WorldWideScience

Sample records for classical zero-point radiation

  1. The Blackbody Radiation Spectrum Follows from Zero-Point Radiation and the Structure of Relativistic Spacetime in Classical Physics

    CERN Document Server

    Boyer, Timothy H

    2011-01-01

    The analysis of this article is entirely within classical physics. Any attempt to describe nature within classical physics requires the presence of Lorentz-invariant classical electromagnetic zero-point radiation so as to account for the Casimir forces between parallel conducting plates at low temperatures. Furthermore, conformal symmetry carries solutions of Maxwell's equations into solutions. In an inertial frame, conformal symmetry leaves zero-point radiation invariant and does not connect it to non-zero-temperature; time-dilating conformal transformations carry the Lorentz-invariant zero-point radiation spectrum into zero-point radiation and carry the thermal radiation spectrum at non-zero temperature into thermal radiation at a different non-zero-temperature. However, in a non-inertial frame, a time-dilating conformal transformation carries classical zero-point radiation into thermal radiation at a finite non-zero-temperature. By taking the no-acceleration limit, one can obtain the Planck radiation spect...

  2. Classical Zero-Point Radiation and Relativity: The Problem of Atomic Collapse Revisited

    Science.gov (United States)

    Boyer, Timothy H.

    2016-07-01

    The physicists of the early twentieth century were unaware of two aspects which are vital to understanding some aspects of modern physics within classical theory. The two aspects are: (1) the presence of classical electromagnetic zero-point radiation, and (2) the importance of special relativity. In classes in modern physics today, the problem of atomic collapse is still mentioned in the historical context of the early twentieth century. However, the classical problem of atomic collapse is currently being treated in the presence of classical zero-point radiation where the problem has been transformed. The presence of classical zero-point radiation indeed keeps the electron from falling into the Coulomb potential center. However, the old collapse problem has been replaced by a new problem where the zero-point radiation may give too much energy to the electron so as to cause "self-ionization." Special relativity may play a role in understanding this modern variation on the atomic collapse problem, just as relativity has proved crucial for a classical understanding of blackbody radiation.

  3. Classical Zero-Point Radiation and Relativity: The Problem of Atomic Collapse Revisited

    CERN Document Server

    Boyer, Timothy H

    2015-01-01

    The physicists of the early 20th century were unaware of two aspects which are vital to understanding some aspects of modern physics within classical theory. The two aspects are: 1) the presence of classical electromagnetic zero-point radiation, and 2) the importance of special relativity. In classes in modern physics today, the problem of atomic collapse is still mentioned in the historical context of the early 20th century. However, the classical problem of atomic collapse is currently being treated in the presence of classical zero-point radiation where the problem has been transformed. The presence of classical zero-point radiation indeed keeps the electron from falling into the Coulomb potential center. However, the old collapse problem has been replaced by a new problem where the zero-point radiation may give too much energy to the electron so as to cause self-ionization. Special relativity may play a role in understanding this modern variation on the atomic collapse problem, just as relativity has prov...

  4. Classical Zero-Point Radiation and Relativity: The Problem of Atomic Collapse Revisited

    OpenAIRE

    Boyer, Timothy H.

    2015-01-01

    The physicists of the early 20th century were unaware of two aspects which are vital to understanding some aspects of modern physics within classical theory. The two aspects are: 1) the presence of classical electromagnetic zero-point radiation, and 2) the importance of special relativity. In classes in modern physics today, the problem of atomic collapse is still mentioned in the historical context of the early 20th century. However, the classical problem of atomic collapse is currently bein...

  5. On Fundamental Properties Of The Classical Electromagnetic Zero-point Radiation And Its Implications

    CERN Document Server

    Matsuoka, Y

    2005-01-01

    There is a classical theory that can explain various quantum phenomena including the Casimir effect, the van der Waals force, the blackbody radiation, and so forth [1]. The classical theory is called “stochastic electrodynamics (SED)” and only the difference from conventional classical physics is the choice of the boundary condition for Maxwell equations. It requires random electromagnetic radiation called “zero-point field (ZPF),” which exists throughout space even at zero temperature. Thus, the ZPF is thought to be an universal background field which corresponds to the vacuum ground state in the language of quantum electrodynamics. In this paper, the fundamental properties, especially the symmetries, of the ZPF are studied at first. It is found that the requirement of the Lorentz invariance of the field might be incompatible with the formulation of classical electrodynamics. Secondly, the behavior of unrestricted charged particle immersed in the ZPF is considered. Unl...

  6. Dynamics Underlying the Gaussian Distribution of the Classical Harmonic Oscillator in Zero-Point Radiation

    Directory of Open Access Journals (Sweden)

    Wayne Cheng-Wei Huang

    2013-01-01

    Full Text Available Stochastic electrodynamics (SED predicts a Gaussian probability distribution for a classical harmonic oscillator in the vacuum field. This probability distribution is identical to that of the ground state quantum harmonic oscillator. Thus, the Heisenberg minimum uncertainty relation is recovered in SED. To understand the dynamics that give rise to the uncertainty relation and the Gaussian probability distribution, we perform a numerical simulation and follow the motion of the oscillator. The dynamical information obtained through the simulation provides insight to the connection between the classic double-peak probability distribution and the Gaussian probability distribution. A main objective for SED research is to establish to what extent the results of quantum mechanics can be obtained. The present simulation method can be applied to other physical systems, and it may assist in evaluating the validity range of SED.

  7. Understanding zero-point energy in the context of classical electromagnetism

    Science.gov (United States)

    Boyer, Timothy H.

    2016-09-01

    Today’s textbooks of electromagnetism give the particular solution to Maxwell’s equations involving the integral over the charge and current sources at retarded times. However, the texts fail to emphasise that the choice of the incoming-wave boundary conditions corresponding to solutions of the homogeneous Maxwell equations must be made based upon experiment. Here we discuss the role of these incoming-wave boundary conditions for an experimenter with a hypothetical charged harmonic oscillator as his equipment. We describe the observations of the experimenter when located near a radio station or immersed in thermal radiation at temperature T. The classical physicists at the end of the 19th century chose the incoming-wave boundary conditions for the homogeneous Maxwell equations based upon the experimental observations of Lummer and Pringsheim which measured only the thermal radiation which exceeded the random radiation surrounding their measuring equipment; the physicists concluded that they could take the homogeneous solutions to vanish at zero temperature. Today at the beginning of the 21st century, classical physicists must choose the incoming-wave boundary conditions for the homogeneous Maxell equations to correspond to the full radiation spectrum revealed by the recent Casimir force measurements which detect all the radiation surrounding conducting parallel plates, including the radiation absorbed and emitted by the plates themselves. The random classical radiation spectrum revealed by the Casimir force measurements includes electromagnetic zero-point radiation, which is missing from the spectrum measured by Lummer and Pringsheim, and which cannot be eliminated by going to zero temperature. This zero-point radiation will lead to zero-point energy for all systems which have electromagnetic interactions. Thus the choice of the incoming-wave boundary conditions on the homogeneous Maxwell equations is intimately related to the ideas of zero-point energy and non-radiating

  8. Zero-point energy constraint in quasi-classical trajectory calculations.

    Science.gov (United States)

    Xie, Zhen; Bowman, Joel M

    2006-04-27

    A method to constrain the zero-point energy in quasi-classical trajectory calculations is proposed and applied to the Henon-Heiles system. The main idea of this method is to smoothly eliminate the coupling terms in the Hamiltonian as the energy of any mode falls below a specified value.

  9. Quantum and classical statistics of the electromagnetic zero-point field

    CERN Document Server

    Ibison, M

    1996-01-01

    A classical electromagnetic zero-point field (ZPF) analogue of the vacuum of quantum field theory has formed the basis for theoretical investigations in the discipline known as random or stochastic electrodynamics (SED) wherein quantum measurements are imitated by the introduction of a stochastic classical background EM field. Random EM fluctuations are assumed to provide perturbations which can mimic some quantum phenomena while retaining a purely classical basis, e.g. the Casimir force, the Van-der-Waals force, the Lamb shift, spontaneous emission, the RMS radius of the harmonic oscillator, and the radius of the Bohr atom. This classical ZPF is represented as a homogeneous, isotropic ensemble of plane waves with fixed amplitudes and random phases. Averaging over the random phases is assumed to be equivalent to taking the ground-state expectation values of the corresponding quantum operator. We demonstrate that this is not precisely correct by examining the statistics of the classical ZPF in contrast to that...

  10. Conversion of the zero-point energy of the quantum vacuum into classical mechanical energy

    Energy Technology Data Exchange (ETDEWEB)

    Turtur, Claus Wilhelm

    2010-07-01

    A perpetual motion machine - this can never exist. But energy sources nearly disregarded up to now - they exist. These are energy sources, which have been hardly under investigation, so that mankind did not yet learn how to get benefit from them. Most part of the universe consists of such energy, which is still called 'invisible'. A part of this energy is to be found within the so called zero-point oscillations of the quantum vacuum, thus within the empty void from the perspective of quantum physics. The author of the book is physicist. He theoretically developed and then experimentally verified a method for the conversion of vacuum energy into classical mechanical energy. His technique is one of the very few approaches known up to know. The most prominent approaches to convert vacuum energy are described in this book in many scientific details, and they are compared with other known proposals for the use of vacuum energy. (orig.)

  11. The Schrödinger Equation, the Zero-Point Electromagnetic Radiation, and the Photoelectric Effect

    Science.gov (United States)

    França, H. M.; Kamimura, A.; Barreto, G. A.

    2016-04-01

    A Schrödinger type equation for a mathematical probability amplitude Ψ( x, t) is derived from the generalized phase space Liouville equation valid for the motion of a microscopic particle, with mass M and charge e, moving in a potential V( x). The particle phase space probability density is denoted Q( x, p, t), and the entire system is immersed in the "vacuum" zero-point electromagnetic radiation. We show, in the first part of the paper, that the generalized Liouville equation is reduced to a simpler Liouville equation in the equilibrium limit where the small radiative corrections cancel each other approximately. This leads us to a simpler Liouville equation that will facilitate the calculations in the second part of the paper. Within this second part, we address ourselves to the following task: Since the Schrödinger equation depends on hbar , and the zero-point electromagnetic spectral distribution, given by ρ 0{(ω )} = hbar ω 3/2 π 2 c3, also depends on hbar , it is interesting to verify the possible dynamical connection between ρ 0( ω) and the Schrödinger equation. We shall prove that the Planck's constant, present in the momentum operator of the Schrödinger equation, is deeply related with the ubiquitous zero-point electromagnetic radiation with spectral distribution ρ 0( ω). For simplicity, we do not use the hypothesis of the existence of the L. de Broglie matter-waves. The implications of our study for the standard interpretation of the photoelectric effect are discussed by considering the main characteristics of the phenomenon. We also mention, briefly, the effects of the zero-point radiation in the tunneling phenomenon and the Compton's effect.

  12. On the magnitude of the energy flow inherent in zero-point radiation

    CERN Document Server

    Alvargonzalez, R

    2003-01-01

    The spectrum of zero-point radiation is relativistically invariant and its spectral density function is therefore inversely proportional to the cubes of its wavelengths. For its energy to be finite, there must exist a minimum wavelength, $q_\\lambda$. The measurements of the apparent attraction between two uncharged conductor plates, placed in a vacuum at a temperature close to absolute zero, made by Sparnaay in 1958 allow us to deduce that the energy flow of the zero-point radiation which comes of or into an area $(q_\\lambda)^2$, corresponds with the emission of one photon of wavelength $q_\\lambda$ per $q_\\tau$ $(q_\\tau=q_\\lambda/c)$, plus one photon of wavelength $2q_\\lambda$ per $2^3q_\\tau$, etc., up to one photon of wavelength $nq_\\lambda$ per $n^3q_\\tau$. This energy flow is enormous, but Sparnaay's experiments implied only photons whose wavelengths were greater than $5\\times10^{-5}$ cm, and zero-point radiation may include only photons with wavelengths greater than $xq_\\lambda$, being $x$ an integer, per...

  13. Understanding Zero-Point Energy in the Context of Classical Electromagnetism

    CERN Document Server

    Boyer, Timothy H

    2015-01-01

    Today's textbooks of electromagnetism give the particular solution to Maxwell's equations involving the integral over the charge and current sources at retarded times. However, the texts fail to emphasize the role played by the choice of the boundary conditions corresponding to solutions of the homogeneous Maxwell equations. Here we discuss the role of these boundary conditions for an experimenter with a hypothetical charged harmonic oscillator as his equipment. We describe the observations of the experimenter when located near a radio station or immersed in thermal radiation at temperature T. The classical physicists at the end of the 19th century chose the homogeneous boundary conditions for Maxwell's equation based upon the experimental observations of Lummer and Pringsheim which measured only the thermal radiation which exceeded the random radiation surrounding their measuring equipment. Today at the beginning of the 21st century, classical physicists must choose the homogeneous boundary conditions for Ma...

  14. Quantum features derived from the classical model of a bouncer-walker coupled to a zero-point field

    Science.gov (United States)

    Schwabl, H.; Mesa Pascasio, J.; Fussy, S.; Grössing, G.

    2012-05-01

    In our bouncer-walker model a quantum is a nonequilibrium steady-state maintained by a permanent throughput of energy. Specifically, we consider a "particle" as a bouncer whose oscillations are phase-locked with those of the energy-momentum reservoir of the zero-point field (ZPF), and we combine this with the random-walk model of the walker, again driven by the ZPF. Starting with this classical toy model of the bouncer-walker we were able to derive fundamental elements of quantum theory [1]. Here this toy model is revisited with special emphasis on the mechanism of emergence. Especially the derivation of the total energy hslashωo and the coupling to the ZPF are clarified. For this we make use of a sub-quantum equipartition theorem. It can further be shown that the couplings of both bouncer and walker to the ZPF are identical. Then we follow this path in accordance with Ref. [2], expanding the view from the particle in its rest frame to a particle in motion. The basic features of ballistic diffusion are derived, especially the diffusion constant D, thus providing a missing link between the different approaches of our previous works [1, 2].

  15. Quantum features derived from the classical model of a bouncer-walker coupled to a zero-point field

    CERN Document Server

    Schwabl, Herbert; Fussy, Siegfried; Groessing, Gerhard; 10.1088/1742-6596/361/1/012021

    2012-01-01

    In our bouncer-walker model a quantum is a nonequilibrium steady-state maintained by a permanent throughput of energy. Specifically, we consider a "particle" as a bouncer whose oscillations are phase-locked with those of the energy-momentum reservoir of the zero-point field (ZPF), and we combine this with the random-walk model of the walker, again driven by the ZPF. Starting with this classical toy model of the bouncer-walker we were able to derive fundamental elements of quantum theory. Here this toy model is revisited with special emphasis on the mechanism of emergence. Especially the derivation of the total energy hbar.omega and the coupling to the ZPF are clarified. For this we make use of a sub-quantum equipartition theorem. It can further be shown that the couplings of both bouncer and walker to the ZPF are identical. Then we follow this path in accordance with previous work, expanding the view from the particle in its rest frame to a particle in motion. The basic features of ballistic diffusion are der...

  16. Mixed quantum/classical investigation of the photodissociation of NH3(A) and a practical method for maintaining zero-point energy in classical trajectories.

    Science.gov (United States)

    Bonhommeau, David; Truhlar, Donald G

    2008-07-07

    The photodissociation dynamics of ammonia upon excitation of the out-of-plane bending mode (mode nu(2) with n(2)=0,[ellipsis (horizontal)],6 quanta of vibration) in the A electronic state is investigated by means of several mixed quantum/classical methods, and the calculated final-state properties are compared to experiments. Five mixed quantum/classical methods are tested: one mean-field approach (the coherent switching with decay of mixing method), two surface-hopping methods [the fewest switches with time uncertainty (FSTU) and FSTU with stochastic decay (FSTU/SD) methods], and two surface-hopping methods with zero-point energy (ZPE) maintenance [the FSTUSD+trajectory projection onto ZPE orbit (TRAPZ) and FSTUSD+minimal TRAPZ (mTRAPZ) methods]. We found a qualitative difference between final NH(2) internal energy distributions obtained for n(2)=0 and n(2)>1, as observed in experiments. Distributions obtained for n(2)=1 present an intermediate behavior between distributions obtained for smaller and larger n(2) values. The dynamics is found to be highly electronically nonadiabatic with all these methods. NH(2) internal energy distributions may have a negative energy tail when the ZPE is not maintained throughout the dynamics. The original TRAPZ method was designed to maintain ZPE in classical trajectories, but we find that it leads to unphysically high internal vibrational energies. The mTRAPZ method, which is new in this work and provides a general method for maintaining ZPE in either single-surface or multisurface trajectories, does not lead to unphysical results and is much less time consuming. The effect of maintaining ZPE in mixed quantum/classical dynamics is discussed in terms of agreement with experimental findings. The dynamics for n(2)=0 and n(2)=6 are also analyzed to reveal details not available from experiment, in particular, the time required for quenching of electronic excitation and the adiabatic energy gap and geometry at the time of quenching.

  17. Classical Physics of Thermal Scalar Radiation in Two Spacetime Dimensions

    CERN Document Server

    Boyer, Timothy H

    2010-01-01

    Thermal scalar radiation in two spacetime dimensions is treated within relativistic classical physics. Part I involves an inertial frame where are given the analogues both of Boltzmann's derivation of the Stefan-Boltzmann law and also Wien's derivation of the displacement theorem using the scaling of relativitic radiation theory. Next the spectrum of classical scalar zero-point radiation in an inertial frame is derived both from scale invariance and from Lorentz invariance. Part II involves the behavior of thermal radiation in a coordinate frame undergoing (relativistic) constant acceleration, a Rindler frame. The radiation normal modes in a Rindler frame are obtained. The classical zero-point radiation of inertial frames is transformed over to the coordinates of a Rindler frame. Although for zero-point radiation the two-field correlation function at different spatial points at a single time is the same between inertial and Rindler frames, the correlation function at two different times at a single Rindler sp...

  18. The effect of zero-point energy differences on the isotope dependence of the formation of ozone: a classical trajectory study.

    Science.gov (United States)

    Schinke, Reinhard; Fleurat-Lessard, Paul

    2005-03-01

    The effect of zero-point energy differences (DeltaZPE) between the possible fragmentation channels of highly excited O(3) complexes on the isotope dependence of the formation of ozone is investigated by means of classical trajectory calculations and a strong-collision model. DeltaZPE is incorporated in the calculations in a phenomenological way by adjusting the potential energy surface in the product channels so that the correct exothermicities and endothermicities are matched. The model contains two parameters, the frequency of stabilizing collisions omega and an energy dependent parameter Delta(damp), which favors the lower energies in the Maxwell-Boltzmann distribution. The stabilization frequency is used to adjust the pressure dependence of the absolute formation rate while Delta(damp) is utilized to control its isotope dependence. The calculations for several isotope combinations of oxygen atoms show a clear dependence of relative formation rates on DeltaZPE. The results are similar to those of Gao and Marcus [J. Chem. Phys. 116, 137 (2002)] obtained within a statistical model. In particular, like in the statistical approach an ad hoc parameter eta approximately 1.14, which effectively reduces the formation rates of the symmetric ABA ozone molecules, has to be introduced in order to obtain good agreement with the measured relative rates of Janssen et al. [Phys. Chem. Chem. Phys. 3, 4718 (2001)]. The temperature dependence of the recombination rate is also addressed.

  19. Solving discrete zero point problems

    NARCIS (Netherlands)

    van der Laan, G.; Talman, A.J.J.; Yang, Z.F.

    2004-01-01

    In this paper an algorithm is proposed to .nd a discrete zero point of a function on the collection of integral points in the n-dimensional Euclidean space IRn.Starting with a given integral point, the algorithm generates a .nite sequence of adjacent integral simplices of varying dimension and termi

  20. Zero Point Energy of Renormalized Wilson Loops

    OpenAIRE

    Hidaka, Yoshimasa; Pisarski, Robert D.

    2009-01-01

    The quark antiquark potential, and its associated zero point energy, can be extracted from lattice measurements of the Wilson loop. We discuss a unique prescription to renormalize the Wilson loop, for which the perturbative contribution to the zero point energy vanishes identically. A zero point energy can arise nonperturbatively, which we illustrate by considering effective string models. The nonperturbative contribution to the zero point energy vanishes in the Nambu model, but is nonzero wh...

  1. Zero-point energy in spheroidal geometries

    OpenAIRE

    Kitson, A. R.; Signal, A. I.

    2005-01-01

    We study the zero-point energy of a massless scalar field subject to spheroidal boundary conditions. Using the zeta-function method, the zero-point energy is evaluated for small ellipticity. Axially symmetric vector fields are also considered. The results are interpreted within the context of QCD flux tubes and the MIT bag model.

  2. Gravitational Zero Point Energy induces Physical Observables

    OpenAIRE

    Garattini, Remo

    2010-01-01

    We consider the contribution of Zero Point Energy on the induced Cosmological Constant and on the induced Electric/Magnetic charge in absence of matter fields. The method is applicable to every spherically symmetric background. Extensions to a generic $f(R) $ theory are also allowed. Only the graviton appears to be fundamental to the determination of Zero Point Energy.

  3. Classical theory of radiating strings

    Science.gov (United States)

    Copeland, Edmund J.; Haws, D.; Hindmarsh, M.

    1990-01-01

    The divergent part of the self force of a radiating string coupled to gravity, an antisymmetric tensor and a dilaton in four dimensions are calculated to first order in classical perturbation theory. While this divergence can be absorbed into a renormalization of the string tension, demanding that both it and the divergence in the energy momentum tensor vanish forces the string to have the couplings of compactified N = 1 D = 10 supergravity. In effect, supersymmetry cures the classical infinities.

