but equivalent form to the Green's function obtained in the present paper. We emphasize the role of the wave eikonal solution, which plays an important role in the form of the solution. The corresponding Green's function for a rotating wind with azimuthal wind velocity ${\\bf u}=\\Omega r{\\bf e}_\\phi$ ($\\Omega=$const.) is also obtained by Fourier methods, in which the advective rotation operator in position space is transformed to a rotation operator in ${\\bf k}$ transform space. The finite Rossby defo...

  17. Evaluation techniques for Gutzwiller wave functions in finite dimensions

    Science.gov (United States)

    Kaczmarczyk, Jan; Schickling, Tobias; Bünemann, Jörg

    2015-09-01

    We give a comprehensive introduction into a diagrammatic method that allows for the evaluation of Gutzwiller wave functions in finite spatial dimensions. We discuss in detail some numerical schemes that turned out to be useful in the real-space evaluation of the diagrams. The method is applied to the problem of d-wave superconductivity in a two-dimensional single-band Hubbard model. Here, we discuss in particular the role of long-range contributions in our diagrammatic expansion. We further reconsider our previous analysis on the kinetic energy gain in the superconducting state.

  18. Wind-Wave Model with an Optimized Source Function

    CERN Document Server

    Polnikov, Vladislav

    2010-01-01

    On the basis of the author's earlier results, a new source function for a numerical wind-wave model optimized by the criterion of accuracy and speed of calculation is substantiated. The proposed source function includes (a) an optimized version of the discrete interaction approximation for parametrization of the nonlinear evolution mechanism, (b) a generalized empirical form of the input term modified by adding a special block of the dynamic boundary layer of the atmosphere, and (c) a dissipation term quadratic in the wave spectrum. Particular attention is given to a theoretical substantiation of the least investigated dissipation term. The advantages of the proposed source function are discussed by its comparison to the analogues used in the widespread models of the third generation WAM and WAVEWATCH. At the initial stage of assessing the merits of the proposed model, the results of its testing by the system of academic tests are presented. In the course of testing, some principals of this procedure are form...

  19. Constraining quantum collapse inflationary models with CMB data

    Science.gov (United States)

    Benetti, Micol; Landau, Susana J.; Alcaniz, Jailson S.

    2016-12-01

    The hypothesis of the self-induced collapse of the inflaton wave function was proposed as responsible for the emergence of inhomogeneity and anisotropy at all scales. This proposal was studied within an almost de Sitter space-time approximation for the background, which led to a perfect scale-invariant power spectrum, and also for a quasi-de Sitter background, which allows to distinguish departures from the standard approach due to the inclusion of the collapse hypothesis. In this work we perform a Bayesian model comparison for two different choices of the self-induced collapse in a full quasi-de Sitter expansion scenario. In particular, we analyze the possibility of detecting the imprint of these collapse schemes at low multipoles of the anisotropy temperature power spectrum of the Cosmic Microwave Background (CMB) using the most recent data provided by the Planck Collaboration. Our results show that one of the two collapse schemes analyzed provides the same Bayesian evidence of the minimal standard cosmological model ΛCDM, while the other scenario is weakly disfavoured with respect to the standard cosmology.

  20. Constraining quantum collapse inflationary models with CMB data

    CERN Document Server

    Benetti, Micol; Alcaniz, Jailson S

    2016-01-01

    The hypothesis of the self-induced collapse of the inflaton wave function was proposed as responsible for the emergence of inhomogeneity and anisotropy at all scales. This proposal was studied within an almost de Sitter space-time approximation for the background, which led to a perfect scale-invariant power spectrum, and also for a quasi-de Sitter background, which allows to distinguish departures from the standard approach due to the inclusion of the collapse hypothesis. In this work we perform a Bayesian model comparison for two different choices of the self-induced collapse in a full quasi-de Sitter expansion scenario. In particular, we analyze the possibility of detecting the imprint of these collapse schemes at low multipoles of the anisotropy temperature power spectrum of the Cosmic Microwave Background (CMB) using the most recent data provided by the Planck Collaboration. Our results show that one of the two collapse schemes analyzed provides the same Bayesian evidence of the minimal standard cosmolog...

  1. Collapsing granular suspensions

    OpenAIRE

    Kadau, D.; Andrade Jr, J. S.; Herrmann, H. J.

    2009-01-01

    A 2D contact dynamics model is proposed as a microscopic description of a collapsing suspension/soil to capture the essential physical processes underlying the dynamics of generation and collapse of the system. Our physical model is compared with real data obtained from in situ measurements performed with a natural collapsing/suspension soil. We show that the shear strength behavior of our collapsing suspension/soil model is very similar to the behavior of this collapsing suspension soil, for...

  2. Self-Collapse Lithography.

    Science.gov (United States)

    Zhao, Chuanzhen; Xu, Xiaobin; Yang, Qing; Man, Tianxing; Jonas, Steven J; Schwartz, Jeffrey J; Andrews, Anne M; Weiss, Paul S

    2017-08-09

    We report a facile, high-throughput soft lithography process that utilizes nanoscale channels formed naturally at the edges of microscale relief features on soft, elastomeric stamps. Upon contact with self-assembled monolayer (SAM) functionalized substrates, the roof of the stamp collapses, resulting in the selective removal of SAM molecules via a chemical lift-off process. With this technique, which we call self-collapse lithography (SCL), sub-30 nm patterns were achieved readily using masters with microscale features prepared by conventional photolithography. The feature sizes of the chemical patterns can be varied continuously from ∼2 μm to below 30 nm by decreasing stamp relief heights from 1 μm to 50 nm. Likewise, for fixed relief heights, reducing the stamp Young's modulus from ∼2.0 to ∼0.8 MPa resulted in shrinking the features of resulting patterns from ∼400 to ∼100 nm. The self-collapse mechanism was studied using finite element simulation methods to model the competition between adhesion and restoring stresses during patterning. These results correlate well with the experimental data and reveal the relationship between the line widths, channel heights, and Young's moduli of the stamps. In addition, SCL was applied to pattern two-dimensional arrays of circles and squares. These chemical patterns served as resists during etching processes to transfer patterns to the underlying materials (e.g., gold nanostructures). This work provides new insights into the natural propensity of elastomeric stamps to self-collapse and demonstrates a means of exploiting this behavior to achieve patterning via nanoscale chemical lift-off lithography.

  3. Collapsing cavities in reactive and nonreactive media

    Science.gov (United States)

    Bourne, Neil K.; Field, John E.

    1991-04-01

    This paper presents results of a high-speed photographic study of cavities collapsed asymmetrically by shocks of strengths in the range 0.26 GPa to 3.5 GPa. Two-dimensional collapses of cavity configurations punched into a 12% by weight gelatine in water sheet, and an ammonium nitrate/sodium nitrate (AN/SN) emulsion explosive were photographed using schlieren optics. The single cavity collapses were characterized by the velocity of the liquid jet formed by the upstream wall as it was accelerated by the shock and by the time taken for the cavity to collapse. The shock pressure did not qualitatively affect the collapse behaviour but jet velocities were found to exceed incident shock velocities at higher pressures. The more violent collapses induced light emission from the compressed gas in the cavity. When an array of cavities collapsed, a wave, characterized by the particle velocity in the medium, the cavity diameter and the inter-cavity spacing, was found to run through the array. When such an array was created within an emulsion explosive, ignition of the reactive matrix occurred ahead of the collapse wave when the incident shock was strong.

  4. Configuration interaction wave functions: A seniority number approach

    Energy Technology Data Exchange (ETDEWEB)

    Alcoba, Diego R. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Física de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Torre, Alicia; Lain, Luis, E-mail: qfplapel@lg.ehu.es [Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, E-48080 Bilbao (Spain); Massaccesi, Gustavo E. [Departamento de Ciencias Exactas, Ciclo Básico Común, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Oña, Ofelia B. [Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Universidad Nacional de La Plata, CCT La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Diag. 113 y 64 (S/N), Sucursal 4, CC 16, 1900 La Plata (Argentina)

    2014-06-21

    This work deals with the configuration interaction method when an N-electron Hamiltonian is projected on Slater determinants which are classified according to their seniority number values. We study the spin features of the wave functions and the size of the matrices required to formulate states of any spin symmetry within this treatment. Correlation energies associated with the wave functions arising from the seniority-based configuration interaction procedure are determined for three types of molecular orbital basis: canonical molecular orbitals, natural orbitals, and the orbitals resulting from minimizing the expectation value of the N-electron seniority number operator. The performance of these bases is analyzed by means of numerical results obtained from selected N-electron systems of several spin symmetries. The comparison of the results highlights the efficiency of the molecular orbital basis which minimizes the mean value of the seniority number for a state, yielding energy values closer to those provided by the full configuration interaction procedure.

  5. GPView: A program for wave function analysis and visualization.

    Science.gov (United States)

    Shi, Tian; Wang, Ping

    2016-11-01

    In this manuscript, we will introduce a recently developed program GPView, which can be used for wave function analysis and visualization. The wave function analysis module can calculate and generate 3D cubes for various types of molecular orbitals and electron density of electronic excited states, such as natural orbitals, natural transition orbitals, natural difference orbitals, hole-particle density, detachment-attachment density and transition density. The visualization module of GPView can display molecular and electronic (iso-surfaces) structures. It is also able to animate single trajectories of molecular dynamics and non-adiabatic excited state molecular dynamics using the data stored in existing files. There are also other utilities to extract and process the output of quantum chemistry calculations. The GPView provides full graphic user interface (GUI), so it very easy to use. It is available from website http://life-tp.com/gpview.

  6. Horizon Wave-Function and the Quantum Cosmic Censorship

    CERN Document Server

    Casadio, Roberto; Stojkovic, Dejan

    2015-01-01

    We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF) formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superxtremal case (with charge-to-mass ratio $\\alpha>1$), which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for $\\alpha^2 2$, and the uncertainty in the location of the horizon blows up at $\\alpha^2=2$, signalling that such an object is no more well-defined. This perhaps implies that a {\\em quantum\\/} Cosmic Censorhip might be conjectured by stating that no black holes with charge-to-mass ratio greater than a critical value (of the order of $\\sqrt{2}$) can exist.

  7. GPView: a program for wave function analysis and visualization

    CERN Document Server

    Shi, Tian

    2016-01-01

    In this manuscript, we will introduce a recently developed program GPView, which can be used for wave function analysis and visualization. The wave function analysis module can calculate and generate 3D cubes for various types of molecular orbitals and electron density related with electronic excited states, such as natural orbitals, natural transition orbitals, natural difference orbitals, hole-particle density, detachment-attachment density and transition density. The visualization module of GPView can display molecular and electronic (iso-surfaces) structures. It is also able to animate single trajectories of molecular dynamics and non-adiabatic excited state molecular dynamics using the data stored in existing files. There are also other utilities help to extract and process the output of quantum chemistry calculations. The GPView provides full graphic user interface (GUI) which makes it very easy to use. The software, manual and tutorials are available in the website http://www.life-tp.com/gpview.

  8. Horizon wave-function and the quantum cosmic censorship

    Directory of Open Access Journals (Sweden)

    Roberto Casadio

    2015-07-01

    Full Text Available We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superextremal case (with charge-to-mass ratio α>1, which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for α22, and the uncertainty in the location of the horizon blows up at α2=2, signalling that such an object is no more well-defined. This perhaps implies that a quantum Cosmic Censorship might be conjectured by stating that no black holes with charge-to-mass ratio greater than a critical value (of the order of 2 can exist.

  9. Reactive Scattering Wave Functions by Linear Combination of Arrangement Channels

    Institute of Scientific and Technical Information of China (English)

    邓从豪; 冯大诚; 蔡政亭

    1994-01-01

    The similarity and dissimilarity of reactive scattering wave functions and molecular orbitalby linear combination of atomic orbitals(LCAOMO)are examined.Based on the similarity a method is pro-posed to construct the reactive scattering wave functions by linear combination of arrangement channel wavefunctions(LCACSW).Based on the dissimilarity,it is shown that the combination coefficients can be deter-mined by solving s set of simultaneous algebraic equations.The elements of the reactive scattering matrix areshown to be related to the combination coefficients of open arrangement channels.The differential and totalreactive scattering cross-section derived by this method agrees completely with that derived by other meth-ods.

  10. Spin-orbit decomposition of ab initio nuclear wave functions

    Science.gov (United States)

    Johnson, Calvin W.

    2015-03-01

    Although the modern shell-model picture of atomic nuclei is built from single-particle orbits with good total angular momentum j , leading to j -j coupling, decades ago phenomenological models suggested that a simpler picture for 0 p -shell nuclides can be realized via coupling of the total spin S and total orbital angular momentum L . I revisit this idea with large-basis, no-core shell-model calculations using modern ab initio two-body interactions and dissect the resulting wave functions into their component L - and S -components. Remarkably, there is broad agreement with calculations using the phenomenological Cohen-Kurath forces, despite a gap of nearly 50 years and six orders of magnitude in basis dimensions. I suggest that L -S decomposition may be a useful tool for analyzing ab initio wave functions of light nuclei, for example, in the case of rotational bands.

  11. Anatomy of quantum critical wave functions in dissipative impurity problems

    Science.gov (United States)

    Blunden-Codd, Zach; Bera, Soumya; Bruognolo, Benedikt; Linden, Nils-Oliver; Chin, Alex W.; von Delft, Jan; Nazir, Ahsan; Florens, Serge

    2017-02-01

    Quantum phase transitions reflect singular changes taking place in a many-body ground state; however, computing and analyzing large-scale critical wave functions constitutes a formidable challenge. Physical insights into the sub-Ohmic spin-boson model are provided by the coherent-state expansion (CSE), which represents the wave function by a linear combination of classically displaced configurations. We find that the distribution of low-energy displacements displays an emergent symmetry in the absence of spontaneous symmetry breaking while experiencing strong fluctuations of the order parameter near the quantum critical point. Quantum criticality provides two strong fingerprints in critical low-energy modes: an algebraic decay of the average displacement and a constant universal average squeezing amplitude. These observations, confirmed by extensive variational matrix-product-state (VMPS) simulations and field theory arguments, offer precious clues into the microscopics of critical many-body states in quantum impurity models.

  12. De Novo collapsing glomerulopathy in renal allograft in association with BK virus nephropathy in a child and stabilization of renal function by elimination of viremia

    Directory of Open Access Journals (Sweden)

    D N Gera

    2017-01-01

    Full Text Available Well-recognized association between HIV 1 infection and collapsing glomerulopathy (CG raises the possibility that intrarenal infection by other viruses may also contribute to the development of this lesion in native or post-transplant kidneys. There is evidence in literature about association of these lesions with cytomegalovirus, Epstein–Barr virus, hepatitis C virus, and parvovirus B19 infections. Here, we present a case report of post-transplant BK virus nephropathy in a male child who was found to have CG in subsequent biopsy 2 months later. His renal function and proteinuria were stabilized on elimination of viremia.

  13. Lattice effects on Laughlin wave functions and parent Hamiltonians

    Science.gov (United States)

    Glasser, Ivan; Cirac, J. Ignacio; Sierra, Germán; Nielsen, Anne E. B.

    2016-12-01

    We investigate lattice effects on wave functions that are lattice analogs of bosonic and fermionic Laughlin wave functions with number of particles per flux ν =1 /q in the Landau levels. These wave functions are defined analytically on lattices with μ particles per lattice site, where μ may be different than ν . We give numerical evidence that these states have the same topological properties as the corresponding continuum Laughlin states for different values of q and for different fillings μ . These states define, in particular, particle-hole symmetric lattice fractional quantum Hall states when the lattice is half filled. On the square lattice it is observed that for q ≤4 this particle-hole symmetric state displays the topological properties of the continuum Laughlin state at filling fraction ν =1 /q , while for larger q there is a transition towards long-range ordered antiferromagnets. This effect does not persist if the lattice is deformed from a square to a triangular lattice, or on the kagome lattice, in which case the topological properties of the state are recovered. We then show that changing the number of particles while keeping the expression of these wave functions identical gives rise to edge states that have the same correlations in the bulk as the reference lattice Laughlin states but a different density at the edge. We derive an exact parent Hamiltonian for which all these edge states are ground states with different number of particles. In addition this Hamiltonian admits the reference lattice Laughlin state as its unique ground state of filling factor 1 /q . Parent Hamiltonians are also derived for the lattice Laughlin states at other fillings of the lattice, when μ ≤1 /q or μ ≥1 -1 /q and when q =4 also at half filling.

  14. Detecting topological order in a ground state wave function

    OpenAIRE

    2005-01-01

    A large class of topological orders can be understood and classified using the string-net condensation picture. These topological orders can be characterized by a set of data (N, d_i, F^{ijk}_{lmn}, \\delta_{ijk}). We describe a way to detect this kind of topological order using only the ground state wave function. The method involves computing a quantity called the ``topological entropy'' which directly measures the quantum dimension D = \\sum_i d^2_i.

  15. Wave functions in SUSY cosmological models with matter

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, C. [Instituto de Fisica de la Universidad de Guanajuato, A.P. E-143, C.P. 37150, Leon, Guanajuato (Mexico); Rosales, J.J. [Facultad de Ingenieria Mecanica Electrica y Electronica, Universidad de Guanajuato, Prolongacion Tampico 912, Bellavista, Salamanca, Guanajuato (Mexico); Socorro, J. [Instituto de Fisica de la Universidad de Guanajuato, A.P. E-143, C.P. 37150, Leon, Guanajuato (Mexico)]. E-mail: socorro@fisica.ugto.mx; Torres, J. [Instituto de Fisica de la Universidad de Guanajuato, A.P. E-143, C.P. 37150, Leon, Guanajuato (Mexico); Tkach, V.I. [Instituto de Fisica de la Universidad de Guanajuato, A.P. E-143, C.P. 37150, Leon, Guanajuato (Mexico)

    2005-06-06

    In this work we consider the n=2 supersymmetric superfield approach for the FRW cosmological model and the corresponding term of matter content, perfect fluid with barotropic state equation p={gamma}{rho}. We are able to obtain a normalizable wave function (at zero energy) of the universe. Besides, the mass parameter spectrum is found for the closed FRW case in the Schrodinger picture, being similar to those obtained by other methods, using a black hole system.

  16. Heavy quarkonia spectra using wave function with gluonic components

    OpenAIRE

    Bartnik, E. A.; Al-Nadary, H.

    2009-01-01

    We calculate the spectra of charmonium and bottomium in an approximation scheme which treats hard gluons perturbatively while soft gluons are expanded in a set of localized wave functions. Quark-antiquark and quark-antiquark-gluon sectors are included. Reasonable agreement with 2 parameters only is found but the spectra are too coulombic. Despite large coupling constant the admixture of the quark-antiquark-gluon sector is found to be remarkably small.

  17. Two-Variable Hermite Function as Quantum Entanglement of Harmonic Oscillator's Wave Functions

    Institute of Scientific and Technical Information of China (English)

    LU Hai-Liang; FAN Hong-Yi

    2007-01-01

    We reveal that the two-variable Hermite function hm,n, which is the generalized Bargmann representation of the two-mode Fock state, involves quantum entanglement of harmonic oscillator's wave functions.The Schmidt decomposition of hm,n is derived. It also turns out that hm,n can be generated by windowed Fourier transform of the single-variable Hermite functions. As an application, the wave function of the two-variable Hermite polynomial state S(r)Hm,n(μa1+, μa2+)|00〉, which is the minimum uncertainty state for sum squeezing, in 〈η| representation is calculated.

  18. Improved variational many-body wave function in light nuclei

    Science.gov (United States)

    Usmani, Q. N.; Singh, A.; Anwar, K.; Rawitscher, G.

    2009-09-01

    We propose and implement a simple method for improving the variational wave function of a many-body system. We have obtained a significant improvement in the binding energies, wave functions, and variance for the light nuclei H3, He4, and Li6, using the fully realistic Argonne (AV18) two-body and Urbana-IX (UIX) three-body interactions. The energy of He4 was improved by about 0.2 MeV and the Li6 binding energy was increased by ≈1.7 MeV compared to earlier variational Monte Carlo results. The latter result demonstrates the significant progress achieved by our method, and detailed analyses of the improved results are given. With central interactions the results are found to be in agreement with the “exact” calculations. Our study shows that the relative error in the many-body wave functions, compared to two-body pair correlations, increases rapidly at least proportionally to the number of pairs in the system. However, this error does not increase indefinitely since the pair interactions saturate owing to convergence of cluster expansion.

  19. Computational aspects of the continuum quaternionic wave functions for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Morais, J., E-mail: joao.pedro.morais@ua.pt

    2014-10-15

    Over the past few years considerable attention has been given to the role played by the Hydrogen Continuum Wave Functions (HCWFs) in quantum theory. The HCWFs arise via the method of separation of variables for the time-independent Schrödinger equation in spherical coordinates. The HCWFs are composed of products of a radial part involving associated Laguerre polynomials multiplied by exponential factors and an angular part that is the spherical harmonics. In the present paper we introduce the continuum wave functions for hydrogen within quaternionic analysis ((R)QHCWFs), a result which is not available in the existing literature. In particular, the underlying functions are of three real variables and take on either values in the reduced and full quaternions (identified, respectively, with R{sup 3} and R{sup 4}). We prove that the (R)QHCWFs are orthonormal to one another. The representation of these functions in terms of the HCWFs are explicitly given, from which several recurrence formulae for fast computer implementations can be derived. A summary of fundamental properties and further computation of the hydrogen-like atom transforms of the (R)QHCWFs are also discussed. We address all the above and explore some basic facts of the arising quaternionic function theory. As an application, we provide the reader with plot simulations that demonstrate the effectiveness of our approach. (R)QHCWFs are new in the literature and have some consequences that are now under investigation.

  20. Love wave propagation in functionally graded piezoelectric material layer.

    Science.gov (United States)

    Du, Jianke; Jin, Xiaoying; Wang, Ji; Xian, Kai

    2007-03-01

    An exact approach is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded to a semi-infinite homogeneous solid. The piezoelectric material is polarized in z-axis direction and the material properties change gradually with the thickness of the layer. We here assume that all material properties of the piezoelectric layer have the same exponential function distribution along the x-axis direction. The analytical solutions of dispersion relations are obtained for electrically open or short circuit conditions. The effects of the gradient variation of material constants on the phase velocity, the group velocity, and the coupled electromechanical factor are discussed in detail. The displacement, electric potential, and stress distributions along thickness of the graded layer are calculated and plotted. Numerical examples indicate that appropriate gradient distributing of the material properties make Love waves to propagate along the surface of the piezoelectric layer, or a bigger electromechanical coupling factor can be obtained, which is in favor of acquiring a better performance in surface acoustic wave (SAW) devices.

  1. An Argument Against the Realistic Interpretation of the Wave Function

    Science.gov (United States)

    Rovelli, Carlo

    2016-10-01

    Testable predictions of quantum mechanics are invariant under time reversal. But the evolution of the quantum state in time is not so, neither in the collapse nor in the no-collapse interpretations of the theory. This is a fact that challenges any realistic interpretation of the quantum state. On the other hand, this fact raises no difficulty if we interpret the quantum state as a mere calculation device, bookkeeping past real quantum events.

  2. Wave Function Structure in Two-Body Random Matrix Ensembles

    CERN Document Server

    Kaplan, L; Kaplan, Lev; Papenbrock, Thomas

    2000-01-01

    We study the structure of eigenstates in two-body interaction random matrix ensembles and find significant deviations from random matrix theory expectations. The deviations are most prominent in the tails of the spectral density and indicate localization of the eigenstates in Fock space. Using ideas related to scar theory we derive an analytical formula that relates fluctuations in wave function intensities to fluctuations of the two-body interaction matrix elements. Numerical results for many-body fermion systems agree well with the theoretical predictions.

  3. OPERA Collaboration have observed phase speed of neutrino wave function

    CERN Document Server

    Li, Shi-Yuan

    2011-01-01

    First we call the attention that velocity defined by ratio between some intervals of space and time respectively is sometimes ambiguous, in the framework of quantum theory. Velocity in general is not possible to be well defined as some generator of certain space-time symmetry operation. Then by analyzing the OPERA experiment we show that the OPERA Collaboration may have measured the phase speed of the neutrino wave function. Employing a very (maybe too) simple model which is just a reproduction from Brillouin's classical book, we demonstrate the phase velocity and group velocity. These are just a qualitative illustration rather than aiming to quantitively explain the OPERA data.

  4. Baryon Wave Functions in Covariant Relativistic Quark Models

    CERN Document Server

    Dillig, M

    2002-01-01

    We derive covariant baryon wave functions for arbitrary Lorentz boosts. Modeling baryons as quark-diquark systems, we reduce their manifestly covariant Bethe-Salpeter equation to a covariant 3-dimensional form by projecting on the relative quark-diquark energy. Guided by a phenomenological multigluon exchange representation of a covariant confining kernel, we derive for practical applications explicit solutions for harmonic confinement and for the MIT Bag Model. We briefly comment on the interplay of boosts and center-of-mass corrections in relativistic quark models.

  5. New Forms of Deuteron Equations and Wave Function Representations

    CERN Document Server

    Fachruddin, I; Glöckle, W; Elster, Ch.

    2001-01-01

    A recently developed helicity basis for nucleon-nucleon (NN) scattering is applied to th e deuteron bound state. Here the total spin of the deuteron is treated in such a helicity representation. For the bound state, two sets of two coupled eigenvalue equations are developed, where the amplitudes depend on two and one variable, respectively. Numerical illustrations based on the realistic Bonn-B NN potential are given. In addition, an `operator form' of the deuteron wave function is presented, and several momentum dependent spin densities are derived and shown, in which the angular dependence is given analytically.

  6. Cosmic Wave Functions with the Brans-Dicke Theory

    Institute of Scientific and Technical Information of China (English)

    ZHU Zong-Hong

    2000-01-01

    Using the standard Wentzel-Kramers-Brillouin method, the Wheeler-De Witt equation for the Brans-Dicke theory is solved under three kinds of boundary conditions (proposed by Hattie-Hawking, Vilenkin and Linde, respectively). It is found that, although the gravitational and cosmological"constants" are dynamical and timedependent in the classical models, they will acquire constant values when the universe comes from the quantum creation, and that in particular, the amplitude of the resulting wave function under Linde or Vilenkin boundary conditions reaches its maximum if the cosmological constant is the minimum.

  7. On the Convergence to Ergodic Behaviour of Quantum Wave Functions

    CERN Document Server

    Jacquod, P; Jacquod, Ph.

    1996-01-01

    We study the decrease of fluctuations of diagonal matrix elements of observables and of Husimi densities of quantum mechanical wave functions around their mean value upon approaching the semi-classical regime ($\\hbar strongly chaotic regime. We show that the fluctuations are Gaussian distributed, with a width $\\sigma^2$ decreasing as the square root of Planck's constant. This is consistent with Random Matrix Theory (RMT) predictions, and previous studies on these fluctuations. We further study the width of the probability distribution of $\\hbar$-dependent fluctuations and compare it to the Gaussian Orthogonal Ensemble (GOE) of RMT.

  8. Electromagnetism and multiple-valued loop-dependent wave functionals

    CERN Document Server

    Leal, Lorenzo

    2009-01-01

    We quantize the Maxwell theory in the presence of a electric charge in a "dual" Loop Representation, i.e. a geometric representation of magnetic Faraday's lines. It is found that the theory can be seen as a theory without sources, except by the fact that the wave functional becomes multivalued. This can be seen as the dual counterpart of what occurs in Maxwell theory with a magnetic pole, when it is quantized in the ordinary Loop Representation. The multivaluedness can be seen as a result of the multiply-connectedness of the configuration space of the quantum theory.

  9. Relativistic Covariance and Quark-Diquark Wave Functions

    CERN Document Server

    Dillig, M

    2006-01-01

    We derive covariant wave functions for hadrons composed of two constituents for arbitrary Lorentz boosts. Focussing explicitly on baryons as quark-diquark systems, we reduce their manifestly covariant Bethe-Salpeter equation to covariant 3-dimensional forms by projecting on the relative quark-diquark energy. Guided by a phenomenological multi gluon exchange representation of covariant confining kernels, we derive explicit solutions for harmonic confinement and for the MIT Bag Model. We briefly sketch implications of breaking the spherical symmetry of the ground state and the transition from the instant form to the light cone via the infinite momentum frame.

  10. Considerable MHC diversity suggests that the functional extinction of baiji is not related to population genetic collapse.

    Directory of Open Access Journals (Sweden)

    Shixia Xu

    Full Text Available To further extend our understanding of the mechanism causing the current nearly extinct status of the baiji (Lipotes vexillifer, one of the most critically endangered species in the world, genetic diversity at the major histocompatibility complex (MHC class II DRB locus was investigated in the baiji. Nine highly divergent DRB alleles were identified in 17 samples, with an average of 28.4 (13.2% nucleotide difference and 16.7 (23.5% amino acid difference between alleles. The unexpectedly high levels of DRB allelic diversity in the baiji may partly be attributable to its evolutionary adaptations to the freshwater environment which is regarded to have a higher parasite diversity compared to the marine environment. In addition, balancing selection was found to be the main mechanisms in generating sequence diversity at baiji DRB gene. Considerable sequence variation at the adaptive MHC genes despite of significant loss of neutral genetic variation in baiji genome might suggest that intense selection has overpowered random genetic drift as the main evolutionary forces, which further suggested that the critically endangered or nearly extinct status of the baiji is not an outcome of genetic collapse.

  11. Collapsing granular suspensions.

    Science.gov (United States)

    Kadau, D; Andrade, J S; Herrmann, H J

    2009-11-01

    A 2D contact dynamics model is proposed as a microscopic description of a collapsing suspension/soil to capture the essential physical processes underlying the dynamics of generation and collapse of the system. Our physical model is compared with real data obtained from in situ measurements performed with a natural collapsing/suspension soil. We show that the shear strength behavior of our collapsing suspension/soil model is very similar to the behavior of this collapsing suspension soil, for both the unperturbed and the perturbed phases of the material.