  4. Zero-point quantum fluctuations in cosmology

    CERN Document Server

    Hollenstein, Lukas; Maggiore, Michele; Mitsou, Ermis

    2011-01-01

    We re-examine the classic problem of the renormalization of zero-point quantum fluctuations in a Friedmann-Robertson-Walker background. We discuss a number of issues that arise when regularizing the theory with a momentum-space cutoff, and show explicitly how introducing non-covariant counter-terms allows to obtain covariant results for the renormalized vacuum energy-momentum tensor. We clarify some confusion in the literature concerning the equation of state of vacuum fluctuations. Further, we point out that the general structure of the effective action becomes richer if the theory contains a scalar field phi with mass m smaller than the Hubble parameter H(t). Such an ultra-light particle cannot be integrated out completely to get the effective action. Apart from the volume term and the Einstein-Hilbert term, that are reabsorbed into renormalizations of the cosmological constant and Newton's constant, the effective action in general also has a term proportional to F(phi)R, for some function F(phi). As a resu...

  5. Zero-point energy of confined fermions

    Energy Technology Data Exchange (ETDEWEB)

    Milton, K.A.

    1980-01-01

    A closed form for the reduced Green's function of massless fermions in the interior of a spherical bag is obtained. In terms of this Green's function, the corresponding zero-point or Casimir energy is computed. It is proposed that a resulting quadratic divergence can be absorbed by renormalizing a suitable parameter in the bag model (that is, absorbed by a contact term). The residual Casimir stress is attractive, but smaller than the repulsive Casimir stress of gluons in the model. The result for the total zero-point energy is in substantial disagreement with bag model phenomenological values.

  6. Zero Point Energy and the Dirac Equation

    DEFF Research Database (Denmark)

    Forouzbakhsh, Farshid

    2007-01-01

    Zero Point Energy (ZPE) describes the random electromagnetic oscillations that are left in the vacuum after all other energy has been removed. One way to explain this is by means of the uncertainty principle of quantum physics, which implies that it is impossible to have a zero energy condition. ...

  7. Zero-point energy effects in anion solvation shells.

    Science.gov (United States)

    Habershon, Scott

    2014-05-21

    By comparing classical and quantum-mechanical (path-integral-based) molecular simulations of solvated halide anions X(-) [X = F, Cl, Br and I], we identify an ion-specific quantum contribution to anion-water hydrogen-bond dynamics; this effect has not been identified in previous simulation studies. For anions such as fluoride, which strongly bind water molecules in the first solvation shell, quantum simulations exhibit hydrogen-bond dynamics nearly 40% faster than the corresponding classical results, whereas those anions which form a weakly bound solvation shell, such as iodide, exhibit a quantum effect of around 10%. This observation can be rationalized by considering the different zero-point energy (ZPE) of the water vibrational modes in the first solvation shell; for strongly binding anions, the ZPE of bound water molecules is larger, giving rise to faster dynamics in quantum simulations. These results are consistent with experimental investigations of anion-bound water vibrational and reorientational motion.

  8. Zero point energy of polyhedral water clusters.

    Science.gov (United States)

    Anick, David J

    2005-06-30

    Polyhedral water clusters (PWCs) are cage-like (H2O)n clusters where every O participates in exactly three H bonds. For a database of 83 PWCs, 8 zero point energy (ZPE) was calculated at the B3LYP/6-311++G** level. ZPE correlates negatively with electronic energy (E0): each increase of 1 kcal/mol in E0 corresponds to a decrease of about 0.11 kcal/mol in ZPE. For each n, a set of four connectivity parameters accounts for 98% or more of the variance in ZPE. Linear regression of ZPE against n and this set gives an RMS error of 0.13 kcal/mol. The contributions to ZPE from stretch modes only (ZPE(S)) and from torsional modes only (ZPE(T)) also correlate strongly with E0 and with each other.

  9. Contrasting Classical and Quantum Vacuum States in Non-Inertial Frames

    CERN Document Server

    Boyer, Timothy H

    2013-01-01

    Classical electron theory with classical electromagnetic zero-point radiation (stochastic electrodynamics) is the classical theory which most closely approximates quantum electrodynamics. Indeed, in inertial frames, there is a general connection between classical field theories with classical zero-point radiation and quantum field theories. However, this connection does not extend to noninertial frames where the time parameter is not a geodesic coordinate. Quantum field theory applies the canonical quantization procedure (depending on the local time coordinate) to a mirror-walled box, and, in general, each non-inertial coordinate frame has its own vacuum state. In complete contrast, the spectrum of random classical zero-point radiation is based upon symmetry principles of relativistic spacetime; in empty space, the correlation functions depend upon only the geodesic separations (and their coordinate derivatives) between the spacetime points. It makes no difference whether a box of classical zero-point radiati...

  10. Hawking Radiation and Classical Tunneling

    CERN Document Server

    Tracy, Eugene R

    2015-01-01

    Acoustic waves in fluids undergoing the transition from sub- to supersonic flow satisfy governing equations similar to those for light waves in the immediate vicinity of a black hole event horizon. This acoustic analogy has been used by Unruh and others as a conceptual model for `Hawking radiation.' Here we use variational methods, originally introduced by Brizard for the study of linearized MHD, and ray phase space methods, to analyze linearized acoustics in the presence of background flows. The variational formulation endows the evolution equations with natural Hermitian and symplectic structures that prove useful for later analysis. We derive a $2\\times 2$ normal form governing the wave evolution in the vicinity of the `event horizon.' This shows that the acoustic model can be reduced locally (in ray phase space) to a standard (scalar) tunneling process weakly coupled to a unidirectional non-dispersive wave (the `incoming wave'). Given the normal form, the Hawking `thermal spectrum' can be derived by invok...

  11. Understanding the Planck blackbody spectrum and Landau diamagnetism within classical electromagnetism

    Science.gov (United States)

    Boyer, Timothy H.

    2016-11-01

    Electromagnetism is a relativistic theory, and one must exercise care in coupling this theory with nonrelativistic classical mechanics and with nonrelativistic classical statistical mechanics. Indeed historically, both the blackbody radiation spectrum and diamagnetism within classical theory have been misunderstood because of two crucial failures: (1) the neglect of classical electromagnetic zero-point radiation, and (2) the use of erroneous combinations of nonrelativistic mechanics with relativistic electrodynamics. Here we review the treatment of classical blackbody radiation, and show that the presence of Lorentz-invariant classical electromagnetic zero-point radiation can explain both the Planck blackbody spectrum and Landau diamagnetism at thermal equilibrium within classical electromagnetic theory. The analysis requires that relativistic electromagnetism is joined appropriately with simple nonrelativistic mechanical systems which can be regarded as the zero-velocity limits of relativistic systems, and that nonrelativistic classical statistical mechanics is applied only in the low-frequency limit when zero-point energy makes no contribution.

  12. Radiative corrections in symmetrized classical electrodynamics

    Science.gov (United States)

    Van Meter JR; Kerman; Chen; Hartemann

    2000-12-01

    The physics of radiation reaction for a point charge is discussed within the context of classical electrodynamics. The fundamental equations of classical electrodynamics are first symmetrized to include magnetic charges: a double four-potential formalism is introduced, in terms of which the field tensor and its dual are employed to symmetrize Maxwell's equations and the Lorentz force equation in covariant form. Within this framework, the symmetrized Dirac-Lorentz equation is derived, including radiation reaction (self-force) for a particle possessing both electric and magnetic charge. The connection with electromagnetic duality is outlined, and an in-depth discussion of nonlocal four-momentum conservation for the wave-particle system is given.

  13. q-Deformed Boson Oscillators and Zero Point Energy

    OpenAIRE

    Swamy, P. Narayana

    1999-01-01

    Just as for the ordinary quantum harmonic oscillators, we expect the zero-point energy to play a crucial role in the correct high temperature behavior. We accordingly reformulate the theory of the statistical distribution function for the q-deformed boson oscillators and develop an approximate theory incorporating the zero-point energy. We are then able to demonstrate that for small deformations, the theory reproduces the correct limits both for very high temperatures and for very low tempera...

  14. Classical helium atom with radiation reaction.

    Science.gov (United States)

    Camelio, G; Carati, A; Galgani, L

    2012-06-01

    We study a classical model of helium atom in which, in addition to the Coulomb forces, the radiation reaction forces are taken into account. This modification brings in the model a new qualitative feature of a global character. Indeed, as pointed out by Dirac, in any model of classical electrodynamics of point particles involving radiation reaction one has to eliminate, from the a priori conceivable solutions of the problem, those corresponding to the emission of an infinite amount of energy. We show that the Dirac prescription solves a problem of inconsistency plaguing all available models which neglect radiation reaction, namely, the fact that in all such models, most initial data lead to a spontaneous breakdown of the atom. A further modification is that the system thus acquires a peculiar form of dissipation. In particular, this makes attractive an invariant manifold of special physical interest, the zero-dipole manifold that corresponds to motions in which no energy is radiated away (in the dipole approximation). We finally study numerically the invariant measure naturally induced by the time-evolution on such a manifold, and this corresponds to studying the formation process of the atom. Indications are given that such a measure may be singular with respect to that of Lebesgue.

  15. Indelible Rules of Josephson Coupling Energy and Zero-Point Energy in High-Tc Cuprates

    Institute of Scientific and Technical Information of China (English)

    LIU Fu-Sui; CHEN Wan-Fang

    2004-01-01

    This paper shows that the Josephson coupling energy and the zero-point energy have indelible rules on the superfluid density and the superconductivity in the high-Tc cuprates.This paper also shows that the values of Tc at underdoped and overdoped regions are determined by the damage conditions of the phase coherence in the classical and the quantum XY-models,respectively.

  16. DISTANCE SCALE ZERO POINTS FROM GALACTIC RR LYRAE STAR PARALLAXES

    Energy Technology Data Exchange (ETDEWEB)

    Benedict, G. Fritz; McArthur, Barbara E.; Barnes, Thomas G. [McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Feast, Michael W. [Centre for Astrophysics, Cosmology and Gravitation, Astronomy Department, University of Cape Town, Rondebosch 7701 (South Africa); Harrison, Thomas E. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Bean, Jacob L.; Kolenberg, Katrien [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Menzies, John W.; Laney, C. D. [South African Astronomical Observatory, Observatory 7935 (South Africa); Chaboyer, Brian [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Fossati, Luca [Department of Physics and Astronomy, Open University, Milton Keynes MK7 6AA (United Kingdom); Nesvacil, Nicole [Institute of Astronomy, University of Vienna, A-1180 Vienna (Austria); Smith, Horace A. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Kochukhov, Oleg [Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden); Nelan, Edmund P.; Taylor, Denise [STScI, Baltimore, MD 21218 (United States); Shulyak, D. V. [Institute of Astrophysics, Georg-August-University, Friedrich-Hund-Platz 1, D-37077 Goettingen (Germany); Freedman, Wendy L. [The Observatories, Carnegie Institution of Washington, Pasadena, CA 91101 (United States)

    2011-12-15

    We present new absolute trigonometric parallaxes and proper motions for seven Population II variable stars-five RR Lyr variables: RZ Cep, XZ Cyg, SU Dra, RR Lyr, and UV Oct; and two type 2 Cepheids: VY Pyx and {kappa} Pav. We obtained these results with astrometric data from Fine Guidance Sensors, white-light interferometers on Hubble Space Telescope. We find absolute parallaxes in milliseconds of arc: RZ Cep, 2.12 {+-} 0.16 mas; XZ Cyg, 1.67 {+-} 0.17 mas; SU Dra, 1.42 {+-} 0.16 mas; RR Lyr, 3.77 {+-} 0.13 mas; UV Oct, 1.71 {+-} 0.10 mas; VY Pyx, 6.44 {+-} 0.23 mas; and {kappa} Pav, 5.57 {+-} 0.28 mas; an average {sigma}{sub {pi}}/{pi} = 5.4%. With these parallaxes, we compute absolute magnitudes in V and K bandpasses corrected for interstellar extinction and Lutz-Kelker-Hanson bias. Using these RR Lyrae variable star absolute magnitudes, we then derive zero points for M{sub V} -[Fe/H] and M{sub K} -[Fe/H]-log P relations. The technique of reduced parallaxes corroborates these results. We employ our new results to determine distances and ages of several Galactic globular clusters and the distance of the Large Magellanic Cloud. The latter is close to that previously derived from Classical Cepheids uncorrected for any metallicity effect, indicating that any such effect is small. We also discuss the somewhat puzzling results obtained for our two type 2 Cepheids.

  17. Zero Point of Charge of Organo—Mineral Complexes

    Institute of Scientific and Technical Information of China (English)

    M.T.ANSARI; XUJIAN-MING; 等

    1994-01-01

    Five soil sapmles collected from China and two soil samples from Pakistan with widely different origin and characterstics were used to study the zero point of charge(ZPC) of soil colloids.The results showed that the value of zero point of charge of H-clay complexes was lower than that of H-clays in all the samples.Natural clay complexes had the highest ZPC as compared to -Hclay complex and H-clay in alfisol,closer to H-clays rather than H-clay complexes in oxisol and udult.The Delta Value of ZPT(zero point of titration )to ZPC was higher in H-Clay complexes than in H-Clays.

  18. Zero-point vibrational effects on optical rotation

    DEFF Research Database (Denmark)

    Ruud, K.; Taylor, P.R.; Åstrand, P.-O.

    2001-01-01

    We investigate the effects of molecular vibrations on the optical rotation in two chiral molecules, methyloxirane and trans-2,3-dimethylthiirane. It is shown that the magnitude of zero-point vibrational corrections increases as the electronic contribution to the optical rotation increases....... Vibrational effects thus appear to be important for an overall estimate of the molecular optical rotation, amounting to about 20-30% of the electronic counterpart. We also investigate the special case of chirality introduced in a molecule through isotopic substitution. In this case, the zero-point vibrational...

  19. ON THE EXISTENCE OF ZERO POINTS OF A CONTINUOUS FUNCTION

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A sufficient condition is given to assert that a continuous mapping between Rm and Rn has a zero. The constructive proof of the result is based upon continuation methods and supplies the existence of a path leading to the zero point.

  20. Zero-point fluctuations in direct-action electrodynamics

    Science.gov (United States)

    Pegg, D. T.

    1980-03-01

    In quantized direct interparticle Wheeler-Feynman electrodynamics, no free-field bosonic commutation relations exist. It is shown that a test atom will nevertheless detect a zero-point fluctuating “field” whose source is the atoms of the absorber.

  1. Uncertainty relations, zero point energy and the linear canonical group

    Science.gov (United States)

    Sudarshan, E. C. G.

    1993-01-01

    The close relationship between the zero point energy, the uncertainty relations, coherent states, squeezed states, and correlated states for one mode is investigated. This group-theoretic perspective enables the parametrization and identification of their multimode generalization. In particular the generalized Schroedinger-Robertson uncertainty relations are analyzed. An elementary method of determining the canonical structure of the generalized correlated states is presented.

  2. Conversion of zero point energy into high-energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Ivlev, B. I. [Universidad Autonoma de San Luis Potosi, Instituto de Fisica, Av. Manuel Nava No. 6, Zona Universitaria, 78290 San Luis Potosi, SLP (Mexico)

    2016-11-01

    An unusual phenomenon, observed in experiments is studied. X-ray laser bursts of keV energy are emitted from a metal where long-living states, resulting in population inversion, are totally unexpected. Anomalous electron-photon states are revealed to be formed inside the metal. These states are associated with narrow, 10{sup -11} cm, potential well created by the local reduction of zero point electromagnetic energy. In contrast to analogous van der Waals potential well, leading to attraction of two hydrogen atoms, the depth of the anomalous well is on the order of 1 MeV. The states in that well are long-living which results in population inversion and subsequent laser generation observed. The X-ray emission, occurring in transitions to lower levels, is due to the conversion of zero point electromagnetic energy. (Author)

  3. IAU 2015 Resolution B2 on Recommended Zero Points for the Absolute and Apparent Bolometric Magnitude Scales

    DEFF Research Database (Denmark)

    Mamajek, E. E.; Torres, G.; Prsa, A.

    2015-01-01

    The XXIXth IAU General Assembly in Honolulu adopted IAU 2015 Resolution B2 on recommended zero points for the absolute and apparent bolometric magnitude scales. The resolution was proposed by the IAU Inter-Division A-G Working Group on Nominal Units for Stellar and Planetary Astronomy after...... consulting with a broad spectrum of researchers from the astronomical community. Resolution B2 resolves the long-standing absence of an internationally-adopted zero point for the absolute and apparent bolometric magnitude scales. Resolution B2 defines the zero point of the absolute bolometric magnitude scale...... such that a radiation source with $M_{\\rm Bol}$ = 0 has luminosity L$_{\\circ}$ = 3.0128e28 W. The zero point of the apparent bolometric magnitude scale ($m_{\\rm Bol}$ = 0) corresponds to irradiance $f_{\\circ}$ = 2.518021002e-8 W/m$^2$. The zero points were chosen so that the nominal solar luminosity (3.828e26 W...

  4. IAU 2015 Resolution B2 on Recommended Zero Points for the Absolute and Apparent Bolometric Magnitude Scales

    CERN Document Server

    Mamajek, E E; Prsa, A; Harmanec, P; Asplund, M; Bennett, P D; Capitaine, N; Christensen-Dalsgaard, J; Depagne, E; Folkner, W M; Haberreiter, M; Hekker, S; Hilton, J L; Kostov, V; Laskar, J; Kutz, D W; Mason, B D; Milone, E F; Montgomery, M M; Richards, M T; Schou, J; Stewart, S G

    2015-01-01

    The XXIXth IAU General Assembly in Honolulu adopted IAU 2015 Resolution B2 on recommended zero points for the absolute and apparent bolometric magnitude scales. The resolution was proposed by the IAU Inter-Division A-G Working Group on Nominal Units for Stellar and Planetary Astronomy after consulting with a broad spectrum of researchers from the astronomical community. Resolution B2 resolves the long-standing absence of an internationally-adopted zero point for the absolute and apparent bolometric magnitude scales. Resolution B2 defines the zero point of the absolute bolometric magnitude scale such that a radiation source with $M_{\\rm Bol}$ = 0 has luminosity L$_{\\circ}$ = 3.0128e28 W. The zero point of the apparent bolometric magnitude scale ($m_{\\rm Bol}$ = 0) corresponds to irradiance $f_{\\circ}$ = 2.518021002e-8 W/m$^2$. The zero points were chosen so that the nominal solar luminosity (3.828e26 W) adopted by IAU 2015 Resolution B3 corresponds approximately to $M_{\\rm Bol}$(Sun) = 4.74, the value most com...

  5. Reducing Zero-point Systematics in Dark Energy Supernova Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Faccioli, Lorenzo; Kim, Alex G; Miquel, Ramon; Bernstein, Gary; Bonissent, Alain; Brown, Matthew; Carithers, William; Christiansen, Jodi; Connolly, Natalia; Deustua, Susana; Gerdes, David; Gladney, Larry; Kushner, Gary; Linder, Eric; McKee, Shawn; Mostek, Nick; Shukla, Hemant; Stebbins, Albert; Stoughton, Chris; Tucker, David

    2011-04-01

    We study the effect of filter zero-point uncertainties on future supernova dark energy missions. Fitting for calibration parameters using simultaneous analysis of all Type Ia supernova standard candles achieves a significant improvement over more traditional fit methods. This conclusion is robust under diverse experimental configurations (number of observed supernovae, maximum survey redshift, inclusion of additional systematics). This approach to supernova fitting considerably eases otherwise stringent mission cali- bration requirements. As an example we simulate a space-based mission based on the proposed JDEM satellite; however the method and conclusions are general and valid for any future supernova dark energy mission, ground or space-based.

  6. Gaia Parallax Zero Point from RR Lyrae Stars

    Science.gov (United States)

    Gould, Andrew; Kollmeier, Juna A.

    2017-02-01

    Like Hipparcos, Gaia is designed to give absolute parallaxes, independent of any astrophysical reference system. And indeed, Gaia's internal zero-point error for parallaxes is likely to be smaller than any individual parallax error. Nevertheless, due in part to mechanical issues of unknown origin, there are many astrophysical questions for which the parallax zero-point error σ(π_0) will be the fundamentally limiting constraint. These include the distance to the Large Magellanic Cloud and the Galactic Center. We show that by using the photometric parallax estimates for RR Lyrae stars (RRL) within 8kpc, via the ultra-precise infrared period-luminosity relation, one can independently determine a hyper-precise value for π_{0}. Despite their paucity relative to bright quasars, we show that RRL are competitive due to their order-of-magnitude improved parallax precision for each individual object relative to bright quasars. We show that this method is mathematically robust and well-approximated by analytic formulae over a wide range of relevant distances.

  7. Gaia Parallax Zero Point From RR Lyrae Stars

    CERN Document Server

    Gould, Andrew

    2016-01-01

    Like Hipparcos, Gaia is designed to give absolute parallaxes, independent of any astrophysical reference system. And indeed, Gaia's internal zero-point error for parallaxes is likely to be smaller than any individual parallax error. Nevertheless, due in part to mechanical issues of unknown origin, there are many astrophysical questions for which the parallax zero-point error $\\sigma(\\pi_0)$ will be the fundamentally limiting constraint. These include the distance to the Large Magellanic Cloud and the Galactic Center. We show that by using the photometric parallax estimates for RR Lyrae stars (RRL) within 8kpc, via the ultra-precise infrared period-luminosity relation, one can independently determine a hyper-precise value for $\\pi_{0}$. Despite their paucity relative to bright quasars, we show that RRL are competitive due to their order-of-magnitude improved parallax precision for each individual object relative to bright quasars. We show that this method is mathematically robust and well-approximated by analy...

  8. Doing it with Mirrors Classical analogues for Black Hole radiation

    CERN Document Server

    Srinivasan, K

    1998-01-01

    We construct analogues for the quantum phenomena of black hole radiation in the context of {\\it classical field theory}. Hawking radiation from a (radially) collapsing star is mathematically equivalent to radiation from a mirror moving along a specific trajectory in Minkowski spacetime. We construct a classical analogue for this quantum phenomenon and use it to construct a classical analogue for black hole radiation. The radiation spectrum in quantum field theory has the power spectrum as its classical analogue. Monochromatic light is continually reflected off a moving mirror or the silvered surface of a collapsing star.The reflected light is fourier analysed by the observer and the power spectrum is constructed. For a mirror moving along the standard black hole trajectory,it is seen that the power spectrum has a ``thermal'' nature. Mirror-observer configurations like an inertial mirror observed in an accelerated observer's frame and an accelerated mirror observed in a Rindler frame are investigated and condi...