  12. Inhomogeneities from quantum collapse scheme without inflation

    Directory of Open Access Journals (Sweden)

    Gabriel R. Bengochea

    2015-04-01

    Full Text Available In this work, we consider the problem of the emergence of seeds of cosmic structure in the framework of the non-inflationary model proposed by Hollands and Wald. In particular, we consider a modification to that proposal designed to account for breaking the symmetries of the initial quantum state, leading to the generation of the primordial inhomogeneities. This new ingredient is described in terms of a spontaneous reduction of the wave function. We investigate under which conditions one can recover an essentially scale free spectrum of primordial inhomogeneities, and which are the dominant deviations that arise in the model as a consequence of the introduction of the collapse of the quantum state into that scenario.

  13. Inhomogeneities from quantum collapse scheme without inflation

    Energy Technology Data Exchange (ETDEWEB)

    Bengochea, Gabriel R., E-mail: gabriel@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Cañate, Pedro, E-mail: pedro.canate@nucleares.unam.mx [Instituto de Ciencias Nucleares, UNAM, México D.F. 04510, México (Mexico); Sudarsky, Daniel, E-mail: sudarsky@nucleares.unam.mx [Instituto de Ciencias Nucleares, UNAM, México D.F. 04510, México (Mexico)

    2015-04-09

    In this work, we consider the problem of the emergence of seeds of cosmic structure in the framework of the non-inflationary model proposed by Hollands and Wald. In particular, we consider a modification to that proposal designed to account for breaking the symmetries of the initial quantum state, leading to the generation of the primordial inhomogeneities. This new ingredient is described in terms of a spontaneous reduction of the wave function. We investigate under which conditions one can recover an essentially scale free spectrum of primordial inhomogeneities, and which are the dominant deviations that arise in the model as a consequence of the introduction of the collapse of the quantum state into that scenario.

  14. Black hole mass function from gravitational wave measurements

    Science.gov (United States)

    Kovetz, Ely D.; Cholis, Ilias; Breysse, Patrick C.; Kamionkowski, Marc

    2017-05-01

    We examine how future gravitational-wave measurements from merging black holes (BHs) can be used to infer the shape of the black-hole mass function, with important implications for the study of star formation and evolution and the properties of binary BHs. We model the mass function as a power law, inherited from the stellar initial mass function, and introduce lower and upper mass cutoff parametrizations in order to probe the minimum and maximum BH masses allowed by stellar evolution, respectively. We initially focus on the heavier BH in each binary, to minimize model dependence. Taking into account the experimental noise, the mass measurement errors and the uncertainty in the redshift dependence of the merger rate, we show that the mass function parameters, as well as the total rate of merger events, can be measured to years of advanced LIGO observations at its design sensitivity. This can be used to address important open questions such as the upper limit on the stellar mass which allows for BH formation and to confirm or refute the currently observed mass gap between neutron stars and BHs. In order to glean information on the progenitors of the merging BH binaries, we then advocate the study of the two-dimensional mass distribution to constrain parameters that describe the two-body system, such as the mass ratio between the two BHs, in addition to the merger rate and mass function parameters. We argue that several years of data collection can efficiently probe models of binary formation, and show, as an example, that the hypothesis that some gravitational-wave events may involve primordial black holes can be tested. Finally, we point out that in order to maximize the constraining power of the data, it may be worthwhile to lower the signal-to-noise threshold imposed on each candidate event and amass a larger statistical ensemble of BH mergers.

  15. Observation of Weak Collapse in a Bose-Einstein Condensate

    CERN Document Server

    Eigen, Christoph; Suleymanzade, Aziza; Navon, Nir; Hadzibabic, Zoran; Smith, Robert P

    2016-01-01

    We study the collapse of an attractive atomic Bose-Einstein condensate prepared in the uniform potential an optical-box trap. We characterise the critical point for collapse and the collapse dynamics, observing universal behaviour in agreement with theoretical expectations. Most importantly, we observe a clear experimental signature of the counterintuitive weak collapse, namely that making the system more unstable can result in a smaller particle loss. We experimentally determine the scaling laws that govern the weak-collapse atom loss, providing a benchmark for the general theories of nonlinear wave phenomena.

  16. Stochastic wave function approach to the calculation of multitime correlation functions of open quantum systems

    CERN Document Server

    Breuer, H P; Petruccione, F; Breuer, Heinz-Peter; Kappler, Bernd; Petruccione, Francesco

    1997-01-01

    Within the framework of probability distributions on projective Hilbert space a scheme for the calculation of multitime correlation functions is developed. The starting point is the Markovian stochastic wave function description of an open quantum system coupled to an environment consisting of an ensemble of harmonic oscillators in arbitrary pure or mixed states. It is shown that matrix elements of reduced Heisenberg picture operators and general time-ordered correlation functions can be expressed by time-symmetric expectation values of extended operators in a doubled Hilbert space. This representation allows the construction of a stochastic process in the doubled Hilbert space which enables the determination of arbitrary matrix elements and correlation functions. The numerical efficiency of the resulting stochastic simulation algorithm is investigated and compared with an alternative Monte Carlo wave function method proposed first by Dalibard et al. [Phys. Rev. Lett. {\\bf 68}, 580 (1992)]. By means of a stan...

  17. Extracting Supersymmetry-Breaking Effects from Wave-Function Renormalization

    CERN Document Server

    Giudice, Gian Francesco

    1998-01-01

    We show that in theories in which supersymmetry breaking is communicated by renormalizable perturbative interactions, it is possible to extract the soft terms for the observable fields from wave-function renormalization. Therefore all the information about soft terms can be obtained from anomalous dimensions and beta functions, with no need to further compute any Feynman diagram. This method greatly simplifies calculations which are rather involved if performed in terms of component fields. For illustrative purposes we reproduce known results of theories with gauge-mediated supersymmetry breaking. We then use our method to obtain new results of phenomenological importance. We calculate the next-to-leading correction to the Higgs mass parameters, the two-loop soft terms induced by messenger-matter superpotential couplings, and the soft terms generated by messengers belonging to vector supermultiplets.

  18. Quantum canonical tensor model and an exact wave function

    CERN Document Server

    Sasakura, Naoki

    2013-01-01

    Tensor models in various forms are being studied as models of quantum gravity. Among them the canonical tensor model has a canonical pair of rank-three tensors as dynamical variables, and is a pure constraint system with first-class constraints. The Poisson algebra of the first-class constraints has structure functions, and provides an algebraically consistent way of discretizing the Dirac first-class constraint algebra for general relativity. This paper successfully formulates the Wheeler-DeWitt scheme of quantization of the canonical tensor model; the ordering of operators in the constraints is determined without ambiguity by imposing Hermiticity and covariance on the constraints, and the commutation algebra of constraints takes essentially the same from as the classical Poisson algebra, i.e. is first-class. Thus one could consistently obtain, at least locally in the configuration space, wave functions of "universe" by solving the partial differential equations representing the constraints, i.e. the Wheeler...

  19. Can We Falsify the Consciousness-Causes-Collapse Hypothesis in Quantum Mechanics?

    Science.gov (United States)

    de Barros, J. Acacio; Oas, Gary

    2017-06-01

    In this paper we examine some proposals to disprove the hypothesis that the interaction between mind and matter causes the collapse of the wave function, showing that such proposals are fundamentally flawed. We then describe a general experimental setup retaining the key features of the ones examined, and show that even a more general case is inadequate to disprove the mind-matter collapse hypothesis. Finally, we use our setup provided to argue that, under some reasonable assumptions about consciousness, such hypothesis is unfalsifiable.

  20. The Black Hole Mass Function from Gravitational Wave Measurements

    CERN Document Server

    Kovetz, Ely D; Breysse, Patrick C; Kamionkowski, Marc

    2016-01-01

    We examine how future gravitational-wave measurements from merging black holes (BHs) can be used to infer the shape of the black-hole mass function, with important implications for the study of star formation and evolution and the properties of binary BHs. We model the mass function as a power law, inherited from the stellar initial mass function, and introduce lower and upper mass cutoff parameterizations in order to probe the minimum and maximum BH masses allowed by stellar evolution, respectively. We initially focus on the heavier BH in each binary, to minimize model dependence. Taking into account the experimental noise, the mass measurement errors and the uncertainty in the redshift-dependence of the merger rate, we show that the mass function parameters, as well as the total rate of merger events, can be measured to <10% accuracy within a few years of advanced LIGO observations at its design sensitivity. This can be used to address important open questions such as the upper limit on the stellar mass ...

  1. Beyond quantum mechanics? Hunting the 'impossible' atoms (Pauli Exclusion Principle violation and spontaneous collapse of the wave function at test)

    CERN Document Server

    Piscicchia, K; Bartalucci, S; Bassi, A; Bertolucci, S; Berucci, C; Bragadireanu, A M; Cargnelli, M; Clozza, A; De Paolis, L; Di Matteo, S; Donadi, S; d'Uffizi, A; Egger, J-P; Guaraldo, C; Iliescu, M; Ishiwatari, T; Laubenstein, M; Marton, J; Milotti, E; Pietreanu, D; Ponta, T; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Sperandio, L; Doce, O Vazquez; Zmeskal, J

    2015-01-01

    The development of mathematically complete and consistent models solving the so-called "measurement problem", strongly renewed the interest of the scientific community for the foundations of quantum mechanics, among these the Dynamical Reduction Models posses the unique characteristic to be experimentally testable. In the first part of the paper an upper limit on the reduction rate parameter of such models will be obtained, based on the analysis of the X-ray spectrum emitted by an isolated slab of germanium and measured by the IGEX experiment. The second part of the paper is devoted to present the results of the VIP (Violation of the Pauli exclusion principle) experiment and to describe its recent upgrade. The VIP experiment established a limit on the probability that the Pauli Exclusion Principle (PEP) is violated by electrons, using the very clean method of searching for PEP forbidden atomic transitions in copper.

  2. Precise wave-function engineering with magnetic resonance

    Science.gov (United States)

    Wigley, P. B.; Starkey, L. M.; Szigeti, S. S.; Jasperse, M.; Hope, J. J.; Turner, L. D.; Anderson, R. P.

    2017-07-01

    Controlling quantum fluids at their fundamental length scale will yield superlative quantum simulators, precision sensors, and spintronic devices. This scale is typically below the optical diffraction limit, precluding precise wave-function engineering using optical potentials alone. We present a protocol to rapidly control the phase and density of a quantum fluid down to the healing length scale using strong time-dependent coupling between internal states of the fluid in a magnetic field gradient. We demonstrate this protocol by simulating the creation of a single stationary soliton and double soliton states in a Bose-Einstein condensate with control over the individual soliton positions and trajectories, using experimentally feasible parameters. Such states are yet to be realized experimentally, and are a path towards engineering soliton gases and exotic topological excitations.

  3. Human brain networks function in connectome-specific harmonic waves.

    Science.gov (United States)

    Atasoy, Selen; Donnelly, Isaac; Pearson, Joel

    2016-01-21

    A key characteristic of human brain activity is coherent, spatially distributed oscillations forming behaviour-dependent brain networks. However, a fundamental principle underlying these networks remains unknown. Here we report that functional networks of the human brain are predicted by harmonic patterns, ubiquitous throughout nature, steered by the anatomy of the human cerebral cortex, the human connectome. We introduce a new technique extending the Fourier basis to the human connectome. In this new frequency-specific representation of cortical activity, that we call 'connectome harmonics', oscillatory networks of the human brain at rest match harmonic wave patterns of certain frequencies. We demonstrate a neural mechanism behind the self-organization of connectome harmonics with a continuous neural field model of excitatory-inhibitory interactions on the connectome. Remarkably, the critical relation between the neural field patterns and the delicate excitation-inhibition balance fits the neurophysiological changes observed during the loss and recovery of consciousness.

  4. Norm of Bethe Wave Function as a Determinant

    CERN Document Server

    Korepin, Vladimir E

    2009-01-01

    This is a historical note. Bethe Ansatz solvable models are considered, for example XXZ Heisenberg anti-ferromagnet and Bose gas with delta interaction. Periodic boundary conditions lead to Bethe equation. The square of the norm of Bethe wave function is equal to a determinant of linearized system of Bethe equations (determinant of matrix of second derivatives of Yang action). The proof was first published in Communications in Mathematical Physics, vol 86, page 391 in l982. Also domain wall boundary conditions for 6 vertex model were discovered in the same paper [see Appendix D]. These play an important role for algebraic combinatorics: alternating sign matrices, domino tiling and plane partition. Many publications are devoted to six vertex model with domain wall boundary conditions.

  5. From Bethe-Salpeter Wave functions to Generalised Parton Distributions

    Science.gov (United States)

    Mezrag, C.; Moutarde, H.; Rodríguez-Quintero, J.

    2016-09-01

    We review recent works on the modelling of generalised parton distributions within the Dyson-Schwinger formalism. We highlight how covariant computations, using the impulse approximation, allows one to fulfil most of the theoretical constraints of the GPDs. Specific attention is brought to chiral properties and especially the so-called soft pion theorem, and its link with the Axial-Vector Ward-Takahashi identity. The limitation of the impulse approximation are also explained. Beyond impulse approximation computations are reviewed in the forward case. Finally, we stress the advantages of the overlap of lightcone wave functions, and possible ways to construct covariant GPD models within this framework, in a two-body approximation.

  6. From Bethe-Salpeter Wave Functions to Generalised Parton Distributions

    CERN Document Server

    Mezrag, C; Rodriguez-Quintero, J

    2016-01-01

    We review recent works on the modelling of Generalised Parton Distributions within the Dyson-Schwinger formalism. We highlight how covariant computations, using the impulse approximation, allows one to fulfil most of the theoretical constraints of the GPDs. Specific attention is brought to chiral properties and especially the so-called soft pion theorem, and its link with the Axial-Vector Ward-Takahashi identity. The limitation of the impulse approximation are also explained. Beyond impulse approximation computations are reviewed in the forward case. Finally, we stress the advantages of the overlap of lightcone wave functions, and possible ways to construct covariant GPD models within this framework, in a two-body approximation.

  7. The wave function essays on the metaphysics of quantum mechanics

    CERN Document Server

    Albert, David Z

    2013-01-01

    This is a new volume of original essays on the metaphysics of quantum mechanics. The essays address questions such as: What fundamental metaphysics is best motivated by quantum mechanics? What is the ontological status of the wave function? Does quantum mechanics support the existence of any other fundamental entities, e.g. particles? What is the nature of the fundamental space (or space-time manifold) of quantum mechanics? What is the relationship between the fundamental ontology of quantum mechanics and ordinary, macroscopic objects like tables, chairs, and persons? This collection includes a comprehensive introduction with a history of quantum mechanics and the debate over its metaphysical interpretation focusing especially on the main realist alternatives.

  8. Semiclassical-wave-function perspective on high-harmonic generation

    Science.gov (United States)

    Mauger, François; Abanador, Paul M.; Lopata, Kenneth; Schafer, Kenneth J.; Gaarde, Mette B.

    2016-04-01

    We introduce a semiclassical-wave-function (SCWF) model for strong-field physics and attosecond science. When applied to high-harmonic generation (HHG), this formalism allows one to show that the natural time-domain separation of the contribution of ionization, propagation, and recollisions to the HHG process leads to a frequency-domain factorization of the harmonic yield into these same contributions, for any choice of atomic or molecular potential. We first derive the factorization from the natural expression of the dipole signal in the temporal domain by using a reference system, as in the quantitative rescattering (QRS) formalism [J. Phys. B 43, 122001 (2010), 10.1088/0953-4075/43/12/122001]. Alternatively, we show how the trajectory component of the SCWF can be used to express the factorization, which also allows one to attribute individual contributions to the spectrum to the underlying trajectories.

  9. The one loop gluon emission light cone wave function

    CERN Document Server

    Lappi, Tuomas

    2016-01-01

    Light cone perturbation theory has become an essential tool to calculate cross sections for various small-$x$ dilute-dense processes such as deep inelastic scattering and forward proton-proton and proton-nucleus collisions. Here we set out to do one loop calculations in an explicit helicity basis in the four dimensional helicity scheme. As a first process we calculate light cone wave function for one gluon emission to one-loop order in Hamiltonian perturbation theory on the light front. We regulate ultraviolet divergences with transverse dimensional regularization and soft divergences with using a cut-off on longitudinal momentum. We show that when all the renormalization constants are combined, the ultraviolet divergences can be absorbed into the standard QCD running coupling constant, and give an explicit expression for the remaining finite part.

  10. Topological wave functions and the 4D-5D lift

    CERN Document Server

    Gao, Peng

    2008-01-01

    We revisit the holomorphic anomaly equations satisfied by the topological string amplitude from the perspective of the 4D-5D lift, in the context of ``magic'' N=2 supergravity theories. In particular, we interpret the Gopakumar-Vafa relation between 5D black hole degeneracies and the topological string amplitude as the result of a canonical transformation from 4D to 5D charges. Moreover we use the known Bekenstein-Hawking entropy of 5D black holes to constrain the asymptotic behavior of the topological wave function at finite topological coupling but large K\\"ahler classes. In the process, some subtleties in the relation between 5D black hole degeneracies and the topological string amplitude are uncovered, but not resolved. Finally we extend these considerations to the putative one-parameter generalization of the topological string amplitude, and identify the canonical transformation as a Weyl reflection inside the 3D duality group.

  11. Dominant partition method. [based on a wave function formalism

    Science.gov (United States)

    Dixon, R. M.; Redish, E. F.

    1979-01-01

    By use of the L'Huillier, Redish, and Tandy (LRT) wave function formalism, a partially connected method, the dominant partition method (DPM) is developed for obtaining few body reductions of the many body problem in the LRT and Bencze, Redish, and Sloan (BRS) formalisms. The DPM maps the many body problem to a fewer body one by using the criterion that the truncated formalism must be such that consistency with the full Schroedinger equation is preserved. The DPM is based on a class of new forms for the irreducible cluster potential, which is introduced in the LRT formalism. Connectivity is maintained with respect to all partitions containing a given partition, which is referred to as the dominant partition. Degrees of freedom corresponding to the breakup of one or more of the clusters of the dominant partition are treated in a disconnected manner. This approach for simplifying the complicated BRS equations is appropriate for physical problems where a few body reaction mechanism prevails.

  12. Multi-Determinant Wave-functions in Quantum Monte Carlo

    CERN Document Server

    Morales, M A; Clark, B K; Kim, J; Scuseria, G; 10.1021/ct3003404

    2013-01-01

    Quantum Monte Carlo (QMC) methods have received considerable attention over the last decades due to their great promise for providing a direct solution to the many-body Schrodinger equation in electronic systems. Thanks to their low scaling with number of particles, QMC methods present a compelling competitive alternative for the accurate study of large molecular systems and solid state calculations. In spite of such promise, the method has not permeated the quantum chemistry community broadly, mainly because of the fixed-node error, which can be large and whose control is difficult. In this Perspective, we present a systematic application of large scale multi-determinant expansions in QMC, and report on its impressive performance with first row dimers and the 55 molecules of the G1 test set. We demonstrate the potential of this strategy for systematically reducing the fixed-node error in the wave function and for achieving chemical accuracy in energy predictions. When compared to traditional quantum chemistr...

  13. Unitary Networks from the Exact Renormalization of Wave Functionals

    CERN Document Server

    Fliss, Jackson R; Parrikar, Onkar

    2016-01-01

    The exact renormalization group (ERG) for $O(N)$ vector models (at large $N$) on flat Euclidean space can be interpreted as the bulk dynamics corresponding to a holographically dual higher spin gauge theory on $AdS_{d+1}$. This was established in the sense that at large $N$ the generating functional of correlation functions of single trace operators is reproduced by the on-shell action of the bulk higher spin theory, which is most simply presented in a first-order (phase space) formalism. In this paper, we extend the ERG formalism to the wave functionals of arbitrary states of the $O(N)$ vector model at the free fixed point. We find that the ERG flow of the ground state and a specific class of excited states is implemented by the action of unitary operators which can be chosen to be local. Consequently, the ERG equations provide a continuum notion of a tensor network. We compare this tensor network with the entanglement renormalization networks, MERA, and its continuum version, cMERA, which have appeared rece...

  14. Quantum collapse as a source of the seeds of cosmic structure during the radiation era

    Science.gov (United States)

    León, Gabriel; Landau, Susana J.; Piccirilli, María Pía

    2014-10-01

    The emergence of the seeds of cosmic structure, from a perfect isotropic and homogeneous Universe, has not been clearly explained by the standard version of inflationary models as the dynamics involved preserve the homogeneity and isotropy at all times. A proposal that attempts to deal with this problem, by introducing "the self-induced collapse hypothesis," has been introduced by D. Sudarsky and collaborators in previous papers. In all these works, the collapse of the wave function of the inflaton mode is restricted to occur during the inflationary period. In this paper, we analyze the possibility that the collapse happens during the radiation era. A viable model can be constructed under the condition that the inflaton field variable must be affected by the collapse while the momentum variable can or cannot be affected. Another condition to be fulfilled is that the time of collapse must be independent of k . However, when comparing with recent observational data, the predictions of the model cannot be distinguished from the ones provided by the standard inflationary scenario. The main reason for this arises from the requirement that primordial power spectrum obtained for the radiation era matches the amplitude of scalar fluctuations consistent with the latest cosmic microwave background observations. This latter constraint results in a limit on the possible times of collapse and ensures that the contribution of the inflaton field to the energy-momentum tensor is negligible compared to the contribution of the radiation fields.

  15. Wave-function and density functional theory studies of dihydrogen complexes

    CERN Document Server

    Fabiano, E; Della Sala, F

    2014-01-01

    We performed a benchmark study on a series of dihydrogen bond complexes and constructed a set of reference bond distances and interaction energies. The test set was employed to assess the performance of several wave-function correlated and density functional theory methods. We found that second-order correlation methods describe relatively well the dihydrogen complexes. However, for high accuracy inclusion of triple contributions is important. On the other hand, none of the considered density functional methods can simultaneously yield accurate bond lengths and interaction energies. However, we found that improved results can be obtained by the inclusion of non-local exchange contributions.

  16. On the Galilean transformation of the few-electron wave functions

    CERN Document Server

    Frolov, Alexei M

    2013-01-01

    The Galilean transformations of the few-electron atomic wave functions are considered. We discuss the few-electron wave functions constructed in the model of independent electrons as well as the truly correlated (or highly accurate) wave functions. Results of our analysis are applied to determine the probability of formation of the negatively charged tritium/protium ions during the nuclear $(n,{}^{3}$He$;t,p)-$reaction of the helium-3 atoms with thermal/slow neutrons.

  17. Gravitational Collapse End States

    OpenAIRE

    Joshi, Pankaj S.

    2004-01-01

    Recent developments on the final state of a gravitationally collapsing massive matter cloud are summarized and reviewed here. After a brief background on the problem, we point out how the black hole and naked singularity end states arise naturally in spherical collapse. We see that it is the geometry of trapped surfaces that governs this phenomena.

  18. Collapsing spherical null shells in general relativity

    Directory of Open Access Journals (Sweden)

    S Khakshournia

    2011-03-01

    Full Text Available In this work, the gravitational collapse of a spherically symmetric null shell with the flat interior and a charged Vaidya exterior spacetimes is studied. There is no gravitational impulsive wave present on the null hypersurface which is shear-free and contracting. It follows that there is a critical radius at which the shell bounces and starts expanding.

  19. Photon wave function formalism for analysis of Mach–Zehnder interferometer and sum-frequency generation

    Energy Technology Data Exchange (ETDEWEB)

    Ritboon, Atirach, E-mail: atirach.3.14@gmail.com [School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand); Daengngam, Chalongrat, E-mail: chalongrat.d@psu.ac.th [Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand); Pengpan, Teparksorn, E-mail: teparksorn.p@psu.ac.th [Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand)

    2016-08-15

    Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach–Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.

  20. Metal-Insulator Transition of Solid Hydrogen by the Antisymmetric Shadow Wave Function

    CERN Document Server

    Calcavecchia, Francesco

    2016-01-01

    We present an improved shadow wave function approach to quantum Monte Carlo for large-scale fermionic systems. It is based on employing the antisymmetric shadow wave function in conjunction with the Gaussian determinant method to reduce the variance and an enhanced stochastic reconfiguration scheme to efficiently optimize the trail wave function, as well as refined twist averaged boundary conditions and periodic coordinates techniques. The predictive power of this approach is demonstrated by revisiting the pressure-induced metal-insulator-transition of solid hydrogen. It is found that the ameliorated accuracy of the antisymmetric shadow wave function results in a significantly increased transition pressure.

  1. The Fractional Statistics of Generalized Haldane Wave Function in 4D Quantum Hall Effect

    Institute of Scientific and Technical Information of China (English)

    WANGKe-Lin; WANShao-Long; CHENQing; XUFei

    2003-01-01

    Recently, a generalization of Laughlin's wave function expressed in Haldane's spherical geometry is con-structed in 4D quantum Hall effect. In fact, it is a membrane wave function in CP3 space. In this article, we use non-Abelian Berry phase to anaJyze the statistics of this membrane wave function. Our results show that the membrane wave function obeys fractional statistics. It is the rare example to realize fractional statistics in higher-dimensiona space than 2D. And, it will help to make clear the unresolved problems in 4D quantum Hall effect.

  2. Four Tails Problems for Dynamical Collapse Theories

    CERN Document Server

    McQueen, Kelvin J

    2015-01-01

    The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem di...

  3. Multidimensional Wave Field Signal Theory: Transfer Function Relationships

    Directory of Open Access Journals (Sweden)

    Natalie Baddour

    2012-01-01

    Full Text Available The transmission of information by propagating or diffusive waves is common to many fields of engineering and physics. Such physical phenomena are governed by a Helmholtz (real wavenumber or pseudo-Helmholtz (complex wavenumber equation. Since these equations are linear, it would be useful to be able to use tools from signal theory in solving related problems. The aim of this paper is to derive multidimensional input/output transfer function relationships in the spatial domain for these equations in order to permit such a signal theoretic approach to problem solving. This paper presents such transfer function relationships for the spatial (not Fourier domain within appropriate coordinate systems. It is shown that the relationships assume particularly simple and computationally useful forms once the appropriate curvilinear version of a multidimensional spatial Fourier transform is used. These results are shown for both real and complex wavenumbers. Fourier inversion of these formulas would have applications for tomographic problems in various modalities. In the case of real wavenumbers, these inversion formulas are presented in closed form, whereby an input can be calculated from a given or measured wavefield.

  4. The effects of extracorporeal shock wave therapy on frozen shoulder patients’ pain and functions

    OpenAIRE

    2015-01-01

    [Purpose] The present study was conducted to examine the effects of extracorporeal shock wave therapy on frozen shoulder patients’ pain and functions. [Subjects] In the present study, 30 frozen shoulder patients were divided into two groups: an extracorporeal shock wave therapy group of 15 patients and a conservative physical therapy group of 15 patients. [Methods] Two times per week for six weeks, the extracorporeal shock wave therapy group underwent extracorporeal shock wave therapy, and th...

  5. Wave function of the Universe in the early stage of its evolution

    CERN Document Server

    Maydanyuk, Sergei P

    2007-01-01

    In quantum cosmological models, constructed in the Friedmann-Robertson-Walker metrics, a nucleation of Universe with its further extension is described as a tunneling transition (or leaving out) of wave through effective barrier between regions with small and large values of scale factor a at nonzero (or zero) energy. An approach for description of tunneling with leaving outside consists in construction of wave function under choice of needed boundary condition. There are different ways for definition of the boundary condition that leads to different estimations of barrier penetrability and duration of the Universe nucleation. In given paper, with a purpose to describe a process of leaving of the wave from the tunneling region outside accurately as possible, to construct the total wave function on the basis of its two partial solutions unambiguously, the tunneling boundary condition (the total wave function must represent only the wave outgoing outside) is used at point of the wave leaving from the barrier ou...

  6. Collapse dynamics of bubble raft under compression

    Science.gov (United States)

    Kuo, Chin-Chang; Kachan, Devin; Levine, Alexander; Dennin, Michael; Department of Physics; Astronomy, University of California, Irvine Collaboration; Department of Physics; Astronomy, University of California, Los Angeles Collaboration

    2015-03-01

    We report on the collapse of bubble rafts under compression in a closed rectangular geometry. A bubble raft is a single layer of bubbles at the air-water interface. A collapse event occurs when bubbles submerge beneath the neighboring bubbles under applied compression causing the structure of the bubble raft to go from single-layer to multi-layer. We studied the collapse dynamics as a function of compression velocity. At higher compression velocity we observe a more uniform distribution of collapse events, whereas at lower compression velocities, the collapse events accumulate at the system boundaries. We will present results that compare the distribution of collapse probability in the experiments to simulations based on a one-dimensional Ising model with elastic coupling between spin elements. Both the experimental system and simulations are excellent models for collapse in a number of complex systems. By comparing the two systems, we can tune the simulation to better understand the role of the Ising and elastic couplings in determining the collapse dynamics. We acknowledge DMR-1309402.

  7. Shadow wave-function variational calculations of crystalline and liquid phases of 4He

    Science.gov (United States)

    Vitiello, S. A.; Runge, K. J.; Chester, G. V.; Kalos, M. H.

    1990-07-01

    A new class of variational wave functions for boson systems, shadow wave functions, is used to investigate the properties of solid and liquid 4He. The wave function is translationally invariant and symmetric under particle interchange. In principle, the calculations for the crystalline phase do not require the use of any auxiliary lattice. Using the Metropolis Monte Carlo algorithm, we show that the additional variational degrees of freedom in the wave function lower the energy significantly. This wave function also allows the crystalization of an equilibrated liquid phase when a crystalline seed is used. The pair correlation function and structure factor S(k) are determined in the liquid phase. The condensate fraction is calculated as well. Results are given for the single-particle distribution function around the lattice positions in the solid phase.

  8. A single-sided representation for the homogeneous Green's function of a unified scalar wave equation.

    Science.gov (United States)

    Wapenaar, Kees

    2017-06-01

    A unified scalar wave equation is formulated, which covers three-dimensional (3D) acoustic waves, 2D horizontally-polarised shear waves, 2D transverse-electric EM waves, 2D transverse-magnetic EM waves, 3D quantum-mechanical waves and 2D flexural waves. The homogeneous Green's function of this wave equation is a combination of the causal Green's function and its time-reversal, such that their singularities at the source position cancel each other. A classical representation expresses this homogeneous Green's function as a closed boundary integral. This representation finds applications in holographic imaging, time-reversed wave propagation and Green's function retrieval by cross correlation. The main drawback of the classical representation in those applications is that it requires access to a closed boundary around the medium of interest, whereas in many practical situations the medium can be accessed from one side only. Therefore, a single-sided representation is derived for the homogeneous Green's function of the unified scalar wave equation. Like the classical representation, this single-sided representation fully accounts for multiple scattering. The single-sided representation has the same applications as the classical representation, but unlike the classical representation it is applicable in situations where the medium of interest is accessible from one side only.

  9. Covariant nucleon wave function with S, D, and P-state components

    CERN Document Server

    Gross, Franz; Pena, M T

    2012-01-01

    Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.

  10. Covariant nucleon wave function with S, D, and P-state components

    Energy Technology Data Exchange (ETDEWEB)

    Franz Gross, G. Ramalho, M. T. Pena

    2012-05-01

    Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.

  11. Experimental determination of wave function spread in Si inversion layers

    Science.gov (United States)

    Majumdar, Amlan

    2010-08-01

    We have experimentally determined the extent of wave function spread TQM in Si inversion layers on (100)-oriented surface in metal-oxide-semiconductor field-effect transistors (MOSFETs) using the back gate bias sensitivity of front gate threshold voltage of planar fully depleted silicon-on-insulator (SOI) MOSFETs. We show that the sum of TQM for large positive and negative F is an electrically determined value of the SOI thickness TSI. We find that the electric field dependence of TQM for electrons and holes is given by TQM˜F-0.4 and F-0.6, respectively, at high electric fields with TQM being larger for holes at a given F. Larger TQM for holes can be explained by the fact that holes have a smaller effective mass along the confinement direction than electrons in (100) Si. The field dependences of TQM are, however, not consistent with the results of variational calculations that assume single-subband occupancy and predict TQM˜F-1/3. The discrepancy likely indicates that the effects of multiple-subband occupation are significant at room temperature, especially for holes.

  12. Multiple-resonance local wave functions for accurate excited states in quantum Monte Carlo

    NARCIS (Netherlands)

    Zulfikri, Habiburrahman; Amovilli, Claudio; Filippi, Claudia

    2016-01-01

    We introduce a novel class of local multideterminant Jastrow–Slater wave functions for the efficient and accurate treatment of excited states in quantum Monte Carlo. The wave function is expanded as a linear combination of excitations built from multiple sets of localized orbitals that correspond to

  13. The Meaning of the Wave Function: In Search of the Ontology of Quantum Mechanics

    CERN Document Server

    Gao, Shan

    2016-01-01

    The meaning of the wave function has been a hot topic of debate since the early days of quantum mechanics. Recent years have witnessed a growing interest in this long-standing question. Is the wave function ontic, directly representing a state of reality, or epistemic, merely representing a state of (incomplete) knowledge, or something else? If the wave function is not ontic, then what, if any, is the underlying state of reality? If the wave function is indeed ontic, then exactly what physical state does it represent? In this book, I aim to make sense of the wave function in quantum mechanics and find the ontological content of the theory. The book can be divided into three parts. The first part addresses the question of the nature of the wave function (Chapters 1-5). After giving a comprehensive and critical review of the competing views of the wave function, I present a new argument for the ontic view in terms of protective measurements. In addition, I also analyze the origin of the wave function by derivin...

  14. Short-range spin- and pair-correlations : a variational wave-function

    NARCIS (Netherlands)

    van der Marel, D

    2004-01-01

    A many-body wave-function is postulated, which is sufficiently general to describe superconducting pair-correlations, and/or spin-correlations, which can occur either as long-range order or as finite-range correlations. The proposed wave-function appears to summarize some of the more relevant aspect

  15. Structure of the channeling electrons wave functions under dynamical chaos conditions

    CERN Document Server

    Shul'ga, N F; Tarnovsky, A I; Isupov, A Yu

    2015-01-01

    The stationary wave functions of fast electrons axially channeling in the silicon crystal near [110] direction have been found numerically for integrable and non-integrable cases, for which the classical motion is regular and chaotic, respectively. The nodal structure of the wave functions in the quasi-classical region, where the energy levels density is high, is agreed with quantum chaos theory predictions.

  16. Coherent cooling of atoms in a frequency-modulated standing laser wave: wave function and stochastic trajectory approaches

    CERN Document Server

    Argonov, Victor

    2013-01-01

    The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, we show that frequency modulation of the field may suppress packet splitting for some atoms having specific velocities in a narrow range. These atoms remain localized in a small space for a long time. We demonstrate and explain this effect numerically and analytically. Also we demonstrate that modulated field can not only trap, but also cool the atoms. We perform a numerical experiment with a large atomic ensebmble having wide initial velocity and energy distribution. During the experiment, most of atoms leave the wave while trapped atoms have narrow energy distribution

  17. Exact density functional and wave function embedding schemes based on orbital localization

    Science.gov (United States)

    Hégely, Bence; Nagy, Péter R.; Ferenczy, György G.; Kállay, Mihály

    2016-08-01

    Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up the system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.

  18. Collapse of axion stars

    Science.gov (United States)

    Eby, Joshua; Leembruggen, Madelyn; Suranyi, Peter; Wijewardhana, L. C. R.

    2016-12-01

    Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leading-order expansion of the axion potential. Heavier states are susceptible to gravitational collapse. Inclusion of higher-order interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leading-order expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present in the full potential, providing evidence that such objects do not form black holes. In the last moments of collapse, the binding energy of the axion star grows rapidly, and we provide evidence that a large amount of its energy is lost through rapid emission of relativistic axions.

  19. Collapse of Axion Stars

    CERN Document Server

    Eby, Joshua; Suranyi, Peter; Wijewardhana, L C R

    2016-01-01

    Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leading-order expansion of the axion potential. Heavier states are susceptible to gravitational collapse. Inclusion of higher-order interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leading-order expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present in the full potential, providing evidence that such objects do not form black holes. These dense configurations, which are the endpoints of collapse, have extremely high binding energy, and as a result, decay through number changing $3\\,a\\rightarrow a$ interactions with an extremely short lifetime.

  20. Cosmogenesis and Collapse

    CERN Document Server

    Pearle, Philip

    2010-01-01

    Some possible benefits of dynamical collapse for a quantum theory of cosmogenesis are discussed. These are a possible long wait before creation begins, creation of energy and space, and choice of a particular universe out of a superposition.

  1. Collapse of axion stars

    Energy Technology Data Exchange (ETDEWEB)

    Eby, Joshua [Department of Physics, University of Cincinnati,2600 Clifton Ave, Cincinnati, OH, 45221 (United States); Fermi National Accelerator Laboratory,P.O. Box 500, Batavia, IL, 60510 (United States); Leembruggen, Madelyn; Suranyi, Peter; Wijewardhana, L.C.R. [Department of Physics, University of Cincinnati,2600 Clifton Ave, Cincinnati, OH, 45221 (United States)

    2016-12-15

    Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leading-order expansion of the axion potential. Heavier states are susceptible to gravitational collapse. Inclusion of higher-order interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leading-order expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present in the full potential, providing evidence that such objects do not form black holes. In the last moments of collapse, the binding energy of the axion star grows rapidly, and we provide evidence that a large amount of its energy is lost through rapid emission of relativistic axions.

  2. Alba Patera Collapse Pits

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form. This image of the Alba Patera region has both lava tube collapse pits (running generally east/west) and subsidence related collapse within structural grabens. Image information: IR instrument. Latitude 26.9, Longitude 256.5 East (103.5 West). 100 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science

  3. Lava Tube Collapse Pits

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form. These collapse pits are found in the southern hemisphere of Mars. They are likely lava tube collapse pits related to flows from Hadriaca Patera. Image information: VIS instrument. Latitude -36.8, Longitude 89.6 East (270.4 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D

  4. Realism and instrumentalism about the wave function. How should we choose?

    CERN Document Server

    Dorato, Mauro

    2014-01-01

    The main claim of the paper is that one can be 'realist' (in some sense) about quantum mechanics without requiring any form of realism about the wave function. We begin by discussing various forms of realism about the wave function, namely Albert's configuration-space realism, Duerr Zanghi and Goldstein's nomological realism about the wave function, Esfeld's dispositional reading of the wave function and Pusey Barrett and Rudolph's realism about the quantum state. By discussing the articulation of these four positions, and their interrelation, we conclude that instrumentalism about the wave function is by itself not sufficient to choose one over the other interpretations of quantum mechanics, thereby confirming in a different way the indetermination of the metaphysical interpretations of quantum mechanics.

  5. Fractal dimensions of wave functions and local spectral measures on the Fibonacci chain

    Science.gov (United States)

    Macé, Nicolas; Jagannathan, Anuradha; Piéchon, Frédéric

    2016-05-01

    We present a theoretical framework for understanding the wave functions and spectrum of an extensively studied paradigm for quasiperiodic systems, namely the Fibonacci chain. Our analytical results, which are obtained in the limit of strong modulation of the hopping amplitudes, are in good agreement with published numerical data. In the perturbative limit, we show a symmetry of wave functions under permutation of site and energy indices. We compute the wave-function renormalization factors and from them deduce analytical expressions for the fractal exponents corresponding to individual wave functions, as well as their global averages. The multifractality of wave functions is seen to appear at next-to-leading order in ρ . Exponents for the local spectral density are given, in extremely good accord with numerical calculations. Interestingly, our analytical results for exponents are observed to describe the system rather well even for values of ρ well outside the domain of applicability of perturbation theory.

  6. Gravity wave propagation in the realistic atmosphere based on a three-dimensional transfer function model

    Directory of Open Access Journals (Sweden)

    L. Sun

    2007-10-01

    Full Text Available In order to study the filter effect of the background winds on the propagation of gravity waves, a three-dimensional transfer function model is developed on the basis of the complex dispersion relation of internal gravity waves in a stratified dissipative atmosphere with background winds. Our model has successfully represented the main results of the ray tracing method, e.g. the trend of the gravity waves to travel in the anti-windward direction. Furthermore, some interesting characteristics are manifest as follows: (1 The method provides the distribution characteristic of whole wave fields which propagate in the way of the distorted concentric circles at the same altitude under the control of the winds. (2 Through analyzing the frequency and wave number response curve of the transfer function, we find that the gravity waves in a wave band of about 15–30 min periods and of about 200–400 km horizontal wave lengths are most likely to propagate to the 300-km ionospheric height. Furthermore, there is an obvious frequency deviation for gravity waves propagating with winds in the frequency domain. The maximum power of the transfer function with background winds is smaller than that without background winds. (3 The atmospheric winds may act as a directional filter that will permit gravity wave packets propagating against the winds to reach the ionospheric height with minimum energy loss.

  7. Ascraeus Mons Collapse Pits

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form. These collapse pits are found on the flank of Ascraeus Mons. The pits and channels are all related to lava tube formation and emptying. Image information: IR instrument. Latitude 8, Longitude 253.9 East (106.1 West). 100 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal

  8. Sulci Collapse Pits

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form. This is the Noctis Labyrinthus region of Mars. These collapse pits are forming along structural fractures that are allowing the release of volatiles from the subsurface. This is believed to be the way that chaos terrain forms on Mars. This area represents the early stage of chaos formation. Image information: VIS instrument. Latitude -12.6, Longitude 264 East (96 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project

  9. Tharsis Collapse Pits

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form. These collapse pits are found within the extensive lava flows of the Tharsis region. They are related to lava tubes, likely coming from Ascraeus Mons. Image information: VIS instrument. Latitude 22.8, Longitude 266.8 East (93.2 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington

  10. Tractus Catena Collapse Pits

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form. These collapse pits are found in graben located in Tractus Catena. These features are related to subsidence after magma chamber evacuation of Alba Patera. Image information: VIS instrument. Latitude 35.8, Longitude 241.7 East (118.3 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science

  11. Motion of three vortices near collapse

    Science.gov (United States)

    Leoncini, X.; Kuznetsov, L.; Zaslavsky, G. M.

    2000-08-01

    A system of three point vortices in an unbounded plane has a special family of self-similarly contracting or expanding solutions: during the motion, the vortex triangle remains similar to the original one, while its area decreases (grows) at a constant rate. A contracting configuration brings three vortices to a single point in a finite time; this phenomenon known as vortex collapse is of principal importance for many-vortex systems. Dynamics of close-to-collapse vortex configurations depends on the way the collapse conditions are violated. Using an effective potential representation, a detailed quantitative analysis of all the different types of near-collapse dynamics is performed when two of the vortices are identical. We discuss time and length scales, emerging in the problem, and their behavior as the initial vortex triangle is approaching an exact collapse configuration. Different types of critical behaviors, such as logarithmic or power-law divergences are exhibited, which emphasize the importance of the way the collapse is approached. Period asymptotics for all singular cases are presented as functions of the initial vortice's configurations. Special features of passive particle mixing by near-collapse flows are illustrated numerically.

  12. Covariant spectator theory of $np$ scattering:\\\\ Effective range expansions and relativistic deuteron wave functions

    Energy Technology Data Exchange (ETDEWEB)

    Franz Gross, Alfred Stadler

    2010-09-01

    We present the effective range expansions for the 1S0 and 3S1 scattering phase shifts, and the relativistic deuteron wave functions that accompany our recent high precision fits (with \\chi^2/N{data} \\simeq 1) to the 2007 world np data below 350 MeV. The wave functions are expanded in a series of analytical functions (with the correct asymptotic behavior at both large and small arguments) that can be Fourier-transformed from momentum to coordinate space and are convenient to use in any application. A fortran subroutine to compute these wave functions can be obtained from the authors.

  13. The Fractional Statistics of Generalized Haldane Wave Function in 4D Quantum Hall Effect

    Institute of Scientific and Technical Information of China (English)

    XU Fei; WANG Ke-Lin; WAN Shao-Long; CHEN Qing

    2003-01-01

    Recently, a generalization of Laughlin's wave function expressed in Haldane's spherical geometry is con-structed in 4D quantum Hall effect. In fact, it is a membrane wave function in CP3 space. In this article, we usenon-Abelian Berry phase to analyze the statistics of this membrane wave function. Our results show that the membranewave function obeys fractional statistics. It is the rare example to realize fractional statistics in higher-dimensional spacethan 2D. And, it will help to make clear the unresolved problems in 4D quantum Hall effect.

  14. Relativistic Axions from Collapsing Bose Stars

    Science.gov (United States)

    Levkov, D. G.; Panin, A. G.; Tkachev, I. I.

    2017-01-01

    The substructures of light bosonic (axionlike) dark matter may condense into compact Bose stars. We study the collapse of critical-mass stars caused by attractive self-interaction of the axionlike particles and find that these processes proceed in an unexpected universal way. First, nonlinear self-similar evolution (called "wave collapse" in condensed matter physics) forces the particles to fall into the star center. Second, interactions in the dense center create an outgoing stream of mildly relativistic particles which carries away an essential part of the star mass. The collapse stops when the star remnant is no longer able to support the self-similar infall feeding the collisions. We shortly discuss possible astrophysical and cosmological implications of these phenomena.

  15. Relativistic axions from collapsing Bose stars

    CERN Document Server

    Levkov, D G; Tkachev, I I

    2016-01-01

    The substructures of light bosonic (axion-like) dark matter may condense into compact Bose stars. We study collapses of the critical-mass stars caused by attractive self-interaction of the axion-like particles and find that these processes proceed in an unexpected universal way. First, nonlinear self-similar evolution (similar to "wave collapse" in plasma physics) forces the particles to fall into the star center. Second, collisions in the dense center create an outgoing stream of mildly relativistic particles which carries away an essential part of the star mass. The collapse stops when the star remnant is no longer able to support the self-similar infall feeding the collisions. We shortly discuss possible astrophysical and cosmological implications of these phenomena.

  16. Quantum collapse as source of the seeds of cosmic structure during the radiation era

    CERN Document Server

    León, Gabriel; Piccirilli, María Pía

    2014-01-01

    The emergence of the seeds of cosmic structure, from a perfect isotropic and homogeneous Universe, has not been clearly explained by the standard version of inflationary models as the dynamics involved preserve the homogeneity and isotropy at all times. A proposal that attempts to deal with this problem, by introducing "the self-induced collapse hypothesis," has been introduced by D. Sudarsky and collaborators in previous papers. In all these works, the collapse of the wave function of the inflaton mode is restricted to occur during the inflationary period. In this paper, we analyse the possibility that the collapse happens during the radiation era. A viable model can be constructed under the condition that the inflaton field variable must be affected by the collapse while the momentum variable can or cannot be affected. Another condition to be fulfilled is that the time of collapse must be independent of $k$. However, when comparing with recent observational data, the predictions of the model cannot be disti...

  17. Detection of gravitational waves in Michelson interferometer by the use of second order correlation functions

    CERN Document Server

    Ben-Aryeh, Y

    2006-01-01

    The possibility of measuring the second order correlation function of the gravitational waves detectors' currents or photonumbers, and the observation of the gravitational signals by using a spectrum analyzer is discussed. The method is based on complicated data processing and is expected to be efficient for coherent periodic gravitational waves. It is suggested as an alternative method to the conventional one which is used now in the gravitational waves observatories.

  18. Ocean wave-radar modulation transfer functions from the West Coast experiment

    Science.gov (United States)

    Wright, J. W.; Plant, W. J.; Keller, W. C.; Jones, W. L.

    1980-01-01

    Short gravity-capillary waves, the equilibrium, or the steady state excitations of the ocean surface are modulated by longer ocean waves. These short waves are the predominant microwave scatterers on the ocean surface under many viewing conditions so that the modulation is readily measured with CW Doppler radar used as a two-scale wave probe. Modulation transfer functions (the ratio of the cross spectrum of the line-of-sight orbital speed and backscattered microwave power to the autospectrum of the line-of-sight orbital speed) were measured at 9.375 and 1.5 GHz (Bragg wavelengths of 2.3 and 13 cm) for winds up to 10 m/s and ocean wave periods from 2-18 s. The measurements were compared with the relaxation-time model; the principal result is that a source of modulation other than straining by the horizontal component of orbital speed, possibly the wave-induced airflow, is responsible for most of the modulation by waves of typical ocean wave period (10 s). The modulations are large; for unit coherence, spectra of radar images of deep-water waves should be proportional to the quotient of the slope spectra of the ocean waves by the ocean wave frequency.

  19. Propagation of ultrasonic Love waves in nonhomogeneous elastic functionally graded materials.

    Science.gov (United States)

    Kiełczyński, P; Szalewski, M; Balcerzak, A; Wieja, K

    2016-02-01

    This paper presents a theoretical study of the propagation behavior of ultrasonic Love waves in nonhomogeneous functionally graded elastic materials, which is a vital problem in the mechanics of solids. The elastic properties (shear modulus) of a semi-infinite elastic half-space vary monotonically with the depth (distance from the surface of the material). The Direct Sturm-Liouville Problem that describes the propagation of Love waves in nonhomogeneous elastic functionally graded materials is formulated and solved by using two methods: i.e., (1) Finite Difference Method, and (2) Haskell-Thompson Transfer Matrix Method. The dispersion curves of phase and group velocity of surface Love waves in inhomogeneous elastic graded materials are evaluated. The integral formula for the group velocity of Love waves in nonhomogeneous elastic graded materials has been established. The effect of elastic non-homogeneities on the dispersion curves of Love waves is discussed. Two Love wave waveguide structures are analyzed: (1) a nonhomogeneous elastic surface layer deposited on a homogeneous elastic substrate, and (2) a semi-infinite nonhomogeneous elastic half-space. Obtained in this work, the phase and group velocity dispersion curves of Love waves propagating in the considered nonhomogeneous elastic waveguides have not previously been reported in the scientific literature. The results of this paper may give a deeper insight into the nature of Love waves propagation in elastic nonhomogeneous functionally graded materials, and can provide theoretical guidance for the design and optimization of Love wave based devices.

  20. Application of wave-shape functions and Synchrosqueezing transform to pulse signal analysis

    CERN Document Server

    Wu, Hau-tieng; Wu, Han-Kuei; Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang

    2015-01-01

    We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and study the pulse wave signal. Based on the wave shape function model and SST, we extract features, called the spectral pulse signature, based on the functional regression technique, to characterize the hemodynamics from the pulse wave signals. To demonstrate how the algorithm and the extracted features work, we study the radial pulse wave signal recorded by the sphygmomanometer from normal subjects and patients with congestive heart failure. The analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features. In addition, it shows that different positions of the radial artery contain significant different information, which is compatible with the empirical conclusion of the pulse diagnosis in the traditional Chinese medicine.

  1. Analytic calculations of trial wave functions of the fractional quantum Hall effect on the sphere

    Energy Technology Data Exchange (ETDEWEB)

    Souza Batista, C.L. de [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Dingping Li [Perugia Univ. (Italy). Dipt. di Fisica

    1996-07-01

    We present a framework for the analytic calculations of the hierarchical wave functions and the composite fermion wave functions in the fractional quantum Hall effect on the sphere by using projective coordinates. Then we calculate the overlaps between these two wave functions at various fillings and small numbers of electrons. We find that the overlaps are most equal to one. This gives a further evidence that two theories of the fractional quantum Hall effect, the hierarchical theory, are physically equivalent. (author). 31 refs., 2 tabs.

  2. Four tails problems for dynamical collapse theories

    Science.gov (United States)

    McQueen, Kelvin J.

    2015-02-01

    The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory.

  3. A nonorthogonal state-interaction approach for matrix product state wave functions

    CERN Document Server

    Knecht, Stefan; Autschbach, Jochen; Reiher, Markus

    2016-01-01

    We present a state-interaction approach for matrix product state (MPS) wave functions in a nonorthogonal molecular orbital basis. Our approach allows us to calculate for example transition and spin-orbit coupling matrix elements between arbitrary electronic states provided that they share the same one-electron basis functions and active orbital space, respectively. The key element is the transformation of the MPS wave functions of different states from a nonorthogonal to a biorthonormal molecular orbital basis representation exploiting a sequence of non-unitary transformations following a proposal by Malmqvist (Int. J. Quantum Chem. 30, 479 (1986)). This is well-known for traditional wave-function parametrizations but has not yet been exploited for MPS wave functions.

  4. Degenerate RS perturbation theory. [Rayleigh-Schroedinger energies and wave functions

    Science.gov (United States)

    Hirschfelder, J. O.; Certain, P. R.

    1974-01-01

    A concise, systematic procedure is given for determining the Rayleigh-Schroedinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n + 1)-th order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite-order operators which are determined by the successive resolution of the space of the zeroth-order functions.

  5. Functionally graded piezoelectric materials for modal transducers for exciting bulk and surface acoustic waves.

    Science.gov (United States)

    Yang, Jiashi; Jin, Zhihe; Li, Jiangyu

    2008-07-01

    We show that functionally graded piezoelectric materials can be used to make modal actuators through theoretical analyses of the excitation of extensional motion in an elastic rod and Rayleigh surface waves over an elastic half-plane. The results suggest alternatives with certain advantages for the excitation of bulk and surface acoustic waves.

  6. Growth cone collapse assay.

    Science.gov (United States)

    Cook, Geoffrey M W; Jareonsettasin, Prem; Keynes, Roger J

    2014-01-01

    The growth cone collapse assay has proved invaluable in detecting and purifying axonal repellents. Glycoproteins/proteins present in detergent extracts of biological tissues are incorporated into liposomes, added to growth cones in culture and changes in morphology are then assessed. Alternatively purified or recombinant molecules in aqueous solution may be added directly to the cultures. In both cases after a defined period of time (up to 1 h), the cultures are fixed and then assessed by inverted phase contrast microscopy for the percentage of growth cones showing a collapsed profile with loss of flattened morphology, filopodia, and lamellipodia.

  7. On bore collapse

    Science.gov (United States)

    Yeh, Harry H.; Ghazali, A.

    1988-06-01

    Using the laser-induced fluorescent method, the transition process from bore to runup mode, i.e., "bore collapse," is investigated experimentally. The observed process appears to be different from both previous analytical and numerical predictions. The results indicate that momentum exchange takes place between the incident bore and the quiescent water body along the shoreline. Turbulence generated in a bore nearshore is highly three-dimensional and sporadic. Very close to the shore, turbulence is advected with the bore front, and consequently, the bore collapse process involves strong turbulent action onto the dry beach bed.

  8. A Stream Function Theory Based Calculation of Wave Kinematics for Very Steep Waves Using a Novel Non-linear Stretching Technique

    DEFF Research Database (Denmark)

    Stroescu, Ionut Emanuel; Sørensen, Lasse; Frigaard, Peter Bak

    2016-01-01

    A non-linear stretching method was implemented for stream function theory to solve wave kinematics for physical conditions close to breaking waves in shallow waters, with wave heights limited by the water depth. The non-linear stretching method proves itself robust, efficient and fast, showing good...

  9. Rogue Waves of Nonlinear Schrödinger Equation with Time-Dependent Linear Potential Function

    Directory of Open Access Journals (Sweden)

    Ni Song

    2016-01-01

    Full Text Available The rogue waves of the nonlinear Schrödinger equation with time-dependent linear potential function are investigated by using the similarity transformation in this paper. The first-order and second-order rogue waves solutions are obtained and the nonlinear dynamic behaviors of these solutions are discussed in detail. In addition, the amplitudes of the rogue waves under the effect of the gravity field and external magnetic field changing with the time are analyzed by using numerical simulation. The results can be used to study the matter rogue waves in the Bose-Einstein condensates and other fields of nonlinear science.

  10. Potential applications of low-energy shock waves in functional urology.

    Science.gov (United States)

    Wang, Hung-Jen; Cheng, Jai-Hong; Chuang, Yao-Chi

    2017-08-01

    A shock wave, which carries energy and can propagate through a medium, is a type of continuous transmitted sonic wave with a frequency of 16 Hz-20 MHz. It is accompanied by processes involving rapid energy transformations. The energy associated with shock waves has been harnessed and used for various applications in medical science. High-energy extracorporeal shock wave therapy is the most successful application of shock waves, and has been used to disintegrate urolithiasis for 30 years. At lower energy levels, however, shock waves have enhanced expression of vascular endothelial growth factor, endothelial nitric oxide synthase, proliferating cell nuclear antigen, chemoattractant factors and recruitment of progenitor cells; shock waves have also improved tissue regeneration. Low-energy shock wave therapy has been used clinically with musculoskeletal disorders, ischemic cardiovascular disorders and erectile dysfunction, through the mechanisms of neovascularization, anti-inflammation and tissue regeneration. Furthermore, low-energy shock waves have been proposed to temporarily increase tissue permeability and facilitate intravesical drug delivery. The present review article provides information on the basics of shock wave physics, mechanisms of action on the biological system and potential applications in functional urology. © 2017 The Japanese Urological Association.

  11. Characterizing the parent Hamiltonians for a complete set of orthogonal wave functions: An inverse quantum problem

    Science.gov (United States)

    Ramezanpour, A.

    2016-06-01

    We study the inverse problem of constructing an appropriate Hamiltonian from a physically reasonable set of orthogonal wave functions for a quantum spin system. Usually, we are given a local Hamiltonian and our goal is to characterize the relevant wave functions and energies (the spectrum) of the system. Here, we take the opposite approach; starting from a reasonable collection of orthogonal wave functions, we try to characterize the associated parent Hamiltonians, to see how the wave functions and the energy values affect the structure of the parent Hamiltonian. Specifically, we obtain (quasi) local Hamiltonians by a complete set of (multilayer) product states and a local mapping of the energy values to the wave functions. On the other hand, a complete set of tree wave functions (having a tree structure) results to nonlocal Hamiltonians and operators which flip simultaneously all the spins in a single branch of the tree graph. We observe that even for a given set of basis states, the energy spectrum can significantly change the nature of interactions in the Hamiltonian. These effects can be exploited in a quantum engineering problem optimizing an objective functional of the Hamiltonian.

  12. Interpolated wave functions for nonadiabatic simulations with the fixed-node quantum Monte Carlo method

    CERN Document Server

    Tubman, Norm; Hammes-Schiffer, Sharon; Ceperley, David

    2016-01-01

    Simulating nonadiabatic effects with many-body wave function approaches is an open field with many challenges. Recent interest has been driven by new algorithmic developments and improved theoretical understanding of properties unique to electron-ion wave functions. Fixed-node diffusion Monte Caro is one technique that has shown promising results for simulating electron-ion systems. In particular, we focus on the CH molecule for which previous results suggested a relatively significant contribution to the energy from nonadiabatic effects. We propose a new wave function ansatz for diatomic systems which involves interpolating the determinant coefficients calculated from configuration interaction methods. We find this to be an improvement beyond previous wave function forms that have been considered. The calculated nonadiabatic contribution to the energy in the CH molecule is reduced compared to our previous results, but still remains the largest among the molecules under consideration.