  9. Planck's radiation law: is a quantum-classical perspective possible?

    Science.gov (United States)

    Marrocco, Michele

    2016-05-01

    Planck's radiation law provides the solution to the blackbody problem that marks the decline of classical physics and the rise of the quantum theory of the radiation field. Here, we venture to suggest the possibility that classical physics might be equally suitable to deal with the blackbody problem. A classical version of the Planck's radiation law seems to be achievable if we learn from the quantum-classical correspondence between classical Mie theory and quantum-mechanical wave scattering from spherical scatterers (partial wave analysis). This correspondence designs a procedure for countable energy levels of the radiation trapped within the blackbody treated within the multipole approach of classical electrodynamics (in place of the customary and problematic expansion in terms of plane waves that give rise to the ultraviolet catastrophe). In turn, introducing the Boltzmann discretization of energy levels, the tools of classical thermodynamics and statistical theory become available for the task. On the other hand, the final result depends on a free parameter whose physical units are those of an action. Tuning this parameter on the value given by the Planck constant makes the classical result agree with the canonical Planck's radiation law.

  10. Modern Classical Electrodynamics and Electromagnetic Radiation - Vacuum Field Theory Aspects

    OpenAIRE

    2011-01-01

    The work is devoted to studying some new classical electrodynamics models of interacting charged point particles and related with them physical aspects. Based on the vacuum field theory no-geometry approach, developed in \\cite{BPT,BPT1}, the Lagrangian and Hamiltonian reformulations of some alternative classical electrodynamics models are devised. A problem closely related to the radiation reaction force is analyzed aiming to explain the Wheeler and Feynman reaction radiation mechanism, well ...

  11. The classical essence of black hole radiation

    CERN Document Server

    Nouri-Zonoz, M

    1998-01-01

    We show that the mathematics of Hawking process can be interpreted classically as the Fourier analysis of an exponentially redshifted wave mode which scatters off the black hole and travels to infinity at late times. We use this method to derive the Planckian power spectrum for Schwarzchild, Reissner-Nordstrom and Kerr black holes.

  12. Investigation of classical radiation reaction with aligned crystals

    CERN Document Server

    Di Piazza, A; Uggerhøj, Ulrik I

    2015-01-01

    Classical radiation reaction is the effect of the radiation emitted by an accelerated electric charge on the trajectory of the charge itself. The self-consistent underlying classical equation of motion including radiation-reaction effects, the Landau-Lifshitz equation, has never been tested experimentally, in spite of the first theoretical treatments having been developed more than a century ago. Here, we show that classical radiation reaction effects, as predicted by the Landau-Lifshitz equation, can be measured using presently available facilities, in the energy emission spectrum of a parallel $10$-$\\text{GeV}$ electron beam crossing a $1.1$-$\\text{mm}$ thick diamond crystal in the axial channeling regime. Our theoretical results demonstrate the feasibility of the suggested setup, e.g., at the CERN Secondary Beam Areas (SBA) beamlines.

  13. Investigation of classical radiation reaction with aligned crystals

    Science.gov (United States)

    Di Piazza, A.; Wistisen, Tobias N.; Uggerhøj, Ulrik I.

    2017-02-01

    Classical radiation reaction is the effect of the electromagnetic field emitted by an accelerated electric charge on the motion of the charge itself. The self-consistent underlying classical equation of motion including radiation-reaction effects, the Landau-Lifshitz equation, has never been tested experimentally, in spite of the first theoretical treatments of radiation reaction having been developed more than a century ago. Here we show that classical radiation reaction effects, in particular those due to the near electromagnetic field, as predicted by the Landau-Lifshitz equation, can be measured in principle using presently available facilities, in the energy emission spectrum of 30-GeV electrons crossing a 0.55-mm thick diamond crystal in the axial channeling regime. Our theoretical results indicate the feasibility of the suggested setup, e.g., at the CERN Secondary Beam Areas (SBA) beamlines.

  14. Classical electromagnetic radiation of the Dirac electron

    Science.gov (United States)

    Lanyi, G.

    1973-01-01

    A wave-function-dependent four-vector potential is added to the Dirac equation in order to achieve conservation of energy and momentum for a Dirac electron and its emitted electromagnetic field. The resultant equation contains solutions which describe transitions between different energy states of the electron. As a consequence it is possible to follow the space-time evolution of such a process. This evolution is shown in the case of the spontaneous emission of an electromagnetic field by an electron bound in a hydrogen-like atom. The intensity of the radiation and the spectral distribution are calculated for transitions between two eigenstates. The theory gives a self-consistent deterministic description of some simple radiation processes without using quantum electrodynamics or the correspondence principle.

  15. Zero-Point Spin-Fluctuations of Single Adatoms.

    Science.gov (United States)

    Ibañez-Azpiroz, Julen; Dos Santos Dias, Manuel; Blügel, Stefan; Lounis, Samir

    2016-07-13

    Stabilizing the magnetic signal of single adatoms is a crucial step toward their successful usage in widespread technological applications such as high-density magnetic data storage devices. The quantum mechanical nature of these tiny objects, however, introduces intrinsic zero-point spin-fluctuations that tend to destabilize the local magnetic moment of interest by dwindling the magnetic anisotropy potential barrier even at absolute zero temperature. Here, we elucidate the origins and quantify the effect of the fundamental ingredients determining the magnitude of the fluctuations, namely, the (i) local magnetic moment, (ii) spin-orbit coupling, and (iii) electron-hole Stoner excitations. Based on a systematic first-principles study of 3d and 4d adatoms, we demonstrate that the transverse contribution of the fluctuations is comparable in size to the magnetic moment itself, leading to a remarkable ≳50% reduction of the magnetic anisotropy energy. Our analysis gives rise to a comprehensible diagram relating the fluctuation magnitude to characteristic features of adatoms, providing practical guidelines for designing magnetically stable nanomagnets with minimal quantum fluctuations.

  16. Crystal Power: Piezo Coupling to the Quantum Zero Point

    CERN Document Server

    November, Laurence J

    2011-01-01

    We consider electro-optical constructions in which the Casimir force is modulated in opposition to piezo-crystal elasticity, as in a stack of alternating tunably conductive and piezo layers. Adjacent tunably conducting layers tuned to conduct, attract by the Casimir force compressing the intermediate piezo, but when subsequently detuned to insulate, sandwiched piezo layers expand elastically to restore their original dimension. In each cycle some electrical energy is made available from the quantum zero point (zp). We estimate that the maximum power that could be derived at semiconductor THz modulation rates is megawatts/cm3. Similarly a permittivity wave generated by a THz acoustic wave in a single crystal by the acousto-optic effect produces multiple coherent Casimir wave mode overtones and a bulk mode. We model the Casimir effect in a sinusoidally graded medium finding it to be very enhanced over what is found in a multilayer stack for the equivalent permittivity contrast, and more slowly decreasing with s...

  17. Duality Fixed Point and Zero Point Theorems and Applications

    Directory of Open Access Journals (Sweden)

    Qingqing Cheng

    2012-01-01

    Full Text Available The following main results have been given. (1 Let E be a p-uniformly convex Banach space and let T:E→E* be a (p-1-L-Lipschitz mapping with condition 0<(pL/c21/(p-1<1. Then T has a unique generalized duality fixed point x*∈E and (2 let E be a p-uniformly convex Banach space and let T:E→E* be a q-α-inverse strongly monotone mapping with conditions 1/p+1/q=1, 0<(q/(q-1c2q-1<α. Then T has a unique generalized duality fixed point x*∈E. (3 Let E be a 2-uniformly smooth and uniformly convex Banach space with uniformly convex constant c and uniformly smooth constant b and let T:E→E* be a L-lipschitz mapping with condition 0<2b/c2<1. Then T has a unique zero point x*. These main results can be used for solving the relative variational inequalities and optimal problems and operator equations.

  18. Zero-Point Energy Constraint for Unimolecular Dissociation Reactions. Giving Trajectories Multiple Chances To Dissociate Correctly.

    Science.gov (United States)

    Paul, Amit K; Hase, William L

    2016-01-28

    A zero-point energy (ZPE) constraint model is proposed for classical trajectory simulations of unimolecular decomposition and applied to CH4* → H + CH3 decomposition. With this model trajectories are not allowed to dissociate unless they have ZPE in the CH3 product. If not, they are returned to the CH4* region of phase space and, if necessary, given additional opportunities to dissociate with ZPE. The lifetime for dissociation of an individual trajectory is the time it takes to dissociate with ZPE in CH3, including multiple possible returns to CH4*. With this ZPE constraint the dissociation of CH4* is exponential in time as expected for intrinsic RRKM dynamics and the resulting rate constant is in good agreement with the harmonic quantum value of RRKM theory. In contrast, a model that discards trajectories without ZPE in the reaction products gives a CH4* → H + CH3 rate constant that agrees with the classical and not quantum RRKM value. The rate constant for the purely classical simulation indicates that anharmonicity may be important and the rate constant from the ZPE constrained classical trajectory simulation may not represent the complete anharmonicity of the RRKM quantum dynamics. The ZPE constraint model proposed here is compared with previous models for restricting ZPE flow in intramolecular dynamics, and connecting product and reactant/product quantum energy levels in chemical dynamics simulations.

  19. Investigation of classical radiation reaction with aligned crystals

    Directory of Open Access Journals (Sweden)

    A. Di Piazza

    2017-02-01

    Full Text Available Classical radiation reaction is the effect of the electromagnetic field emitted by an accelerated electric charge on the motion of the charge itself. The self-consistent underlying classical equation of motion including radiation–reaction effects, the Landau–Lifshitz equation, has never been tested experimentally, in spite of the first theoretical treatments of radiation reaction having been developed more than a century ago. Here we show that classical radiation reaction effects, in particular those due to the near electromagnetic field, as predicted by the Landau–Lifshitz equation, can be measured in principle using presently available facilities, in the energy emission spectrum of 30-GeV electrons crossing a 0.55-mm thick diamond crystal in the axial channeling regime. Our theoretical results indicate the feasibility of the suggested setup, e.g., at the CERN Secondary Beam Areas (SBA beamlines.

  20. Investigating the significance of zero-point motion in small molecular clusters of sulphuric acid and water

    Energy Technology Data Exchange (ETDEWEB)

    Stinson, Jake L., E-mail: j.stinson@ucl.ac.uk; Ford, Ian J. [Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT (United Kingdom); Kathmann, Shawn M. [Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

    2014-01-14

    The nucleation of particles from trace gases in the atmosphere is an important source of cloud condensation nuclei, and these are vital for the formation of clouds in view of the high supersaturations required for homogeneous water droplet nucleation. The methods of quantum chemistry have increasingly been employed to model nucleation due to their high accuracy and efficiency in calculating configurational energies; and nucleation rates can be obtained from the associated free energies of particle formation. However, even in such advanced approaches, it is typically assumed that the nuclei have a classical nature, which is questionable for some systems. The importance of zero-point motion (also known as quantum nuclear dynamics) in modelling small clusters of sulphuric acid and water is tested here using the path integral molecular dynamics method at the density functional level of theory. The general effect of zero-point motion is to distort the mean structure slightly, and to promote the extent of proton transfer with respect to classical behaviour. In a particular configuration of one sulphuric acid molecule with three waters, the range of positions explored by a proton between a sulphuric acid and a water molecule at 300 K (a broad range in contrast to the confinement suggested by geometry optimisation at 0 K) is clearly affected by the inclusion of zero point motion, and similar effects are observed for other configurations.

  1. Investigating the significance of zero-point motion in small molecular clusters of sulphuric acid and water

    CERN Document Server

    Stinson, Jake; Ford, Ian

    2014-01-01

    The nucleation of particles from trace gases in the atmosphere is an important source of cloud condensation nuclei (CCN), and these are vital for the formation of clouds in view of the high supersaturations required for homogeneous water droplet nucleation. The methods of quantum chemistry have increasingly been employed to model nucleation due to their high accuracy and efficiency in calculating configurational energies; and nucleation rates can be obtained from the associated free energies of particle formation. However, even in such advanced approaches, it is typically assumed that the nuclei have a classical nature, which is questionable for some systems. The importance of zero-point motion (also known as quantum nuclear dynamics) in modelling small clusters of sulphuric acid and water is tested here using the path integral molecular dynamics (PIMD) method at the density functional theory (DFT) level of theory. The general effect of zero-point motion is to distort the mean structure slightly, and to promo...

  2. A semi-classical treatment of channeling radiation reaction

    Science.gov (United States)

    Huang, Zhirong; Chen, Pisin; Ruth, Ronald D.

    1996-10-01

    A semi-classical formalism is used to calculate the radiation reaction of a relativistic particle in a straight, continuous focusing system. Due to the absence of quantum excitation in such a focusing system, the radiation damping rate of the transverse action obtained using this formalism agrees exactly with the result from the classical Lorentz-Dirac radiation reaction equation. In the limit where the pitch angle of the particle is much smaller than the radiation opening angle, the transverse action damps exponentially with an energy-independent rate that is much faster than the energy decay rate. In the opposite limit, both the transverse action and the energy damp with power laws and their relative rates are comparable. The general time-dependence of the transverse action damping and the energy decay are obtained analytically from these rate equations.

  3. Classical Radiation Reaction in Particle-In-Cell Simulations

    CERN Document Server

    Vranic, Marija; Fonseca, Ricardo A; Silva, Luis O

    2015-01-01

    Under the presence of ultra high intensity lasers or other intense electromagnetic fields the motion of particles in the ultrarelativistic regime can be severely affected by radiation reaction. The standard particle-in-cell (PIC) algorithms do not include radiation reaction effects. Even though this is a well known mechanism, there is not yet a definite algorithm nor a standard technique to include radiation reaction in PIC codes. We have compared several models for the calculation of the radiation reaction force, with the goal of implementing an algorithm for classical radiation reaction in the Osiris framework, a state-of-the-art PIC code. The results of the different models are compared with standard analytical results, and the relevance/advantages of each model are discussed. Numerical issues relevant to PIC codes such as resolution requirements, application of radiation reaction to macro particles and computational cost are also addressed. The Landau and Lifshitz reduced model is chosen for implementatio...

  4. Energy conservation for a radiating charge in classical electrodynamics

    CERN Document Server

    Singal, Ashok K

    2014-01-01

    It is shown that the well-known disparity in classical electrodynamics between the power radiated in electromagnetic fields and the power-loss, as calculated from the radiation reaction on a charge undergoing a non-uniform motion, is successfully resolved when a proper distinction is made between quantities expressed in terms of a "real time" and those expressed in terms of a retarded time. It is shown that the expression for the real-time radiative power loss from a charged particle is somewhat different from the familiar Larmor's formula, or in a relativistic case, from Li\\'{e}nard's formula.

  5. Modern Classical Electrodynamics and Electromagnetic Radiation - Vacuum Field Theory Aspects

    CERN Document Server

    Bogolubov, N N

    2012-01-01

    The work is devoted to studying some new classical electrodynamics models of interacting charged point particles and related with them physical aspects. Based on the vacuum field theory no-geometry approach, developed in \\cite{BPT,BPT1}, the Lagrangian and Hamiltonian reformulations of some alternative classical electrodynamics models are devised. A problem closely related to the radiation reaction force is analyzed aiming to explain the Wheeler and Feynman reaction radiation mechanism, well known as the absorption radiation theory, and strongly dependent on the Mach type interaction of a charged point particle in an ambient vacuum electromagnetic medium. There are discussed some relationships between this problem and the one derived within the context of the vacuum field theory approach. The R. \\ Feynman's \\textquotedblleft heretical\\textquotedblright\\ approach \\cite{Dy1,Dy2} to deriving the Lorentz force based Maxwell electromagnetic equations is also revisited, its complete legacy is argued both by means o...

  6. Classical radiation reaction in particle-in-cell simulations

    Science.gov (United States)

    Vranic, M.; Martins, J. L.; Fonseca, R. A.; Silva, L. O.

    2016-07-01

    Under the presence of ultra high intensity lasers or other intense electromagnetic fields the motion of particles in the ultrarelativistic regime can be severely affected by radiation reaction. The standard particle-in-cell (PIC) algorithms do not include radiation reaction effects. Even though this is a well known mechanism, there is not yet a definite algorithm nor a standard technique to include radiation reaction in PIC codes. We have compared several models for the calculation of the radiation reaction force, with the goal of implementing an algorithm for classical radiation reaction in the Osiris framework, a state-of-the-art PIC code. The results of the different models are compared with standard analytical results, and the relevance/advantages of each model are discussed. Numerical issues relevant to PIC codes such as resolution requirements, application of radiation reaction to macro particles and computational cost are also addressed. For parameters of interest where the classical description of the electron motion is applicable, all the models considered are shown to give comparable results. The Landau and Lifshitz reduced model is chosen for implementation as one of the candidates with the minimal overhead and no additional memory requirements.

  7. Lorentz invariance and the zero-point stress-energy tensor

    CERN Document Server

    Visser, Matt

    2016-01-01

    Some 65 years ago (1951) Wolfgang Pauli noted that the zero-point energy density could be set to zero by a carefully fine-tuned cancellation between bosons and fermions. In the current article I will argue in a slightly different direction: The zero-point energy density is only one component of the zero-point stress energy tensor, and it is this tensor quantity that is in many ways the more fundamental object of interest. I shall demonstrate that Lorentz invariance of the zero-point stress energy tensor implies finiteness of the zero-point stress energy tensor, and vice versa. I shall then relate the discussion to BSM physics, to the cosmological constant, and to Sakharov-style induced gravity.

  8. Non-classical radiation emission by a coherent conductor

    Science.gov (United States)

    Forgues, Jean-Charles; Gasse, Gabriel; Lupien, Christian; Reulet, Bertrand

    2016-08-01

    We report experimental evidence that the microwave electromagnetic field generated by a normal conductor, here a tunnel junction placed at ultra-low temperature, can be non-classical. By measuring the quadratures of the electromagnetic field at one or two frequencies in the GHz range, we demonstrate the existence of squeezing as well as entanglement in such radiation. In one experiment, we observe that the variance of one quadrature of the photo-assisted noise generated by the junction goes below its vacuum level. In the second experiment, we demonstrate the existence of correlations between the quadratures taken at two frequencies, which can be stronger than allowed by classical mechanics, proving that the radiation at those two frequencies are entangled. xml:lang="fr"

  9. Stable long-time semiclassical description of zero-point energy in high-dimensional molecular systems.

    Science.gov (United States)

    Garashchuk, Sophya; Rassolov, Vitaly A

    2008-07-14

    Semiclassical implementation of the quantum trajectory formalism [J. Chem. Phys. 120, 1181 (2004)] is further developed to give a stable long-time description of zero-point energy in anharmonic systems of high dimensionality. The method is based on a numerically cheap linearized quantum force approach; stabilizing terms compensating for the linearization errors are added into the time-evolution equations for the classical and nonclassical components of the momentum operator. The wave function normalization and energy are rigorously conserved. Numerical tests are performed for model systems of up to 40 degrees of freedom.

  10. On the problem of the acceleration of particles by the zero-point field of quantum electrodynamics. Exploration with the quantum Einstein-Hopf model

    Energy Technology Data Exchange (ETDEWEB)

    Rueda, A.

    1986-11-11

    Further discussions and detailed calculations on the problem of the spontaneous acceleration of free electromagnetically interacting particles by the zero-point field in the light of a quantum version of the Einstein-Hopf model are presented. It is shown that acceleration occurs if the zero-point field is represented in a time-symmetric fashion within the viewpoint of the Wheeler-Feynman radiant-absorber theory. However, if the zero-point field is represented in the time-asymmetric form, the quantum Einstein-Hopf model yields no translational kinetic-energy growth in disagreement with the previous prediction and with the result of the classical version of the zero-point field in stochastic electrodynamics. The calculations are clear and compelling. Despite that the last no-acceleration result is germane to phenomenological thermodynamics expectations and to a more consistent perspective of quantum theory, the second quantization that leads to the time-symmetric zero-point field yields a conceptually more satisfactory view of this background field which is no longer a free virtual field but becomes a real field which is originated in and is associated with particles. The discussion is based on the different boundary conditions for the electromagnetic-field tensor that the zero-point field (asymmetric vs. symmetric) requires in quantum and in classical theory: time symmetry presupposes a universe that is opaque. If this condition does not hold, we are forced to ordinary time asymmetry and, if a correspondence with quantum electrodynamics is desired, some modification of the hypothesis of stochastic electrodynamics would be required to prevent acceleration. The possible form of that modification is suggested.

  11. Classical tunneling as a consequence of radiation reaction forces

    Science.gov (United States)

    Denef, Frederik; Raeymaekers, Joris; Studer, Urban M.; Troost, Walter

    1997-09-01

    We show that the classical equation of motion of a radiating charged point particle (the Lorentz-Dirac equation) has ``tunneling'' solutions. For a given initial position and velocity we find that, contrary to common belief, several different physically acceptable solutions exist for a range of initial data. Both features are demonstrated for a rectangular barrier. To check that these phenomena are not dependent on the discontinuities of the potential, we also study in detail the solutions for a smoothened (single) potential step.