  13. Continuity Conditions on Schrodinger Wave Functions at Discontinuities of the Potential.

    Science.gov (United States)

    Branson, David

    1979-01-01

    Several standard arguments which attempt to show that the wave function and its derivative must be continuous across jump discontinuities of the potential are reviewed and their defects discussed. (Author/HM)

  14. The meaning of the wave function in search of the ontology of quantum mechanics

    CERN Document Server

    Gao, Shan

    2017-01-01

    At the heart of quantum mechanics lies the wave function, a powerful but mysterious mathematical object which has been a hot topic of debate from its earliest stages. Covering much of the recent debate and providing a comprehensive and critical review of competing approaches, this ambitious text provides new, decisive proof of the reality of the wave function. Aiming to make sense of the wave function in quantum mechanics and to find the ontological content of the theory, this book explores new ontological interpretations of the wave function in terms of random discontinuous motion of particles. Finally, the book investigates whether the suggested quantum ontology is complete in solving the measurement problem and if it should be revised in the relativistic domain. A timely addition to the literature on the foundations of quantum mechanics, this book is of value to students and researchers with an interest in the philosophy of physics. Presents a concise introduction to quantum mechanics, including the c...

  15. Second-Order Perturbation Theory for Generalized Active Space Self-Consistent-Field Wave Functions.

    Science.gov (United States)

    Ma, Dongxia; Li Manni, Giovanni; Olsen, Jeppe; Gagliardi, Laura

    2016-07-12

    A multireference second-order perturbation theory approach based on the generalized active space self-consistent-field (GASSCF) wave function is presented. Compared with the complete active space (CAS) and restricted active space (RAS) wave functions, GAS wave functions are more flexible and can employ larger active spaces and/or different truncations of the configuration interaction expansion. With GASSCF, one can explore chemical systems that are not affordable with either CASSCF or RASSCF. Perturbation theory to second order on top of GAS wave functions (GASPT2) has been implemented to recover the remaining electron correlation. The method has been benchmarked by computing the chromium dimer ground-state potential energy curve. These calculations show that GASPT2 gives results similar to CASPT2 even with a configuration interaction expansion much smaller than the corresponding CAS expansion.

  16. Many-body nodal hypersurface and domain averages for correlated wave functions

    CERN Document Server

    Hu, Shuming; Mitas, Lubos

    2013-01-01

    We outline the basic notions of nodal hypersurface and domain averages for antisymmetric wave functions. We illustrate their properties and analyze the results for a few electron explicitly solvable cases and discuss possible further developments.

  17. Weak Equivalence Principle and Propagation of the Wave Function in Quantum Mechanics

    CERN Document Server

    de Matos, Clovis Jacinto

    2010-01-01

    The propagation of the wave function of a particle is characterised by a group and a phase velocity. The group velocity is associated with the particle's classical velocity, which is always smaller than the speed of light, and the phase velocity is associated with the propagation speed of the wave function phase and is treated as being unphysical, since its value is always greater than the speed of light. Here we show, using Sciama's Machian formulation of rest mass energy, that this physical interpretation, for the group and the phase velocity of the wave function, is only valid if the weak equivalence principle strictly holds for the propagating particle, except for the photon. In case this constraint is released the phase velocity of the wave function could acquire a physical meaning in quantum condensates.

  18. Globally singularity-free semi-classical wave functions in closed form

    CERN Document Server

    Jung, C; Seligman, T H

    2000-01-01

    We use a factorization technique and representation of canonical transformations to construct globally valid closed form expressions without singularities of semi-classical wave functions for arbitrary smooth potentials over a one-dimensional position space.

  19. Transformation between harmonic-oscillator wave functions in different coordinate bases

    Energy Technology Data Exchange (ETDEWEB)

    Davies, K.T.R.; Krieger, S.J.

    1981-10-01

    Coefficients are derived for transformations between harmonic oscillator wave functions in different coordinate representations. Such coefficients have been found especially useful in performing static Hartree-Fock calculations for nuclei of widely varying shapes.

  20. Revival of the Phase-Amplitude Description of a Quantum-Mechanical Wave Function

    Science.gov (United States)

    Rawitscher, George

    2017-01-01

    The phase-amplitude description of a wave function is formulated by means of a new linear differential-integral equation, which is valid in the region of turning points. A numerical example for a Coulomb potential is presented.

  1. Collapsible Geostrut Structure

    Science.gov (United States)

    Robertson, Glen A.

    1994-01-01

    Portable truss structure collapsible into smaller volume for storage and transportation. At new site, reerected quickly, without need to reassemble parts. Structure could be tent, dome, tunnel, or platform. Key element in structure joint, called "geostrut joint," includes internal cable. Structure is network of struts attached to geostrut joints. Pulling cables taut in all joints makes structure rigid. Releasing cables relaxes structure.

  2. Scapholunate advanced collapse.

    Science.gov (United States)

    Pomeranz, Stephen J; Salazar, Peter

    2015-01-01

    This case study reviews the pathophysiology of scapholunate advanced collapse (SLAC), which is the most common etiology of degenerative arthritis in the wrist. The scapholunate ligament serves a critical role in stability of the carpus. Disruption of the scapholunate ligament, its sequela, and the magnetic resonance imaging evaluation are discussed, with review of the defining features of this disease and its progression.

  3. Impact Crater Collapse

    Science.gov (United States)

    Melosh, H. J.; Ivanov, B. A.

    The detailed morphology of impact craters is now believed to be mainly caused by the collapse of a geometrically simple, bowl-shaped "transient crater." The transient crater forms immediately after the impact. In small craters, those less than approximately 15 km diameter on the Moon, the steepest part of the rim collapses into the crater bowl to produce a lens of broken rock in an otherwise unmodified transient crater. Such craters are called "simple" and have a depth-to-diameter ratio near 1:5. Large craters collapse more spectacularly, giving rise to central peaks, wall terraces, and internal rings in still larger craters. These are called "complex" craters. The transition between simple and complex craters depends on 1/g, suggesting that the collapse occurs when a strength threshold is exceeded. The apparent strength, however, is very low: only a few bars, and with little or no internal friction. This behavior requires a mechanism for temporary strength degradation in the rocks surrounding the impact site. Several models for this process, including acoustic fluidization and shock weakening, have been considered by recent investigations. Acoustic fluidization, in particular, appears to produce results in good agreement with observations, although better understanding is still needed.

  4. Modeling Core Collapse Supernovae

    Science.gov (United States)

    Mezzacappa, Anthony

    2017-01-01

    Core collapse supernovae, or the death throes of massive stars, are general relativistic, neutrino-magneto-hydrodynamic events. The core collapse supernova mechanism is still not in hand, though key components have been illuminated, and the potential for multiple mechanisms for different progenitors exists. Core collapse supernovae are the single most important source of elements in the Universe, and serve other critical roles in galactic chemical and thermal evolution, the birth of neutron stars, pulsars, and stellar mass black holes, the production of a subclass of gamma-ray bursts, and as potential cosmic laboratories for fundamental nuclear and particle physics. Given this, the so called ``supernova problem'' is one of the most important unsolved problems in astrophysics. It has been fifty years since the first numerical simulations of core collapse supernovae were performed. Progress in the past decade, and especially within the past five years, has been exponential, yet much work remains. Spherically symmetric simulations over nearly four decades laid the foundation for this progress. Two-dimensional modeling that assumes axial symmetry is maturing. And three-dimensional modeling, while in its infancy, has begun in earnest. I will present some of the recent work from the ``Oak Ridge'' group, and will discuss this work in the context of the broader work by other researchers in the field. I will then point to future requirements and challenges. Connections with other experimental, observational, and theoretical efforts will be discussed, as well.

  5. On the accuracy of density functional theory and wave function methods for calculating vertical ionization energies

    Energy Technology Data Exchange (ETDEWEB)

    McKechnie, Scott [Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Booth, George H. [Theory and Simulation of Condensed Matter, King’s College London, The Strand, London WC2R 2LS (United Kingdom); Cohen, Aron J. [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Cole, Jacqueline M., E-mail: jmc61@cam.ac.uk [Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Argonne National Laboratory, 9700 S Cass Avenue, Argonne, Illinois 60439 (United States)

    2015-05-21

    The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared.

  6. On the accuracy of density functional theory and wave function methods for calculating vertical ionization energies

    Science.gov (United States)

    McKechnie, Scott; Booth, George H.; Cohen, Aron J.; Cole, Jacqueline M.

    2015-05-01

    The best practice in computational methods for determining vertical ionization energies (VIEs) is assessed, via reference to experimentally determined VIEs that are corroborated by highly accurate coupled-cluster calculations. These reference values are used to benchmark the performance of density functional theory (DFT) and wave function methods: Hartree-Fock theory, second-order Møller-Plesset perturbation theory, and Electron Propagator Theory (EPT). The core test set consists of 147 small molecules. An extended set of six larger molecules, from benzene to hexacene, is also considered to investigate the dependence of the results on molecule size. The closest agreement with experiment is found for ionization energies obtained from total energy difference calculations. In particular, DFT calculations using exchange-correlation functionals with either a large amount of exact exchange or long-range correction perform best. The results from these functionals are also the least sensitive to an increase in molecule size. In general, ionization energies calculated directly from the orbital energies of the neutral species are less accurate and more sensitive to an increase in molecule size. For the single-calculation approach, the EPT calculations are in closest agreement for both sets of molecules. For the orbital energies from DFT functionals, only those with long-range correction give quantitative agreement with dramatic failing for all other functionals considered. The results offer a practical hierarchy of approximations for the calculation of vertical ionization energies. In addition, the experimental and computational reference values can be used as a standardized set of benchmarks, against which other approximate methods can be compared.

  7. Shoulder function after extracorporal shock wave therapy for calcific tendinitis.

    Science.gov (United States)

    Rompe, J D; Bürger, R; Hopf, C; Eysel, P

    1998-01-01

    We report a controlled, prospective study that explored the effect of extracorporal shock waves of low- versus high-energy density in patients with chronic shoulder pain and calcific tendinitis. We assigned at random 100 patients who had had calcific tendinitis for more than 12 months to 2 groups to receive shock wave therapy either of a low- or high-energy density. Group 1 received 1500 impulses of 0.06 mJ/mm2, whereas group 2 received 1500 impulses of 0.28 mJ/mm2. Unlike group 1, in which the shock wave application could be performed without local anesthesia, all patients in group 2 required brachial plexus anesthesia. The patients were reviewed at 6 and 24 weeks. Partial or complete disintegration of the calcareous deposit was observed in 50% of the patients in group 1 and 64% of the patients in group 2 (P < .01). According to the Constant score, ratings increased from 48 to 71 points in group 1 (P < .001) and from 53 to 88 in group 2 (P < .001) (out of a total possible 100 points), the end values of both groups differing significantly (P < .01). After 24 weeks, 52% of the patients in group 1 rated the results of treatment as good or excellent, compared with 68% in group 2 (P < .01). No improvement was reported by 24% versus 10%, respectively, at the 24-week follow-up.

  8. Structure of the channeling electrons wave functions under dynamical chaos conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shul’ga, N.F. [National Science Center “Kharkov Institute of Physics and Technology”, 1, Akademicheskaya St., Kharkov 61108 (Ukraine); V.N. Karazin National University, 4, Svodody Sq., Kharkov 61022 (Ukraine); Syshchenko, V.V., E-mail: syshch@yandex.ru [Belgorod National Research University, 85, Pobedy St., Belgorod 308015 (Russian Federation); Tarnovsky, A.I. [Belgorod National Research University, 85, Pobedy St., Belgorod 308015 (Russian Federation); Isupov, A.Yu. [Laboratory of High Energy Physics, Joint Institute for Nuclear Research, 141980 Dubna, Moscow region (Russian Federation)

    2016-03-01

    The stationary wave functions of fast electrons axially channeling in the silicon crystal near [1 1 0] direction have been found numerically for integrable and non-integrable cases, for which the classical motion is regular and chaotic, respectively. The nodal structure of the wave functions in the quasi-classical region, where the energy levels density is high, is agreed with quantum chaos theory predictions.

  9. Nonperturbative Strange Sea in Proton Using Wave Functions Inspired by Light Front Holography

    Science.gov (United States)

    Vega, Alfredo; Schmidt, Ivan; Gutsche, Thomas; Lyubovitskij, Valery E.

    2017-03-01

    We use different light-front wave functions (two inspired by the AdS/QCD formalism), together with a model of the nucleon in terms of meson-baryon fluctuations to calculate the nonperturbative (intrinsic) contribution to the s(x) - bar{s}(x) asymmetry of the proton sea. The holographic wave functions for an arbitrary number of constituents, recently derived by us, give results quite close to known parametrizations that appear in the literature.

  10. Spinless relativistic particle in energy-dependent potential and normalization of the wave function

    Science.gov (United States)

    Benchikha, Amar; Chetouani, Lyazid

    2014-06-01

    The problem of normalization related to a Klein-Gordon particle subjected to vector plus scalar energy-dependent potentials is clarified in the context of the path integral approach. In addition the correction relating to the normalizing constant of wave functions is exactly determined. As examples, the energy dependent linear and Coulomb potentials are considered. The wave functions obtained via spectral decomposition, were found exactly normalized.

  11. Reciprocity between Moduli and Phases in Time-Dependent Wave-Functions

    CERN Document Server

    Englman, R; Bär, M

    1999-01-01

    For time (t) dependent wave functions we derive rigorous conjugate relations between analytic decompositions (in the complex t-plane) of the phases and of the log moduli. We then show that reciprocity, taking the form of Kramers-Kronig integral relations (but in the time domain), holds between observable phases and moduli in several physically important instances. These include the nearly adiabatic (slowly varying) case, a class of cyclic wave-functions, wave packets and non-cyclic states in an "expanding potential". The results exhibit the interdependence of geometric-phases and related decay probabilities. Several known quantum mechanical theories possess the reciprocity property obtained in the paper.

  12. Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform.

    Directory of Open Access Journals (Sweden)

    Hau-Tieng Wu

    Full Text Available We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features.

  13. Elliptic Function Waves of Spinor Bose-Einstein Condensates in an Optical Lattice

    Institute of Scientific and Technical Information of China (English)

    XIE Yuan-Dong

    2009-01-01

    An improved nonlinear Schrodinger equation different from usual one of spinor Bose-Einstein condensates (BECs) in an optical lattice are obtained by taking into account a nonlinear term in the equation of motion for probability amplitude of spins carefully. The elliptic function wave solutions of the model are found under specific boundary condition, for example, the two ends of the atomic chain are fixed. In the case of limit the elliptic function wave solutions are reduced into spin-wave-like or solitons.

  14. Auxiliary-field-based trial wave functions in quantum Monte Carlo calculations

    Science.gov (United States)

    Chang, Chia-Chen; Rubenstein, Brenda M.; Morales, Miguel A.

    2016-12-01

    Quantum Monte Carlo (QMC) algorithms have long relied on Jastrow factors to incorporate dynamic correlation into trial wave functions. While Jastrow-type wave functions have been widely employed in real-space algorithms, they have seen limited use in second-quantized QMC methods, particularly in projection methods that involve a stochastic evolution of the wave function in imaginary time. Here we propose a scheme for generating Jastrow-type correlated trial wave functions for auxiliary-field QMC methods. The method is based on decoupling the two-body Jastrow into one-body projectors coupled to auxiliary fields, which then operate on a single determinant to produce a multideterminant trial wave function. We demonstrate that intelligent sampling of the most significant determinants in this expansion can produce compact trial wave functions that reduce errors in the calculated energies. Our technique may be readily generalized to accommodate a wide range of two-body Jastrow factors and applied to a variety of model and chemical systems.

  15. Polynomial scaling approximations and dynamic correlation corrections to doubly occupied configuration interaction wave functions.

    Science.gov (United States)

    Van Raemdonck, Mario; Alcoba, Diego R; Poelmans, Ward; De Baerdemacker, Stijn; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E; Van Neck, Dimitri; Bultinck, Patrick

    2015-09-14

    A class of polynomial scaling methods that approximate Doubly Occupied Configuration Interaction (DOCI) wave functions and improve the description of dynamic correlation is introduced. The accuracy of the resulting wave functions is analysed by comparing energies and studying the overlap between the newly developed methods and full configuration interaction wave functions, showing that a low energy does not necessarily entail a good approximation of the exact wave function. Due to the dependence of DOCI wave functions on the single-particle basis chosen, several orbital optimisation algorithms are introduced. An energy-based algorithm using the simulated annealing method is used as a benchmark. As a computationally more affordable alternative, a seniority number minimising algorithm is developed and compared to the energy based one revealing that the seniority minimising orbital set performs well. Given a well-chosen orbital basis, it is shown that the newly developed DOCI based wave functions are especially suitable for the computationally efficient description of static correlation and to lesser extent dynamic correlation.

  16. Two-body wave functions and compositeness from scattering amplitudes. I. General properties with schematic models

    CERN Document Server

    Sekihara, Takayasu

    2016-01-01

    For a general two-body bound state in quantum mechanics, both in the stable and decaying cases, we establish a way to extract its two-body wave function in momentum space from the scattering amplitude of the constituent two particles. For this purpose, we first show that the two-body wave function of the bound state corresponds to the residue of the off-shell scattering amplitude at the bound state pole. Then, we examine our scheme to extract the two-body wave function from the scattering amplitude in several schematic models. As a result, the two-body wave functions from the Lippmann--Schwinger equation coincides with that from the Schr\\"{o}dinger equation for an energy-independent interaction. Of special interest is that the two-body wave function from the scattering amplitude is automatically scaled; the norm of the two-body wave function, to which we refer as the compositeness, is unity for an energy-independent interaction, while the compositeness deviates from unity for an energy-dependent interaction, ...

  17. Structure of Ground state Wave Functions for the Fractional Quantum Hall Effect: A Variational Approach

    Science.gov (United States)

    Mukherjee, Sutirtha; Mandal, Sudhansu

    The internal structure and topology of the ground states for fractional quantum Hall effect (FQHE) are determined by the relative angular momenta between all the possible pairs of electrons. Laughlin wave function is the only known microscopic wave function for which these relative angular momenta are homogeneous (same) for any pair of electrons and depend solely on the filling factor. Without invoking any microscopic theory, considering only the relationship between number of flux quanta and particles in spherical geometry, and allowing the possibility of inhomogeneous (different) relative angular momenta between any two electrons, we develop a general method for determining a closed-form ground state wave function for any incompressible FQHE state. Our procedure provides variationally obtained very accurate wave functions, yet having simpler structure compared to any other known complex microscopic wave functions for the FQHE states. This method, thus, has potential in predicting a very accurate ground state wave function for the puzzling states such as the state at filling fraction 5/2. We acknowledge support from Department of Science and Technology, India.

  18. Effect of Rotation in Cloud Core Collapse

    Science.gov (United States)

    Tsuribe, T.

    The collapse of rotating clouds is investigated.At first, isothermal collapse of an initially uniform-density, uniform-rotating, molecular cloud core with pressure and self-gravity is investigated to determine the conditions under which a cloud is unstable to fragmentation. A semianalytic model for the collapse of rotating spheroids is developed with the method of characteristics for inwardly propagating rarefaction waves. Three-dimensional self-gravitating hydrodynamical calculations are performed for the initially uniform-density rigid-rotating sphere. Both investigations show that the criterion for fragmentation is modified from the one in the literature if the property of the non-homologous collapse is taken into account. It is shown that the central flatness, that is, the axial ratio of the isodensity contour in the central region, is a good indicator for the fate of the cloud. We derive the criterion for the fragmentation considering the evolution of the flatness of the central core. If the central flatness becomes greater than the critical value ˜ 4π, a collapsing cloud with moderate perturbations is unstable for fragmentation, while if the central flatness stays smaller than the critical value, it does not fragment at least before adiabatic core formation. Warm clouds (α0 ≳ 0.5) are not expected to fragment before adiabatic core formation almost independent of the initial rotation (β0) and the properties of the initial perturbation. The effect of the initial density central concentration is also investigated. If it exists, distortion or flattening of a cloud core is suppressed even if α0 ≲ 0.5 in small rotation cases due to stronger nonhomologous property of the collapse. We conclude that the binary fragmentation is difficult during isothermal stage if a core collapse had started from near spherical configurations with moderate thermal energy or small rotation. We suggest that the close binary fragmentation may be possible in the nonisothermal

  19. Similarity Structure of Wave-Collapse

    DEFF Research Database (Denmark)

    Rypdal, Kristoffer; Juul Rasmussen, Jens; Thomsen, Kenneth

    1985-01-01

    Similarity transformations of the cubic Schrödinger equation (CSE) are investigated. The transformations are used to remove the explicit time variation in the CSE and reduce it to differential equations in the spatial variables only. Two different methods for similarity reduction are employed and...

  20. CAUSES AND COUNTERMEASURES FOR CHAOHU LAKESHORE COLLAPSE

    Institute of Scientific and Technical Information of China (English)

    GAO Chao; WANG Xin-yuan; YANG Ze-dong; LU Ying-cheng; HE Hui

    2005-01-01

    By interpreting the remote sensing data of aerial photos and satellite images in different time, combining with field investigation, landform and water level observation, collecting data of weather, hydrology in Chaohu Lake, Anhui Province from 1957 to 2003, the reasons for collapse of Chaohu lakeshore were analyzed. The results are as follows: 1) The collapse of the Chaohu lakeshore is controlled macroscopically by two sets of north-east and the north-west faults, and the degree of collapse is determined microcosmically by lithology. 2) The constant change of water level, resulting from precipitation, wind speed and its direction, is one of the main reasons for intermittence collapse. 3) The soil and water loss or mud and sand filling up, resulting from artificial factors, such as inconsequence control of Chaohu sluice or irrational agricultural and industrial activities, etc., can uplift the lake's bed and drive water level up. The high water level also results in the collapse. Judging from the above mentioned reasons for the collapse, we have proposed some countermeasures: 1) Putting the lakeshore slope protection project such as stone and cement mortar into practice, and upstream slope should be 1:2.5 or 1:3, some parts of them should be 1:4, if they were not stable. The back slope, which is from Gui Mountain to Zhongmiao Temple, should be 1:1.5-1:3.2) Constructing a greenbelt for the lakeshore, planting some vegetation such as osier, bulrush and poplar, to resist waves between the high and the low water level. 3) Controlling Chaohu Lake water level scientifically. Corrosion of lakeshore that contains gravel clay and ferruginous-manganese concretionary structures, can decrease at low water level. 4) Renovating Chaohu Lake drainage area, strengthening the administration and supervision, breaking regionalism and establishing special administration organization.

  1. Quantum gravitational dust collapse does not result in a black hole

    Energy Technology Data Exchange (ETDEWEB)

    Vaz, Cenalo, E-mail: Cenalo.Vaz@uc.edu

    2015-02-15

    Quantum gravity suggests that the paradox recently put forward by Almheiri et al. (AMPS) can be resolved if matter does not undergo continuous collapse to a singularity but condenses on the apparent horizon. One can then expect a quasi-static object to form even after the gravitational field has overcome any degeneracy pressure of the matter fields. We consider dust collapse. If the collapse terminates on the apparent horizon, the Misner–Sharp mass function of the dust ball is predicted and we construct static solutions with no tangential pressure that would represent such a compact object. The collapse wave functions indicate that there will be processes by which energy extraction from the center occurs. These leave behind a negative point mass at the center which contributes to the total energy of the system but has no effect on the energy density of the dust ball. The solutions describe a compact object whose boundary lies outside its Schwarzschild radius and which is hardly distinguishable from a neutron star.

  2. Quantum gravitational dust collapse does not result in a black hole

    Directory of Open Access Journals (Sweden)

    Cenalo Vaz

    2015-02-01

    Full Text Available Quantum gravity suggests that the paradox recently put forward by Almheiri et al. (AMPS can be resolved if matter does not undergo continuous collapse to a singularity but condenses on the apparent horizon. One can then expect a quasi-static object to form even after the gravitational field has overcome any degeneracy pressure of the matter fields. We consider dust collapse. If the collapse terminates on the apparent horizon, the Misner–Sharp mass function of the dust ball is predicted and we construct static solutions with no tangential pressure that would represent such a compact object. The collapse wave functions indicate that there will be processes by which energy extraction from the center occurs. These leave behind a negative point mass at the center which contributes to the total energy of the system but has no effect on the energy density of the dust ball. The solutions describe a compact object whose boundary lies outside its Schwarzschild radius and which is hardly distinguishable from a neutron star.

  3. Small Components of the Wave Function of Electron

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper shows that the moving or time-varying large components of four-component wavefunction of electron would induce small components, and vice versa. Then when a wave packet of electron is moving with high speeds or varies rapidly, or its size is sufficiently small, or in the presence of a strong electromagnetic field, its small components and the related effects cannot be ignored. Furthermore, the spin quantum states of both a moving electron and a motionless electron can be affected by some special electrostatic fields. This may open a new pathway for spintronics to the manipulation of electron spins in the absence of applied magnetic fields.

  4. Riemann zeta function from wave-packet dynamics

    DEFF Research Database (Denmark)

    Mack, R.; Dahl, Jens Peder; Moya-Cessa, H.

    2010-01-01

    is governed by the temperature of the thermal phase state and tau is proportional to t. We use the JWKB method to solve the inverse spectral problem for a general logarithmic energy spectrum; that is, we determine a family of potentials giving rise to such a spectrum. For large distances, all potentials...... index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann zeta wave-packet dynamics using cold atoms...

  5. Duality and helicity: the photon wave function approach

    Science.gov (United States)

    Elbistan, M.; Horváthy, P. A.; Zhang, P.-M.

    2017-08-01

    The photon wave equation proposed in terms of the Riemann-Silberstein vector is derived from a first-order Dirac/Weyl-type action principle. It is symmetric w.r.t. duality transformations, but the associated Noether quantity vanishes. Replacing the fields by potentials and using instead a quadratic Klein-Gordon-type Lagrangian allows us to recover the double-Chern-Simons expression of conserved helicity and is shown to be equivalent to recently proposed alternative frameworks. Applied to the potential-modified theory the Dirac/Weyl-type approach yields again zero conserved charge, whereas the Klein-Gordon-type approach applied to the original setting yields Lipkin's ;zilch;.

  6. Collapse in the Endurance Athlete

    Institute of Scientific and Technical Information of China (English)

    Robert Sallis

    2005-01-01

    @@ KEY POINTS · Most cases of collapse are benign in nature and occur after an athlete crosses the finish line or stops exercising. Athletes who collapse before finishing are more likely to have a serious condition.

  7. The dynamic dielectric at a brain functional site and an EM wave approach to functional brain imaging.

    Science.gov (United States)

    Li, X P; Xia, Q; Qu, D; Wu, T C; Yang, D G; Hao, W D; Jiang, X; Li, X M

    2014-11-04

    Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging.

  8. The effects of extracorporeal shock wave therapy on frozen shoulder patients' pain and functions.

    Science.gov (United States)

    Park, Chan; Lee, Sangyong; Yi, Chae-Woo; Lee, Kwansub

    2015-12-01

    [Purpose] The present study was conducted to examine the effects of extracorporeal shock wave therapy on frozen shoulder patients' pain and functions. [Subjects] In the present study, 30 frozen shoulder patients were divided into two groups: an extracorporeal shock wave therapy group of 15 patients and a conservative physical therapy group of 15 patients. [Methods] Two times per week for six weeks, the extracorporeal shock wave therapy group underwent extracorporeal shock wave therapy, and the conservative physical therapy group underwent general physical therapy. Visual analog scales were used to measure frozen shoulder patients' pain, and patient-specific functional scales were used to evaluate the degree of functional disorders. [Results] In intra-group comparisons, the two groups showed significant decreases in terms of visual analog scales and patient-specific functional scales, although the extracorporeal shock wave therapy group showed significantly lower scores than the conservative physical therapy group. [Conclusion] Extracorporeal shock wave therapy is considered an effective intervention for improving frozen shoulder patients' pain and functions.

  9. On the precanonical structure of the Schr\\"odinger wave functional

    CERN Document Server

    Kanatchikov, I V

    2013-01-01

    An expression of the Schr\\"odinger wave functional as the product integral of precanonical wave functions on the space of fields and space-time variables is obtained. A functional derivative Schr\\"odinger equation in the canonical quantization is derived from the partial derivative covariant analogue of the Schr\\"odinger equation, which appears in the precanonical quantization based on the De Donder-Weyl Hamiltonization of field theory. The representation of precanonical quantum operators typically contains a parameter $\\varkappa$ of the dimension of the inverse spatial volume. The transition from the precanonical description of quantum fields in terms of Clifford-valued wave functions and partial derivative operators to the standard functional Schr\\"odinger representation obtained from canonical quantization is accomplished if $\\varkappa \\rightarrow 0$ and $\\gamma^0 / \\varkappa$ is mapped to the infinitesimal spatial volume element $d\\mathbf{x}$. Thus the standard QFT corresponds to the precanonical QFT in t...

  10. Mapping crustal S-wave velocity structure with SV-component receiver function method

    Institute of Scientific and Technical Information of China (English)

    邹最红; 陈晓非

    2003-01-01

    In this article, we analyze the characters of SV-component receiver function of teleseismic body waves and its advantages in mapping the S-wave velocity structure of crust in detail. Similar to radial receiver function, SV-component receiver function can be obtained by directly deconvolving the P-component from the SV-component of teleseismic recordings. Our analyses indicate that the change of amplitude of SV-component receiver function against the change of epicentral distance is less than that of radial receiver function. Moreover, the waveform of SV-component receiver function is simpler than the radial receiver function and gives prominence to the PS converted phases that are the most sensitive to the shear wave velocity structure in the inversion. The synthetic tests show that the convergence of SV-component receiver function inversion is faster than that of the radial receiver function inversion. As an example, we investigate the S-wave velocity structure beneath HIA station by using the SV-component receiver function inversion method.