  12. Zero-Point Energy Leakage in Quantum Thermal Bath Molecular Dynamics Simulations.

    Science.gov (United States)

    Brieuc, Fabien; Bronstein, Yael; Dammak, Hichem; Depondt, Philippe; Finocchi, Fabio; Hayoun, Marc

    2016-12-13

    The quantum thermal bath (QTB) has been presented as an alternative to path-integral-based methods to introduce nuclear quantum effects in molecular dynamics simulations. The method has proved to be efficient, yielding accurate results for various systems. However, the QTB method is prone to zero-point energy leakage (ZPEL) in highly anharmonic systems. This is a well-known problem in methods based on classical trajectories where part of the energy of the high-frequency modes is transferred to the low-frequency modes leading to a wrong energy distribution. In some cases, the ZPEL can have dramatic consequences on the properties of the system. Thus, we investigate the ZPEL by testing the QTB method on selected systems with increasing complexity in order to study the conditions and the parameters that influence the leakage. We also analyze the consequences of the ZPEL on the structural and vibrational properties of the system. We find that the leakage is particularly dependent on the damping coefficient and that increasing its value can reduce and, in some cases, completely remove the ZPEL. When using sufficiently high values for the damping coefficient, the expected energy distribution among the vibrational modes is ensured. In this case, the QTB method gives very encouraging results. In particular, the structural properties are well-reproduced. The dynamical properties should be regarded with caution although valuable information can still be extracted from the vibrational spectrum, even for large values of the damping term.

  13. Semi-classical quantum theory for cyclotron radiation

    Institute of Scientific and Technical Information of China (English)

    陈军锋; 邓劲松; 徐毅; 尤峻汉

    1997-01-01

    A semi-classical quantum theory of the cyclotron radiation of the nonrelativistic thermal electrons in a very strong magnetic field is presented.The basic formulae of the absorption coefficient of cyclotron resonance kv and the absorption (scattering) cross-section of cyclotron resonance σv have been derived under the quadrupole approximation.σv is an important quantity in the study of the "magnetic inverse-Compton scattering".It is shown that σv is greatly larger than the Thomson cross-sectron σT,which is important in discussing the magnetic inverse-Compton scattering of the relativistic electrons in a very strong magnetic field.

  14. Classically conformal radiative neutrino model with gauged B - L symmetry

    Science.gov (United States)

    Okada, Hiroshi; Orikasa, Yuta

    2016-09-01

    We propose a classically conformal model in a minimal radiative seesaw, in which we employ a gauged B - L symmetry in the standard model that is essential in order to work the Coleman-Weinberg mechanism well that induces the B - L symmetry breaking. As a result, nonzero Majorana mass term and electroweak symmetry breaking simultaneously occur. In this framework, we show a benchmark point to satisfy several theoretical and experimental constraints. Here theoretical constraints represent inert conditions and Coleman-Weinberg condition. Experimental bounds come from lepton flavor violations (especially μ → eγ), the current bound on the Z‧ mass at the CERN Large Hadron Collider, and neutrino oscillations.

  15. Plasmon-supported emission of entangled photons and zero-point energy

    OpenAIRE

    Hizhnyakov, Vladimir

    2013-01-01

    Emission of pairs of photons in the interface metal-dielectric under the laser excitation arising due to the time-dependent perturbation of the zero-point fluctuations of the electromagnetic field by photons of the laser is considered. The enhancement of this emission by surface plasmons may be used for getting polarization-entangled photons. A possibility to compensate the energy of the zero-point fluctuations of bosons by other fluctuations with negative energy is discussed.

  16. Classical theory of resonant transition radiation in multilayer structures.

    Science.gov (United States)

    Pardo, B; André, J M

    2001-01-01

    A rigorous classical electromagnetic theory of the transition radiation in finite and infinite multilayer structures is presented. It makes the standard results of thin-film optics, such as the matrix formalism, accountable; it allows thus an exact treatment of the propagation of the waves induced by the electron. This method is applied to the particular case of the periodic structures to treat the resonant transition radiation (RTR). It is noted that the present theory gives, in the hard x-ray domain, results previously published. The reason for this approach is to make the numerical calculations rigorous and easy. The numerical results of our theory are compared to experimental RTR data obtained recently by Yamada et al. [Phys. Rev. A 59, 3673 (1999)] with a nickel-carbon multilayer structure.

  17. Investigating the significance of zero-point motion in small molecular clusters of sulphuric acid and water

    Energy Technology Data Exchange (ETDEWEB)

    Stinson, Jake L.; Kathmann, Shawn M.; Ford, Ian J.

    2014-01-14

    The nucleation of particles from trace gases in the atmosphere is an important source of cloud condensation nuclei (CCN), and these are vital for the formation of clouds in view of the high supersaturations required for homogeneous water droplet nucleation. The methods of quantum chemistry have increasingly been employed to model nucleation due to their high accuracy and efficiency in calculating configurational energies; and nucleation rates can be obtained from the associated free energies of particle formation. However, even in such advanced approaches, it is typically assumed that the nuclei have a classical nature, which is questionable for some systems. The importance of zero-point motion (also known as quantum nuclear dynamics) in modelling small clusters of sulphuric acid and water is tested here using the path integral molecular dynamics (PIMD) method at the density functional theory (DFT) level of theory. We observe a small zero-point effect on the the equilibrium structures of certain clusters. One configuration is found to display a bimodal behaviour at 300 K in contrast to the stable ionised state suggested from a zero temperature classical geometry optimisation. The general effect of zero-point motion is to promote the extent of proton transfer with respect to classical behaviour. We thank Prof. Angelos Michaelides and his group in University College London (UCL) for practical advice and helpful discussions. This work benefited from interactions with the Thomas Young Centre through seminar and discussions involving the PIMD method. SMK was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. JLS and IJF were supported by the IMPACT scheme at UCL and by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. We are grateful for use of the UCL Legion High Performance Computing Facility and the

  18. Zero-point term and quantum effects in the Johnson noise of resistors: a critical appraisal

    Science.gov (United States)

    Kish, Laszlo B.; Niklasson, Gunnar A.; Granqvist, Claes G.

    2016-05-01

    There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor. This term originates from a quantum-theoretical treatment of the fluctuation-dissipation theorem (FDT). Is the zero-point term really there, or is it only an experimental artifact, due to the uncertainty principle, for phase-sensitive amplifiers? Could it be removed by renormalization of theories? We discuss some historical measurement schemes that do not lead to the effect predicted by the FDT, and we analyse new features that emerge when the consequences of the zero-point term are measured via the mean energy and force in a capacitor shunting the resistor. If these measurements verify the existence of a zero-point term in the noise, then two types of perpetual motion machines can be constructed. Further investigation with the same approach shows that, in the quantum limit, the Johnson-Nyquist formula is also invalid under general conditions even though it is valid for a resistor-antenna system. Therefore we conclude that in a satisfactory quantum theory of the Johnson noise, the FDT must, as a minimum, include also the measurement system used to evaluate the observed quantities. Issues concerning the zero-point term may also have implications for phenomena in advanced nanotechnology.

  19. Radiation and the classical double copy for color charges

    CERN Document Server

    Goldberger, Walter D

    2016-01-01

    We construct perturbative classical solutions of the Yang-Mills equations coupled to dynamical point particles carrying color charge. By applying a set of color to kinematics replacement rules first introduced by Bern, Carrasco and Johansson (BCJ), these are shown to generate solutions of d-dimensional dilaton gravity, which we also explicitly construct. Agreement between the gravity result and the gauge theory double copy implies a correspondence between non-Abelian particles and gravitating sources with dilaton charge. When the color sources are highly relativistic, dilaton exchange decouples, and the solutions we obtain match those of pure gravity. We comment on possible implications of our findings to the calculation of gravitational waveforms in astrophysical black hole collisions, directly from computationally simpler gluon radiation in Yang-Mills theory.

  20. A modified variation-perturbation approach to zero-point vibrational motion

    DEFF Research Database (Denmark)

    Åstrand, Per-Olof; Ruud, K.; Sundholm, D.

    2000-01-01

    We present a detailed investigation of the perturbation approach for calculating zero-point vibrational contributions to molecular properties. It is demonstrated that if the sum of the potential energy and the zero-point vibrational energy is regarded as an effective potential energy, the leading...... contribution to the first-order wave function vanishes in the perturbation approach. Two different perturbation approaches have been investigated numerically by calculations of some magnetic properties for a few diatomic molecules and the results obtained have been compared to the exact numerical results...

  1. The Cepheid PL zero-point based on the revised Hipparcos trigonometrical parallaxes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; ZHU Zi

    2009-01-01

    Revised Hipparcos data were released by van Leeuwen in 2007. In this article revised Hipparcos trigo-nometrical parallaxes are used to derive a period-luminosity zero-point in the optical V band. Adopting a fixed slope of -2.81 from the LMC, a zero-point value of p= -1.37±0.07 is derived based on the method by Feast and Catchpole (1997). This value yields an LMC distance modulus of 18.64 mag, which makes a minor change in H0 expected from Feast and Catchpole's result in 1997.

  2. On the Origins of the Planck Zero Point Energy in Relativistic Quantum Field Theory

    CERN Document Server

    Widom, A; Srivastava, Y N

    2015-01-01

    It is argued that the zero point energy in quantum field theory is a reflection of the particle anti-particle content of the theory. This essential physical content is somewhat disguised in electromagnetic theory wherein the photon is its own anti-particle. To illustrate this point, we consider the case of a charged Boson theory $(\\pi^+,\\pi^-)$ wherein the particle and anti-particle can be distinguished by the charge $\\pm e$. Starting from the zero point energy, we derive the Boson pair production rate per unit time per unit volume from the vacuum in a uniform external electric field. The result is further generalized for arbitrary spin $s$.

  3. Zero-point energy in the Johnson noise of resistors: Is it there?

    CERN Document Server

    Kish, Laszlo B

    2015-01-01

    There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor: Is it indeed there or is it only an experimental artifact due to the uncertainty principle for phase-sensitive amplifiers? We show that, when the zero-point term is measured by the mean energy and force in a shunting capacitor and, if these measurements confirm its existence, two types of perpetual motion machines could be constructed. Therefore an exact quantum theory of the Johnson noise must include also the measurement system used to evaluate the observed quantities. The results have implications also for phenomena in advanced nanotechnology.

  4. Role of zero-point vibrational corrections to carbon hyperfine coupling constants in organic π radicals

    Science.gov (United States)

    Chen, X.; Rinkevicius, Z.; Ruud, K.; Ågren, H.

    2013-02-01

    By analyzing a set of organic π radicals, we demonstrate that zero-point vibrational corrections give significant contributions to carbon hyperfine coupling constants, in one case even inducing a sign reversal for the coupling constant. We discuss the implications of these findings for the computational analysis of electron paramagnetic spectra based on hyperfine coupling constants evaluated at the equilibrium geometry of radicals. In particular, we note that a dynamical description that involves the nuclear motion is in many cases necessary in order to achieve a semi-quantitatively predictive theory for carbon hyperfine coupling constants. In addition, we discuss the implications of the strong dependence of the carbon hyperfine coupling constants on the zero-point vibrational corrections for the selection of exchange-correlation functionals in density functional theory studies of these constants.

  5. The Apparent Lack of Lorentz Invariance in Zero-Point Fields with Truncated Spectra

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-01-01

    Full Text Available The integrals that describe the expectation values of the zero-point quantum-field-theoretic vacuum state are semi-infinite, as are the integrals for the stochastic electrodynamic vacuum. The unbounded upper limit to these integrals leads in turn to infinite energy densities and renormalization masses. A number of models have been put forward to truncate the integrals so that these densities and masses are finite. Unfortunately the truncation apparently destroys the Lorentz invariance of the integrals. This note argues that the integrals are naturally truncated by the graininess of the negative-energy Planck vacuum state from which the zero-point vacuum arises, and are thus automatically Lorentz invariant.

  6. Zero-Point Fluctuations in the Nuclear Born-Oppenheimer Ground State

    Science.gov (United States)

    Zettili, Nouredine

    The small-amplitude oscillations of rigid nuclei around the equilibrium state are described by means of the nuclear Born-Oppenheimer (NBO) method. In this limit, the method is shown to give back the random phase approximation (RPA) equations of motion. The contribution of the zero-point fluctuations to the ground state are examined, and the NBO ground state energy derived is shown to be identical to the RPA ground state energy.

  7. Blackbody radiation, conformal symmetry, and the mismatch between classical mechanics and electromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, Timothy H [Department of Physics, City College of the City University of New York, New York, NY 10031 (United States)

    2005-02-25

    The blackbody radiation problem within classical physics is reviewed. It is again suggested that conformal symmetry is the crucial unrecognized aspect, and that only scattering by classical electromagnetic systems will provide equilibrium at the Planck spectrum. It is pointed out that the several calculations of radiation scattering using nonlinear mechanical systems do not preserve the Boltzmann distribution under adiabatic change of a parameter, and this fact seems at variance with our expectations in connection with derivations of Wien's displacement theorem. By contrast, the striking properties of charged particle motion in a Coulomb potential or in a uniform magnetic field suggest the possibility that these systems will fit with classical thermal radiation. It may be possible to give a full scattering calculation in the case of cyclotron motion in order to provide the needed test of the connection between conformal symmetry and classical thermal radiation.

  8. Zero point energy leakage in condensed phase dynamics: an assessment of quantum simulation methods for liquid water.

    Science.gov (United States)

    Habershon, Scott; Manolopoulos, David E

    2009-12-28

    The approximate quantum mechanical ring polymer molecular dynamics (RPMD) and linearized semiclassical initial value representation (LSC-IVR) methods are compared and contrasted in a study of the dynamics of the flexible q-TIP4P/F water model at room temperature. For this water model, a RPMD simulation gives a diffusion coefficient that is only a few percent larger than the classical diffusion coefficient, whereas a LSC-IVR simulation gives a diffusion coefficient that is three times larger. We attribute this discrepancy to the unphysical leakage of initially quantized zero point energy (ZPE) from the intramolecular to the intermolecular modes of the liquid as the LSC-IVR simulation progresses. In spite of this problem, which is avoided by construction in RPMD, the LSC-IVR may still provide a useful approximation to certain short-time dynamical properties which are not so strongly affected by the ZPE leakage. We illustrate this with an application to the liquid water dipole absorption spectrum, for which the RPMD approximation breaks down at frequencies in the O-H stretching region owing to contamination from the internal modes of the ring polymer. The LSC-IVR does not suffer from this difficulty and it appears to provide quite a promising way to calculate condensed phase vibrational spectra.

  9. Transmission of Helium Isotopes through Graphdiyne Pores: Tunneling versus Zero Point Energy Effects.

    Science.gov (United States)

    Hernández, Marta I; Bartolomei, Massimiliano; Campos-Martínez, José

    2015-10-29

    Recent progress in the production of new two-dimensional (2D) nanoporous materials is attracting considerable interest for applications to isotope separation in gases. In this paper we report a computational study of the transmission of (4)He and (3)He through the (subnanometer) pores of graphdiyne, a recently synthesized 2D carbon material. The He-graphdiyne interaction is represented by a force field parametrized upon ab initio calculations, and the (4)He/(3)He selectivity is analyzed by tunneling-corrected transition state theory. We have found that both zero point energy (of the in-pore degrees of freedom) and tunneling effects play an extraordinary role at low temperatures (≈20-30 K). However, both quantum features work in opposite directions in such a way that the selectivity ratio does not reach an acceptable value. Nevertheless, the efficiency of zero point energy is in general larger, so that (4)He tends to diffuse faster than (3)He through the graphdiyne membrane, with a maximum performance at 23 K. Moreover, it is found that the transmission rates are too small in the studied temperature range, precluding practical applications. It is concluded that the role of the in-pore degrees of freedom should be included in computations of the transmission probabilities of molecules through nanoporous materials.

  10. Electronic Zero-Point Oscillations in the Strong-Interaction Limit of Density Functional Theory.

    Science.gov (United States)

    Gori-Giorgi, Paola; Vignale, Giovanni; Seidl, Michael

    2009-04-14

    The exchange-correlation energy in Kohn-Sham density functional theory can be expressed exactly in terms of the change in the expectation of the electron-electron repulsion operator when, in the many-electron Hamiltonian, this same operator is multiplied by a real parameter λ varying between 0 (Kohn-Sham system) and 1 (physical system). In this process, usually called adiabatic connection, the one-electron density is kept fixed by a suitable local one-body potential. The strong-interaction limit of density functional theory, defined as the limit λ→∞, turns out to be like the opposite noninteracting Kohn-Sham limit (λ→0) mathematically simpler than the physical (λ = 1) case and can be used to build an approximate interpolation formula between λ→0 and λ→∞ for the exchange-correlation energy. Here we extend the systematic treatment of the λ→∞ limit [Phys. Rev. A 2007, 75, 042511] to the next leading term, describing zero-point oscillations of strictly correlated electrons, with numerical examples for small spherical atoms. We also propose an improved approximate functional for the zero-point term and a revised interpolation formula for the exchange-correlation energy satisfying more exact constraints.

  11. IAU 2015 Resolution B2 on Recommended Zero Points for the Absolute and Apparent Bolometric Magnitude Scales

    OpenAIRE

    Mamajek, E. E.; Torres, G.; Prsa, A.; Harmanec, P.; Asplund, M.; Bennett, P. D.; Capitaine, N.; Christensen-Dalsgaard, J.; Depagne, E.; Folkner, W. M.; Haberreiter, M.; Hekker, S.; Hilton, J. L.; Kostov, V.; Kurtz, D. W.

    2015-01-01

    The XXIXth IAU General Assembly in Honolulu adopted IAU 2015 Resolution B2 on recommended zero points for the absolute and apparent bolometric magnitude scales. The resolution was proposed by the IAU Inter-Division A-G Working Group on Nominal Units for Stellar and Planetary Astronomy after consulting with a broad spectrum of researchers from the astronomical community. Resolution B2 resolves the long-standing absence of an internationally-adopted zero point for the absolute and apparent bolo...

  12. On Irreversibility and Radiation in Classical Electrodynamics of Point Particles

    OpenAIRE

    Bauer, G.; Deckert, D. -A.; Dürr, Detlef; Hinrichs, Günter

    2013-01-01

    The direct interaction theory of electromagnetism, also known as Wheeler-Feynman electrodynamics, is often misinterpreted and found unappealing because of its reference to the absorber and, more importantly, to the so-called absorber condition. Here we remark that the absorber condition is indeed questionable and presumably not relevant for the explanation of irreversible radiation phenomena in our universe. What is relevant and deserves further scrutiny is the emergent effective description ...

  13. On the Zero-Point Energy of a Conducting Spherical Shell

    CERN Document Server

    Esposito, G; Kirsten, K; Esposito, Giampiero; Kamenshchik, Alexander Yu.; Kirsten, Klaus

    1999-01-01

    The zero-point energy of a conducting spherical shell is evaluated by imposing boundary conditions on the potential A, and on the ghost fields. The scheme requires that temporal and tangential components of perturbations of A should vanish at the boundary, jointly with the gauge-averaging functional, here chosen of the Lorenz type. Gauge invariance of such boundary conditions is then obtained provided that the ghost fields vanish at the boundary. Normal and longitudinal modes of the potential obey an entangled system of eigenvalue equations, whose solution is a linear combination of Bessel functions under the above assumptions, and with the help of the Feynman choice for a dimensionless gauge parameter. Interestingly, ghost modes cancel exactly the contribution to the Casimir energy resulting from transverse and temporal modes of A, jointly with the decoupled normal mode of A. Moreover, normal and longitudinal components of A for the interior and the exterior problem give a result in complete agreement with t...

  14. Sensing Atomic Motion from the Zero Point to Room Temperature with Ultrafast Atom Interferometry

    CERN Document Server

    Johnson, K G; Mizrahi, J; Wong-Campos, J D; Monroe, C

    2015-01-01

    We sense the motion of a trapped atomic ion using a sequence of state-dependent ultrafast momentum kicks. We use this atom interferometer to characterize a nearly-pure quantum state with $n=1$ phonon and accurately measure thermal states ranging from near the zero-point energy to $\\bar{n}\\sim 10^4$, with the possibility of extending at least 100 times higher in energy. The complete energy range of this method spans from the ground state to far outside of the Lamb-Dicke regime, where atomic motion is greater than the optical wavelength. These interferometric techniques are useful for characterizing ultrafast entangling gates between multiple trapped ions, and may also be used for sensing electromagnetic fields over a wide dynamic range.

  15. Mesoscopic capacitor and zero-point energy: Poisson's distribution for virtual charges, pressure, and decoherence control

    Science.gov (United States)

    Flores, J. C.

    2014-08-01

    Mesoscopic capacitor theory, which includes intrinsic inductive effects from quantum tunneling, is applied to conducting spherical shells. The zero-point pressure and the number of virtual charged pairs are determined assuming a Poisson distribution. They are completely defined by a dimensionless mesoscopic parameter (χc) measuring the average number of virtual pairs per solid angle and carrying mesoscopic information. Fluctuations remain finite and well defined. Connections with usual quantum-field-theory limit enables us to evaluate χc 1.007110. Equivalently, for a mesoscopic parallel-plate capacitor, the shot noise distribution becomes operative with χc 0.94705 as well being related to the density of virtual pairs. Temperature decoherence and capacitor control are discussed by considering typical values of quantum dot devices and Coulomb blockade theory.

  16. On Irreversibility and Radiation in Classical Electrodynamics of Point Particles

    Science.gov (United States)

    Bauer, Gernot; Deckert, Dirk-André; Dürr, Detlef; Hinrichs, Günter

    2013-09-01

    The direct interaction theory of electromagnetism, also known as Wheeler-Feynman electrodynamics, is often misinterpreted and found unappealing because of its reference to the absorber and, more importantly, to the so-called absorber condition. Here we remark that the absorber condition is indeed questionable and presumably not relevant for the explanation of irreversible radiation phenomena in our universe. What is relevant and deserves further scrutiny is the emergent effective description of a source particle in an environment. We therefore rephrase what we consider the relevant calculation by Wheeler and Feynman and comment on the status of the theory.

  17. On Irreversibility and Radiation in Classical Electrodynamics of Point Particles

    CERN Document Server

    Bauer, G; Dürr, Detlef; Hinrichs, Günter

    2013-01-01

    The direct interaction theory of electromagnetism, also known as Wheeler-Feynman electrodynamics, is often misinterpreted and found unappealing because of its reference to the absorber and, more importantly, to the so-called absorber condition. Here we remark that the absorber condition is indeed questionable and presumably not relevant for the explanation of irreversible radiation phenomena in our universe. What is relevant and deserves further scrutiny is the emergent effective description of a test particle in an environment. We therefore rephrase what we consider the relevant calculation by Wheeler and Feynman and comment on the status of the theory.

  18. Synthetic Lorentz force in classical atomic gases via Doppler effect and radiation pressure

    CERN Document Server

    Dubček, T; Jukić, D; Aumiler, D; Ban, T; Buljan, H

    2014-01-01

    We theoretically predict a novel type of synthetic Lorentz force for classical (cold) atomic gases, which is based on the Doppler effect and radiation pressure. A fairly uniform and strong force can be constructed for gases in macroscopic volumes of several cubic millimeters and more. This opens the possibility to mimic classical charged gases in magnetic fields, such as those in a tokamak, in cold atom experiments.

  19. Hawking radiation and classical tunneling: A ray phase space approach

    Science.gov (United States)

    Tracy, E. R.; Zhigunov, D.

    2016-01-01

    Acoustic waves in fluids undergoing the transition from sub- to supersonic flow satisfy governing equations similar to those for light waves in the immediate vicinity of a black hole event horizon. This acoustic analogy has been used by Unruh and others as a conceptual model for "Hawking radiation." Here, we use variational methods, originally introduced by Brizard for the study of linearized MHD, and ray phase space methods, to analyze linearized acoustics in the presence of background flows. The variational formulation endows the evolution equations with natural Hermitian and symplectic structures that prove useful for later analysis. We derive a 2 × 2 normal form governing the wave evolution in the vicinity of the "event horizon." This shows that the acoustic model can be reduced locally (in ray phase space) to a standard (scalar) tunneling process weakly coupled to a unidirectional non-dispersive wave (the "incoming wave"). Given the normal form, the Hawking "thermal spectrum" can be derived by invoking standard tunneling theory, but only by ignoring the coupling to the incoming wave. Deriving the normal form requires a novel extension of the modular ray-based theory used previously to study tunneling and mode conversion in plasmas. We also discuss how ray phase space methods can be used to change representation, which brings the problem into a form where the wave functions are less singular than in the usual formulation, a fact that might prove useful in numerical studies.

  20. Radiation from relativistic electrons in "light" and in conventional undulators. Classical and quantum approaches

    Science.gov (United States)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.; Strokov, S. A.

    2016-07-01

    A photon spectrum of undulator radiation (UR) is calculated in the semi-classical approach. The UR intensity spectrum is determined by an electron trajectory in the undulator neglecting by energy losses for radiation. Using the Planck's law, the UR photon spectrum can be calculated from the classical intensity spectrum both for linear and nonlinear regimes. The radiation of an electron in a field of strong electromagnetic wave (radiation in the "light" undulator) is considered in the quantum electromagnetic frame. Comparison of results obtained by both approaches has been shown that UR spectra in the whole cone coincide with high accuracy for the case xbeam were simulated with taking into account the discrete process of photon emission along an electron trajectory in both kinds of undulators.

  1. Nuclear motion is classical

    CERN Document Server

    Frank, Irmgard

    2016-01-01

    The notion from ab-initio molecular dynamics simulations that nuclear motion is best described by classical Newton dynamics instead of the time-dependent Schr{\\"o}dinger equation is substantiated. In principle a single experiment should bring clarity. Caution is however necessary, as temperature dependent effects must be eliminated when trying to determine the existence of a zero-point energy.

  2. Classical and quantum cosmology with two perfect fluids: stiff matter and radiation

    CERN Document Server

    Alvarenga, F G; Freitas, R C; Gonçalves, S V B

    2016-01-01

    In this work the homogeneous and isotropic Universe of Friedmann-Robertson-Walker is studied in the presence of two fluids: stiff matter and radiation described by the Schutz's formalism. We obtain to the classic case the behaviour of the scale factor of the universe. For the quantum case the wave packets are constructed and the wave function of the universe is found.

  3. Electromagnetic Zero Point Field as Active Energy Source in the Intergalactic Medium

    CERN Document Server

    Rueda, A; Haisch, B; Rueda, Alfonso; Sunahata, Hiroki; Haisch, Bernhard

    1999-01-01

    For over twenty years the possibility that the electromagnetic zero point field (ZPF) may actively accelerate electromagnetically interacting particles in regions of extremely low particle density (as those extant in intergalactic space (IGS) with n < 1 particle/m^3 has been studied and analyzed. This energizing phenomenon has been one of the few contenders for acceleration of cosmic rays (CR), particularly at ultrahigh energies. The recent finding by the AGASA collaboration (Phys. Rev. Lett., 81, 1163, 1998) that the CR energy spectrum does not display any signs of the Greisen-Zatsepin-Kuzmin cut-off (that should be present if these CR particles were indeed generated in localized ultrahigh energies CR sources, as e.g., quasars and other highly active galactic nuclei), may indicate the need for an acceleration mechanism that is distributed throughout IGS as is the case with the ZPF. Other unexplained phenomena that receive an explanation from this mechanism are the generation of X-ray and gamma-ray backgro...

  4. Advances in the proposed electromagnetic zero-point field theory of inertia

    CERN Document Server

    Haisch, B; Puthoff, H E; Haisch, Bernhard; Rueda, Alfonso

    1998-01-01

    A NASA-funded research effort has been underway at the Lockheed Martin Advanced Technology Center in Palo Alto and at California State University in Long Beach to develop and test a recently published theory that Newton's equation of motion can be derived from Maxwell's equations of electrodynamics as applied to the zero-point field (ZPF) of the quantum vacuum. In this ZPF-inertia theory, mass is postulated to be not an intrinsic property of matter but rather a kind of electromagnetic drag force that proves to be acceleration dependent by virtue of the spectral characteristics of the ZPF. The theory proposes that interactions between the ZPF and matter take place at the level of quarks and electrons, hence would account for the mass of a composite neutral particle such as the neutron. An effort to generalize the exploratory study of Haisch, Rueda and Puthoff (1994) into a proper relativistic formulation has been successful. Moreover the principle of equivalence implies that in this view gravitation would also...

  5. Zero-point energy, tunneling, and vibrational adiabaticity in the Mu + H2 reaction

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, Steven L.; Garrett, Bruce C.; Fleming, Donald G.; Truhlar, Donald G.

    2015-01-09

    Abstract: Isotopic substitution of muonium for hydrogen provides an unparalleled opportunity to deepen our understanding of quantum mass effects on chemical reactions. A recent topical review [Aldegunde et al., Mol. Phys. 111, 3169 (2013)] of the thermal and vibrationally-stateselected reaction of Mu with H2 raises a number of issues that are addressed here. We show that some earlier quantum mechanical calculations of the Mu + H2 reaction, which are highlighted in this review and which have been used to benchmark approximate methods, are in error by as much as 19% in the low-temperature limit. We demonstrate that an approximate treatment of the Born–Oppenheimer diagonal correction that was used in some recent studies is not valid for treating the vibrationally-state-selected reaction. We also discuss why vibrationally adiabatic potentials that neglect bend zero-point energy are not a useful analytical tool for understanding reaction rates and why vibrationally nonadiabatic transitions cannot be understood by considering tunneling through vibrationally adiabatic potentials. Finally, we present calculations on a hierarchical family of potential energy surfaces to assess the sensitivity of rate constants to the quality of the potential surface.

  6. Novel aspects of radiation reaction in the classical and the quantum regime

    CERN Document Server

    Neitz, Norman; Mackenroth, Felix; Hatsagortsyan, Karen Z; Keitel, Christoph H; Di Piazza, Antonino

    2014-01-01

    This work is dedicated to the study of radiation reaction signatures in the framework of classical and quantum electrodynamics. Since there has been no distinct experimental validation of radiation reaction and its underlying equations so far and its impact is expected to be substantial for the construction of new experimental devices, e.g., quantum x-free electron lasers, a profound understanding of radiation reaction effects is of special interest. Here, we describe how the inclusion of quantum radiation reaction effects changes the dynamics of ultra-relativistic electron beams colliding with intense laser pulses significantly. Thereafter, the angular distribution of emitted radiation is demonstrated to be strongly altered in the quantum framework, if in addition to single photon emission also higher order photon emissions are considered. Furthermore, stimulated Raman scattering of an ultra-intense laser pulse in plasmas is examined and forward Raman scattering is found to be significantly increased by the ...

  7. Classical Radiation Reaction Off-Shell Corrections to the Covariant Lorentz Force

    OpenAIRE

    Oron, O.; Horwitz, L. P.

    2000-01-01

    It has been shown by Gupta and Padmanabhan that the radiation reaction force of the Abraham-Lorentz-Dirac equation can be obtained by a coordinate transformation from the inertial frame of an accelerating charged particle to that of the laboratory. We show that the problem may be formulated in a flat space of five dimensions, with five corresponding gauge fields in the framework of the classical version of a fully gauge covariant form of the Stueckelberg- Feynman-Schwinger covariant mechanics...

  8. On the relativistic classical motion of a radiating spinning particle in a magnetic field

    Science.gov (United States)

    Kar, Arnab; Rajeev, S. G.

    2011-04-01

    We propose classical equations of motion for a charged particle with magnetic moment, taking radiation reaction into account. This generalizes the Landau-Lifshitz equations for the spinless case. In the special case of spin-polarized motion in a constant magnetic field (synchrotron motion) we verify that the particle does lose energy. Previous proposals did not predict dissipation of energy and also suffered from runaway solutions analogous to those of the Lorentz-Dirac equations of motion.

  9. On The Relativistic Classical Motion of a Radiating Spinning Particle in a Magnetic Field

    CERN Document Server

    Kar, Arnab

    2010-01-01

    We propose classical equations of motion for a charged particle with magnetic moment, taking radiation reaction into account. This generalizes the Landau-Lifshitz equations for the spinless case. In the special case of spin-polarized motion in a constant magnetic field (synchrotron motion) we verify that the particle does lose energy. Previous proposals did not predict dissipation of energy and also suffered from runaway solutions analogous to those of the Lorentz-Dirac equations of motion.

  10. On the contribution of intramolecular zero point energy to the equation of state of solid H2

    Science.gov (United States)

    Chandrasekharan, V.; Etters, R. D.

    1978-01-01

    Experimental evidence shows that the internal zero-point energy of the H2 molecule exhibits a relatively strong pressure dependence in the solid as well as changing considerably upon condensation. It is shown that these effects contribute about 6% to the total sublimation energy and to the pressure in the solid state. Methods to modify the ab initio isolated pair potential to account for these environmental effects are discussed.

  11. Semiclassical wave packet treatment of scattering resonances: application to the delta zero-point energy effect in recombination reactions.

    Science.gov (United States)

    Vetoshkin, Evgeny; Babikov, Dmitri

    2007-09-28

    For the first time Feshbach-type resonances important in recombination reactions are characterized using the semiclassical wave packet method. This approximation allows us to determine the energies, lifetimes, and wave functions of the resonances and also to observe a very interesting correlation between them. Most important is that this approach permits description of a quantum delta-zero-point energy effect in recombination reactions and reproduces the anomalous rates of ozone formation.

  12. Iterative Schemes for Zero Points of Maximal Monotone Operators and Fixed Points of Nonexpansive Mappings and Their Applications

    Directory of Open Access Journals (Sweden)

    Yeol Je Cho

    2008-03-01

    Full Text Available Two iterative schemes for finding a common element of the set of zero points of maximal monotone operators and the set of fixed points of nonexpansive mappings in the sense of Lyapunov functional in a real uniformly smooth and uniformly convex Banach space are obtained. Two strong convergence theorems are obtained which extend some previous work. Moreover, the applications of the iterative schemes are demonstrated.

  13. Iterative Schemes for Zero Points of Maximal Monotone Operators and Fixed Points of Nonexpansive Mappings and Their Applications

    Directory of Open Access Journals (Sweden)

    Cho YeolJe

    2007-01-01

    Full Text Available Two iterative schemes for finding a common element of the set of zero points of maximal monotone operators and the set of fixed points of nonexpansive mappings in the sense of Lyapunov functional in a real uniformly smooth and uniformly convex Banach space are obtained. Two strong convergence theorems are obtained which extend some previous work. Moreover, the applications of the iterative schemes are demonstrated.

  14. A SIMPLICIAL ALGORITHM FOR COMPUTING AN INTEGER ZERO POINT OF A MAPPING WITH THE DIRECTION PRESERVING PROPERTY

    Institute of Scientific and Technical Information of China (English)

    Chuang-yin Dang

    2006-01-01

    A mapping f: Zn → Rn is said to possess the direction preserving property if fi (x) > 0 implies fi(y) ≥ 0 for any integer points x and y with ‖ix - y‖∞≤ 1. In this paper,a simplicial algorithm is developed for computing an integer zero point of a mapping with the direction preserving property. We assume that there is an integer point x0 with c ≤ x0 ≤ d satisfying that max1≤i≤n(xi - xi0)fi(x) > 0 for any integer point x with f(x) ≠ 0 on the boundary of H = {x ∈ Rn | c- e ≤ x ≤ d + e}, where c and d are two finite integer points with c ≤ d and e = (1, 1, ... , 1)T ∈ Rn. This assumption is implied by one of two conditions for the existence of an integer zero point of a mapping with the preserving property in van der Laan et al. (2004). Under this assumption, starting at x0,the algorithm follows a finite simplicial path and terminates at an integer zero point of the mapping. This result has applications in general economic equilibrium models with indivisible commodities.

  15. Dissociation energies of six NO2 isotopologues by laser induced fluorescence spectroscopy and zero point energy of some triatomic molecules.

    Science.gov (United States)

    Michalski, G; Jost, R; Sugny, D; Joyeux, M; Thiemens, M

    2004-10-15

    We have measured the rotationless photodissociation threshold of six isotopologues of NO2 containing 14N, 15N, 16O, and 18O isotopes using laser induced fluorescence detection and jet cooled NO2 (to avoid rotational congestion). For each isotopologue, the spectrum is very dense below the dissociation energy while fluorescence disappears abruptly above it. The six dissociation energies ranged from 25 128.56 cm(-1) for 14N16O2 to 25 171.80 cm(-1) for 15N18O2. The zero point energy for the NO2 isotopologues was determined from experimental vibrational energies, application of the Dunham expansion, and from canonical perturbation theory using several potential energy surfaces. Using the experimentally determined dissociation energies and the calculated zero point energies of the parent NO2 isotopologue and of the NO product(s) we determined that there is a common De = 26 051.17+/-0.70 cm(-1) using the Born-Oppenheimer approximation. The canonical perturbation theory was then used to calculate the zero point energy of all stable isotopologues of SO2, CO2, and O3, which are compared with previous determinations.

  16. Breakdown of the Migdal approximation at Lifshitz transitions with giant zero-point motion in the H3S superconductor.

    Science.gov (United States)

    Jarlborg, Thomas; Bianconi, Antonio

    2016-04-20

    While 203 K high temperature superconductivity in H3S has been interpreted by BCS theory in the dirty limit here we focus on the effects of hydrogen zero-point-motion and the multiband electronic structure relevant for multigap superconductivity near Lifshitz transitions. We describe how the topology of the Fermi surfaces evolves with pressure giving different Lifshitz-transitions. A neck-disrupting Lifshitz-transition (type 2) occurs where the van Hove singularity, vHs, crosses the chemical potential at 210 GPa and new small 2D Fermi surface portions appear with slow Fermi velocity where the Migdal-approximation becomes questionable. We show that the neglected hydrogen zero-point motion ZPM, plays a key role at Lifshitz transitions. It induces an energy shift of about 600 meV of the vHs. The other Lifshitz-transition (of type 1) for the appearing of a new Fermi surface occurs at 130 GPa where new Fermi surfaces appear at the Γ point of the Brillouin zone here the Migdal-approximation breaks down and the zero-point-motion induces large fluctuations. The maximum Tc = 203 K occurs at 160 GPa where EF/ω0 = 1 in the small Fermi surface pocket at Γ. A Feshbach-like resonance between a possible BEC-BCS condensate at Γ and the BCS condensate in different k-space spots is proposed.

  17. 场与约瑟夫森结耦合系统中的零点能和零点涨落%Zero-Point Energy and Fluctuation in a Field-Josephson Junction-Coupled System

    Institute of Scientific and Technical Information of China (English)

    邵彬; 邹健; 李前树

    2000-01-01

    To investigate the interaction of a mesoscopic Josephson junction with a single mode quantized electromagnetic field, the diagnonalizing process of the coupled system Hamiltonian was performed by using an unitary transformation. Zero-point energy and zero?-point fluctuation of the coupled system were shown. For the ground state of the coupled system, the quantum fluctuations of the flux and charge operators in the field and junction subsystems can exhibit smaller quantum noise than the zero-point fluctuations of the individual subsystems. Thus, when the coupled system is in its lowest-energy state, which means that no radiation appear, the two subsystems exhibit nonclassical behavior.%研究介观约瑟夫森结与量子化电磁场相互作用系统.用幺正变换技术对耦合系统的哈密顿实施对角化,得到耦合系统的零点能和零点涨落,显示了场与约瑟夫森结子系统磁通和电荷的基态量子涨落特点.当耦合系统处于其最低能态(无辐射状态),场结子系统能够显示非经典行为.

  18. Radiation reaction and renormalization in classical electrodynamics of a point particle in any dimension

    Science.gov (United States)

    Kazinski, P. O.; Lyakhovich, S. L.; Sharapov, A. A.

    2002-07-01

    The effective equations of motion for a point charged particle taking into account the radiation reaction are considered in various space-time dimensions. The divergences stemming from the pointness of the particle are studied and an effective renormalization procedure is proposed encompassing uniformly the cases of all even dimensions. It is shown that in any dimension the classical electrodynamics is a renormalizable theory if not multiplicatively beyond d=4. For the cases of three and six dimensions the covariant analogues of the Lorentz-Dirac equation are explicitly derived.

  19. Modelling radiation emission in the transition from the classical to the quantum regime

    CERN Document Server

    Martins, J L; Grismayer, T; Vieira, J; Fonseca, R A; Silva, L O

    2015-01-01

    An emissivity formula is derived using the generalised Fermi-Weizacker-Williams method of virtual photons which accounts for the recoil the charged particle experiences as it emits radiation. It is found that through this derivation the formula obtained by Sokolov et al using QED perturbation theory is recovered. The corrected emissivity formula is applied to nonlinear Thomson scattering scenarios in the transition from the classical to the quantum regime, for small values of the nonlinear quantum parameter \\chi. Good agreement is found between this method and a QED probabilistic approach for scenarios where both are valid. In addition, signatures of the quantum corrections are identified and explored.

  20. Radiation reaction and renormalization in classical electrodynamics of point particle in any dimension

    CERN Document Server

    Kazinski, P O; Sharapov, A A

    2002-01-01

    The effective equations of motion for a point charged particle taking account of radiation reaction are considered in various space-time dimensions. The divergencies steaming from the pointness of the particle are studied and the effective renormalization procedure is proposed encompassing uniformly the cases of all even dimensions. It is shown that in any dimension the classical electrodynamics is a renormalizable theory if not multiplicatively beyond d=4. For the cases of three and six dimensions the covariant analogs of the Lorentz-Dirac equation are explicitly derived.

  1. Suppression of Classical and Quantum Radiation Pressure Noise via Electro-Optic Feedback

    CERN Document Server

    Buchler, B C; Shaddock, D A; Ralph, T C; McClelland, D E; Buchler, Ben C.; Gray, Malcolm B.; Shaddock, Daniel A.; Ralph, Timothy C.; Clelland, David E. Mc

    1998-01-01

    We present theoretical results that demonstrate a new technique to be used to improve the sensitivity of thermal noise measurements: intra-cavity intensity stabilisation. It is demonstrated that electro-optic feedback can be used to reduce intra-cavity intensity fluctuations, and the consequent radiation pressure fluctuations, by a factor of two below the quantum noise limit. We show that this is achievable in the presence of large classical intensity fluctuations on the incident laser beam. The benefits of this scheme are a consequence of the sub-Poissonian intensity statistics of the field inside a feedback loop, and the quantum non-demolition nature of radiation pressure noise as a readout system for the intra-cavity intensity fluctuations.

  2. Reassessing the Ritz-Einstein debate on the radiation asymmetry in classical electrodynamics

    Science.gov (United States)

    Frisch, Mathias; Pietsch, Wolfgang

    2016-08-01

    We investigate the debate between Walter Ritz and Albert Einstein on the origin and nature of the radiation asymmetry. We argue that Ritz's views on the radiation asymmetry were far richer and nuanced than the oft-cited joint letter with Einstein (Ritz & Einstein, 1909) suggests, and that Einstein's views in 1909 on the asymmetry are far more ambiguous than is commonly recognized. Indeed, there is strong evidence that Einstein ultimately came to agree with Ritz that elementary radiation processes in classical electrodynamics are non-symmetric and fully retarded. (Sommerfeld, 1968, p. 290; italics in the original). That is, what Sommerfeld is looking for is a mathematical condition that can restrict the solution space of the equation to those solutions that are physically possible. Rather than taking the wave equation as delimiting the range of what is physically possible and then looking for an explanation of why a large class of physically possible solutions is not actualized, the problem for Sommerfeld seems to be with the mathematics: the wave equation has 'too many' solutions. The Sommerfeld radiation condition, according to this view, does not explain the asymmetry, but is merely the mathematical condition imposing a restriction on the electromagnetic field in large distances that enables us to exclude non-physical solutions of the wave equation and restrict the solutions to the physically plausible purely diverging waves.

  3. White-light interferometers with polarizing optics for length measurements with an applicable zero-point detection

    Science.gov (United States)

    Ullmann, V.; Emam, S.; Manske, E.