  11. Rigid collapsible dish structure

    Science.gov (United States)

    Palmer, William B. (Inventor); Giebler, Martin M. (Inventor)

    1982-01-01

    A collapsible dish structure composed of a plurality of rows of rigid radial petal assemblies concentric with the axis of the dish. The petal assemblies consist of a center petal and two side petals, the center petal hinged on an axis tangent to a circle concentric with the axis of the dish and the side petals hinged to the center petal at their mating edge. The center petal is foldable inwardly and the side petals rotate about their hinges such that the collapsed dish structure occupies a much smaller volume than the deployed dish. Means of controlling the shape of the dish to compensate for differential expansion of the deployed dish are also provided.

  12. On the Wavefunction Collapse

    Directory of Open Access Journals (Sweden)

    Ovidiu Cristinel Stoica

    2016-01-01

    Full Text Available Wavefunction collapse is usually seen as a discontinuous violation of the unitary evolution of a quantum system, caused by the observation. Moreover, the collapse appears to be nonlocal in a sense which seems at odds with general relativity. In this article the possibility that the wavefunction evolves continuously and hopefully unitarily during the measurement process is analyzed. It is argued that such a solution has to be formulated using a time symmetric replacement of the initial value problem in quantum mechanics. Major difficulties in apparent conflict with unitary evolution are identified, but eventually its possibility is not completely ruled out. This interpretation is in a weakened sense both local and realistic, without contradicting Bell's theorem. Moreover, if it is true, it makes general relativity consistent with quantum mechanics in the semiclassical framework.Quanta 2016; 5: 19–33.

  13. Shock induced cavity collapse

    Science.gov (United States)

    Skidmore, Jonathan; Doyle, Hugo; Tully, Brett; Betney, Matthew; Foster, Peta; Ringrose, Tim; Ramasamy, Rohan; Parkin, James; Edwards, Tom; Hawker, Nicholas

    2016-10-01

    Results from the experimental investigation of cavity collapse driven by a strong planar shock (>6km/s) are presented. Data from high speed framing cameras, laser backlit diagnostics and time-resolved pyromety are used to validate the results of hydrodynamic front-tracking simulations. As a code validation exercise, a 2-stage light gas gun was used to accelerate a 1g Polycarbonate projectile to velocities exceeding 6km/s; impact with a PMMA target containing a gas filled void results in the formation of a strong shockwave with pressures exceeding 1Mbar. The subsequent phenomena associated with the collapse of the void and excitation of the inert gas fill are recorded and compared to simulated data. Variation of the mass density and atomic number of the gas fill is used to alter the plasma parameters furthering the extent of the code validation.

  14. Gravitational collapse of generalised Vaidya spacetime

    CERN Document Server

    Mkenyeleye, Maombi D; Maharaj, Sunil D

    2014-01-01

    We study the gravitational collapse of a generalised Vaidya spacetime in the context of the Cosmic Censorship hypothesis. We develop a general mathematical framework to study the conditions on the mass function so that future directed non-spacelike geodesics can terminate at the singularity in the past. Thus our result generalises earlier works on gravitational collapse of the combinations of Type-I and Type-II matter fields. Our analysis shows transparently that there exist classes of generalised Vaidya mass functions for which the collapse terminates with a locally naked central singularity. We calculate the strength of the these singularities to show that they are strong curvature singularities and there can be no extension of spacetime through them.

  15. Bleustein-Gulyaev waves in a functionally graded piezoelectric material layered structure

    Institute of Scientific and Technical Information of China (English)

    CAO Xiaoshan; JIN Feng; WANG ZiKun; LU TianJian

    2009-01-01

    This work presents a theoretical study of the propagation behavior of Bleustein-Gulyaev waves in a layered structure consisting of a functionally graded piezoelectric material (FGPM) layer and a trans-versely isotropic piezoelectric substrate. The influence of the graded variation of FGPM coefficients on the dispersion relations of Bleustein-Gulyaev waves in the layered structure is investigated. It is dem-onstrated that, for a certain frequency range of Bleustein-Gulyaev waves, the mechanical perturbations of the particles are restricted in the FPGM layer and the phase velocity is independent of the electrical boundary conditions at the free surface. Results presented in this study can not only provide further Insight on the electromechanical coupling behavior of surface waves in FGPM layered structures, but also lend a theoretical basis for the design of high-performance surface acoustic wave (SAW) devices.

  16. Bleustein-Gulyaev waves in a functionally graded piezoelectric material layered structure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This work presents a theoretical study of the propagation behavior of Bleustein-Gulyaev waves in a layered structure consisting of a functionally graded piezoelectric material(FGPM) layer and a transversely isotropic piezoelectric substrate. The influence of the graded variation of FGPM coefficients on the dispersion relations of Bleustein-Gulyaev waves in the layered structure is investigated. It is demonstrated that,for a certain frequency range of Bleustein-Gulyaev waves,the mechanical perturbations of the particles are restricted in the FPGM layer and the phase velocity is independent of the electrical boundary conditions at the free surface. Results presented in this study can not only provide further insight on the electromechanical coupling behavior of surface waves in FGPM layered structures,but also lend a theoretical basis for the design of high-performance surface acoustic wave(SAW) devices.

  17. Collapse, environment, and society.

    Science.gov (United States)

    Butzer, Karl W

    2012-03-06

    Historical collapse of ancient states poses intriguing social-ecological questions, as well as potential applications to global change and contemporary strategies for sustainability. Five Old World case studies are developed to identify interactive inputs, triggers, and feedbacks in devolution. Collapse is multicausal and rarely abrupt. Political simplification undermines traditional structures of authority to favor militarization, whereas disintegration is preconditioned or triggered by acute stress (insecurity, environmental or economic crises, famine), with breakdown accompanied or followed by demographic decline. Undue attention to stressors risks underestimating the intricate interplay of environmental, political, and sociocultural resilience in limiting the damages of collapse or in facilitating reconstruction. The conceptual model emphasizes resilience, as well as the historical roles of leaders, elites, and ideology. However, a historical model cannot simply be applied to contemporary problems of sustainability without adjustment for cumulative information and increasing possibilities for popular participation. Between the 14th and 18th centuries, Western Europe responded to environmental crises by innovation and intensification; such modernization was decentralized, protracted, flexible, and broadly based. Much of the current alarmist literature that claims to draw from historical experience is poorly focused, simplistic, and unhelpful. It fails to appreciate that resilience and readaptation depend on identified options, improved understanding, cultural solidarity, enlightened leadership, and opportunities for participation and fresh ideas.

  18. Collapse of a self-gravitating Bose-Einstein condensate with attractive self-interaction

    Science.gov (United States)

    Chavanis, Pierre-Henri

    2016-10-01

    We study the collapse of a self-gravitating Bose-Einstein condensate with attractive self-interaction. Equilibrium states in which the gravitational attraction and the attraction due to the self-interaction are counterbalanced by the quantum pressure (Heisenberg's uncertainty principle) exist only below a maximum mass Mmax=1.012 ℏ/√{G m |as| } where asMmax the system is expected to collapse and form a black hole. We study the collapse dynamics by making a Gaussian ansatz for the wave function and reducing the problem to the study of the motion of a particle in an effective potential. We find that the collapse time scales as (M /Mmax-1 )-1 /4 for M →Mmax+ and as M-1 /2 for M ≫Mmax. Other analytical results are given above and below the critical point corresponding to a saddle-node bifurcation. We apply our results to QCD axions with mass m =10-4 eV /c2 and scattering length as=-5.8 ×10-53 m for which Mmax=6.5 ×10-14M⊙ and R =3.3 ×10-4R⊙. We confirm our previous claim that bosons with attractive self-interaction, such as QCD axions, may form low mass stars (axion stars or dark matter stars) but cannot form dark matter halos of relevant mass and size. These mini axion stars could be the constituents of dark matter. They can collapse into mini black holes of mass ˜10-14M⊙ in a few hours. In that case, dark matter halos would be made of mini black holes. We also apply our results to ultralight axions with mass m =1.93 ×10-20 eV /c2 and scattering length as=-8.29 ×10-60 fm for which Mmax=0.39 ×1 06M⊙ and R =33 pc . These ultralight axions could cluster into dark matter halos. Axionic dark matter halos with attractive self-interaction can collapse into supermassive black holes of mass ˜1 06M⊙ (similar to those reported at the center of galaxies) in about one million years. We point out the limitations of the Gaussian ansatz to describe the late stages of the collapse dynamics. We also mention the possibility that, instead of forming a black hole

  19. Cerebral functional connectivity and Mayer waves in mice: Phenomena and separability.

    Science.gov (United States)

    Bumstead, Jonathan R; Bauer, Adam Q; Wright, Patrick W; Culver, Joseph P

    2017-02-01

    Resting-state functional connectivity is a growing neuroimaging approach that analyses the spatiotemporal structure of spontaneous brain activity, often using low-frequency (waves. Despite how close in frequency these phenomena exist, there is little research on how vasomotion and Mayer waves are related to or affect resting-state functional connectivity. In this study, we analyze spontaneous hemodynamic fluctuations over the mouse cortex using optical intrinsic signal imaging. We found spontaneous occurrence of oscillatory hemodynamics ∼0.2 Hz consistent with the properties of Mayer waves reported in the literature. Across a group of mice (n = 19), there was a large variability in the magnitude of Mayer waves. However, regardless of the magnitude of Mayer waves, functional connectivity patterns could be recovered from hemodynamic signals when filtered to the lower frequency band, 0.01-0.08 Hz. Our results demonstrate that both Mayer waves and resting-state functional connectivity patterns can co-exist simultaneously, and that they can be separated by applying bandpass filters.

  20. Photon reflection by a quantum mirror: a wave function approach

    CERN Document Server

    Corrêa, Raul

    2016-01-01

    We derive from first principles the momentum exchange between a photon and a quantum mirror upon reflection, by considering the boundary conditions imposed by the mirror surface on the photon wave equation. We show that the system generally ends up in an entangled state, unless the mirror position uncertainty is much smaller than the photon wavelength, when the mirror behaves classically. Our treatment leads us directly to the conclusion that the photon momentum has the known value hk/2{\\pi}. This implies that when the mirror is immersed in a dielectric medium the photon radiation pressure is proportional to the medium refractive index n. Our work thus contributes to the longstanding Abraham-Minkowski debate about the momentum of light in a medium. We interpret the result by associating the Minkowski momentum (which is proportional to n) with the canonical momentum of light, which appears naturally in quantum formulations.

  1. Basis of symmetric polynomials for many-boson light-front wave functions.

    Science.gov (United States)

    Chabysheva, Sophia S; Hiller, John R

    2014-12-01

    We provide an algorithm for the construction of orthonormal multivariate polynomials that are symmetric with respect to the interchange of any two coordinates on the unit hypercube and are constrained to the hyperplane where the sum of the coordinates is one. These polynomials form a basis for the expansion of bosonic light-front momentum-space wave functions, as functions of longitudinal momentum, where momentum conservation guarantees that the fractions are on the interval [0,1] and sum to one. This generalizes earlier work on three-boson wave functions to wave functions for arbitrarily many identical bosons. A simple application in two-dimensional ϕ(4) theory illustrates the use of these polynomials.

  2. A Fortran program to calculate the matrix elements of the Coulomb interaction involving hydrogenic wave functions

    Science.gov (United States)

    Sarkadi, L.

    2017-03-01

    The program MTRXCOUL [1] calculates the matrix elements of the Coulomb interaction between a charged particle and an atomic electron, ∫ ψf∗ (r) | R - r | - 1ψi(r) d r. Bound-free transitions are considered, and non-relativistic hydrogenic wave functions are used. In this revised version a bug discovered in the F3Y CPC Program Library (PL) subprogram [2] is fixed. Furthermore, the COULCC CPC PL subprogram [3] applied for the calculations of the radial wave functions of the free states and the Bessel functions is replaced by the CPC PL subprogram DCOUL [4].

  3. Generalized Extended tanh-function Metho d for Traveling Wave Solutions of Nonlinear Physical Equations

    Institute of Scientific and Technical Information of China (English)

    Chang Jing; Gao Yi-xian; Cai Hua

    2014-01-01

    In this paper, the generalized extended tanh-function method is used for constructing the traveling wave solutions of nonlinear evolution equations. We choose Fisher’s equation, the nonlinear schr¨odinger equation to illustrate the validity and ad-vantages of the method. Many new and more general traveling wave solutions are obtained. Furthermore, this method can also be applied to other nonlinear equations in physics.

  4. Combination of sequential chemical extraction and modelling of dam-break wave propagation to aid assessment of risk related to the possible collapse of a roasted sulphide tailings dam.

    Science.gov (United States)

    Pérez-López, Rafael; Sáez, Reinaldo; Alvarez-Valero, Antonio M; Miguel Nieto, José; Pace, Gaetano

    2009-10-15

    The Sotiel-Coronada abandoned mining district (Iberian Pyrite Belt) produced complex massive sulphide ores which were processed by flotation to obtain Cu, Zn and Pb concentrates. The crude pyrite refuses were roasted for sulphuric acid production in a plant located close to the flotation site, and waste stored in a tailing dam. The present study was focused on the measurements of flow properties, chemical characterization and mineralogical determination of the roasted pyrite refuses with the aim of assessing the potential environmental impact in case of dam collapse. Chemical studies include the determination of the total contaminant content and information about their bio-availability or mobility using sequential extraction techniques. In the hypothetical case of the tailing dam breaking up and waste spilling (ca. 4.54Mt), a high density mud flow would flood the Odiel river valley and reach both Estuary of Huelva (Biosphere Reserve by UNESCO, 1983) and Atlantic Ocean in matter of a couple of days, as it was predicted by numerical simulations of dam-break waves propagation through the river valley based on quasi-2D Saint-Venant equations. The total amount of mobile pollutants that would be released into the surrounding environment is approximately of 7.1.10(4)t of S, 1.6.10(4)t of Fe, 1.4.10(4)t of As, 1.2.10(4)t of Zn, 1.0.10(4)t of Pb, 7.4.10(3)t of Mn, 2.2.10(3)t of Cu, 1.5.10(2)t of Co, 36t of Cd and 17t of Ni. Around 90-100% of S, Zn, Co and Ni, 60-70% of Mn and Cd, 30-40% of Fe and Cu, and 5% of As and Pb of the mobile fraction would be easily in the most labile fraction (water-soluble pollutants), and therefore, the most dangerous and bio-available for the environment. This gives an idea of the extreme potential risk of roasted pyrite ashes to the environment, until now little-described in the scientific literature.

  5. Transfer function and near-field detection of evanescent waves

    DEFF Research Database (Denmark)

    Radko, Ylia P.; Bozhevolnyi, Sergey I.; Gregersen, Niels

    2006-01-01

    for the transfer function, which is derived by introducing an effective pointof (dipolelike) detection inside the probe tip. It is found to be possible to fit reasonably well both the experimental and the simulation data for evanescent field components, implying that the developed approximation of the near......-field transfer function can serve as a simple, rational, and sufficiently reliable means of fiber probe characterization....... of collection and illumination modes. Making use of a collection near-field microscope with a similar fiber tip illuminated by an evanescent field, we measure the collected power as a function of the field spatial frequency in different polarization configurations. Considering a two-dimensional probe...

  6. Atomistic modeling of shock-induced void collapse in copper

    Energy Technology Data Exchange (ETDEWEB)

    Davila, L P; Erhart, P; Bringa, E M; Meyers, M A; Lubarda, V A; Schneider, M S; Becker, R; Kumar, M

    2005-03-09

    Nonequilibrium molecular dynamics (MD) simulations show that shock-induced void collapse in copper occurs by emission of shear loops. These loops carry away the vacancies which comprise the void. The growth of the loops continues even after they collide and form sessile junctions, creating a hardened region around the collapsing void. The scenario seen in our simulations differs from current models that assume that prismatic loop emission is responsible for void collapse. We propose a new dislocation-based model that gives excellent agreement with the stress threshold found in the MD simulations for void collapse as a function of void radius.

  7. Prolate Spheroidal Wave Functions, Quadrature, Interpolation, And Asymptotic Formulae

    CERN Document Server

    Xiao, H

    2001-01-01

    Whenever physical signals are measured or generated, the results tend to be band-limited (i.e. to have compactly supported Fourier transforms). Indeed, measurements of electromagnetic and acoustic data are band-limited due to the oscillatory character of the processes that have generated the quantities being measured. When the signals being measured come from heat propagation or diffusion processes, they are (practically speaking) band-limited, since the underlying physical processes operate as low- pass filters. The importance of band-limited functions has been recognized for hundreds of years; classical Fourier analysis can be viewed as an apparatus for dealing with such functions. When band-limited functions are defined on the whole line (or on the circle), classical tools are very satisfactory. However, in many cases, we are confronted with band- limited functions defined on intervals (or, more generally, on compact regions in R n). In this environment, standard tools based on polynomials are often effe...

  8. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many t...

  9. Single-valued definition of the multivalued function for borehole acoustic waves in transversely isotropic formations

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is useful to extract all components, including compressional, shear, and guided waves, from the full waveforms when we investigate the acoustic log data. The component waves can be simulated by calculating the contributions from poles and branch points of the borehole acoustic function according to Cauchy’s theorem. For such an algorithm to be implemented, the multivalued function for the borehole wave field in the frequency-axial-wavenumber domain has to be rendered single-valued first. Assuming that the borehole axis is parallel to the symmetry axis of transverse isotropy, this paper derives the branch points of the borehole acoustic function. We discover that the number and the locations of those branch points are determined by the relation among the formation parameters c33, c44, ε, and δ. Thus the single-valued definitions in the acoustic-wave computation are sorted into two different cases. After building the Riemann surface related to each radial wavenumber, we give the single-valued definition of the borehole acoustic function inside and on the integration contour based on the radiation condition. In a formation with δ > ε + c44/2c33, if we choose the integration contour and the single-valued definition of the acoustic function in the way used in isotropic cases, the simulation results of component waves will be wrong.

  10. Anterior septal deviation and contralateral alar collapse.

    Science.gov (United States)

    Schalek, P; Hahn, A

    2011-01-01

    Septal deviation is often found in conjunction with other pathological conditions that adversely affect nasal patency. Anterior septal deviation, together with contralateral alar collapse, is a relatively rare type of anatomical and functional incompetence. In our experience, it can often be resolved with septoplasty, without the necessity of surgery involving the external valve. The aim of this paper was to verify this hypothesis prospectively. Twelve patients with anterior septal deviation and simultaneous alar collapse on the opposite side were prospectively enrolled in the study. Subjective assessment of nasal patency was made on post-operative day 1, and again 6 months after surgery, using a subjective evaluation of nasal breathing. The width of the nostril (alar-columellar distance) on the side with the alar collapse was measured during inspiration pre-operatively, 1 day after surgery and again 6 months after surgery. Immediately after surgery, all patients reported improved or excellent nasal breathing on the side of the original septal deviation. On the collapsed side, one patient reported no change in condition. With the exception of one patient, all measurements showed some degree of improvement in the extension of the alar-columellar distance. The average benefit 6 months after surgery was an improvement of 4.54 mm. In our group of patients (anterior septal deviation and simultaneous contralateral alar collapse and no obvious structural changes of the alar cartilage) we found septoplasty to be entirely suitable and we recommend it as the treatment of choice in such cases.

  11. The wave-function description of the electromagnetic field

    CERN Document Server

    Friedman, Yaakov

    2013-01-01

    For an arbitrary electromagnetic field, we define a prepotential $S$, which is a complex-valued function of spacetime. The prepotential is a modification of the two scalar potential functions introduced by E. T. Whittaker. The prepotential is Lorentz covariant under a spin half representation. For a moving charge and any observer, we obtain a complex dimensionless scalar. The prepotential is a function of this dimensionless scalar. The prepotential $S$ of an arbitrary electromagnetic field is described as an integral over the charges generating the field. The Faraday vector at each point may be derived from $S$ by a convolution of the differential operator with the alpha matrices of Dirac. Some explicit examples will be calculated. We also present the Maxwell equations for the prepotential.

  12. Collapse of biodiversity in fractured metacommunities

    Science.gov (United States)

    Fisher, Charles; Mehta, Pankaj

    2014-03-01

    The increasing threat to global biodiversity from climate change, habitat destruction, and other anthropogenic factors motivates the search for features that increase the resistance of ecological communities to destructive disturbances. Recently, Gibson et al (Science 2013) observed that the damming of the Khlong Saeng river in Thailand caused a rapid collapse of biodiversity in the remaining tropical forests. Using a theoretical model that maps the distribution of coexisting species in an ecological community to a disordered system of Ising spins, we show that fracturing a metacommunity by inhibiting species dispersal leads to a collapse in biodiversity in the constituent local communities. The biodiversity collapse can be modeled as a diffusion on a rough energy landscape, and the resulting estimate for the rate of extinction highlights the role of species functional diversity in maintaining biodiversity following a disturbance.

  13. Cosmological constraints on non-standard inflationary quantum collapse models

    CERN Document Server

    Landau, Susana J; Sudarsky, Daniel

    2011-01-01

    We briefly review an important shortcoming --unearthed in previous works-- of the standard version of the inflationary model for the emergence of the seeds of cosmic structure. We consider here some consequences emerging from a proposal inspired on ideas of Penrose and Di\\'osi about a quantum-gravity induced reduction of the wave function, which has been put forward to address the shortcomings, arguing that its effect on the inflaton field is what can lead to the emergence of the seeds of cosmic structure. The proposal leads to a deviation of the primordial spectrum from the scale-invariant Harrison-Zel'dovich one, and consequently, to a different CMB power spectrum. We perform statistical analyses to test two quantum collapse schemes with recent data from the CMB, including the 7-yr release of WMAP and the matter power spectrum measured using LRGs by the Sloan Digital Sky Survey. Results from the statistical analyses indicate that several collapse models are compatible with CMB and LRG data, and establish co...

  14. Collapse of Incoherent Light Beams in Inertial Bulk Kerr Media

    DEFF Research Database (Denmark)

    Bang, Ole; Edmundson, Darran; Królikowski, Wieslaw

    1999-01-01

    We use the coherent density function theory to show that partially coherent beams are unstable and may collapse in inertial bulk Kerr media. The threshold power for collapse, and its dependence on the degree of coherence, is found analytically and checked-numerically. The internal dynamics of the...

  15. Symmetric multivariate polynomials as a basis for three-boson light-front wave functions.

    Science.gov (United States)

    Chabysheva, Sophia S; Elliott, Blair; Hiller, John R

    2013-12-01

    We develop a polynomial basis to be used in numerical calculations of light-front Fock-space wave functions. Such wave functions typically depend on longitudinal momentum fractions that sum to unity. For three particles, this constraint limits the two remaining independent momentum fractions to a triangle, for which the three momentum fractions act as barycentric coordinates. For three identical bosons, the wave function must be symmetric with respect to all three momentum fractions. Therefore, as a basis, we construct polynomials in two variables on a triangle that are symmetric with respect to the interchange of any two barycentric coordinates. We find that, through the fifth order, the polynomial is unique at each order, and, in general, these polynomials can be constructed from products of powers of the second- and third-order polynomials. The use of such a basis is illustrated in a calculation of a light-front wave function in two-dimensional ϕ(4) theory; the polynomial basis performs much better than the plane-wave basis used in discrete light-cone quantization.

  16. New Semiclassical and Numerical Approaches to Locate Zeros of Wave Functions

    Institute of Scientific and Technical Information of China (English)

    AsiriNanayakkara

    2004-01-01

    A new semiclassical method is presented for evaluating zeros of wave functions. In this method, locating zeros of the wave functions of Schrodinger equation is converted to finding roots of a polynomial. The coefficients of this polynomial are evaluated using WKB and semi quantum action variable methods. For certain potentials WKB expressions for moments are obtained exactly. Almost explicit formulae for moments are obtained for the potential V(x)=xN. Examples are given to illustrate both methods. Using semi quantum action variable method, complex zeros of the wave functions of the PT symmetric complex system V(x)=x4+iAx are obtained. These zeros exhibit complex version of in terlacing.

  17. New Semiclassical and Numerical Approaches to Locate Zeros of Wave Functions Asiri Nanayakkara

    Institute of Scientific and Technical Information of China (English)

    Asiri Nanayakkara

    2004-01-01

    A new semiclassical method is presented for evaluating zeros of wave functions. In this method, locating zeros of the wave functions of Schrodinger equation is converted to finding roots of a polynomial. The coefficients of this polynomial are evaluated using WKB and semi quantum action variable methods. For certain potentials WKB expressions for moments are obtained exactly. Almost explicit formulae for moments are obtained for the potential V (x) = xN. Examples are given to illustrate both methods. Using semi quantum action variable method, complex zeros of the wave functions of the PT symmetric complex system V(x) = x4 + iAx are obtained. These zeros exhibit complex version of interlacing.

  18. Assessment of large basis shell model wave functions for the Li isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Karataglidis, S.; Brown, B.A. [Michigan State Univ., East Lansing, MI (United States); Dortmans, P.J.; Amos, K. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-06-01

    The Li isotopes are good examples with which the shell model can be tested for cluster-like behaviour, as large space (no core) shell model wave functions may be constructed. The cross sections and analysing power for the inelastic scattering of electron and proton scattering data for {sup 6,7}Li ground states were analysed using the same shell model wave functions. It was found that the results obtained by using 0{Dirac_h}{omega} structure model wave functions is unable to reproduce the magnitude of the data. Meanwhile, those obtained by using the larger space models are able to reproduce the low-angle part of the cross section, but all model results severely underestimate the cross section above 20 deg. Meanwhile, in the case of analysing power, all model calculations give reasonable representation of the data. 13 refs., 3 figs.

  19. On the construction of CASCI-type wave functions for very large active spaces

    CERN Document Server

    Boguslawski, Katharina; Reiher, Markus

    2011-01-01

    We present an efficient procedure to construct configuration-interaction-type electronic wave functions of molecular systems that require very large active spaces for a qualitatively correct description of their electronic structure. Our procedure is based on the density-matrix renormalization group algorithm that provides the necessary information in terms of the eigenstates of the reduced density matrices to calculate the coefficient of any basis state in the many-particle Hilbert space of the molecular system under study. Since the dimension of the Hilbert space scales factorially with the size of the active space, a sophisticated Monte Carlo sampling routine has been implemented that constructs an accurate representation of the electronic wave function. We emphasize that our sampling routine can also construct complete-active-space configuration-interaction-type wave functions from any other type of tensor network states, such as the complete-graph tensor network states or the correlator product states.

  20. U (1 )×U (1 ) symmetry-protected topological order in Gutzwiller wave functions

    Science.gov (United States)

    Liu, Zheng-Xin; Mei, Jia-Wei; Ye, Peng; Wen, Xiao-Gang

    2014-12-01

    Gutzwiller projection is a way to construct many-body wave functions that could carry topological order or symmetry-protected topological (SPT) order. However, an important issue is to determine whether or not a given Gutzwiller-projected wave function (GWF) carries a nontrivial SPT order, and which SPT order is carried by the wave function. In this paper, we numerically study the SPT order in a spin S =1 GWF on the kagome lattice. Using the standard Monte Carlo method, we directly confirm that the GWF has (1) gapped bulk with short-range correlations, (2) a trivial topological order via a nondegenerate ground state, and zero topological entanglement entropy, (3) a nontrivial U (1 )×U (1 ) SPT order via the Hall conductances of the protecting U (1 )×U (1 ) symmetry, and (4) a symmetry-protected gapless boundary. This represents numerical evidence of continuous symmetry-protected topological order in two-dimensional bosonic lattice systems.

  1. Electronic structure and correlated wave functions of a few electron quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Sako, Tokuei [Laboratory of Physics, College of Science and Technology, Nihon University, 7-24-1 Narashinodai, Funabashi, Chiba 274-8501 (Japan); Ishida, Hiroshi [College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Fujikawa, Kazuo [Institute of Quantum Science, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308 (Japan)

    2015-01-22

    The energy spectra and wave functions of a few electrons confined by a quasi-one-dimensional harmonic and anharmonic potentials have been studied by using a full configuration interaction method employing a Cartesian anisotropic Gaussian basis set. The energy spectra are classified into three regimes of the strength of confinement, namely, large, medium and small. The polyad quantum number defined by a total number of nodes in the wave functions is shown to be a key ingredient to interpret the energy spectra for the whole range of the confinement strength. The nodal pattern of the wave functions exhibits normal modes for the harmonic confining potential, indicating collective motions of electrons. These normal modes are shown to undergo a transition to local modes for an anharmonic potential with large anharmonicity.

  2. Multiple-Resonance Local Wave Functions for Accurate Excited States in Quantum Monte Carlo.

    Science.gov (United States)

    Zulfikri, Habiburrahman; Amovilli, Claudio; Filippi, Claudia

    2016-03-08

    We introduce a novel class of local multideterminant Jastrow-Slater wave functions for the efficient and accurate treatment of excited states in quantum Monte Carlo. The wave function is expanded as a linear combination of excitations built from multiple sets of localized orbitals that correspond to the bonding patterns of the different Lewis resonance structures of the molecule. We capitalize on the concept of orbital domains of local coupled-cluster methods, which is here applied to the active space to select the orbitals to correlate and construct the important transitions. The excitations are further grouped into classes, which are ordered in importance and can be systematically included in the Jastrow-Slater wave function to ensure a balanced description of all states of interest. We assess the performance of the proposed wave function in the calculation of vertical excitation energies and excited-state geometry optimization of retinal models whose π → π* state has a strong intramolecular charge-transfer character. We find that our multiresonance wave functions recover the reference values of the total energies of the ground and excited states with only a small number of excitations and that the same expansion can be flexibly used at very different geometries. Furthermore, significant computational saving can also be gained in the orbital optimization step by selectively mixing occupied and virtual orbitals based on spatial considerations without loss of accuracy on the excitation energy. Our multiresonance wave functions are therefore compact, accurate, and very promising for the calculation of multiple excited states of different character in large molecules.