    2015-08-01

    For absolute length and form measurements at a large working distance (>150 mm) two special interferometers, a tandem interferometer and a Michelson interferometer with achromatic polarizing optics are constructed. In our experiments, both consist of a combination of one low-coherence interferometer and one laser interferometer. For the low-coherence interferometer part, a simple white-light source with less than 100 µW optical power output is chosen. It bases upon a low-cost fiber-coupled near-infrared LED with a large spectral width (FWHM > 68 nm at 825 nm). The use of achromatic polarizing optics such as broadband polarizing beamsplitters and achromatic quarter-wave plates in the low-coherence interferometer parts increases the contrast level of the white-light signal fringe pattern to nearly 100%. Furthermore, the fringe pattern in a polarized interferometer has no subsignatures and is unique. Hence, different algorithms are tested for signal processing and automated zero-point detection of the white-light signature. The software for an automated measurement is tested in a standard room without thermal control and without damped oscillation. Therefore, in experiments with the tandem interferometer, it was possible to measure the zero-point position of a white-light signature with a peak-to-peak difference of 154 nm under uncontrolled environmental conditions without thermal stabilization. The white-light Michelson interferometer with polarizing achromatic optics allows zero-point detections with a standard deviation (mean value) of less than 15 nm. The drift is proved through measurement results.

  4. Solvent effects on zero-point vibrational corrections to optical rotations and nuclear magnetic resonance shielding constants

    Science.gov (United States)

    Kongsted, Jacob; Ruud, Kenneth

    2008-01-01

    We present a study of solvent effects on the zero-point vibrational corrections (ZPVC) to optical rotations and nuclear magnetic resonance shielding constants of solvated molecules. The model used to calculate vibrational corrections rely on an expansion of the potential and property surfaces around an effective molecular geometry and includes both harmonic and anharmonic corrections. Numerical examples are presented for ( S)-propylene oxide in various solvents as well as for acetone and the three diazene molecules. We find that solvent effects on the ZPVCs may be significant and in some cases crucial to accurately predict solvent shifts on molecular properties.

  5. Active tuning of epsilon-near-zero point of hyperbolic metamaterial at visible and near-infrared regimes

    Science.gov (United States)

    Wang, Hao; Zhao, Hua; Su, Hang; Hu, Guangwei; Zhang, Jingwen

    2016-09-01

    An active method of continuously tuning the effective permittivity of a hyperbolic metamaterial at visible and near-infrared spectra is introduced in this letter. A transparent conducting oxide, whose optical properties can be altered accurately by applying an external voltage, is inserted into a traditional metal-dielectric multilayer structure to increase the degree of freedom for tuning the epsilon-near-zero point by shifting the topological transition point. The tuning effect is explained in detail by combining the relationship between permittivity and voltage with wavevector analysis. This may promote other active applications of hyperbolic metamaterials and ultrafast tunable optoelectronic devices.

  6. Trajectory dynamics study of the Ar + CH4 dissociation reaction at high temperatures: the importance of zero-point-energy effects.

    Science.gov (United States)

    Marques, J M C; Martínez-Núñez, E; Fernandez-Ramos, A; Vazquez, S A

    2005-06-23

    Large-scale classical trajectory calculations have been performed to study the reaction Ar + CH4--> CH3 +H + Ar in the temperature range 2500 energy surface used for ArCH4 is the sum of the nonbonding pairwise potentials of Hase and collaborators (J. Chem. Phys. 2001, 114, 535) that models the intermolecular interaction and the CH4 intramolecular potential of Duchovic et al. (J. Phys. Chem. 1984, 88, 1339), which has been modified to account for the H-H repulsion at small bending angles. The thermal rate coefficient has been calculated, and the zero-point energy (ZPE) of the CH3 product molecule has been taken into account in the analysis of the results; also, two approaches have been applied for discarding predissociative trajectories. In both cases, good agreement is observed between the experimental and trajectory results after imposing the ZPE of CH3. The energy-transfer parameters have also been obtained from trajectory calculations and compared with available values estimated from experiment using the master equation formalism; in general, the agreement is good.

  7. Nonradiating normal modes in a classical many-body model of matter-radiation interaction

    Science.gov (United States)

    Carati, A.; Galgani, L.

    2003-08-01

    We consider a classical model of matter-radiation interaction, in which the matter is represented by a system of infinitely many dipoles on a one-dimensional lattice, and the system is dealt with in the so-called dipole ( linearized) approximation. We prove that there exist normal-mode solutions of the complete system, so that in particular the dipoles, though performing accelerated motions, do not radiate energy. This comes about in virtue of an exact compensation which we prove to occur, for each dipole, between the “radiation reaction force” and a part of the retarded forces due to all the other dipoles. This fact corresponds to a certain identity which we name after Oseen, since it occurs that this researcher did actually propose it, already in the year 1916. We finally make a connection with a paper of Wheeler and Feynman on the foundations of electrodynamics. It turns out indeed that the Oseen identity, which we prove here in a particular model, is in fact a weak form of a general identity that such authors were assuming as an independent postulate.

  8. Quasars can be used to verify the parallax zero-point of the Tycho-Gaia Astrometric Solution

    CERN Document Server

    Michalik, Daniel

    2016-01-01

    Context. The Gaia project will determine positions, proper motions, and parallaxes for more than one billion stars in our Galaxy. It is known that Gaia's two telescopes are affected by a small but significant variation of the basic angle between them. Unless this variation is taken into account during data processing, e.g. using on-board metrology, it causes systematic errors in the astrometric parameters, in particular a shift of the parallax zero-point. Previously, we suggested an early reduction of Gaia data for the subset of Tycho-2 stars (Tycho-Gaia Astrometric Solution; TGAS). Aims. We aim to investigate whether quasars can be used to independently verify the parallax zero-point already in early data reductions. This is not trivially possible as the observation interval is too short to disentangle parallax and proper motion for the quasar subset. Methods. We repeat TGAS simulations but additionally include simulated Gaia observations of quasars from ground-based surveys. All observations are simulated w...

  9. Isotope effects on nuclear magnetic shieldings calculated by including zero-point vibration corrections: the VMF approach

    Energy Technology Data Exchange (ETDEWEB)

    Dransfeld, Alk

    2004-03-08

    As a minimal dynamic correction the 'zero-point vibration', ZPV, was included in the ab initio calculation of the isotropic magnetic shielding of {sup 13}C, {sup 19}F, {sup 29}Si, {sup 31}P, and {sup 35}Cl in some molecules including the references of NMR spectroscopy (f.i. CFCl{sub 3}, CH{sub 3}-NO{sub 2}, and TMS). In contrast to most previous works the ZPV correction is not based on gradients of internal coordinates, but uses derivatives obtained by 'vibration mode following' (VMF, the coordinates of the gradients describing the magnetic shielding hypersurface are the normal coordinates of the ground state vibration motion). The vibrational corrections obtained at the applied DFT level of theory are slightly smaller than those reported for MP2 calculations. Isotope effects computed with the ZPV/VMF correction are in reasonable agreement with experimental data. Contributions from individual vibration modes to the zero-point correction show that rotational motions have a large effect.

  10. Bound state potential energy surface construction: ab initio zero-point energies and vibrationally averaged rotational constants.

    Science.gov (United States)

    Bettens, Ryan P A

    2003-01-15

    Collins' method of interpolating a potential energy surface (PES) from quantum chemical calculations for reactive systems (Jordan, M. J. T.; Thompson, K. C.; Collins, M. A. J. Chem. Phys. 1995, 102, 5647. Thompson, K. C.; Jordan, M. J. T.; Collins, M. A. J. Chem. Phys. 1998, 108, 8302. Bettens, R. P. A.; Collins, M. A. J. Chem. Phys. 1999, 111, 816) has been applied to a bound state problem. The interpolation method has been combined for the first time with quantum diffusion Monte Carlo calculations to obtain an accurate ground state zero-point energy, the vibrationally average rotational constants, and the vibrationally averaged internal coordinates. In particular, the system studied was fluoromethane using a composite method approximating the QCISD(T)/6-311++G(2df,2p) level of theory. The approach adopted in this work (a) is fully automated, (b) is fully ab initio, (c) includes all nine nuclear degrees of freedom, (d) requires no assumption of the functional form of the PES, (e) possesses the full symmetry of the system, (f) does not involve fitting any parameters of any kind, and (g) is generally applicable to any system amenable to quantum chemical calculations and Collins' interpolation method. The calculated zero-point energy agrees to within 0.2% of its current best estimate. A0 and B0 are within 0.9 and 0.3%, respectively, of experiment.

  11. Thermodynamic Stability of Ice II and Its Hydrogen-Disordered Counterpart: Role of Zero-Point Energy.

    Science.gov (United States)

    Nakamura, Tatsuya; Matsumoto, Masakazu; Yagasaki, Takuma; Tanaka, Hideki

    2016-03-03

    We investigate why no hydrogen-disordered form of ice II has been found in nature despite the fact that most of hydrogen-ordered ices have hydrogen-disordered counterparts. The thermodynamic stability of a set of hydrogen-ordered ice II variants relative to ice II is evaluated theoretically. It is found that ice II is more stable than the disordered variants so generated as to satisfy the simple ice rule due to the lower zero-point energy as well as the pair interaction energy. The residual entropy of the disordered ice II phase gradually compensates the unfavorable free energy with increasing temperature. The crossover, however, occurs at a high temperature well above the melting point of ice III. Consequently, the hydrogen-disordered phase does not exist in nature. The thermodynamic stability of partially hydrogen-disordered ices is also scrutinized by examining the free-energy components of several variants obtained by systematic inversion of OH directions in ice II. The potential energy of one variant is lower than that of the ice II structure, but its Gibbs free energy is slightly higher than that of ice II due to the zero-point energy. The slight difference in the thermodynamic stability leaves the possibility of the partial hydrogen-disorder in real ice II.

  12. Classically conformal radiative neutrino model with gauged B−L symmetry

    Directory of Open Access Journals (Sweden)

    Hiroshi Okada

    2016-09-01

    Full Text Available We propose a classically conformal model in a minimal radiative seesaw, in which we employ a gauged B−L symmetry in the standard model that is essential in order to work the Coleman–Weinberg mechanism well that induces the B−L symmetry breaking. As a result, nonzero Majorana mass term and electroweak symmetry breaking simultaneously occur. In this framework, we show a benchmark point to satisfy several theoretical and experimental constraints. Here theoretical constraints represent inert conditions and Coleman–Weinberg condition. Experimental bounds come from lepton flavor violations (especially μ→eγ, the current bound on the Z′ mass at the CERN Large Hadron Collider, and neutrino oscillations.

  13. Radiation reaction on charged particles in three-dimensional motion in classical and quantum electrodynamics

    Science.gov (United States)

    Higuchi, Atsushi; Martin, Giles D. R.

    2006-01-01

    We extend our previous work [A. Higuchi and G. D. R. Martin, Found. Phys. 35, 1149 (2005)FNDPA40015-901810.1007/s10701-005-6405-0], which compared the predictions of quantum electrodynamics concerning radiation reaction with those of the Abraham-Lorentz-Dirac theory for a charged particle in linear motion. Specifically, we calculate the predictions for the change in position of a charged-scalar particle, moving in three-dimensional space, due to the effect of radiation reaction in the one-photon-emission process in quantum electrodynamics. The scalar particle is assumed to be accelerated for a finite period of time by a three-dimensional electromagnetic potential dependent only on one of the spacetime coordinates. We perform this calculation in the ℏ→0 limit and show that the change in position agrees with that obtained in classical electrodynamics with the Lorentz-Dirac force treated as a perturbation. We also show for a time-dependent but space-independent electromagnetic potential that the forward-scattering amplitude at order e2 does not contribute to the position change in the ℏ→0 limit after the mass renormalization is taken into account.

  14. Geometric constraints in semiclassical initial value representation calculations in Cartesian coordinates: accurate reduction in zero-point energy.

    Science.gov (United States)

    Issack, Bilkiss B; Roy, Pierre-Nicholas

    2005-08-22

    An approach for the inclusion of geometric constraints in semiclassical initial value representation calculations is introduced. An important aspect of the approach is that Cartesian coordinates are used throughout. We devised an algorithm for the constrained sampling of initial conditions through the use of multivariate Gaussian distribution based on a projected Hessian. We also propose an approach for the constrained evaluation of the so-called Herman-Kluk prefactor in its exact log-derivative form. Sample calculations are performed for free and constrained rare-gas trimers. The results show that the proposed approach provides an accurate evaluation of the reduction in zero-point energy. Exact basis set calculations are used to assess the accuracy of the semiclassical results. Since Cartesian coordinates are used, the approach is general and applicable to a variety of molecular and atomic systems.

  15. Zero-Point Energy and Modified Freidmann Equation%零点能与修正的Friedmann方程

    Institute of Scientific and Technical Information of China (English)

    程龙

    2011-01-01

    将引力理论视为宏观衍生理论,根据固体物理中的Debye模型,引入零点能修正能量均分定理。进而利用Verlinde熵力的方法去得到修正的Friedmann方程,并将修正项解释为与时间相关的真空能量密度。%Regarding gravity as an emergent phenomenon,we modify the equipartition energy theorem based on zero-point energy in Debye model of solid physcis. Then the modified Friedmann equation can be obtained with the use of Verlinde's scenario and the correction is interpreted as the time-dependent vacuum energy density.

  16. Cosmological consequences of classical flavor-space locked gauge field radiation

    Science.gov (United States)

    Bielefeld, Jannis; Caldwell, Robert R.

    2015-06-01

    We propose a classical SU(2) gauge field in a flavor-space locked configuration as a species of radiation in the early Universe and show that it would have a significant imprint on a primordial stochastic gravitational wave spectrum. In the flavor-space locked configuration, the electric and magnetic fields of each flavor are parallel and mutually orthogonal to other flavors, with isotropic and homogeneous stress energy. Due to the non-Abelian coupling, the gauge field breaks the symmetry between left- and right-circularly polarized gravitational waves. This broken chiral symmetry results in a unique signal: nonzero cross-correlation of the cosmic microwave background temperature and polarization, T B and E B , both of which should be zero in the standard, chiral symmetric case. We forecast the ability of current and future cosmic microwave background experiments to constrain this model. Furthermore, a wide range of behavior is shown to emerge, depending on the gauge field coupling, abundance, and allocation into electric and magnetic field energy density. The fluctuation power of primordial gravitational waves oscillates back and forth into fluctuations of the gauge field. In certain cases, the gravitational wave spectrum is shown to be suppressed or amplified by up to an order of magnitude depending on the initial conditions of the gauge field.

  17. Induced fractional zero-point angular momentum for charged particles of the Bohm-Aharonov system by means of a 'spectator' magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jianzu [Institute for Theoretical Physics, East China University of Science and Technology, Box 316, Shanghai 200237 (China)], E-mail: jzzhang@ecust.edu.cn

    2008-12-18

    An induced fractional zero-point angular momentum of charged particles by the Bohm-Aharonov (BA) vector potential is realized via a modified combined trap. It explores a 'spectator' mechanism in this type of quantum effects: In the limit of the kinetic energy approaching one of its eigenvalues the BA vector potential alone cannot induce a fractional zero-point angular momentum at quantum mechanical level in the BA magnetic field-free region; But when there is a 'spectator' magnetic field the BA vector potential induces a fractional zero-point angular momentum. The 'spectator' does not contribute to such a fractional angular momentum, but plays essential role in guaranteeing non-trivial dynamics at quantum mechanical level in the required limit. This 'spectator' mechanism is significant in investigating the BA effects and related topics in both aspects of theory and experiment.

  18. Method and basis set dependence of anharmonic ground state nuclear wave functions and zero-point energies: application to SSSH.

    Science.gov (United States)

    Kolmann, Stephen J; Jordan, Meredith J T

    2010-02-07

    One of the largest remaining errors in thermochemical calculations is the determination of the zero-point energy (ZPE). The fully coupled, anharmonic ZPE and ground state nuclear wave function of the SSSH radical are calculated using quantum diffusion Monte Carlo on interpolated potential energy surfaces (PESs) constructed using a variety of method and basis set combinations. The ZPE of SSSH, which is approximately 29 kJ mol(-1) at the CCSD(T)/6-31G* level of theory, has a 4 kJ mol(-1) dependence on the treatment of electron correlation. The anharmonic ZPEs are consistently 0.3 kJ mol(-1) lower in energy than the harmonic ZPEs calculated at the Hartree-Fock and MP2 levels of theory, and 0.7 kJ mol(-1) lower in energy at the CCSD(T)/6-31G* level of theory. Ideally, for sub-kJ mol(-1) thermochemical accuracy, ZPEs should be calculated using correlated methods with as big a basis set as practicable. The ground state nuclear wave function of SSSH also has significant method and basis set dependence. The analysis of the nuclear wave function indicates that SSSH is localized to a single symmetry equivalent global minimum, despite having sufficient ZPE to be delocalized over both minima. As part of this work, modifications to the interpolated PES construction scheme of Collins and co-workers are presented.

  19. The ground state tunneling splitting and the zero point energy of malonaldehyde: a quantum Monte Carlo determination.

    Science.gov (United States)

    Viel, Alexandra; Coutinho-Neto, Maurício D; Manthe, Uwe

    2007-01-14

    Quantum dynamics calculations of the ground state tunneling splitting and of the zero point energy of malonaldehyde on the full dimensional potential energy surface proposed by Yagi et al. [J. Chem. Phys. 1154, 10647 (2001)] are reported. The exact diffusion Monte Carlo and the projection operator imaginary time spectral evolution methods are used to compute accurate benchmark results for this 21-dimensional ab initio potential energy surface. A tunneling splitting of 25.7+/-0.3 cm-1 is obtained, and the vibrational ground state energy is found to be 15 122+/-4 cm-1. Isotopic substitution of the tunneling hydrogen modifies the tunneling splitting down to 3.21+/-0.09 cm-1 and the vibrational ground state energy to 14 385+/-2 cm-1. The computed tunneling splittings are slightly higher than the experimental values as expected from the potential energy surface which slightly underestimates the barrier height, and they are slightly lower than the results from the instanton theory obtained using the same potential energy surface.

  20. A Genuine Jahn-Teller System with Compressed Geometry and Quantum Effects Originating from Zero-Point Motion.

    Science.gov (United States)

    Aramburu, José Antonio; García-Fernández, Pablo; García-Lastra, Juan María; Moreno, Miguel

    2016-07-18

    First-principle calculations together with analysis of the experimental data found for 3d(9) and 3d(7) ions in cubic oxides proved that the center found in irradiated CaO:Ni(2+) corresponds to Ni(+) under a static Jahn-Teller effect displaying a compressed equilibrium geometry. It was also shown that the anomalous positive g∥ shift (g∥ -g0 =0.065) measured at T=20 K obeys the superposition of the |3 z(2) -r(2) ⟩ and |x(2) -y(2) ⟩ states driven by quantum effects associated with the zero-point motion, a mechanism first put forward by O'Brien for static Jahn-Teller systems and later extended by Ham to the dynamic Jahn-Teller case. To our knowledge, this is the first genuine Jahn-Teller system (i.e. in which exact degeneracy exists at the high-symmetry configuration) exhibiting a compressed equilibrium geometry for which large quantum effects allow experimental observation of the effect predicted by O'Brien. Analysis of the calculated energy barriers for different Jahn-Teller systems allowed us to explain the origin of the compressed geometry observed for CaO:Ni(+) .

  1. Hubbard model for ultracold bosonic atoms interacting via zero-point-energy-induced three-body interactions

    Science.gov (United States)

    Paul, Saurabh; Johnson, P. R.; Tiesinga, Eite

    2016-04-01

    We show that, for ultracold neutral bosonic atoms held in a three-dimensional periodic potential or optical lattice, a Hubbard model with dominant, attractive three-body interactions can be generated. In fact, we derive that the effect of pairwise interactions can be made small or zero starting from the realization that collisions occur at the zero-point energy of an optical lattice site and the strength of the interactions is energy dependent from effective-range contributions. We determine the strength of the two- and three-body interactions for scattering from van der Waals potentials and near Fano-Feshbach resonances. For van der Waals potentials, which for example describe scattering of alkaline-earth atoms, we find that the pairwise interaction can only be turned off for species with a small negative scattering length, leaving the 88Sr isotope a possible candidate. Interestingly, for collisional magnetic Feshbach resonances this restriction does not apply and there often exist magnetic fields where the two-body interaction is small. We illustrate this result for several known narrow resonances between alkali-metal atoms as well as chromium atoms. Finally, we compare the size of the three-body interaction with hopping rates and describe limits due to three-body recombination.

  2. The Effect of de-Sitter Like Background on Increasing the Zero Point Budget of Dark Energy

    Directory of Open Access Journals (Sweden)

    Haidar Sheikhahmadi

    2016-01-01

    Full Text Available During this work, using subtraction renormalization mechanism, zero point quantum fluctuations for bosonic scalar fields in a de-Sitter like background are investigated. By virtue of the observed value for spectral index, ns(k, for massive scalar field the best value for the first slow roll parameter, ϵ, is achieved. In addition, the energy density of vacuum quantum fluctuations for massless scalar field is obtained. The effects of these fluctuations on other components of the universe are studied. By solving the conservation equation, for some different examples, the energy density for different components of the universe is obtained. In the case which all components of the universe are in an interaction, the different dissipation functions, Q~i, are considered. The time evolution of ρDE(z/ρcri(z shows that Q~=3γH(tρm has the best agreement in comparison to observational data including CMB, BAO, and SNeIa data set.

  3. Dynamical and anharmonic effects on the electron-phonon coupling and the zero-point renormalization of the band structure

    Science.gov (United States)

    Antonius, Gabriel; Poncé, Samuel; Lantagne-Hurtubise, Étienne; Auclair, Gabriel; Côté, Michel; Gonze, Xavier

    2015-03-01

    The electron-phonon coupling in solids renormalizes the band structure, reducing the band gap by several tenths of an eV in light-atoms semiconductors. Using the Allen-Heine-Cardona theory (AHC), we compute the zero-point renormalization (ZPR) as well as the quasiparticle lifetimes of the full band structure in diamond, BN, LiF and MgO. We show how dynamical effects can be included in the AHC theory, and still allow for the use of a Sternheimer equation to avoid the summation over unoccupied bands. The convergence properties of the electron-phonon coupling self-energy with respect to the Brillouin zone sampling prove to be strongly affected by dynamical effects. We complement our study with a frozen-phonon approach, which reproduces the static AHC theory, but also allows to probe the phonon wavefunctions at finite displacements and include anharmonic effects in the self-energy. We show that these high-order components tend to reduce the strongest electron-phonon coupling elements, which affects significantly the band gap ZPR.