  3. Automatic determination of important mode-mode correlations in many-mode vibrational wave functions.

    Science.gov (United States)

    König, Carolin; Christiansen, Ove

    2015-04-14

    We introduce new automatic procedures for parameterizing vibrational coupled cluster (VCC) and vibrational configuration interaction wave functions. Importance measures for individual mode combinations in the wave function are derived based on upper bounds to Hamiltonian matrix elements and/or the size of perturbative corrections derived in the framework of VCC. With a threshold, this enables an automatic, system-adapted way of choosing which mode-mode correlations are explicitly parameterized in the many-mode wave function. The effect of different importance measures and thresholds is investigated for zero-point energies and infrared spectra for formaldehyde and furan. Furthermore, the direct link between important mode-mode correlations and coordinates is illustrated employing water clusters as examples: Using optimized coordinates, a larger number of mode combinations can be neglected in the correlated many-mode vibrational wave function than with normal coordinates for the same accuracy. Moreover, the fraction of important mode-mode correlations compared to the total number of correlations decreases with system size. This underlines the potential gain in efficiency when using optimized coordinates in combination with a flexible scheme for choosing the mode-mode correlations included in the parameterization of the correlated many-mode vibrational wave function. All in all, it is found that the introduced schemes for parameterizing correlated many-mode vibrational wave functions lead to at least as systematic and accurate calculations as those using more standard and straightforward excitation level definitions. This new way of defining approximate calculations offers potential for future calculations on larger systems.

  4. How to Probe for Dynamical Structure in the Collapse of Entangled States Using Nuclear Magnetic Resonance

    CERN Document Server

    Fivel, D I

    1998-01-01

    The spin state of two magnetically inequivalent protons in contiguous atoms of a molecule becomes entangeled by the indirect spin-spin interaction (j-coupling). The degree of entanglement oscillates at the beat frequency resulting from the splitting of a degeneracy. This beating is manifest in NMR spectroscopy as an envelope of the transverse magnetization and should be visible in the free induction decay signal. The period (approximately 1 sec) is long enough for interference between the linear dynamics and collapse of the wave-function induced by a Stern-Gerlach inhomogeneity to significantly alter the shape of that envelope. Various dynamical collapse theories can be distinguished by their observably different predictions with respect to this alteration. Adverse effects of detuning due to the Stern-Gerlach inhomogeneity can be reduced to an acceptable level by having a sufficiently thin sample or a strong rf field.

  5. Orthogonality of embedded wave functions for different states in frozen-density embedding theory

    Energy Technology Data Exchange (ETDEWEB)

    Zech, Alexander; Wesolowski, Tomasz A. [Département de Chimie Physique, Université de Genève, 30 quai Ernest-Ansermet, CH-1211 Genève 4 (Switzerland); Aquilante, Francesco [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy)

    2015-10-28

    Other than lowest-energy stationary embedded wave functions obtained in Frozen-Density Embedding Theory (FDET) [T. A. Wesolowski, Phys. Rev. A 77, 012504 (2008)] can be associated with electronic excited states but they can be mutually non-orthogonal. Although this does not violate any physical principles — embedded wave functions are only auxiliary objects used to obtain stationary densities — working with orthogonal functions has many practical advantages. In the present work, we show numerically that excitation energies obtained using conventional FDET calculations (allowing for non-orthogonality) can be obtained using embedded wave functions which are strictly orthogonal. The used method preserves the mathematical structure of FDET and self-consistency between energy, embedded wave function, and the embedding potential (they are connected through the Euler-Lagrange equations). The orthogonality is built-in through the linearization in the embedded density of the relevant components of the total energy functional. Moreover, we show formally that the differences between the expectation values of the embedded Hamiltonian are equal to the excitation energies, which is the exact result within linearized FDET. Linearized FDET is shown to be a robust approximation for a large class of reference densities.

  6. Complex Tanh-Function Expansion Method and Exact Solutions to Two Systems of Nonlinear Wave Equations

    Institute of Scientific and Technical Information of China (English)

    ZHANGJin-Liang; WANGMing-Liang

    2004-01-01

    The complex tanh-function expansion method was presented recently, and it can be applied to derive exact solutions to the Schroedinger-type nonlinear evolution equations directly without transformation. In this paper,the complex tanh-function expansion method is applied to derive the exact solutions to the general coupled nonlinear evolution equations. Zakharov system and a long-short-wave interaction system are considered as examples, and the new applications of the complex tanh-function expansion method are shown.

  7. Complex Tanh-Function Expansion Method and Exact Solutions to Two Systems of Nonlinear Wave Equations

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jin-Liang; WANG Ming-Liang

    2004-01-01

    The complex tanh-function expansion method was presented recently, and it can be applied to derive exact solutions to the Schrodinger-type nonlinear evolution equations directly without transformation. In this paper,the complex tanh-function expansion method is applied to derive the exact solutions to the general coupled nonlinear evolution equations. Zakharov system and a long-short-wave interaction system are considered as examples, and the new applications of the complex tanh-function expansion method are shown.

  8. The incomplete plasma dispersion function: properties and application to waves in bounded plasmas

    OpenAIRE

    Baalrud, Scott D.

    2013-01-01

    The incomplete plasma dispersion function is a generalization of the plasma dispersion function in which the defining integral spans a semi-infinite, rather than infinite, domain. It is useful for describing the linear dielectric response and wave dispersion in non-Maxwellian plasmas when the distribution functions can be approximated as Maxwellian over finite, or semi-infinite, intervals in velocity phase-space. A ubiquitous example is the depleted Maxwellian electron distribution found near...

  9. Interacting relativistic quantum dynamics for multi-time wave functions

    Directory of Open Access Journals (Sweden)

    Lienert Matthias

    2016-01-01

    Full Text Available In this paper, we report on recent progress about a rigorous and manifestly covariant interacting model for two Dirac particles in 1+1 dimensions [9, 10]. It is formulated using the multi-time formalism of Dirac, Tomonaga and Schwinger. The mechanism of interaction is a relativistic generalization of contact interactions, and it is achieved going beyond the usual functional-analytic Hamiltonian method.

  10. Interacting relativistic quantum dynamics for multi-time wave functions

    Science.gov (United States)

    Lienert, Matthias

    2016-11-01

    In this paper, we report on recent progress about a rigorous and manifestly covariant interacting model for two Dirac particles in 1+1 dimensions [9, 10]. It is formulated using the multi-time formalism of Dirac, Tomonaga and Schwinger. The mechanism of interaction is a relativistic generalization of contact interactions, and it is achieved going beyond the usual functional-analytic Hamiltonian method.

  11. Spontaneous collapse: A solution to the measurement problem and a source of the decay in mesonic systems

    Science.gov (United States)

    Simonov, Kyrylo; Hiesmayr, Beatrix C.

    2016-11-01

    Dynamical reduction models propose a solution to the measurement problem in quantum mechanics: the collapse of the wave function becomes a physical process. We compute the predictions to decaying and flavor-oscillating neutral mesons for the two most promising collapse models, the QMUPL (quantum mechanics with universal position localization) model and the mass-proportional CSL (continuous spontaneous localization) model. Our results are showing (i) a strong sensitivity to the very assumptions of the noise field underlying those two collapse models and (ii) under particular assumptions the CSL case allows one even to recover the decay dynamics. This in turn allows one to predict the effective collapse rates solely based on the measured values for the oscillation (mass differences) and the measured values of the decay constants. The four types of neutral mesons (K meson, D meson, Bd meson, and Bs meson) lead surprisingly to ranges comparable to those put forward by Adler [J. Phys. A: Math. Theor. 40, 2935 (2007), 10.1088/1751-8113/40/12/S03] and Ghirardi, Rimini, and Weber [Phys. Rev. D 34, 470 (1986), 10.1103/PhysRevD.34.470]. Our results show that these systems at high energies are very sensitive to possible modifications of the standard quantum theory, making them a very powerful laboratory to rule out certain collapse scenarios and study the detailed physical processes solving the measurement problem.

  12. A system’s wave function is uniquely determined by its underlying physical state

    Science.gov (United States)

    Colbeck, Roger; Renner, Renato

    2017-01-01

    We address the question of whether the quantum-mechanical wave function Ψ of a system is uniquely determined by any complete description Λ of the system’s physical state. We show that this is the case if the latter satisfies a notion of ‘free choice’. This notion requires that certain experimental parameters—those that according to quantum theory can be chosen independently of other variables—retain this property in the presence of Λ. An implication of this result is that, among all possible descriptions Λ of a system’s state compatible with free choice, the wave function {{\\Psi }} is as objective as Λ.

  13. Visualization of superluminal pulses inside a white light cavity using plane wave spatio temporal transfer functions.

    Science.gov (United States)

    Yum, H N; Jang, Y J; Liu, X; Shahriar, M S

    2012-08-13

    In a white light cavity (WLC), the group velocity is superluminal over a finite bandwidth. For a WLC-based data buffering system we recently proposed, it is important to visualize the behavior of pulses inside such a cavity. The conventional plane wave transfer functions, valid only over space that is translationally invariant, cannot be used for the space inside WLC or any cavity, which is translationally variant. Here, we develop the plane wave spatio temporal transfer function (PWSTTF) method to solve this problem, and produce visual representations of a Gaussian input pulse incident on a WLC, for all times and positions.

  14. PREFACE: Collapse Calderas Workshop

    Science.gov (United States)

    Gottsmann, Jo; Aguirre-Diaz, Gerardo

    2008-10-01

    Caldera-formation is one of the most awe-inspiring and powerful displays of nature's force. Resultant deposits may cover vast areas and significantly alter the immediate topography. Post-collapse activity may include resurgence, unrest, intra-caldera volcanism and potentially the start of a new magmatic cycle, perhaps eventually leading to renewed collapse. Since volcanoes and their eruptions are the surface manifestation of magmatic processes, calderas provide key insights into the generation and evolution of large-volume silicic magma bodies in the Earth's crust. Despite their potentially ferocious nature, calderas play a crucial role in modern society's life. Collapse calderas host essential economic deposits and supply power for many via the exploitation of geothermal reservoirs, and thus receive considerable scientific, economic and industrial attention. Calderas also attract millions of visitors world-wide with their spectacular scenic displays. To build on the outcomes of the 2005 calderas workshop in Tenerife (Spain) and to assess the most recent advances on caldera research, a follow-up meeting was proposed to be held in Mexico in 2008. This abstract volume presents contributions to the 2nd Calderas Workshop held at Hotel Misión La Muralla, Querétaro, Mexico, 19-25 October 2008. The title of the workshop `Reconstructing the evolution of collapse calderas: Magma storage, mobilisation and eruption' set the theme for five days of presentations and discussions, both at the venue as well as during visits to the surrounding calderas of Amealco, Amazcala and Huichapan. The multi-disciplinary workshop was attended by more than 40 scientist from North, Central and South America, Europe, Australia and Asia. Contributions covered five thematic topics: geology, geochemistry/petrology, structural analysis/modelling, geophysics, and hazards. The workshop was generously supported by the International Association of Volcanology and the Chemistry of The Earth's Interior

  15. Probability Density Function for Waves Propagating in a Straight PEC Rough Wall Tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Pao, H

    2004-11-08

    The probability density function for wave propagating in a straight perfect electrical conductor (PEC) rough wall tunnel is deduced from the mathematical models of the random electromagnetic fields. The field propagating in caves or tunnels is a complex-valued Gaussian random processing by the Central Limit Theorem. The probability density function for single modal field amplitude in such structure is Ricean. Since both expected value and standard deviation of this field depend only on radial position, the probability density function, which gives what is the power distribution, is a radially dependent function. The radio channel places fundamental limitations on the performance of wireless communication systems in tunnels and caves. The transmission path between the transmitter and receiver can vary from a simple direct line of sight to one that is severely obstructed by rough walls and corners. Unlike wired channels that are stationary and predictable, radio channels can be extremely random and difficult to analyze. In fact, modeling the radio channel has historically been one of the more challenging parts of any radio system design; this is often done using statistical methods. In this contribution, we present the most important statistic property, the field probability density function, of wave propagating in a straight PEC rough wall tunnel. This work only studies the simplest case--PEC boundary which is not the real world but the methods and conclusions developed herein are applicable to real world problems which the boundary is dielectric. The mechanisms behind electromagnetic wave propagation in caves or tunnels are diverse, but can generally be attributed to reflection, diffraction, and scattering. Because of the multiple reflections from rough walls, the electromagnetic waves travel along different paths of varying lengths. The interactions between these waves cause multipath fading at any location, and the strengths of the waves decrease as the distance

  16. Catastrophes in non-equilibrium many-particle wave functions: universality and critical scaling

    Science.gov (United States)

    Mumford, J.; Kirkby, W.; O’Dell, D. H. J.

    2017-02-01

    As part of the quest to uncover universal features of quantum dynamics, we study catastrophes that form in simple many-particle wave functions following a quench, focusing on two-mode systems that include the two-site Bose–Hubbard model, and under some circumstances optomechanical systems and the Dicke model. When the wave function is plotted in Fock space certain characteristic shapes, that we identify as cusp catastrophes, appear under generic conditions. In the vicinity of a cusp the wave function takes on a universal structure described by the Pearcey function and obeys scaling relations which depend on the total number of particles N. In the thermodynamic limit (N\\to ∞ ) the cusp becomes singular, but at finite N it is decorated by an interference pattern. This pattern contains an intricate network of vortex–antivortex pairs, initiating a theory of topological structures in Fock space. In the case where the quench is a δ-kick the problem can be solved analytically and we obtain scaling exponents for the size and position of the cusp, as well as those for the amplitude and characteristic length scales of its interference pattern. Finally, we use these scalings to describe the wave function in the critical regime of a {{{Z}}}2 symmetry-breaking dynamical phase transition.

  17. Disproportionate Collapse in Building Structures.

    OpenAIRE

    JANSSENS, VICTORIA MARIA; O'DWYER, DERMOT WILLIAM

    2010-01-01

    PUBLISHED Cork, Ireland The failure of the Ronan Point apartment tower focused interest in disproportionate collapse, and prompted the ?Fifth Amendment? to the UK Building Regulations which was introduced in 1970. From this point on structures were required to exhibit a minimum level of robustness to resist progressive collapse. These rules have remained relatively unchanged for over 40 years. This paper presents a review of the concepts relating to structural collapse, and the robustne...

  18. On collapsibilities of Yule's measure

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    impson's paradox reminds people that the statistical inference in a low-dimensional space probably distorts the reality in a high one seriously.To study the paradox with respect to Yule's measure,this paper discusses simple collapsibility,strong collapsibility and consecutive collapsibility,and presents necessary and sufficient conditions of them.In fact,these conditions are of great importance for observational and experimental designs,eliminating confounding bias,categorizing discrete variables and so on.

  19. Wave function perturbations propagation in multi-particle systems, Einstein-Podolsky-Rosen (EPR) paradox and entanglement

    CERN Document Server

    Shnaid, Isaac

    2013-01-01

    If a one-particle or multi-particle non-relativistic quantum system is initially in a stationary state, and its wave function field is locally perturbed, then according to classical Schr\\"odinger equation, the perturbation instantaneously affects all infinite region because, according to the equation, speed of the wave function perturbations propagation is infinite. This feature strongly influences all theoretical predictions for time evolution of the system and contradicts the natural limitation of the perturbations propagation speed by speed of light. We develop finite propagation speed concept for multi-particle non-relativistic quantum systems. It consists of (a) eikonal type equation for the wave function perturbation traveltime describing finite speed perturbation waves in hyperspace including coordinates of all paricles in the system; (b) modified multi-particle Schr\\"odinger equation with finite speed of the wave function perturbations propagation; and (c) hypothesis that speed of the wave function pe...

  20. Surface Wave Speed of Functionally Graded Magneto-Electro-Elastic Materials with Initial Stresses

    Directory of Open Access Journals (Sweden)

    Li Li

    2014-09-01

    Full Text Available The shear surface wave at the free traction surface of half- infinite functionally graded magneto-electro-elastic material with initial stress is investigated. The material parameters are assumed to vary ex- ponentially along the thickness direction, only. The velocity equations of shear surface wave are derived on the electrically or magnetically open circuit and short circuit boundary conditions, based on the equations of motion of the graded magneto-electro-elastic material with the initial stresses and the free traction boundary conditions. The dispersive curves are obtained numerically and the influences of the initial stresses and the material gradient index on the dispersive curves are discussed. The investigation provides a basis for the development of new functionally graded magneto-electro-elastic surface wave devices.

  1. Acoustical impedance defined by wave-function solutions of the reduced Webster equation.

    Science.gov (United States)

    Forbes, Barbara J

    2005-07-01

    The electrical impedance was first defined by Heaviside in 1884, and the analogy of the acoustical impedance was made by Webster in 1919. However, it can be shown that Webster did not draw a full analogy with the electromagnetic potential, the potential energy per unit charge. This paper shows that the analogous "acoustical potential" the potential energy per unit displacement of fluid, corresponds to the wave function Psi of the reduced Webster equation, which is of Klein-Gordon form. The wave function is found to obey all of Dirichlet, Von Neumann, and mixed (Robins) boundary conditions, and the latter give rise to resonance phenomena that are not elucidated by Webster's analysis. It is shown that the exact Heaviside analogy yields a complete analytic account of the one-dimensional input impedance, that accounts for both plane- and dispersive-wave propagation both at the origin and throughout the duct.

  2. Scattering cluster wave functions on the lattice using the adiabatic projection method

    CERN Document Server

    Rokash, Alexander; Elhatisari, Serdar; Lee, Dean; Epelbaum, Evgeny; Krebs, Hermann

    2015-01-01

    The adiabatic projection method is a general framework for studying scattering and reactions on the lattice. It provides a low-energy effective theory for clusters which becomes exact in the limit of large Euclidean projection time. Previous studies have used the adiabatic projection method to extract scattering phase shifts from finite periodic-box energy levels using L\\"uschers method. In this paper we demonstrate that scattering observables can be computed directly from asymptotic cluster wave functions. For a variety of examples in one and three spatial dimensions, we extract elastic phase shifts from asymptotic cluster standing waves corresponding to spherical wall boundary conditions. We find that this approach of extracting scattering wave functions from the adiabatic Hamiltonian to be less sensitive to small stochastic and systematic errors as compared with using periodic-box energy levels.

  3. Reconstructing core-collapse supernovae waveforms with advanced era interferometers

    Science.gov (United States)

    McIver, Jessica; LIGO Scientific Collaboration

    2015-04-01

    Among of the wide range of potentially interesting astrophysical sources for Advanced LIGO and Advanced Virgo are galactic core-collapse supernovae. Although detectable core-collapse supernovae have a low expected rate (a few per century, or less) these signals would yield a wealth of new physics in the form of many messengers. Of particular interest is the insight into the explosion mechanism driving core-collapse supernovae that can be gleaned from the reconstructed gravitational wave signal. A well-reconstructed waveform will allow us to assess the likelihood of different explosion models, perform model selection, and potentially map unexpected features to new physics. This talk will present a study evaluating the current performance of the reconstruction of core-collapse supernovae gravitational wave signals. We used simulated waveforms modeled after different explosion mechanisms that we first injected into fake strain data re-colored to the expected Advanced LIGO/Virgo noise curves and then reconstructed using the pipelines Coherent Waveburst 2G and BayesWave. We will discuss the impact of these results on our ability to accurately reconstruct core-collapse supernovae signals, and by extension, other potential astrophysical generators of rich, complex waveforms.

  4. A New Maximum Entropy Probability Function for the Surface Elevation of Nonlinear Sea Waves

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-zhen; XU De-lun

    2005-01-01

    Based on the maximum entropy principle a new probability density function (PDF) f(x) for the surface elevation of nonlinear sea waves, X, is derived through performing a coordinate transform of X and solving a variation problem subject to three constraint conditions of f(x). Compared with the maximum entropy PDFs presented previously, the new PDF has the following merits: (1) it has four parameters to be determined and hence can give more refined fit to observed data and has wider suitability for nonlinear waves in different conditions; (2) these parameters are expressed in terms of distribution moments of X in a relatively simple form and hence are easy to be determined from observed data; (3) the PDF is free of the restriction of weak nonlinearity and possible to be used for sea waves in complicated conditions, such as those in shallow waters with complicated topography; and (4) the PDF is simple in form and hence convenient for theoretical and practical uses. Laboratory wind-wave experiments have been conducted to test the competence of the new PDF for the surface elevation of nonlinear waves. The experimental results manifest that the new PDF gives somewhat better fit to the laboratory wind-wave data than the well-known Gram-Charlier PDF and beta PDF.

  5. Functional data analytic approach of modeling ECG T-wave shape to measure cardiovascular behavior

    CERN Document Server

    Zhou, Yingchun; 10.1214/09-AOAS273

    2010-01-01

    The T-wave of an electrocardiogram (ECG) represents the ventricular repolarization that is critical in restoration of the heart muscle to a pre-contractile state prior to the next beat. Alterations in the T-wave reflect various cardiac conditions; and links between abnormal (prolonged) ventricular repolarization and malignant arrhythmias have been documented. Cardiac safety testing prior to approval of any new drug currently relies on two points of the ECG waveform: onset of the Q-wave and termination of the T-wave; and only a few beats are measured. Using functional data analysis, a statistical approach extracts a common shape for each subject (reference curve) from a sequence of beats, and then models the deviation of each curve in the sequence from that reference curve as a four-dimensional vector. The representation can be used to distinguish differences between beats or to model shape changes in a subject's T-wave over time. This model provides physically interpretable parameters characterizing T-wave sh...

  6. Coupled-cluster Green's function: Analysis of properties originating in the exponential parametrization of the ground-state wave function

    Science.gov (United States)

    Peng, Bo; Kowalski, Karol

    2016-12-01

    In this paper we derive basic properties of the Green's-function matrix elements stemming from the exponential coupled-cluster (CC) parametrization of the ground-state wave function. We demonstrate that all intermediates used to express the retarded (or, equivalently, ionized) part of the Green's function in the ω representation can be expressed only through connected diagrams. Similar properties are also shared by the first-order ω derivative of the retarded part of the CC Green's function. Moreover, the first-order ω derivative of the CC Green's function can be evaluated analytically. This result can be generalized to any order of ω derivatives. Through the Dyson equation, derivatives of the corresponding CC self-energy operator can be evaluated analytically. In analogy to the CC Green's function, the corresponding CC self-energy operator can be represented by connected terms. Our analysis can easily be generalized to the advanced part of the CC Green's function.

  7. Molecular potentials and wave function mapping by high-resolution electron spectroscopy and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kimberg, Victor, E-mail: victor.kimberg@pks.mpi.de [Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden (Germany); Miron, Catalin, E-mail: miron@synchrotron-soleil.fr [Synchrotron SOLEIL, l’Orme des Merisiers, Saint-Aubin, BP 48, FR-91192 Gif-sur-Yvette Cedex (France)

    2014-08-15

    Highlights: • Some studies related to the vibrational wave functions mapping phenomenon are reviewed. • The core-excited vibrational wave functions were mapped using dissociative and bound final states. • High-resolution experimental data is accompanied by ab initio calculations. • The mapping phenomenon allows one to extract constants of the molecular potentials. • The mapping techniques are general and can be applied for the study of many systems. - Abstract: The recent development of high brightness 3{sup rd} generation soft X-ray sources and high energy resolution electron spectrometers made it possible to accurately trace quantum phenomena associated to the vibrational dynamics in core-excited molecules. The present paper reviews the recent results on mapping of vibrational wave functions and molecular potentials based on electron spectroscopy. We discuss and compare the mapping phenomena in various systems, stressing the advantages of the resonant X-ray scattering for studying of the nuclear dynamics and spectroscopic constants of small molecules. The experimental results discussed in the paper are most often accompanied by state-of-the-art ab initio calculations allowing for a deeper understanding of the quantum effects. Besides its fundamental interest, the vibrational wave function mapping is shown to be useful for the analysis of core- and valence-excited molecular states based on the reflection principle.

  8. Alternative Form of the Hydrogenic Wave Functions for an Extended, Uniformly Charged Nucleus.

    Science.gov (United States)

    Ley-Koo, E.; And Others

    1980-01-01

    Presented are forms of harmonic oscillator attraction and Coulomb wave functions which can be explicitly constructed and which lead to numerical results for the energy eigenvalues and eigenfunctions of the atomic system. The Schrodinger equation and its solution and specific cases of muonic atoms illustrating numerical calculations are included.…

  9. Adjustment of Born-Oppenheimer electronic wave functions to simplify close coupling calculations.

    Science.gov (United States)

    Buenker, Robert J; Liebermann, Heinz-Peter; Zhang, Yu; Wu, Yong; Yan, Lingling; Liu, Chunhua; Qu, Yizhi; Wang, Jianguo

    2013-04-30

    Technical problems connected with use of the Born-Oppenheimer clamped-nuclei approximation to generate electronic wave functions, potential energy surfaces (PES), and associated properties are discussed. A computational procedure for adjusting the phases of the wave functions, as well as their order when potential crossings occur, is presented which is based on the calculation of overlaps between sets of molecular orbitals and configuration interaction eigenfunctions obtained at neighboring nuclear conformations. This approach has significant advantages for theoretical treatments describing atomic collisions and photo-dissociation processes by means of ab initio PES, electronic transition moments, and nonadiabatic radial and rotational coupling matrix elements. It ensures that the electronic wave functions are continuous over the entire range of nuclear conformations considered, thereby greatly simplifying the process of obtaining the above quantities from the results of single-point Born-Oppenheimer calculations. The overlap results are also used to define a diabatic transformation of the wave functions obtained for conical intersections that greatly simplifies the computation of off-diagonal matrix elements by eliminating the need for complex phase factors.

  10. The wave function of the universe and spontaneous breaking of supersymmetry

    CERN Document Server

    Obregón, O; Socorro, J; Tkach, V I

    1998-01-01

    In this work we define a scalar product ``weighted'' with the scalar factor $R$ and show how to find a normalized wave function for the supersymmetric quantum FRW cosmological model using the idea of supersymmetry breaking selection rules under local n=2 conformal supersymmetry. We also calculate the expectation value of the scalar factor R in this model and its corresponding behaviour.

  11. Time-dependent density-functional theory in the projector augmented-wave method

    DEFF Research Database (Denmark)

    Walter, Michael; Häkkinen, Hannu; Lehtovaara, Lauri

    2008-01-01

    We present the implementation of the time-dependent density-functional theory both in linear-response and in time-propagation formalisms using the projector augmented-wave method in real-space grids. The two technically very different methods are compared in the linear-response regime where we...

  12. Frequency-Domain Green's Functions for Radar Waves in Heterogeneous 2.5D Media

    Science.gov (United States)

    Green’s functions for radar waves propagating in heterogeneous media may be calculated in the frequency domain using a hybrid of two numerical methods. The model is defined in the Cartesian coordinate system, and its electromagnetic properties may vary in the x and z directions, ...

  13. Influence of wetting layer wave functions on carrier capture in quantum dots

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Markussen, Troels; Tromborg, Bjarne

    2005-01-01

    This work numerically solves the effective mass Schrodinger equation and shows that the capture times are strongly influenced by details of the continuum states not accounted for by the approximate wave functions. Results show that calculations of capture time for phonon mediated carrier capture...

  14. Gutzwiller variational wave function for multiorbital Hubbard models in finite dimensions

    Science.gov (United States)

    Münster, Kevin zu; Bünemann, Jörg

    2016-07-01

    We develop a diagrammatic method for the evaluation of general multiband Gutzwiller wave functions in finite dimensions. Our approach provides a systematic improvement of the widely used Gutzwiller approximation. As a first application, we investigate itinerant ferromagnetism and correlation-induced deformations of the Fermi surface for a two-band Hubbard model on a square lattice.

  15. Size-extensive wave functions for quantum Monte Carlo: A linear scaling generalized valence bond approach

    NARCIS (Netherlands)

    Fracchia, F.; Filippi, C.; Amovilli, C.

    2012-01-01

    We propose a new class of multideterminantal Jastrow–Slater wave functions constructed with localized orbitals and designed to describe complex potential energy surfaces of molecular systems for use in quantum Monte Carlo (QMC). Inspired by the generalized valence bond formalism, we elaborate a coup

  16. Nonlinear waves in lattice materials: Adaptively augmented directivity and functionality enhancement by modal mixing

    Science.gov (United States)

    Ganesh, R.; Gonella, S.

    2017-02-01

    The motive of this work is to understand the complex spatial characteristics of finite-amplitude elastic wave propagation in periodic structures and leverage the unique opportunities offered by nonlinearity to activate complementary functionalities and design adaptive spatial wave manipulators. The underlying assumption is that the magnitude of wave propagation is small with respect to the length scale of the structure under consideration, albeit large enough to elicit the effects of finite deformation. We demonstrate that the interplay of dispersion, nonlinearity and modal complexity involved in the generation and propagation of higher harmonics gives rise to secondary wave packets that feature multiple characteristics, one of which conforms to the dispersion relation of the corresponding linear structure. This provides an opportunity to engineer desired wave characteristics through a geometric and topological design of the unit cell, and results in the ability to activate complementary functionalities, typical of high frequency regimes, while operating at low frequencies of excitation - an effect seldom observed in linear periodic structures. The ability to design adaptive switches is demonstrated here using lattice configurations whose response is characterized by geometric and/or material nonlinearities.

  17. The incomplete plasma dispersion function: properties and application to waves in bounded plasmas

    CERN Document Server

    Baalrud, Scott D

    2013-01-01

    The incomplete plasma dispersion function is a generalization of the plasma dispersion function in which the defining integral spans a semi-infinite, rather than infinite, domain. It is useful for describing the linear dielectric response and wave dispersion in non-Maxwellian plasmas when the distribution functions can be approximated as Maxwellian over finite, or semi-infinite, intervals in velocity phase-space. A ubiquitous example is the depleted Maxwellian electron distribution found near boundary sheaths or double layers, where the passing interval can be modeled as Maxwellian with a lower temperature than the trapped interval. The depleted Maxwellian is used as an example to demonstrate the utility of using the incomplete plasma dispersion function for calculating modifications to wave dispersion relations.