  4. Radiation reaction effects in cascade scattering of intense, tightly focused laser pulses by relativistic electrons: Classical approach

    Science.gov (United States)

    Zhidkov, A.; Masuda, S.; Bulanov, S. S.; Koga, J.; Hosokai, T.; Kodama, R.

    2014-05-01

    Nonlinear cascade scattering of intense, tightly focused laser pulses by relativistic electrons is studied numerically in the classical approximation including radiation damping for the quantum parameter ⟨ℏωxray⟩/ɛ <1 and an arbitrary radiation parameter χ. The electron's energy loss, along with its being scattered to the side by the ponderomotive force, makes scattering in the vicinity of a high laser field nearly impossible at high electron energies. The use of a second, copropagating laser pulse as a booster is shown to partially solve this problem.

  5. 关于增生算子零点的修正Mann迭代的注%A Note on Modified Mann Iterations for Zero Points of Accretive Operators

    Institute of Scientific and Technical Information of China (English)

    魏利; 周海云

    2009-01-01

    A more general form of modified Mann iterations which converges strongly to a zero point of an m-accretive operator is given.The work in this paper is an extension and complement of the corresponding result of Kim T.H.and Xu H.K in 2005

  6. 关于真空能物理实质的讨论%On the Physical Mechanism of Zero Point Energy

    Institute of Scientific and Technical Information of China (English)

    高歌

    2013-01-01

      真空能的物理本质就是信息态能量,这是在宇宙中普遍存在的本源能量。真空能的提取有两种基本方式:一是利用暗能量粒子的高速旋转,直接把虚空间的真空能抽取过来变为物质能流;一是对电磁物质所含的单奇子进行电磁压缩,使实态单奇子的时间缩短、虚态时间延长而释放真空能。%  The physical mechanism of zero point energy is proposed as it equals the original energy of the universe, i.e. the imaginary energy in the information space. The basic methods for obtaining zero point energy may be classified to two major measures. Firstly, one may utilize high-rotating dark energy particle directly to draw zero point energy from the imaginary information space. Secondly, one may apply electro-magnetic pressure onto singularitons , shortening the period of singulariton's solid state and prolonging the imaginary state period, to obtain zero point energy. Above methods perform the foundation of all over-unit energy devices.

  7. Communication: A new ab initio potential energy surface for HCl-H2O, diffusion Monte Carlo calculations of D0 and a delocalized zero-point wavefunction.

    Science.gov (United States)

    Mancini, John S; Bowman, Joel M

    2013-03-28

    We report a global, full-dimensional, ab initio potential energy surface describing the HCl-H2O dimer. The potential is constructed from a permutationally invariant fit, using Morse-like variables, to over 44,000 CCSD(T)-F12b∕aug-cc-pVTZ energies. The surface describes the complex and dissociated monomers with a total RMS fitting error of 24 cm(-1). The normal modes of the minima, low-energy saddle point and separated monomers, the double minimum isomerization pathway and electronic dissociation energy are accurately described by the surface. Rigorous quantum mechanical diffusion Monte Carlo (DMC) calculations are performed to determine the zero-point energy and wavefunction of the complex and the separated fragments. The calculated zero-point energies together with a De value calculated from CCSD(T) with a complete basis set extrapolation gives a D0 value of 1348 ± 3 cm(-1), in good agreement with the recent experimentally reported value of 1334 ± 10 cm(-1) [B. E. Casterline, A. K. Mollner, L. C. Ch'ng, and H. Reisler, J. Phys. Chem. A 114, 9774 (2010)]. Examination of the DMC wavefunction allows for confident characterization of the zero-point geometry to be dominant at the C(2v) double-well saddle point and not the C(s) global minimum. Additional support for the delocalized zero-point geometry is given by numerical solutions to the 1D Schrödinger equation along the imaginary-frequency out-of-plane bending mode, where the zero-point energy is calculated to be 52 cm(-1) above the isomerization barrier. The D0 of the fully deuterated isotopologue is calculated to be 1476 ± 3 cm(-1), which we hope will stand as a benchmark for future experimental work.

  8. 位场垂向导数零值位置空间变化规律研究%Spatial variation law of vertical derivative zero points for potential field data

    Institute of Scientific and Technical Information of China (English)

    王万银; 张功成; 梁建设

    2010-01-01

    In this paper we deduce the analytic solutions of the first-and second-order vertical derivative zero points for gravity anomalies in simple regular models with single,double,and multiple edges and analyze their spatial variation.For another simple regular models where it is difficult to obtain the analytic expression of the zero point,we try to use the profile zero points to analyze the spatial variation.The test results show that the spatial variation laws of both first-and second-order vertical derivative zero points are almost the same but the second-order derivative zero point position is closer to the top surface edge of the geological bodies than the first-order vertical derivative and has a relatively high resolution.Moreover,with an increase in buried depth,for a single boundary model,the vertical derivative zero point location tends to move from the top surface edge to the outside of the buried body but finally converges to a fixed value.For a double boundary model,the vertical derivative zero point location tends to migrate from the top surface edge to the outside of the buried body.For multiple boundary models,the vertical derivative zero point location converges from the top surface edge to the outside of the buried body where some zero points coincide and finally vanish.Finally,the effectiveness and reliability of the proposed method is verified using real field data.

  9. The exact radiation-reaction equation for a classical charged particle

    CERN Document Server

    Tessarotto, M; Cremaschini, C; Nicolini, P; Beklemishev, A

    2008-01-01

    An unsolved problem of classical mechanics and classical electrodynamics is the search of the exact relativistic equations of motion for a classical charged point-particle subject to the force produced by the action of its EM self-field. The problem is related to the conjecture that for a classical charged point-particle there should exist a relativistic equation of motion (RR equation) which results both non-perturbative, in the sense that it does not rely on a perturbative expansion on the electromagnetic field generated by the charged particle and non-asymptotic, i.e., it does not depend on any infinitesimal parameter. In this paper we intend to propose a novel solution to this well known problem, and in particular to point out that the RR equation is necessarily variational. The approach is based on two key elements: 1) the adoption of the relativistic hybrid synchronous Hamilton variational principle recently pointed out (Tessarotto et al, 2006). Its basic feature is that it can be expressed in principle...

  10. Classical electrodynamics with vacuum polarization: electron self-energy and radiation reaction

    Science.gov (United States)

    Blinder, S. M.

    2001-04-01

    The region very close to an electron ( r ⪅ r0 = e2/ mc2 ≈ 2.8 × 10 -13 cm) is, according to quantum electrodynamics, a seething maelstrom of virtual electron-positron pairs flashing in and out of existence. To take account of this well-established physical reality, a phenomenological representation for vacuum polarization is introduced into the framework of classical electrodynamics. Such a model enables a consistent picture of classical point charges with finite electromagnetic self-energy. It is further conjectured that the reaction of a point charge to its own electromagnetic field is tantamount to interaction with its vacuum polarization charge or "aura." This leads to a modification of the Lorentz-Dirac equation for the force on an accelerating electron, a new differential-difference equation which avoids the pathologies of preacceleration and runaway solutions.

  11. Hydrodynamic modelling of accretion impacts in classical T Tauri stars: radiative heating of the pre-shock plasma

    Science.gov (United States)

    Costa, G.; Orlando, S.; Peres, G.; Argiroffi, C.; Bonito, R.

    2017-01-01

    Context. It is generally accepted that, in classical T Tauri stars, the plasma from the circumstellar disc accretes onto the stellar surface with free-fall velocity and the impact generates a shock. The impact region is expected to contribute to emission in different spectral bands; many studies have confirmed that the X-rays arise from the post-shock plasma but, otherwise, there are no studies in the literature investigating the origin of the observed UV emission which is apparently correlated to accretion. Aims: We investigated the effect of radiative heating of the infalling material by the post-shock plasma at the base of the accretion stream, with the aim to identify in which region a significant part of the UV emission originates. Methods: We developed a one-dimensional hydrodynamic model describing the impact of an accretion stream onto the stellar surface; the model takes into account the gravity, the radiative cooling of an optically thin plasma, the thermal conduction, and the heating due to absorption of X-ray radiation. The latter term represents the heating of the infalling plasma due to the absorption of X-rays emitted from the post-shock region. Results: We found that the radiative heating of the pre-shock plasma plays a non-negligible role in the accretion phenomenon. In particular, the dense and cold plasma of the pre-shock accretion column is gradually heated up to a few 105K due to irradiation of X-rays arising from the shocked plasma at the impact region. This heating mechanism does not affect significantly the dynamics of the post-shock plasma. On the other hand, a region of radiatively heated gas (that we consider a precursor) forms in the unshocked accretion column and contributes significantly to UV emission. Our model naturally reproduces the luminosity of UV emission lines correlated to accretion and shows that most of the UV emission originates from the precursor.

  12. Point-source idealization in classical field theories. II. Mechanical energy losses from electromagnetic radiation reaction

    Science.gov (United States)

    Kates, Ronald E.; Rosenblum, Arnold

    1982-05-01

    This paper compares the mechanical energy losses due to electromagnetic radiation reaction on a two-particle, slow-motion system, as calculated from (1) the method of matched asymptotic expansions and (2) the Lorentz-Dirac equation, which assumes point sources. The matching derivation of the preceding paper avoided the assumption of a δ-function source by using Reissner-Nordström matching zones. Despite the differing mathematical assumptions of the two methods, their results are in agreement with each other and with the electromagnetic-field energy losses calculated by the evaluation of flux integrals. Our purpose is eventually to analyze Rosenblum's use of point sources as a possible cause of disagreement between the analogous calculations of gravitational radiation on a slow-motion system of two bodies. We begin with the simpler electromagnetic problem.

  13. An exactly solvable two-body problem with retarded interactions and radiation reaction in classical electrodynamics

    Science.gov (United States)

    Rivera, R.; Villarroel, D.

    1997-11-01

    An exactly solvable two-body problem dealing with the Lorentz-Dirac equation is constructed in this paper. It corresponds to the motion of two identical charges rotating at opposite ends of a diameter, in a fixed circle, at constant angular velocity. The external electromagnetic field that allows this motion consists of a tangential time-independent electric field with a fixed value over the orbit circle, and a homogeneous time-independent magnetic field that points orthogonally to the orbit plane. Because of the geometrical symmetries of the charges' motion, in this case it is possible to obtain the rate of radiation emitted by the charges directly from the equation of motion. The rate of radiation is also calculated by studying the energy flux across a sphere of a very large radius, using the far retarded fields of the charges. Both calculations lead to the same result, in agreement with energy conservation.

  14. A family of solutions with radiation reaction and retarded interactions for two charges in classical electrodynamics

    Science.gov (United States)

    Rivera, R.; Villarroel, D.

    2002-10-01

    A family of solutions of the Lorentz-Dirac equation is constructed. It consists in the motion of two charges e1 and e2 of masses m1 and m2 in two coplanar and concentric circles of radii a and b. The charges rotate with constant angular velocity, and have an angular separation ψ. The radiation reaction forces and the retarded interactions between the charges are taken into account. The external electromagnetic field that allows the motion consists of a tangential time-independent electric field that takes a fixed value on each orbit, and a homogeneous time-independent magnetic field perpendicular to the plane of the motion. For all the solutions energy conservation is rigorously demonstrated by evaluating the energy radiated, with independence of the equation of motion, through the calculation of the instantaneous energy flux across a sphere of an infinitely large radius.

  15. Approach to the classical radiation biology. Ionizing radiation effects and repair mechanism of DNA double strand breaks

    Energy Technology Data Exchange (ETDEWEB)

    Utsumi, Hiroshi [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst

    2000-09-01

    Split-dose recovery has been observed under a variety of experimental conditions in many cell systems and believed to be the recovery of sublethal damage (SLD). It is considered to be one of the most widespread and important cellular responses in clinical radiotherapy. To study the molecular mechanism of this recovery, we analyzed the knockout mutants KU70{sup -/-}, RAD54{sup -/-}, and KU70{sup -/-}/ RAD54{sup -/-} of the chicken B-cell line, DT40. Rad54 participates in the homologous recombinational (HR) repair of DNA double-strand breaks (DSB), while Ku proteins are involved in non-homologous end-joining (NHEJ). Split-dose recovery was observed in the parent DT40 and KU70{sup -/-} cells. Moreover the split-dose survival enhancement had all of the characteristics of SLD recovery that had been demonstrated earlier: e.g., the reappearance of the shoulder of the survival curve with dose fractionation; repair at 25degC; and inhibition by the antibiotic actinomycin D. These results strongly suggest that SLD recovery is due to DSB repair via or mediated by HR, and that these breaks constitute SLD. The tonicity-sensitive potentially lethal damage (PLD) recovery was also found only in DT40 and KU70 {sup -/-} cells. Delayed-plating PLD recovery may be controlled by NHEJ repair that works through the cell cycle. These results lead to the conclusion that the repair of DSBs could explain the classical operational recovery phenomena. We have also investigated RBE/LET using those mutants. (author)

  16. Changes in the zero-point energy of the protons as the source of the binding energy of water to A-phase DNA.

    Science.gov (United States)

    Reiter, G F; Senesi, R; Mayers, J

    2010-10-01

    The measured changes in the zero-point kinetic energy of the protons are entirely responsible for the binding energy of water molecules to A phase DNA at the concentration of 6  water molecules/base pair. The changes in kinetic energy can be expected to be a significant contribution to the energy balance in intracellular biological processes and the properties of nano-confined water. The shape of the momentum distribution in the dehydrated A phase is consistent with coherent delocalization of some of the protons in a double well potential, with a separation of the wells of 0.2 Å.

  17. Zero-point Energy is Needed in Molecular Dynamics Calculations to Access the Saddle Point for H+HCN→H2CN* and cis/trans-HCNH* on a New Potential Energy Surface.

    Science.gov (United States)

    Wang, Xiaohong; Bowman, Joel M

    2013-02-12

    We calculate the probabilities for the association reactions H+HCN→H2CN* and cis/trans-HCNH*, using quasiclassical trajectory (QCT) and classical trajectory (CT) calculations, on a new global ab initio potential energy surface (PES) for H2CN including the reaction channels. The surface is a linear least-squares fit of roughly 60 000 CCSD(T)-F12b/aug-cc-pVDZ electronic energies, using a permutationally invariant basis with Morse-type variables. The reaction probabilities are obtained at a variety of collision energies and impact parameters. Large differences in the threshold energies in the two types of dynamics calculations are traced to the absence of zero-point energy in the CT calculations. We argue that the QCT threshold energy is the realistic one. In addition, trajectories find a direct pathway to trans-HCNH, even though there is no obvious transition state (TS) for this pathway. Instead the saddle point (SP) for the addition to cis-HCNH is evidently also the TS for direct formation of trans-HCNH.

  18. Radiation reaction on a classical charged particle: a modified form of the equation of motion.

    Science.gov (United States)

    Alcaine, Guillermo García; Llanes-Estrada, Felipe J

    2013-09-01

    We present and numerically solve a modified form of the equation of motion for a charged particle under the influence of an external force, taking into account the radiation reaction. This covariant equation is integro-differential, as Dirac-Röhrlich's, but has several technical improvements. First, the equation has the form of Newton's second law, with acceleration isolated on the left hand side and the force depending only on positions and velocities: Thus, the equation is linear in the highest derivative. Second, the total four-force is by construction perpendicular to the four-velocity. Third, if the external force vanishes for all future times, the total force and the acceleration automatically vanish at the present time. We show the advantages of this equation by solving it numerically for several examples of external force.

  19. Radiative accretion shocks along nonuniform stellar magnetic fields in classical T Tauri stars

    CERN Document Server

    Orlando, S; Argiroffi, C; Reale, F; Peres, G; Miceli, M; Matsakos, T; Stehle', C; Ibgui, L; de Sa, L; Chie`ze, J P; Lanz, T

    2013-01-01

    (abridged) AIMS. We investigate the dynamics and stability of post-shock plasma streaming along nonuniform stellar magnetic fields at the impact region of accretion columns. We study how the magnetic field configuration and strength determine the structure, geometry, and location of the shock-heated plasma. METHODS. We model the impact of an accretion stream onto the chromosphere of a CTTS by 2D axisymmetric magnetohydrodynamic simulations. Our model takes into account the gravity, the radiative cooling, and the magnetic-field-oriented thermal conduction. RESULTS. The structure, stability, and location of the shocked plasma strongly depend on the configuration and strength of the magnetic field. For weak magnetic fields, a large component of B may develop perpendicular to the stream at the base of the accretion column, limiting the sinking of the shocked plasma into the chromosphere. An envelope of dense and cold chromospheric material may also develop around the shocked column. For strong magnetic fields, th...

  20. Hydrodynamic Modeling of Accretion Impacts in Classical T Tauri Stars: Radiative Heating of the Pre-shock Plasma

    CERN Document Server

    Costa, G; Peres, G; Argiroffi, C; Bonito, R

    2016-01-01

    Context. It is generally accepted that, in Classical T Tauri Stars, the plasma from the circumstellar disc accretes onto the stellar surface with free fall velocity, and the impact generates a shock. The impact region is expected to contribute to emission in different spectral bands; many studies have confirmed that the X-rays arise from the post-shock plasma but, otherwise, there are no studies in the literature investigating the origin of the observed UV emission which is apparently correlated to accretion. Aims. We investigated the effect of radiative heating of the infalling material by the post-shock plasma at the base of the accretion stream with the aim to identify in which region a significant part of the UV emission originates. Methods. We developed a 1D hydrodynamic model describing the impact of an accretion stream onto the stellar surface; the model takes into account the gravity, the radiative cooling of an optically thin plasma, the thermal conduction, and the heating due to absorption of X-ray ...

  1. The Tip of the Red Giant Branch Distances to Type Ia Supernova Host Galaxies. IV. Color Dependence and Zero-point Calibration

    Science.gov (United States)

    Jang, In Sung; Lee, Myung Gyoon

    2017-01-01

    We present a revised Tip of the Red Giant Branch (TRGB) calibration, accurate to 2.7% of distance. A modified TRGB magnitude corrected for its color dependence, the QT magnitude, is introduced for better measurement of the TRGB. We determine the color–magnitude relation of the TRGB from photometry of deep images of HST/ACS fields around eight nearby galaxies. The zero-point of the TRGB at the fiducial metallicity ([Fe/H] = ‑1.6 ({(V-I)}0,{TRGB}=1.5)) is obtained from photometry of two distance anchors, NGC 4258 (M106) and the Large Magellanic Cloud (LMC), to which precise geometric distances are known: MQT,TRGB = ‑4.023 ± 0.073 mag from NGC 4258 and MQT,TRGB = ‑4.004 ± 0.096 mag from the LMC. A weighted mean of the two zero-points is MQT,TRGB = ‑4.016 ± 0.058 mag. Quoted uncertainty is ∼2× smaller than those of previous calibrations. We compare the empirical TRGB calibration derived in this study with theoretical stellar models, finding that there are significant discrepancies, especially for red color ({({{F}}606{{W}}-{{F}}814{{W}})}0≳ 2.5). We provide the revised TRGB calibration in several magnitude systems for future studies.

  2. The Tip of the Red Giant Branch Distances to Type Ia Supernova Host Galaxies. IV. Color Dependence and Zero-Point Calibration

    CERN Document Server

    Jang, In Sung

    2016-01-01

    We present a revised TRGB calibration, accurate to 2.7% of distance. A modified TRGB magnitude corrected for the color dependence of the TRGB, the QT magnitude, is introduced for better measurement of the TRGB. We determine the color-magnitude relation of the TRGB from photometry of deep images of HST/ACS fields around eight nearby galaxies. The zero-point of the TRGB at the fiducial metallicity ([Fe/H]=-1.6 ((V-I)_{0,TRGB}=1.5)) is obtained from photometry of two distance anchors, NGC 4258 (M106) and the LMC, to which precise geometric distances are known: M_{QT,TRGB}=-4.023+-0.073 mag from NGC 4258 and M_{QT,TRGB}=-4.004+-0.096 mag from the LMC. A weighted mean of the two zero-points is M_{QT,TRGB}=-4.016+-0.058 mag. Quoted uncertainty is ~2 times smaller than those of the previous calibrations. We compare the empirical TRGB calibration derived in this study with theoretical stellar models, finding that there are significant discrepancies, especially for red color ((F606W-F814W)_0 > 2.5). We provide the rev...

  3. Changes in the zero point energy of the protons as the source of the binding energy of water to A phase DNA

    CERN Document Server

    Reiter, G F; Mayers, J

    2010-01-01

    The zero point kinetic energy of protons in water is large on the scale of chemical interaction energies(29 Kj/mol in bulk room temperature water). Its value depends upon the structure of the hydrogen bond network, and can change as the network is confined or as water interacts with surfaces. These changes have been observed to be large on a chemical scale for water confined in carbon nanotubes and in the pores of xerogel, and may play a fundamental, and neglected, role in biological processes involving confined water. We measure the average momentum distribution of the protons in salmon Na-DNA using Deep Inelastic Neutron Scattering, for a weakly hydrated (6w/bp) and a dehydrated fiber sample. This permits the determination of the change in total kinetic energy of the system per water molecule removed from the DNA and placed in the bulk liquid. This energy is equal, within errors, to the measured enthalpy for the same process, demonstrating that changes in the zero point motion of the protons, arising from c...

  4. Zero-point corrections for isotropic coupling constants for cyclohexadienyl radical, C₆H₇ and C₆H₆Mu: beyond the bond length change approximation.