  18. On the excited state wave functions of Dirac fermions in the random gauge potential

    Indian Academy of Sciences (India)

    H Milani Moghaddam

    2010-04-01

    In the last decade, it was shown that the Liouville field theory is an effective theory of Dirac fermions in the random gauge potential (FRGP). We show that the Dirac wave functions in FRGP can be written in terms of descendents of the Liouville vertex operator. In the quasiclassical approximation of the Liouville theory, our model predicts 22.2 that the localization length scales with the energy as $ ∼ E^{−b^{2}(1+b^{2})^{2}}$, where is the strength of the disorder. The self-duality of the theory under the transformation → 1/ is discussed. We also calculate the distribution functions of 0 = |0 ()|2, (i.e. (0); 0 () is the ground state wave function), which behaves as the log-normal distribution function. It is also shown that in small 0, (0) behaves as a chi-square distribution.

  19. On Green's function for 3-D wave-body interaction in a channel

    DEFF Research Database (Denmark)

    Xia, Jinzhu

    1997-01-01

    An analytical and numerical study is presented for efficient evaluation of the Green's function that satisfies the linear free surface condition and the non-penetration condition on the channel bottomand the side walls. the formulation is based on the open-sea green's function and the complete...... series of images is evaluated accurately based on an asmptotic analysis. It is demonstrated that the Green's function has a square-root singular behaviour due to the side walls when the wave frequency approaches one of the resonant frequencies. The numerical results for the Green's function has a square......-root singular behaviour due to the side walls when the wave frequency approaches one of the resonant frequencies. The numerical results for the Green's funciton presented in the present paper are believed to have an absolute accuracy of 10-5....

  20. Relationship between vascular endothelial function and pulse wave velocity in prehypertension

    Institute of Scientific and Technical Information of China (English)

    杨娉婷

    2014-01-01

    Objective To investigate the association between vascular endothelial function and arteriosclerosis in prehypertensive,hypertensive and healthy subjects.Methods 810 consecutive subjects were divided into three groups:hypertension group,prehypertension group and control group.Brachial-ankle pulse wave velocity(ba PWV)and flow-mediated brachial artery dilation(FMD)were used to evaluate the artery vascular stiffness and endothelial function respectively.Results Prehypertension

  1. Universal Probability Distribution for the Wave Function of a Quantum System Entangled with its Environment

    Science.gov (United States)

    Goldstein, Sheldon; Lebowitz, Joel L.; Mastrodonato, Christian; Tumulka, Roderich; Zanghì, Nino

    2016-03-01

    A quantum system (with Hilbert space {H}1) entangled with its environment (with Hilbert space {H}2) is usually not attributed to a wave function but only to a reduced density matrix {ρ1}. Nevertheless, there is a precise way of attributing to it a random wave function {ψ1}, called its conditional wave function, whose probability distribution {μ1} depends on the entangled wave function {ψ in H1 ⊗ H2} in the Hilbert space of system and environment together. It also depends on a choice of orthonormal basis of H2 but in relevant cases, as we show, not very much. We prove several universality (or typicality) results about {μ1}, e.g., that if the environment is sufficiently large then for every orthonormal basis of H2, most entangled states {ψ} with given reduced density matrix {ρ1} are such that {μ1} is close to one of the so-called GAP (Gaussian adjusted projected) measures, {GAP(ρ1)}. We also show that, for most entangled states {ψ} from a microcanonical subspace (spanned by the eigenvectors of the Hamiltonian with energies in a narrow interval {[E, E+ δ E]}) and most orthonormal bases of H2, {μ1} is close to {GAP({tr}2 ρ_{mc})} with {ρ_{mc}} the normalized projection to the microcanonical subspace. In particular, if the coupling between the system and the environment is weak, then {μ1} is close to {GAP(ρ_β)} with {ρ_β} the canonical density matrix on H1 at inverse temperature {β=β(E)}. This provides the mathematical justification of our claim in Goldstein et al. (J Stat Phys 125: 1193-1221, 2006) that GAP measures describe the thermal equilibrium distribution of the wave function.

  2. Multipole expansion of Green's function for guided waves in a transversely isotropic plate

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Heung Son; Kim, Yoon Young [Seoul National University, Seoul (Korea, Republic of)

    2015-05-15

    The multipole expansion of Green's function in a transversely isotropic plate is derived based on the eigenfunction expansion method. For the derivation, Green's function is expressed in a bilinear form composed of the regular and singular Lamb-type (or shear-horizontal) wave eigenfunctions. The specific form of the derived Green's function facilitates the handling of general scattering problems in an elastic plate when numerical methods such as the methods of the null-field integral equations are employed. In the derivation, the integral transform of an arbitrary guided wave field is first constructed by the Lamb-type and shear horizontal wave eigenfunctions that work as the kernel functions. After showing that the thickness-dependent parts of the eigenfunctions are orthogonal to each other in the transformed space, Green's function is explicitly derived by using the orthogonality. As an application of the derived Green's function, a scattering problem is solved by the transition matrix method.

  3. Decoding micro-structural damage related to caldera collapse at Santorini Volcano

    Science.gov (United States)

    Drymoni, Kyriaki; Browning, John; Gudmundsson, Agust; Mitchell, Thomas

    2017-04-01

    Deformation in damage zones, as micro fracture density, can be estimated at a given distance from a fault as a function of fault displacement, based on empirical relationships derived from detailed quantitative field studies of natural faults that cut through low porosity, crystalline rocks in strike-slip tectonic environments. For the first time, we attempt to apply the same method to study the characteristics of a damage zone generated by caldera collapse along a bounding circumferential ring-fault. We have undertaken a field campaign at Santorini Volcano, Greece, and mapped sections of a dyke swarm in the northern caldera wall. The dykes, associated lavas, and eruptive units are partially cut by a series of historic caldera collapses. The dykes represent elastic inclusions in an otherwise heterogeneous and complex edifice which makes up the Santorini Volcano. To study caldera-related damage we sampled dykes at varying distance from the inferred caldera fault. The collected samples were cut into several different orientations to map micro-fracture density and orientation with relation to the strike of the historic caldera faults. In addition, benchtop ultrasonic wave velocity measurements were made on all samples. Preliminary fracture analysis of plagioclase crystals and velocity data suggests relationship between proximity to the fault and micro-fracture density. We also find a mechanical anisotropy control which may relate to the orientation of fractures generated by historic caldera collapses on Santorini. An analysis of the anisotropy and micro-fractures may help to identify the mechanism of caldera faulting at Santorini (e.g. near-surface tension fractures and normal faulting or reverse faulting). In addition to our micro-structural study, we will investigate the presence of hydrothermal/chemical alteration within the inferred caldera damage zone. Our aim is to set up numerical models to investigate stress distribution within the dykes and host rock during

  4. Caldera types and collapse styles

    Science.gov (United States)

    Aguirre-Diaz, G. J.

    2008-12-01

    Three main types of collapse calderas can be defined, 1) summit caldera, 2) classic caldera, and 3) graben caldera. Summit calderas are those formed at the top of large volcanoes and are related to relatively small- volume pyroclastic products that include plinian fallouts and ignimbrites, such as Crater Lake, Las Cañadas, and Somma-Vesuvio. Classic calderas are semi-circular to irregular-shaped large structures, several km in diameter that are related to relatively large-volume pyroclastic products including pumice fallouts and widespread ignimbrites, such as Long-Valley, Campi Flegrei, and Los Humeros. Graben calderas are explosive volcano-tectonic collapse structures from which large-volume, ignimbrite-forming eruptions occurred through several vents along the graben walls and the intra-graben block faults causing the collapse of the graben or of a sector of the graben. The main products of graben calderas are surge-deposits and large-volume widespread ignimbrite sheets. Pumice fallouts are practically absent. Examples include the Sierra Madre Occidental in Mexico, La Pacana (Andes), Catalan Pyrenees, and perhaps Scafell (United Kingdom). Any of the three caldera types mentioned above could have collapsed at least in three different ways, 1) piston, when the collapse occurs as a single crustal block; 2) trap-door, when collapse occurs unevenly along one side while the opposite side remains with no collapse; 3) piece-meal, when collapse occurs as broken pieces of the crust on top of the magma chamber.

  5. The collapsed football pla yer

    African Journals Online (AJOL)

    There are several reasons why football players collapse or appear to have collapsed on ... minor, resulting in mild concussion (brain injury), but ... after being struck by lightning. The match ... does occur, it attracts a great deal of media attention ...

  6. Study of film boiling collapse behavior during vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Abe, Yutaka; Adachi, Hiromichi; Kobayashi, Tomoyoshi

    1996-06-01

    Possible large scale vapor explosions are safety concern in nuclear power plants during severe accident. In order to identify the occurrence of the vapor explosion and to estimate the magnitude of the induced pressure pulse, it is necessary to investigate the triggering condition for the vapor explosion. As a first step of this study, scooping analysis was conducted with a simulation code based on thermal detonation model. It was found that the pressure at the collapse of film boiling much affects the trigger condition of vapor explosion. Based on this analytical results, basic experiments were conducted to clarify the collapse conditions of film boiling on a high temperature solid ball surface. Film boiling condition was established by flooding water onto a high temperature stainless steel ball heated by a high frequency induction heater. After the film boiling was established, the pressure pulse generated by a shock tube was applied to collapse the steam film on the ball surface. As the experimental boundary conditions, materials and size of the balls, magnitude of pressure pulse and initial temperature of the carbon and stainless steel balls were varied. The transients of pressure and surface temperature were measured. It was found that the surface temperature on the balls sharply decreased when the pressure wave passed through the film on balls. Based on the surface temperature behavior, the film boiling collapse pattern was found to be categorized into several types. Especially, the pattern for stainless steel ball was categorized into three types; no collapse, collapse and reestablishment after collapse. It was thus clarified that the film boiling collapse behavior was identified by initial conditions and that the pressure required to collapse film boiling strongly depended on the initial surface temperature. The present results will provide a useful information for the analysis of vapor explosions based on the thermal detonation model. (J.P.N.)

  7. Effect of extracorporeal shock wave therapy on the shoulder joint functional status of patients with calcific tendinitis

    OpenAIRE

    2016-01-01

    [Purpose] This study aimed to analyze the effect of extracorporeal shock wave therapy on the shoulder function of patients with calcific tendinitis through a 12-week follow-up. [Subjects and Methods] A total of 34 patients with calcific tendinitis participated in this study. In the extracorporeal shock wave therapy group, 18 patients received 6-week extracorporeal shock wave therapy and 12-week follow-up. The Constant-Murley scale was used to evaluate shoulder joint function. [Results] Analys...

  8. Mapping collapsed columns in coal mines utilizing Microtremor Survey Methods

    Energy Technology Data Exchange (ETDEWEB)

    Xu, P.F.; Li, C.J.; Ling, S.Q.; Zhang, Y.B.; Hou, Z.; Sun, Y.J. [Chinese Academy of Sciences, Beijing (China)

    2009-07-15

    Collapsed columns post one of the deadly safety risks to coal miners. Therefore, how to effectively map collapsed columns has become an urgent business matter for improving coal mine safety and coal production. This article documents the first application of the microtremor survey method to map geological hazards in the coal mining areas. Our results demonstrated the usefulness and effectiveness of the method, primarily due to the sensitivity of shear waves to the low-velocity collapsed columns. In the 2002 working region within the Shanxi Lu'an Zhangcun coal mine area, both the S-wave velocity structure inverted using the simple-point inversion method and the apparent S-wave velocity section obtained using the 2D microtremor profiling method clearly display the known collapsed columns. The collapsed column positions displayed in the 2D microtremor section are consistent with those seen from the tunnel, having a boundary error approximately 10 m. The microtremor method has been proved a very effective and useful geophysical tool to improve coal mining safety, because of the following characteristics: (1) high resolution, (2) no need of using the artificial source, (3) convenient and low-cost field data acquisition, and (4) little effect from local cultural structures. The microtremor survey method is also technically superior to any other geophysical method in detecting or mapping these low or high S-wave velocity anomalies. Therefore, it has a bright future in many geological and geophysical applications, such as investigation of coal seam structures and collapsed columns underneath villages.

  9. Automated calculation of anharmonic vibrational contributions to first hyperpolarizabilities: quadratic response functions from vibrational configuration interaction wave functions.

    Science.gov (United States)

    Hansen, Mikkel Bo; Christiansen, Ove; Hättig, Christof

    2009-10-21

    Quadratic response functions are derived and implemented for a vibrational configuration interaction state. Combined electronic and vibrational quadratic response functions are derived using Born-Oppenheimer vibronic product wave functions. Computational tractable expressions are derived for determining the total quadratic response contribution as a sum of contributions involving both electronic and vibrational linear and quadratic response functions. In the general frequency-dependent case this includes a new and more troublesome type of electronic linear response function. Pilot calculations for the FH, H(2)O, CH(2)O, and pyrrole molecules demonstrate the importance of vibrational contributions for accurate comparison to experiment and that the vibrational contributions in some cases can be very large. The calculation of transition properties between vibrational states is combined with sum-over-states expressions for analysis purposes. On the basis of this some simple analysis methods are suggested. Also, a preliminary study of the effect of finite lifetimes on quadratic response functions is presented.

  10. The Puzzle of the Tacoma Narrows Bridge Collapse: An Interactive Videodisc Program for Physics Instruction.

    Science.gov (United States)

    Zollman, Dean; Fuller, Robert

    1982-01-01

    An interactive, instructional videodisc was produced using films on wave motion/vibrations and Tacoma Narrows bridge collapse. The disc is appropriate for three levels of physics (physics/algebra; physics/calculus; non-major physics). Program sections (introduction to videodisc player, bridge collapse, influence of wind, bridge properties, and…

  11. Can Bohmian particle be a source of "continuous collapse" in GRW-type theories

    CERN Document Server

    Sverdlov, Roman

    2011-01-01

    The purpose of this paper is to unite Pilot Wave model with GRW ideas through a proposal that Bohmian particle serves as a source of continuous collapse. The continuous trajectory of a particle allows the particle-centered collapse mechanism to be continuous as well. This allows us to remove the "stochastic" element from typical GRW proposals.

  12. Intrinsic Resolution of Molecular Electronic Wave Functions and Energies in Terms of Quasi-atoms and Their Interactions.

    Science.gov (United States)

    West, Aaron C; Schmidt, Michael W; Gordon, Mark S; Ruedenberg, Klaus

    2017-02-09

    A general intrinsic energy resolution has been formulated for strongly correlated wave functions in the full molecular valence space and its subspaces. The information regarding the quasi-atomic organization of the molecular electronic structure is extracted from the molecular wave function without introducing any additional postulated model state wave functions. To this end, the molecular wave function is expressed in terms of quasi-atomic molecular orbitals, which maximize the overlap between subspaces of the molecular orbital space and the free-atom orbital spaces. As a result, the molecular wave function becomes the superposition of a wave function representing the juxtaposed nonbonded quasi-atoms and a wave function describing the interatomic electron migrations that create bonds through electron sharing. The juxtaposed nonbonded quasi-atoms are shown to consist of entangled quasi-atomic states from different atoms. The binding energy is resolved as a sum of contributions that are due to quasi-atom formation, quasiclassical electrostatic interactions, and interatomic interferences caused by electron sharing. The contributions are further resolved according to orbital interactions. The various transformations that generate the analysis are determined by criteria that are independent of the working orbital basis used for calculating the molecular wave function. The theoretical formulation of the resolution is quantitatively validated by an application to the C2 molecule.

  13. Expansion of Arbitrary Electromagnetic Fields in Terms of Vector Spherical Wave Functions

    CERN Document Server

    Moreira, W L; Garbos, M K; Euser, T G; Russell, P St J; Cesar, C L

    2010-01-01

    Since 1908, when Mie reported analytical expressions for the fields scattered by a spherical particle upon incidence of an electromagnetic plane-wave, generalizing his analysis to the case of an arbitrary incident wave has proved elusive. This is due to the presence of certain radially-dependent terms in the equation for the beam-shape coefficients of the expansion of the electromagnetic fields in terms of vector spherical wave functions. Here we show for the first time how these terms can be canceled out, allowing analytical expressions for the beam shape coefficients to be found for a completely arbitrary incident field. We give several examples of how this new method, which is well suited to numerical calculation, can be used. Analytical expressions are found for Bessel beams and the modes of rectangular and cylindrical metallic waveguides. The results are highly relevant for speeding up calculation of the radiation forces acting on small spherical particles placed in an arbitrary electromagnetic field, fo...

  14. A Proton-Cyclotron Wave Storm Generated by Unstable Proton Distribution Functions in the Solar Wind

    Science.gov (United States)

    Wicks, R. T.; Alexander, R. L.; Stevens, M.; Wilson, L. B., III; Moya, P. S.; Vinas, A.; Jian, L. K.; Roberts, D. A.; O’Modhrain, S.; Gilbert, J. A.; Zurbuchen, T. H.

    2016-01-01

    We use audification of 0.092 seconds cadence magnetometer data from the Wind spacecraft to identify waves with amplitudes greater than 0.1 nanoteslas near the ion gyrofrequency (approximately 0.1 hertz) with duration longer than 1 hour during 2008. We present one of the most common types of event for a case study and find it to be a proton-cyclotron wave storm, coinciding with highly radial magnetic field and a suprathermal proton beam close in density to the core distribution itself. Using linear Vlasov analysis, we conclude that the long-duration, large-amplitude waves are generated by the instability of the proton distribution function. The origin of the beam is unknown, but the radial field period is found in the trailing edge of a fast solar wind stream and resembles other events thought to be caused by magnetic field footpoint motion or interchange reconnection between coronal holes and closed field lines in the corona.

  15. Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

    Science.gov (United States)

    Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

    2014-01-01

    The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates.

  16. Relations between low-lying quantum wave functions and solutions of the Hamilton-Jacobi equation

    CERN Document Server

    Friedberg, R; Zhao Wei Qin

    1999-01-01

    We discuss a new relation between the low lying Schroedinger wave function of a particle in a one-dimentional potential V and the solution of the corresponding Hamilton-Jacobi equation with -V as its potential. The function V is $\\geq 0$, and can have several minina (V=0). We assume the problem to be characterized by a small anhamornicity parameter $g^{-1}$ and a much smaller quantum tunneling parameter $\\epsilon$ between these different minima. Expanding either the wave function or its energy as a formal double power series in $g^{-1}$ and $\\epsilon$, we show how the coefficients of $g^{-m}\\epsilon^n$ in such an expansion can be expressed in terms of definite integrals, with leading order term determined by the classical solution of the Hamilton-Jacobi equation. A detailed analysis is given for the particular example of quartic potential $V={1/2}g^2(x^2-a^2)^2$.

  17. Dust heating by Alfvén waves using non-Maxwellian distribution function

    Energy Technology Data Exchange (ETDEWEB)

    Zubia, K. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Shah, H. A. [Department of Physics, Forman Christian College, Lahore 54600 (Pakistan); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2015-08-15

    Quasilinear theory is employed in order to evaluate the resonant heating rate by Alfvén waves, of multiple species dust particles in a hot, collisionless, and magnetized plasma, with the underlying assumption that the dust velocity distribution function can be modeled by a generalized (r, q) distribution function. The kinetic linear dispersion relation for the electromagnetic dust cyclotron Alfvén waves is derived, and the dependence of the heating rate on the magnetic field, mass, and density of the dust species is subsequently investigated. The heating rate and its dependence on the spectral indices r and q of the distribution function are also investigated. It is found that the heating is sensitive to negative value of spectral index r.

  18. Phenomenological analysis of quantum collapse as source of the seeds of cosmic structure

    CERN Document Server

    De Unánue, Adolfo

    2008-01-01

    The standard inflationary version of the origin of the cosmic structure as the result of the quantum fluctuations during the early universe is less than fully satisfactory as has been argued in [A. Perez, H. Sahlmann, and D. Sudarsky, Class. Quantum Grav., 23, 2317, (2006)]. A proposal is made there of a way to address the shortcomings by invoking a process similar to the collapse of the quantum mechanical wave function of the various modes of the inflaton field. This in turn was inspired on the ideas of R. Penrose about the role that quantum gravity might play in bringing about such breakdown of the standard unitary evolution of quantum mechanics. In this paper we study in some detail the two schemes of collapse considered in the original work together with an alternative scheme, which can be considered as "more natural" than the former two. The new scheme, assumes that the collapse follows the correlations indicated in the Wigner functional of the initial state. We end with considerations regarding the degr...

  19. Effect of wave-function localization on the time delay in photoemission from surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, C.-H.; Thumm, U. [Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)

    2011-12-15

    We investigate streaking time delays in the photoemission from a solid model surface as a function of the degree of localization of the initial-state wave functions. We consider a one-dimensional slab with lattice constant a{sub latt} of attractive Gaussian-shaped core potentials of width {sigma}. The parameter {sigma}/a{sub latt} thus controls the overlap between adjacent core potentials and localization of the electronic eigenfunctions on the lattice points. Small values of {sigma}/a{sub latt}<<1 yield lattice eigenfunctions that consist of localized atomic wave functions modulated by a ''Bloch-envelope'' function, while the eigenfunctions become delocalized for larger values of {sigma}/a{sub latt} > or approx 0.4. By numerically solving the time-dependent Schroedinger equation, we calculate photoemission spectra from which we deduce a characteristic bimodal shape of the band-averaged photoemission time delay: as the slab eigenfunctions become increasingly delocalized, the time delay quickly decreases near {sigma}/a{sub latt}=0.3 from relatively large values below {sigma}/a{sub latt}{approx}0.2 to much smaller delays above {sigma}/a{sub latt}{approx}0.4. This change in wave-function localization facilitates the interpretation of a recently measured apparent relative time delay between the photoemission from core and conduction-band levels of a tungsten surface.

  20. The Uniqueness of Single Data Function, Multiple Model Functions, Inverse Problems Including the Rayleigh Wave Dispersion Problem

    Science.gov (United States)

    Menke, William

    2017-02-01

    We prove that the problem of inverting Rayleigh wave phase velocity functions c( k ) , where k is wavenumber, for density ρ ( z ) , rigidity μ ( z ) and Lamé parameter λ ( z ) , where z is depth, is fully non-unique, at least in the highly-idealized case where the base Earth model is an isotropic half space. The model functions completely trade off. This is one special case of a common inversion scenario in which one seeks to determine several model functions from a single data function. We explore the circumstances under which this broad class of problems is unique, starting with very simple scenarios, building up to the somewhat more complicated (and common) case where data and model functions are related by convolutions, and then finally, to scale-independent problems (which include the Rayleigh wave problem). The idealized cases that we examine analytically provide insight into the kinds of nonuniqueness that are inherent in the much more complicated problems encountered in modern geophysical imaging (though they do not necessarily provide methods for solving those problems). We also define what is meant by a Backus and Gilbert resolution kernel in this kind of inversion and show under what circumstances a unique localized average of a single model function can be constructed.

  1. The Uniqueness of Single Data Function, Multiple Model Functions, Inverse Problems Including the Rayleigh Wave Dispersion Problem

    Science.gov (United States)

    Menke, William

    2017-04-01

    We prove that the problem of inverting Rayleigh wave phase velocity functions c( k ), where k is wavenumber, for density ρ ( z ), rigidity μ ( z ) and Lamé parameter λ ( z ), where z is depth, is fully non-unique, at least in the highly-idealized case where the base Earth model is an isotropic half space. The model functions completely trade off. This is one special case of a common inversion scenario in which one seeks to determine several model functions from a single data function. We explore the circumstances under which this broad class of problems is unique, starting with very simple scenarios, building up to the somewhat more complicated (and common) case where data and model functions are related by convolutions, and then finally, to scale-independent problems (which include the Rayleigh wave problem). The idealized cases that we examine analytically provide insight into the kinds of nonuniqueness that are inherent in the much more complicated problems encountered in modern geophysical imaging (though they do not necessarily provide methods for solving those problems). We also define what is meant by a Backus and Gilbert resolution kernel in this kind of inversion and show under what circumstances a unique localized average of a single model function can be constructed.

  2. On the Quantum Mechanical Wave Function as a Link Between Cognition and the Physical World A Role for Psychology

    CERN Document Server

    Snyder, D

    2002-01-01

    A straightforward explanation of fundamental tenets of quantum mechanics concerning the wave function results in the thesis that the quantum mechanical wave function is a link between human cognition and the physical world. The reticence on the part of physicists to adopt this thesis is discussed. A comparison is made to the behaviorists' consideration of mind, and the historical roots of how the problem concerning the quantum mechanical wave function arose are discussed. The basis for an empirical demonstration that the wave function is a link between human cognition and the physical world is provided through developing an experiment using methodology from psychology and physics. Based on research in psychology and physics that relied on this methodology, it is likely that Einstein, Podolsky, and Rosen's theoretical result that mutually exclusive wave functions can simultaneously apply to the same concrete physical circumstances can be implemented on an empirical level.

  3. Simulations of protostellar collapse using multigroup radiation hydrodynamics. II. The second collapse

    CERN Document Server

    Vaytet, N; Audit, E; Commercon, B; Masson, J; Ferguson, J; Delahaye, F

    2013-01-01

    Star formation begins with the gravitational collapse of a dense core inside a molecular cloud. As the collapse progresses, the centre of the core begins to heat up as it becomes optically thick. The temperature and density in the centre eventually reach high enough values where fusion reactions can ignite; the protostar is born. This sequence of events entail many physical processes, of which radiative transfer is of paramount importance. Many simulations of protostellar collapse make use of a grey treatment of radiative transfer coupled to the hydrodynamics. However, interstellar gas and dust opacities present large variations as a function of frequency. In this paper, we follow-up on a previous paper on the collapse and formation of Larson's first core using multigroup radiation hydrodynamics (Paper I) by extending the calculations to the second phase of the collapse and the formation of Larson's second core. We have made the use of a non-ideal gas equation of state as well as an extensive set of spectral ...

  4. Love waves in functionally graded piezoelectric materials by stiffness matrix method.

    Science.gov (United States)

    Ben Salah, Issam; Wali, Yassine; Ben Ghozlen, Mohamed Hédi

    2011-04-01

    A numerical matrix method relative to the propagation of ultrasonic guided waves in functionally graded piezoelectric heterostructure is given in order to make a comparative study with the respective performances of analytical methods proposed in literature. The preliminary obtained results show a good agreement, however numerical approach has the advantage of conceptual simplicity and flexibility brought about by the stiffness matrix method. The propagation behaviour of Love waves in a functionally graded piezoelectric material (FGPM) is investigated in this article. It involves a thin FGPM layer bonded perfectly to an elastic substrate. The inhomogeneous FGPM heterostructure has been stratified along the depth direction, hence each state can be considered as homogeneous and the ordinary differential equation method is applied. The obtained solutions are used to study the effect of an exponential gradient applied to physical properties. Such numerical approach allows applying different gradient variation for mechanical and electrical properties. For this case, the obtained results reveal opposite effects. The dispersive curves and phase velocities of the Love wave propagation in the layered piezoelectric film are obtained for electrical open and short cases on the free surface, respectively. The effect of gradient coefficients on coupled electromechanical factor, on the stress fields, the electrical potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the well known heterostructure PZT-5H/SiO(2), the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Love wave propagation behaviour.

  5. Fermionic spectral functions in backreacting p-wave superconductors at finite temperature

    CERN Document Server

    Giordano, G L; Lugo, A R

    2016-01-01

    We investigate the spectral function of fermions in a $p$-wave superconducting state, at finite both temperature and gravitational coupling, using the $AdS/CFT$ correspondence and extending previous research. We found that, for any coupling below a critical value, the system behaves as its zero temperature limit. By increasing the coupling, the "peak-dip-hump" structure that characterizes the spectral function at fixed momenta disappears. In the region where the normal/superconductor phase transition is first order, the presence of a non-zero order parameter is reflected in the absence of rotational symmetry in the fermionic spectral function at the critical temperature.

  6. Predicting mining collapse: Superjerks and the appearance of record-breaking events in coal as collapse precursors

    Science.gov (United States)

    Jiang, Xiang; Liu, Hanlong; Main, Ian G.; Salje, Ekhard K. H.

    2017-08-01

    The quest for predictive indicators for the collapse of coal mines has led to a robust criterion from scale-model tests in the laboratory. Mechanical collapse under uniaxial stress forms avalanches with a power-law probability distribution function of radiated energy P ˜E-ɛ , with exponent ɛ =1.5 . Impending major collapse is preceded by a reduction of the energy exponent to the mean-field value ɛ =1.32 . Concurrently, the crackling noise increases in intensity and the waiting time between avalanches is reduced when the major collapse is approaching. These latter criteria were so-far deemed too unreliable for safety assessments in coal mines. We report a reassessment of previously collected extensive collapse data sets using "record-breaking analysis," based on the statistical appearance of "superjerks" within a smaller spectrum of collapse events. Superjerks are defined as avalanche signals with energies that surpass those of all previous events. The final major collapse is one such superjerk but other "near collapse" events equally qualify. In this way a very large data set of events is reduced to a sparse sequence of superjerks (21 in our coal sample). The main collapse can be anticipated from the sequence of energies and waiting times of superjerks, ignoring all weaker events. Superjerks are excellent indicators for the temporal evolution, and reveal clear nonstationarity of the crackling noise at constant loading rate, as well as self-similarity in the energy distribution of superjerks as a function of the number of events so far in the sequence Es j˜nδ with δ =1.79 . They are less robust in identifying the precise time of the final collapse, however, than the shift of the energy exponents in the whole data set which occurs only over a short time interval just before the major event. Nevertheless, they provide additional diagnostics that may increase the reliability of such forecasts.

  7. Gravitational collapse of barotropic spherical fluids

    CERN Document Server

    Giambo, R; Magli, G; Piccione, P; Giambo', Roberto; Giannoni, Fabio; Magli, Giulio; Piccione, Paolo

    2003-01-01

    The gravitational collapse of spherical, barotropic perfect fluids is analyzed here. For the first time, the final state of these systems is characterized without resorting to simplifying assumptions - such as self-similarity - using a new approach based on non-linear o.d.e. techniques. Formation of naked singularities is shown to occur for solutions such that the mass function is sufficiently regular in a neighborhood of the spacetime singularity.

  8. Drying Induced Hydrophobic Polymer Collapse

    OpenAIRE

    ten Wolde, Pieter Rein; Chandler, David

    2002-01-01

    We have used computer simulation to study the collapse of a hydrophobic chain in water. We find that the mechanism of collapse is much like that of a first-order phase transition. The evaporation of water in the vicinity of the polymer provides the driving force for collapse, and the rate limiting step is the nucleation of a sufficiently large vapor bubble. The study is made possible through the application of transition path sampling and a coarse-grained treatment of liquid water. Relevance ...

  9. The acoustical Klein-Gordon equation: the wave-mechanical step and barrier potential functions.

    Science.gov (United States)

    Forbes, Barbara J; Pike, E Roy; Sharp, David B

    2003-09-01

    The transformed form of the Webster equation is investigated. Usually described as analogous to the Schrödinger equation of quantum mechanics, it is noted that the second-order time dependency defines a Klein-Gordon problem. This "acoustical Klein-Gordon equation" is analyzed with particular reference to the acoustical properties of wave-mechanical potential functions, U(x), that give rise to geometry-dependent dispersions at rapid variations in tract cross section. Such dispersions are not elucidated by other one-dimensional--cylindrical or conical--duct models. Since Sturm-Liouville analysis is not appropriate for inhomogeneous boundary conditions, the exact solution of the Klein-Gordon equation is achieved through a Green's-function methodology referring to the transfer matrix of an arbitrary string of square potential functions, including a square barrier equivalent to a radiation impedance. The general conclusion of the paper is that, in the absence of precise knowledge of initial conditions on the area function, any given potential function will map to a multiplicity of area functions of identical relative resonance characteristics. Since the potential function maps uniquely to the acoustical output, it is suggested that the one-dimensional wave physics is both most accurately and most compactly described within the Klein-Gordon framework.

  10. Quantum Mechanical Effects in Gravitational Collapse

    CERN Document Server

    Greenwood, Eric

    2010-01-01

    In this thesis we investigate quantum mechanical effects to various aspects of gravitational collapse. These quantum mechanical effects are implemented in the context of the Functional Schr\\"odinger formalism. The Functional Schr\\"odinger formalism allows us to investigate the time-dependent evolutions of the quantum mechanical effects, which is beyond the scope of the usual methods used to investigate the quantum mechanical corrections of gravitational collapse. Utilizing the time-dependent nature of the Functional Schr\\"odinger formalism, we study the quantization of a spherically symmetric domain wall from the view point of an asymptotic and infalling observer, in the absence of radiation. To build a more realistic picture, we then study the time-dependent nature of the induced radiation during the collapse using a semi-classical approach. Using the domain wall and the induced radiation, we then study the time-dependent evolution of the entropy of the domain wall. Finally we make some remarks about the pos...

  11. Collapse Velocity and Prompt Explosion for the Presupernova Model Ws15M⊙

    Institute of Scientific and Technical Information of China (English)

    Zhi-Quan Luo; Men-Quan Liu; Qiu-He Peng; Zuo-Heng Xie

    2006-01-01

    For the presupernova model Ws15M⊙, we re-calculate the electron capture (EC) timescale and hydrodynamical (HD) timescale. We found that the EC timescale can be smaller than the HD timescale in the inner region of the collapse iron core at the moment immediately before the shock wave bounce. The change in these two timescales at the late stage of core collapse is expected to affect the collapse velocity. If the late-time collapse velocity is artificially increased by a small quantity, then prompt explosion of the supernova may happen. Further calculations are still needed to check the plausibility of the acceleration mechanism caused by the faster EC process.

  12. Convergence of many-body wave-function expansions using a plane-wave basis: From homogeneous electron gas to solid state systems

    Science.gov (United States)

    Shepherd, James J.; Grüneis, Andreas; Booth, George H.; Kresse, Georg; Alavi, Ali

    2012-07-01

    Using the finite simulation-cell homogeneous electron gas (HEG) as a model, we investigate the convergence of the correlation energy to the complete-basis-set (CBS) limit in methods utilizing plane-wave wave-function expansions. Simple analytic and numerical results from second-order Møller-Plesset theory (MP2) suggest a 1/M decay of the basis-set incompleteness error where M is the number of plane waves used in the calculation, allowing for straightforward extrapolation to the CBS limit. As we shall show, the choice of basis-set truncation when constructing many-electron wave functions is far from obvious, and here we propose several alternatives based on the momentum transfer vector, which greatly improve the rate of convergence. This is demonstrated for a variety of wave-function methods, from MP2 to coupled-cluster doubles theory and the random-phase approximation plus second-order screened exchange. Finite basis-set energies are presented for these methods and compared with exact benchmarks. A transformation can map the orbitals of a general solid state system onto the HEG plane-wave basis and thereby allow application of these methods to more realistic physical problems. We demonstrate this explicitly for solid and molecular lithium hydride.

  13. Auxiliary-field based trial wave functions in quantum Monte Carlo simulations

    Science.gov (United States)

    Chang, Chia-Chen; Rubenstein, Brenda; Morales, Miguel

    We propose a simple scheme for generating correlated multi-determinant trial wave functions for quantum Monte Carlo algorithms. The method is based on the Hubbard-Stratonovich transformation which decouples a two-body Jastrow-type correlator into one-body projectors coupled to auxiliary fields. We apply the technique to generate stochastic representations of the Gutzwiller wave function, and present benchmark resuts for the ground state energy of the Hubbard model in one dimension. Extensions of the proposed scheme to chemical systems will also be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, 15-ERD-013.

  14. Second-order corrections to the wave function at origin in muonic hydrogen and pionium

    CERN Document Server

    Ivanov, Vladimir G; Karshenboim, Savely G

    2009-01-01

    Non-relativisitic second-order corrections to the wave function at origin in muonic and exotic atoms are considered. The corrections are due to the electronic vacuum polarization. Such corrections are of interest due to various effective approaches, which take into account QED and hadronic effects. The wave function at origin plays a key role in the calculation of the pionium lifetime, various finite nuclear size effects and the hyperfine splitting. The results are obtained for the $1s$ and $2s$ states in pionic and muonic hydrogen and deuterium and in pionium, a bound system of $\\pi^+$ and $\\pi^-$. Applications to the hyperfine structure and the Lamb shift in muonic hydrogen are also considered.

  15. Super-oscillating Electron Wave Functions with Sub-diffraction Spots

    CERN Document Server

    Remez, Roei; Lu, Peng-Han; Tavabi, Amir H; Dunin-Borkowski, Rafal E; Arie, Ady

    2016-01-01

    Almost one and a half centuries ago, Ernst Abbe [1] and shortly after Lord Rayleigh [2] derived the minimum, diffraction-limited spot radius of an optical lens to be 1.22{\\lambda}/(2sin{\\alpha}), where {\\lambda} is the wavelength and {\\alpha} is the semi-angle of the beam's convergence cone. Here, we show how to overcome this limit and realize the first super-oscillating massive-particle wave function, which has an arbitrarily small central spot that is much smaller than the Abbe-Rayleigh limit and theoretically even smaller than the de Broglie wavelength. We experimentally demonstrate an electron central spot of radius 106 pm, which is more than two times smaller than the diffraction limit of the experimental setup used. Such an electronic wave function can serve as a probe in scanning transmission electron microscopy, providing improved imaging of objects at the sub-{\\AA}ngstrom scale.

  16. Quantum Monte Carlo with reoptimized perturbatively selected configuration-interaction wave functions

    CERN Document Server

    Giner, Emmanuel; Toulouse, Julien

    2016-01-01

    We explore the use in quantum Monte Carlo (QMC) of trial wave functions consisting of a Jastrow factor multiplied by a truncated configuration-interaction (CI) expansion in Slater determinants obtained from a CI perturbatively selected iteratively (CIPSI) calculation. In the CIPSI algorithm, the CI expansion is iteratively enlarged by selecting the best determinants using perturbation theory, which provides an optimal and automatic way of constructing truncated CI expansions approaching the full CI limit. We perform a systematic study of variational Monte Carlo (VMC) and fixed-node diffusion Monte Carlo (DMC) total energies of first-row atoms from B to Ne with different levels of optimization of the parameters (Jastrow parameters, coefficients of the determinants, and orbital parameters) in these trial wave functions. The results show that the reoptimization of the coefficients of the determinants in VMC (together with the Jastrow factor) leads to an important lowering of both VMC and DMC total energies, and ...

  17. Form Factors and Wave Functions of Vector Mesons in Holographic QCD

    Energy Technology Data Exchange (ETDEWEB)

    Hovhannes R. Grigoryan; Anatoly V. Radyushkin

    2007-07-01

    Within the framework of a holographic dual model of QCD, we develop a formalism for calculating form factors of vector mesons. We show that the holographic bound states can be described not only in terms of eigenfunctions of the equation of motion, but also in terms of conjugate wave functions that are close analogues of quantum-mechanical bound state wave functions. We derive a generalized VMD representation for form factors, and find a very specific VMD pattern, in which form factors are essentially given by contributions due to the first two bound states in the Q^2-channel. We calculate electric radius of the \\rho-meson, finding the value < r_\\rho^2>_C = 0.53 fm^2.

  18. Calculations of properties of screened He-like systems using correlated wave functions.

    Science.gov (United States)

    Dai, S T; Solovyova, A; Winkler, P

    2001-07-01

    The purpose of the present study is twofold. First, the techniques of correlated wave functions for two-electron systems have been extended to obtain results for P and D states in a screening environment, and in particular for Debye screening. In these calculations, the satisfaction of both the quantum virial theorem and a related sum rule has been enforced and found to provide a high degree of stability of the solutions. Second, in order to facilitate the general use of correlated wave functions in combination with sum rule stability criteria, a rather systematic computational approach to this notoriously cumbersome method has been developed and thoroughly discussed here. Accurate calculations for few-electron systems are of interest to plasma diagnostics; in particular, when inaccuracies in binding energies are drastically magnified as they occur in exponents of Boltzmann factors.

  19. Dynamical Quantum Phase Transitions: Role of Topological Nodes in Wave Function Overlaps

    Science.gov (United States)

    Huang, Zhoushen; Balatsky, Alexander V.

    2016-08-01

    A sudden quantum quench of a Bloch band from one topological phase toward another has been shown to exhibit an intimate connection with the notion of a dynamical quantum phase transition (DQPT), where the returning probability of the quenched state to the initial state—i.e., the Loschmidt echo—vanishes at critical times {t*}. Analytical results to date are limited to two-band models, leaving the exact relation between topology and DQPT unclear. In this Letter, we show that, for a general multiband system, a robust DQPT relies on the existence of nodes (i.e., zeros) in the wave function overlap between the initial band and the postquench energy eigenstates. These nodes are topologically protected if the two participating wave functions have distinctive topological indices. We demonstrate these ideas in detail for both one and two spatial dimensions using a three-band generalized Hofstadter model. We also discuss possible experimental observations.

  20. High Energy QCD at NLO: from light-cone wave function to JIMWLK evolution

    CERN Document Server

    Lublinsky, Michael

    2016-01-01

    Soft components of the light cone wave-function of a fast moving projectile hadron is computed in perturbation theory to third order in QCD coupling constant. At this order, the Fock space of the soft modes consists of one-gluon, two-gluon, and a quark-antiquark states. The hard component of the wave-function acts as a non-Abelian background field for the soft modes and is represented by a valence charge distribution that accounts for non-linear density effects in the projectile. When scattered off a dense target, the diagonal element of the S-matrix reveals the Hamiltonian of high energy evolution, the JIMWLK Hamiltonian. This way we provide a new direct derivation of the JIMWLK Hamiltonian at the Next-to-Leading Order.

  1. Calculation of the matrix elements of the Coulomb interaction involving relativistic hydrogenic wave functions

    Science.gov (United States)

    Sarkadi, L.

    2017-03-01

    The program MTRDCOUL [1] calculates the matrix elements of the Coulomb interaction between a charged particle and an atomic electron, ∫ ψf∗ (r) ∣ R - r∣-1ψi(r) d r. Bound-free transitions are considered, and relativistic hydrogenic wave functions are used. In this revised version a bug discovered in the F3Y CPC Program Library subprogram [2] is fixed.

  2. On the derivation of wave function reduction from Schr\\"odinger's equation: A model

    OpenAIRE

    Omnès, Roland

    2010-01-01

    The possibility of consistency between the basic quantum principles and reduction (wave function reduction) is reexamined. The mathematical description of an organized macroscopic device is constructed explicitly as a convenient tool for this investigation. A derivation of reduction from quantum mechanics is proposed on a specific example, using standard methods of statistical physics. Although these methods are valid only "for all practical purposes", arguments are given to ascribe an emergi...

  3. Inelastic electron scattering as an indicator of clustering in wave functions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    While the shell model is the most fundamental of nuclear structure models, states in light nuclei also have been described successfully in terms of clusters. Indeed, Wildemuth and Tang have shown a correspondence between the cluster and shell models, the clusters arising naturally as correlations out of the shell model Hamiltonian. For light nuclei, the cluster model reduces the many-body problem to a few-body one, with interactions occurring between the clusters. These interactions involve particle exchanges, since the nucleons may still be considered somewhat freely moving, with their motion not strictly confined to the clusters themselves. Such is the relation of the cluster model to the shell model. For a realistic shell model then, one may expect some evidence of clustering in the wave functions for those systems in which the cluster model is valid. The results obtained using the multi-{Dirac_h}{omega}shell model wave functions are closer in agreement with experiment than the results obtained using the 0{Dirac_h}{omega}wave functions. Yet in all cases, that level of agreement is not good, with the calculations underpredicting the measured values by at least a factor of two. This indicates that the shell model wave functions do not exhibit clustering behavior, which is expected to manifest itself at small momentum transfer. The exception is the transition to the 7{sup -}/2 state in {sup 7}Li, for which the value obtained from the {gamma}-decay width is in agreement with the value obtained from the MK3W and (0 + 2 + 4){Dirac_h}{omega}shell model calculations 17 refs., 1 tab., 2 figs.

  4. Universal Wave Function Overlap and Universal Topological Data from Generic Gapped Ground States

    OpenAIRE

    2014-01-01

    We propose a way -- universal wave function overlap -- to extract universal topological data from generic ground states of gapped systems in any dimensions. Those extracted topological data should fully characterize the topological orders with gapped or gapless boundary. For non-chiral topological orders in 2+1D, this universal topological data consist of two matrices, $S$ and $T$, which generate a projective representation of $SL(2,\\mathbb Z)$ on the degenerate ground state Hilbert space on ...

  5. Generalization of Cramer's rule and its application to the projection of Hartree-Fock wave function

    CERN Document Server

    Hage-Hassan, Mehdi

    2009-01-01

    We generalize the Cramer's rule of linear algebra. We apply it to calculate the spectra of nucleus by applying Hill-Wheeler projection operator to Hartree-Fock wave function, and to derive L\\"owdin formula and Thouless theorem. We derive by an elementary method the infinitesimal or L\\"owdin projection operators and its integral representation to be useful for the projection of Slater determinant.

  6. Visualization of a particle's wave function in the double slits experiment

    CERN Document Server

    Postnikov, Eugene B

    2013-01-01

    The double slits experiment is a basic phenomenon, which allows to explain principal behaviour of quantum systems. However, textbooks present static pictures of corresponding interference patterns. At the same time, modern computer software for PDE solution provides an opportunity for dynamical modeling of a wave function behaviour using a numerical solution of Schroedinger's equation and to use the obtained demonstrations in a teaching of physics. This material presents such a dynamical animated simulation.

  7. Modeling shock waves using exponential interpolation functions with the Least-Squares Finite Element method

    Science.gov (United States)

    Smith, Bradford Scott, Jr.

    The hypothesis of this research is that exponential interpolation functions will approximate fluid properties at shock waves with less error than polynomial interpolation functions. Exponential interpolation functions are derived for the purpose of modeling sharp gradients. General equations for conservation of mass, momentum, and energy for an inviscid flow of a perfect gas are converted to finite element equations using the least-squares method. Boundary conditions and a mesh adaptation scheme are also presented. An oblique shock reflection problem is used as a benchmark to determine whether or not exponential interpolation provides any advantages over Lagrange polynomial interpolation. Using exponential interpolation in elements downstream of a shock and having edges coincident with the shock showed a slight reduction in the solution error. However there was very little qualitative difference between solutions using polynomial and exponential interpolation. Regardless of the type of interpolation used, the shocks were smeared and oscillations were present both upstream and downstream of the shock waves. When a mesh adaptation scheme was implemented, exponential elements adjacent to the shock waves became much smaller and the numerical solution diverged. Changing the exponential elements to polynomial elements yielded a convergent solution. There appears to be no significant advantage to using exponential interpolation in comparison to Lagrange polynomial interpolation.

  8. Two Variations On The Theme Of The Wave Function Of The Universe

    CERN Document Server

    Nitti, F

    2005-01-01

    In this work, we analyze two different aspects of the formulation of Quantum Gravity using the Wave Function of the Universe approach. In Part I we search for a way to define nonperturbatively the wave function, in the context of gravity in 2+1 dimensions, making use of the conjectured duality between the latter and 2-d conformal field theory on the spacetime boundary. In the pure gravity case, it has been known that the Wheeler-DeWitt equation, that formally defines the wave function, can be interpreted as a Ward identity for the boundary theory, which in this case can be identified with a model with affine sl(2, R) invariance. We try to extend this method to the general case when gravity is coupled to matter. What makes this possible is our finding that there exist a boundary affine sl(2, R) algebra structure also in the most general case: any two dimensional conformal field theory can be universally embedded into a larger structure that carries an action for that algebra. Part II has a more phenomenologica...

  9. Working With the Wave Equation in Aeroacoustics: The Pleasures of Generalized Functions

    Science.gov (United States)

    Farassat, F.; Brentner, Kenneth S.; Dunn, mark H.

    2007-01-01

    The theme of this paper is the applications of generalized function (GF) theory to the wave equation in aeroacoustics. We start with a tutorial on GFs with particular emphasis on viewing functions as continuous linear functionals. We next define operations on GFs. The operation of interest to us in this paper is generalized differentiation. We give many applications of generalized differentiation, particularly for the wave equation. We discuss the use of GFs in finding Green s function and some subtleties that only GF theory can clarify without ambiguities. We show how the knowledge of the Green s function of an operator L in a given domain D can allow us to solve a whole range of problems with operator L for domains situated within D by the imbedding method. We will show how we can use the imbedding method to find the Kirchhoff formulas for stationary and moving surfaces with ease and elegance without the use of the four-dimensional Green s theorem, which is commonly done. Other subjects covered are why the derivatives in conservation laws should be viewed as generalized derivatives and what are the consequences of doing this. In particular we show how we can imbed a problem in a larger domain for the identical differential equation for which the Green s function is known. The primary purpose of this paper is to convince the readers that GF theory is absolutely essential in aeroacoustics because of its powerful operational properties. Furthermore, learning the subject and using it can be fun.

  10. Compact wave function for bond dissociation and Van der Waals interactions: A natural amplitude assessment

    CERN Document Server

    Giesbertz, K J H

    2014-01-01

    Electron correlations in molecules can be divided in short range dynamical correlations, long range Van der Waals type interactions and near degeneracy static correlations. In this work we analyze how these three types of correlations can be incorporated in a simple wave function of restricted functional form consisting of an orbital product multiplied by a single correlation function $f(r_{12})$ depending on the interelectronic distance $r_{12}$. Since the three types of correlations mentioned lead to different signatures in terms of the natural orbital (NO) amplitudes in two-electron systems we make an analysis of the wave function in terms of the NO amplitudes for a model system of a diatomic molecule. In our numerical implementation we fully optimize the orbitals and the correlation function on a spatial grid without restrictions on their functional form. For the model system we can prove that none of the amplitudes vanishes and moreover that it displays a distinct sign pattern and a series of avoided cro...

  11. Geophysical observations at cavity collapse

    OpenAIRE

    Jousset, Philippe; Bazargan-Sabet, Behrooz; Lebert, François; Bernardie, Séverine; Gourry, Jean-Christophe

    2010-01-01

    International audience; In Lorraine region (France) salt layers at about 200 meters depth are exploited by Solvay using solution mining methodology which consists in extracting the salt by dissolution, collapsing the cavern overburden during the exploitation phase and finally reclaiming the landscape by creating a water area. In this process, one of the main challenges for the exploiting company is to control the initial 120-m diameter collapse so as to minimize possible damages. In order to ...

  12. Scapholunate advanced collapse wrist salvage.

    Science.gov (United States)

    Ashmead, D; Watson, H K; Damon, C; Herber, S; Paly, W

    1994-09-01

    Patients with scapholunate advanced collapse (SLAC) wrist do not have to undergo total wrist arthrodesis; the SLAC pattern spares the radiolunate articulation, providing a basis for salvage. We report the results of 100 cases in which a technique comprised of scaphoid excision and limited wrist arthrodesis was used. The average followup period of 44 months revealed excellent functional status and a high rate of patient satisfaction. The majority of employed patients were able to return to their original jobs, and many chose to resume wrist-related recreational activities. Pain relief was good to excellent in most cases. Extension/flexion averaged 72 degrees (53% of a normal opposite wrist), radioulnar deviation 37 degrees (59%), and grip strength 80% of the opposite side. X-ray films revealed only two instances of radiolunate destruction, both in conjunction with ulnar translation of the carpus. The other 98 patients demonstrated a well-preserved radiolunate joint regardless of followup interval. Complications were few. Nonunion occurred in three cases. A dorsal impingement of the capitate and radius (12%) was felt to be technique-related and avoidable by careful capitolunate alignment.

  13. Plane-wave superpositions defined by orthonormal scalar functions on two- and three-dimensional manifolds

    Science.gov (United States)

    Borzdov

    2000-04-01

    Vector plane-wave superpositions defined by a given set of orthonormal scalar functions on a two- or three-dimensional manifold-beam manifold-are treated. We present a technique for composing orthonormal beams and some other specific types of fields such as three-dimensional standing waves, moving and evolving whirls. It can be used for any linear fields, in particular, electromagnetic fields in complex media and elastic fields in crystals. For electromagnetic waves in an isotropic medium or free space, unique families of exact solutions of Maxwell's equations are obtained. The solutions are illustrated by calculating fields, energy densities, and energy fluxes of beams defined by the spherical harmonics. It is shown that the obtained results can be used for a transition from the plane-wave approximation to more accurate models of real incident beams in free-space techniques for characterizing complex media. A mathematical formalism convenient for the treatment of various beams defined by the spherical harmonics is presented.

  14. Ten reasons why a thermalized system cannot be described by a many-particle wave function

    Science.gov (United States)

    Drossel, Barbara

    2017-05-01

    It is widely believed that the underlying reality behind statistical mechanics is a deterministic and unitary time evolution of a many-particle wave function, even though this is in conflict with the irreversible, stochastic nature of statistical mechanics. The usual attempts to resolve this conflict for instance by appealing to decoherence or eigenstate thermalization are riddled with problems. This paper considers theoretical physics of thermalized systems as it is done in practice and shows that all approaches to thermalized systems presuppose in some form limits to linear superposition and deterministic time evolution. These considerations include, among others, the classical limit, extensivity, the concepts of entropy and equilibrium, and symmetry breaking in phase transitions and quantum measurement. As a conclusion, the paper suggests that the irreversibility and stochasticity of statistical mechanics should be taken as a real property of nature. It follows that a gas of a macroscopic number N of atoms in thermal equilibrium is best represented by a collection of N wave packets of a size of the order of the thermal de Broglie wave length, which behave quantum mechanically below this scale but classically sufficiently far beyond this scale. In particular, these wave packets must localize again after scattering events, which requires stochasticity and indicates a connection to the measurement process.

  15. How electron two-stream instability drives cyclic Langmuir collapse and continuous coherent emission

    Science.gov (United States)

    Che, Haihong; Goldstein, Melvyn L.; Diamond, Patrick H.; Sagdeev, Roald Z.

    2017-02-01

    Continuous plasma coherent emission is maintained by repetitive Langmuir collapse driven by the nonlinear evolution of a strong electron two-stream instability. The Langmuir waves are modulated by solitary waves in the linear stage and electrostatic whistler waves in the nonlinear stage. Modulational instability leads to Langmuir collapse and electron heating that fills in cavitons. The high pressure is released via excitation of a short-wavelength ion acoustic mode that is damped by electrons and reexcites small-scale Langmuir waves; this process closes a feedback loop that maintains the continuous coherent emission.

  16. Vibrational Collapse of Hexapod Packings

    Science.gov (United States)

    Zhao, Yuchen; Ding, Jingqiu; Barés, Jonathan; Dierichs, Karola; Behringer, Robert

    2016-11-01

    Columns made of convex noncohesive grains like sand collapse after being released from a confining container. However, structures built from concave grains can be stable without external support. Previous research show that the stability of the columns depends on column diameter and height, by observing column stability after carefully lifting their confinement tubes. Thinner and taller columns collapse with higher probability. While the column stability weakly depends on packing density, it strongly depends on inter-particle friction. Experiments that cause the column to collapse also reveal similar trends, as more effort (such as heavier loading or shearing) is required to destabilize columns that are intrinsically more stable. In the current experiments, we invesitage the effect of vibration on destructing a column. Short columns collapse following the relaxation dynamics of disorder systems, which coincides with similar experiments on staple packings. However, tall columns collapse faster at the beginning, in addition to the relaxation process coming after. Using high-speed imaging, we analyze column collapse data from different column geometries. Ongoing work is focusing on characterizing the stability of hexapod packings to vibration. We thanks NSF-DMR-1206351 and the William M. Keck Foundation.

  17. Wave function of the Universe and Chern-Simons Perturbation Theory

    CERN Document Server

    Soo, C P

    2002-01-01

    The Chern-Simons exact solution of four-dimensional quantum gravity with nonvanishing cosmological constant is presented in metric variable as the partition function of a Chern-Simons theory with nontrivial source. The perturbative expansion is given, and the wave function is computed to the lowest order of approximation for the Cauchy surface which is topologically a 3-sphere. The state is well-defined even at degenerate and vanishing values of the dreibein. Reality conditions for the Ashtekar variables are also taken into account; and remarkable features of the Chern-Simons state and their relevance to cosmology are pointed out.

  18. Generalized extended tanh-function method and its application to (1+1)-dimensional dispersive long wave equation

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Xuedong; Chen Yong; Zhang Hongqing

    2003-05-12

    Making use of a new generalized ansatzes, we present the generalized extended tanh-function method for constructing the exact solutions of nonlinear partial differential equations (NPDEs) in a unified way. Applying the generalized method, with the aid of MAPLE, we consider the Wu-Zhang equation (which describes (1+1)-dimensional dispersive long wave). As a result, we can successfully obtain the solitary wave solutions that can be found by the extended tanh-function method and the modified extended tanh-function method. More importantly, for the equation, we also obtain other new and more general solutions at the same time. The results include kink-profile solitary wave solutions, bell-profile solitary wave solutions, periodic wave solutions, rational solutions, singular solutions and other new formal solutions. As an illustrative sample, the properties of some soliton solutions for Wu-Zhang equation are shown by some figures.

  19. Exclusive $J/\\psi$ Production in Diffractive Process with AdS/QCD Holographic Wave Function in BLFQ

    CERN Document Server

    Xie, Ya-ping; Zhao, Xingbo

    2016-01-01

    The AdS/QCD holographic wave function of basis light-front quantization (BLFQ) for vector meson $J/\\psi$ is applied in this manuscript. The exclusive production of $J/\\psi$ in diffractive process is computed in dipole model with AdS/QCD holographic wave function. We use IP-Sat and IIM model in the calculation of the differential cross section of the dipole scattering off the proton. The prediction of AdS/QCD holographic wave function in BLFQ gives a good agreement to the experimental data.

  20. Time Reversal Mirrors and Cross Correlation Functions in Acoustic Wave Propagation

    Science.gov (United States)

    Fishman, Louis; Jonsson, B. Lars G.; de Hoop, Maarten V.

    2009-03-01

    In time reversal acoustics (TRA), a signal is recorded by an array of transducers, time reversed, and then retransmitted into the configuration. The retransmitted signal propagates back through the same medium and retrofocuses on the source that generated the signal. If the transducer array is a single, planar (flat) surface, then this configuration is referred to as a planar, one-sided, time reversal mirror (TRM). In signal processing, for example, in active-source seismic interferometry, the measurement of the wave field at two distinct receivers, generated by a common source, is considered. Cross correlating these two observations and integrating the result over the sources yield the cross correlation function (CCF). Adopting the TRM experiments as the basic starting point and identifying the kinematically correct correspondences, it is established that the associated CCF signal processing constructions follow in a specific, infinite recording time limit. This perspective also provides for a natural rationale for selecting the Green's function components in the TRM and CCF expressions. For a planar, one-sided, TRM experiment and the corresponding CCF signal processing construction, in a three-dimensional homogeneous medium, the exact expressions are explicitly calculated, and the connecting limiting relationship verified. Finally, the TRM and CCF results are understood in terms of the underlying, governing, two-way wave equation, its corresponding time reversal invariance (TRI) symmetry, and the absence of TRI symmetry in the associated one-way wave equations, highlighting the role played by the evanescent modal contributions.