    Science.gov (United States)

    Hudson, Bruce S; Chafetz, Suzanne K

    2013-04-25

    Zero-point vibrational level averaging for electron spin resonance (ESR) and muon spin resonance (µSR) hyperfine coupling constants (HFCCs) are computed for H and Mu isotopomers of the cyclohexadienyl radical. A local mode approximation previously developed for computation of the effect of replacement of H by D on ¹³C-NMR chemical shifts is used. DFT methods are used to compute the change in energy and HFCCs when the geometry is changed from the equilibrium values for the stretch and both bend degrees of freedom. This variation is then averaged over the probability distribution for each degree of freedom. The method is tested using data for the methylene group of C₆H₇, cyclohexadienyl radical and its Mu analog. Good agreement is found for the difference between the HFCCs for Mu and H of CHMu and that for H of CHMu and CH₂ of the parent radical methylene group. All three of these HFCCs are the same in the absence of the zero point average, a one-parameter fit of the static HFCC, a(0), can be computed. That value, 45.2 Gauss, is compared to the results of several fixed geometry electronic structure computations. The HFCC values for the ortho, meta and para H atoms are then discussed.

  5. Zero-Point Corrections for Isotropic Coupling Constants for Cyclohexadienyl Radical, C6H7 and C6H6Mu: Beyond the Bond Length Change Approximation

    Directory of Open Access Journals (Sweden)

    Bruce S. Hudson

    2013-04-01

    Full Text Available Zero-point vibrational level averaging for electron spin resonance (ESR and muon spin resonance (µSR hyperfine coupling constants (HFCCs are computed for H and Mu isotopomers of the cyclohexadienyl radical. A local mode approximation previously developed for computation of the effect of replacement of H by D on 13C-NMR chemical shifts is used. DFT methods are used to compute the change in energy and HFCCs when the geometry is changed from the equilibrium values for the stretch and both bend degrees of freedom. This variation is then averaged over the probability distribution for each degree of freedom. The method is tested using data for the methylene group of C6H7, cyclohexadienyl radical and its Mu analog. Good agreement is found for the difference between the HFCCs for Mu and H of CHMu and that for H of CHMu and CH2 of the parent radical methylene group. All three of these HFCCs are the same in the absence of the zero point average, a one-parameter fit of the static HFCC, a(0, can be computed. That value, 45.2 Gauss, is compared to the results of several fixed geometry electronic structure computations. The HFCC values for the ortho, meta and para H atoms are then discussed.

  6. The Kinematics and Zero Point of the log P -- Relation for Galactic Field RR Lyrae Variables via Statistical Parallax

    CERN Document Server

    Dambis, A K

    2003-01-01

    The kinematical parameters of the local field RR Lyrae population and the zero point of the log P-- relation for these variables are inferred by applying the statistical parallax (maximum-likelihood) technique to a sample of 182 RR Lyraes with known periods, radial-velocities, metallicities, K-band photometry, and absolute proper motions on the ICRS system. The K-band magnitudes were adopted from the list of Fernley et al. (1998) and the 2MASS Second Incremental Data Release. The parameters of the velocity distribution are found to be (U_0,V_0,W_0) = (-10 +/- 10, -51 +/- 8, -14 +/- 5) km/s, (sigma_U, sigma_V, sigma_W) = (62 +/- 10, 45 +/- 8, 28 +/- 6) km/s and (U_0,V_0,W_0) = (-23 +/- 13, -213 +/- 12, -5 +/- 8) km/s, (sigma_U, sigma_V, sigma_W) = (157 +/- 12, 98 +/- 8, 91 +/- 7) km/s for the thick-disk (41 stars) and halo (141 stars) objects, respectively. The zero point of the infrared PL relation of Jones et al. (1992) (based on the results obtained using the Baade-Wesselink method) is confirmed: we find =...

  7. A Systematic Approach for Computing Zero-Point Energy, Quantum Partition Function, and Tunneling Effect Based on Kleinert's Variational Perturbation Theory.

    Science.gov (United States)

    Wong, Kin-Yiu; Gao, Jiali

    2008-09-09

    In this paper, we describe an automated integration-free path-integral (AIF-PI) method, based on Kleinert's variational perturbation (KP) theory, to treat internuclear quantum-statistical effects in molecular systems. We have developed an analytical method to obtain the centroid potential as a function of the variational parameter in the KP theory, which avoids numerical difficulties in path-integral Monte Carlo or molecular dynamics simulations, especially at the limit of zero-temperature. Consequently, the variational calculations using the KP theory can be efficiently carried out beyond the first order, i.e., the Giachetti-Tognetti-Feynman-Kleinert variational approach, for realistic chemical applications. By making use of the approximation of independent instantaneous normal modes (INM), the AIF-PI method can readily be applied to many-body systems. Previously, we have shown that in the INM approximation, the AIF-PI method is accurate for computing the quantum partition function of a water molecule (3 degrees of freedom) and the quantum correction factor for the collinear H(3) reaction rate (2 degrees of freedom). In this work, the accuracy and properties of the KP theory are further investigated by using the first three order perturbations on an asymmetric double-well potential, the bond vibrations of H(2), HF, and HCl represented by the Morse potential, and a proton-transfer barrier modeled by the Eckart potential. The zero-point energy, quantum partition function, and tunneling factor for these systems have been determined and are found to be in excellent agreement with the exact quantum results. Using our new analytical results at the zero-temperature limit, we show that the minimum value of the computed centroid potential in the KP theory is in excellent agreement with the ground state energy (zero-point energy) and the position of the centroid potential minimum is the expectation value of particle position in wave mechanics. The fast convergent property

  8. The zero-point field. On the search for the cosmic basic energy; Das Nullpunkt-Feld. Auf der Suche nach der kosmischen Ur-Energie

    Energy Technology Data Exchange (ETDEWEB)

    McTaggart, L.

    2007-02-15

    Does an inexhaustable energy source exist from which all life is fed? A form of energy, which penetrates all dead and living expression forms of life? Does a logical, scientific explanation exist for parapsychological phenomena like clairvoyance, telepathy, ghost healing, synchronicity, and a model for the mode of action of homeopathy? Do serious researchers and scientific studies to be token in ernest exist, which not only deal with this questions but also have found answers? During eight years the British scientific journalist Lynne McTaggart has researched. ''Teh zero-point field'' is the result of numerous speeches with renowned physicists, biophysicists, neuroscientists, biologist, and consciousness researchers on the whole world, which have independently discovered phenomena, which are combined like puzzle pieces to a fascinating total picture.

  9. Direct dynamics trajectory study of the reaction of formaldehyde cation with D2: vibrational and zero-point energy effects on quasiclassical trajectories.

    Science.gov (United States)

    Liu, Jianbo; Song, Kihyung; Hase, William L; Anderson, Scott L

    2005-12-22

    Quasiclassical, direct dynamics trajectories have been used to study the reaction of formaldehyde cation with molecular hydrogen, simulating the conditions in an experimental study of H2CO+ vibrational effects on this reaction. Effects of five different H2CO+ modes were probed, and we also examined different approaches to treating zero-point energy in quasiclassical trajectories. The calculated absolute cross-sections are in excellent agreement with experiments, and the results provide insight into the reaction mechanism, product scattering behavior, and energy disposal, and how they vary with impact parameter and reactant state. The reaction is sharply orientation-dependent, even at high collision energies, and both trajectories and experiment find that H2CO+ vibration inhibits reaction. On the other hand, the trajectories do not reproduce the anomalously strong effect of nu2(+) (the CO stretch). The origin of the discrepancy and approaches for minimizing such problems in quasiclassical trajectories are discussed.

  10. Chemical Reaction Rates from Ring Polymer Molecular Dynamics: Zero Point Energy Conservation in Mu + H2 → MuH + H.

    Science.gov (United States)

    Pérez de Tudela, Ricardo; Aoiz, F J; Suleimanov, Yury V; Manolopoulos, David E

    2012-02-16

    A fundamental issue in the field of reaction dynamics is the inclusion of the quantum mechanical (QM) effects such as zero point energy (ZPE) and tunneling in molecular dynamics simulations, and in particular in the calculation of chemical reaction rates. In this work we study the chemical reaction between a muonium atom and a hydrogen molecule. The recently developed ring polymer molecular dynamics (RPMD) technique is used, and the results are compared with those of other methods. For this reaction, the thermal rate coefficients calculated with RPMD are found to be in excellent agreement with the results of an accurate QM calculation. The very minor discrepancies are within the convergence error even at very low temperatures. This exceptionally good agreement can be attributed to the dominant role of ZPE in the reaction, which is accounted for extremely well by RPMD. Tunneling only plays a minor role in the reaction.

  11. The ground states of iron(III) porphines: Role of entropy–enthalpy compensation, Fermi correlation, dispersion, and zero-point energies

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2011-01-01

    Porphyrins are much studied due to their biochemical relevance and many applications. The density functional TPSSh has previously accurately described the energy of close-lying electronic states of transition metal systems such as porphyrins. However, a recent study questioned this conclusion based...... on calculations of five iron(III) porphines. Here, we compute the geometries of 80 different electronic configurations and the free energies of the most stable configurations with the functionals TPSSh, TPSS, and B3LYP. Zero-point energies and entropy favor high-spin by ~4kJ/mol and 0–10kJ/mol, respectively. When...... these effects are included, and all electronic configurations are evaluated, TPSSh correctly predicts the spin of all the four difficult phenylporphine cases and is within the lower bound of uncertainty of any known theoretical method for the fifth, iron(III) chloroporphine. Dispersion computed with DFT-D3...

  12. On the convergence of zero-point vibrational corrections to nuclear shieldings and shielding anisotropies towards the complete basis set limit in water

    DEFF Research Database (Denmark)

    Faber, Rasmus; Buczek, Aneta; Kupka, Teobald;

    2016-01-01

    convergence of the vibrational corrections is not monotonic and that very large basis sets are needed before a reasonable extrapolation to the basis set limit can be performed. Furthermore, our results suggest that coupled cluster methods and a decent basis set are required before the error of the electronic......The method and basis set dependence of zero-point vibrational corrections (ZPVC) to NMR shielding constants and anisotropies has been investigated using water as a test system. A systematic comparison has been made using the Hartree-Fock (HF), second-order Møller-Plesset perturbation theory (MP2......), coupled cluster singles and doubles (CCSD), coupled cluster singles and doubles with perturbative triples corrections (CCSD(T)) and Kohn-Sham density functional theory (DFT) with the B3LYP exchange-correlation functional methods in combination with the second order vibrational perturbation theory (VPT2...

  13. A density functional theory study on the effect of zero-point energy corrections on the methanation profile on Fe(100).

    Science.gov (United States)

    Govender, Ashriti; Ferré, Daniel Curulla; Niemantsverdriet, J W Hans

    2012-04-23

    The thermodynamics and kinetics of the surface hydrogenation of adsorbed atomic carbon to methane, following the reaction sequence C+4H(-->////energies and overall energy profile are affected when zero-point energy (ZPE) corrections are included. The C, CH and CH(2) species are most stable at the fourfold hollow site, while CH(3) prefers the twofold bridge site. Atomic hydrogen is adsorbed at both the twofold bridge and fourfold hollow sites. Methane is physisorbed on the surface and shows neither orientation nor site preference. It is easily desorbed to the gas phase once formed. The incorporation of ZPE corrections has a very slight, if any, effect on the adsorption energies and does not alter the trends with regards to the most stable adsorption sites. The successive addition of hydrogen to atomic carbon is endothermic up to the addition of the third hydrogen atom resulting in the methyl species, but exothermic in the final hydrogenation step, which leads to methane. The overall methanation reaction is endothermic when starting from atomic carbon and hydrogen on the surface. Zero-point energy corrections are rarely provided in the literature. Since they are derived from C-H bonds with characteristic vibrations on the order of 2500-3000 cm(-1), the equivalent ZPE of 1/2 hν is on the order of 0.2-0.3 eV and its effect on adsorption energy can in principle be significant. Particularly in reactions between CH(x) and H, the ZPE correction is expected to be significant, as additional C-H bonds are formed. In this instance, the methanation reaction energy of +0.77 eV increased to +1.45 eV with the inclusion of ZPE corrections, that is, less favourable. Therefore, it is crucial to include ZPE corrections when reporting reactions involving hydrogen-containing species.

  14. Density functional theory calculations of the lowest energy quintet and triplet states of model hemes: role of functional, basis set, and zero-point energy corrections.

    Science.gov (United States)

    Khvostichenko, Daria; Choi, Andrew; Boulatov, Roman

    2008-04-24

    We investigated the effect of several computational variables, including the choice of the basis set, application of symmetry constraints, and zero-point energy (ZPE) corrections, on the structural parameters and predicted ground electronic state of model 5-coordinate hemes (iron(II) porphines axially coordinated by a single imidazole or 2-methylimidazole). We studied the performance of B3LYP and B3PW91 with eight Pople-style basis sets (up to 6-311+G*) and B97-1, OLYP, and TPSS functionals with 6-31G and 6-31G* basis sets. Only hybrid functionals B3LYP, B3PW91, and B97-1 reproduced the quintet ground state of the model hemes. With a given functional, the choice of the basis set caused up to 2.7 kcal/mol variation of the quintet-triplet electronic energy gap (DeltaEel), in several cases, resulting in the inversion of the sign of DeltaEel. Single-point energy calculations with triple-zeta basis sets of the Pople (up to 6-311G++(2d,2p)), Ahlrichs (TZVP and TZVPP), and Dunning (cc-pVTZ) families showed the same trend. The zero-point energy of the quintet state was approximately 1 kcal/mol lower than that of the triplet, and accounting for ZPE corrections was crucial for establishing the ground state if the electronic energy of the triplet state was approximately 1 kcal/mol less than that of the quintet. Within a given model chemistry, effects of symmetry constraints and of a "tense" structure of the iron porphine fragment coordinated to 2-methylimidazole on DeltaEel were limited to 0.3 kcal/mol. For both model hemes the best agreement with crystallographic structural data was achieved with small 6-31G and 6-31G* basis sets. Deviation of the computed frequency of the Fe-Im stretching mode from the experimental value with the basis set decreased in the order: nonaugmented basis sets, basis sets with polarization functions, and basis sets with polarization and diffuse functions. Contraction of Pople-style basis sets (double-zeta or triple-zeta) affected the results

  15. Determinação do ponto de carga zero em solos Determination of the zero point of charge in soils

    Directory of Open Access Journals (Sweden)

    Bernardo van Raij

    1973-01-01

    Full Text Available São apresentados os fundamentos e dois métodos de determinação do ponto de carga zero (PCZ em solos. Por um dos métodos o PCZ foi determinado como sendo o pH do ponto de cruzamento de curvas de titulação dos solos em soluções de NaCl 1; 0.1; 0 01; c 0,001N. Pelo outro método o PCZ foi determinado por extrapolação ou interpolação da carga líquida dos solos, determinada por retenção de íons em soluções de NaCl 0,2N, CaCl2 0,01N e MgSO4 0,01N, ao valor de pH em que a carga líquida era nula.The zero point of charge (ZPC of soils was determined by the crossing point of acid-base potenciometric titration curves in different concentrations of NaCl. Alternatively, the ZPC was found by extrapolating or interpolating the net electric charge of soils, determined by direct adsorption of ions from solution of NaCl, CaCl2 and MgSO4, to the pH of charge zero.

  16. Adiabatic physics of an exchange-coupled spin-dimer system: Magnetocaloric effect, zero-point fluctuations, and possible two-dimensional universal behavior

    Science.gov (United States)

    Brambleby, J.; Goddard, P. A.; Singleton, J.; Jaime, M.; Lancaster, T.; Huang, L.; Wosnitza, J.; Topping, C. V.; Carreiro, K. E.; Tran, H. E.; Manson, Z. E.; Manson, J. L.

    2017-01-01

    We present the magnetic and thermal properties of the bosonic-superfluid phase in a spin-dimer network using both quasistatic and rapidly changing pulsed magnetic fields. The entropy derived from a heat-capacity study reveals that the pulsed-field measurements are strongly adiabatic in nature and are responsible for the onset of a significant magnetocaloric effect (MCE). In contrast to previous predictions we show that the MCE is not just confined to the critical regions, but occurs for all fields greater than zero at sufficiently low temperatures. We explain the MCE using a model of the thermal occupation of exchange-coupled dimer spin states and highlight that failure to take this effect into account inevitably leads to incorrect interpretations of experimental results. In addition, the heat capacity in our material is suggestive of an extraordinary contribution from zero-point fluctuations and appears to indicate universal behavior with different critical exponents at the two field-induced critical points. The data at the upper critical point, combined with the layered structure of the system, are consistent with a two-dimensional nature of spin excitations in the system.

  17. Frequency and zero-point vibrational energy scale factors for double-hybrid density functionals (and other selected methods): can anharmonic force fields be avoided?

    Science.gov (United States)

    Kesharwani, Manoj K; Brauer, Brina; Martin, Jan M L

    2015-03-05

    We have obtained uniform frequency scaling factors λ(harm) (for harmonic frequencies), λ(fund) (for fundamentals), and λ(ZPVE) (for zero-point vibrational energies (ZPVEs)) for the Weigend-Ahlrichs and other selected basis sets for MP2, SCS-MP2, and a variety of DFT functionals including double hybrids. For selected levels of theory, we have also obtained scaling factors for true anharmonic fundamentals and ZPVEs obtained from quartic force fields. For harmonic frequencies, the double hybrids B2PLYP, B2GP-PLYP, and DSD-PBEP86 clearly yield the best performance at RMSD = 10-12 cm(-1) for def2-TZVP and larger basis sets, compared to 5 cm(-1) at the CCSD(T) basis set limit. For ZPVEs, again, the double hybrids are the best performers, reaching root-mean-square deviations (RMSDs) as low as 0.05 kcal/mol, but even mainstream functionals like B3LYP can get down to 0.10 kcal/mol. Explicitly anharmonic ZPVEs only are marginally more accurate. For fundamentals, however, simple uniform scaling is clearly inadequate.

  18. The ground states of iron(III) porphines: role of entropy-enthalpy compensation, Fermi correlation, dispersion, and zero-point energies.

    Science.gov (United States)

    Kepp, Kasper P

    2011-10-01

    Porphyrins are much studied due to their biochemical relevance and many applications. The density functional TPSSh has previously accurately described the energy of close-lying electronic states of transition metal systems such as porphyrins. However, a recent study questioned this conclusion based on calculations of five iron(III) porphines. Here, we compute the geometries of 80 different electronic configurations and the free energies of the most stable configurations with the functionals TPSSh, TPSS, and B3LYP. Zero-point energies and entropy favor high-spin by ~4kJ/mol and 0-10kJ/mol, respectively. When these effects are included, and all electronic configurations are evaluated, TPSSh correctly predicts the spin of all the four difficult phenylporphine cases and is within the lower bound of uncertainty of any known theoretical method for the fifth, iron(III) chloroporphine. Dispersion computed with DFT-D3 favors low-spin by 3-53kJ/mol (TPSSh) or 4-15kJ/mol (B3LYP) due to the attractive r(-6) term and the shorter distances in low-spin. The very large and diverse corrections from TPSS and TPSSh seem less consistent with the similarity of the systems than when calculated from B3LYP. If the functional-specific corrections are used, B3LYP and TPSSh are of equal accuracy, and TPSS is much worse, whereas if the physically reasonable B3LYP-computed dispersion effect is used for all functionals, TPSSh is accurate for all systems. B3LYP is significantly more accurate when dispersion is added, confirming previous results.

  19. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra

    NARCIS (Netherlands)

    Marashdeh, A.; Frankcombe, T.J.

    2008-01-01

    The dehydrogenation enthalpies of Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4 have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski’s direct method. The dehydrog

  20. Research on zero-point correction technique of gas detector%瓦斯探测器零点校正技术的研究

    Institute of Scientific and Technical Information of China (English)

    于春雨; 潘春鹤; 于晓霞; 张光臻

    2012-01-01

    Aiming at the problems such as large drift, high costs and short maintenance intervals of the extensively used gas detectors at the current stage, the timing automatic zero-point correction approach based on the thermostatic control circuit is presented. This approach uses the catalytic combustion gas sensor as targets, adopts the thermostatic control circuit to provide power for sensors, takes the theoretical analysis of zero drift and large quantities of experimental research as the basis and solves the problem of zero stability of this type of detectors which had not been solved for a long time. It employs the analog electronic switch to match resistance network to realize digital potentiometer design and saves costs. The experimental results demonstrate that the residual deviation of the thermostatic control circuit after zero correction reduces one order of magnitude than the output value without correction and provide technical support for the design of gas detectors which have the function of automatic timing zero setting.%针对目前广泛使用的瓦斯探测器漂移大、成本高、维护周期短等问题,提出了基于恒温控制电路的瓦斯探测器的定时自动零点校正方法.该方法以催化燃烧式气体传感器为对象,采用恒温控制电路为传感器供电,以零点漂移的理论分析和大量实验研究工作为依据,解决了该类探测器长期未能解决的零点稳定性问题.采用模拟电子开关配合电阻网络实现数字电位器设计,节约了成本.实验结果表明:采用恒温控制电路的零点校正后的残留偏差比未经校正的输出值减少了近1个数量级,为设计具有自动定时凋零功能的瓦斯探测器提供了技术支持.

  1. High-resolution studies of tropolone in the S0 and S1 electronic states: isotope driven dynamics in the zero-point energy levels.

    Science.gov (United States)

    Keske, John C; Lin, Wei; Pringle, Wallace C; Novick, Stewart E; Blake, Thomas A; Plusquellic, David F

    2006-02-21

    Rotationally resolved microwave (MW) and ultraviolet (UV) spectra of jet-cooled tropolone have been obtained in S(0) and S(1) electronic states using Fourier-transform microwave and UV-laser/molecular-beam spectrometers. In the ground electronic state, the MW spectra of all heavy-atom isotopomers including one (18)O and four (13)C isotopomers were observed in natural abundance. The OD isotopomer was obtained from isotopically enriched samples. The two lowest tunneling states of each isotopomer except (18)O have been assigned. The observed inversion splitting for the OD isotopomer is 1523.227(5) MHz. For the asymmetric (13)C structures, the magnitudes of tunneling-rotation interactions are found to diminish with decreasing distance between the heavy atom and the tunneling proton. In the limit of closest approach, the 0(+) state of (18)O was well fitted to an asymmetric rotor Hamiltonian, reflecting significant changes in the tautomerization dynamics. Comparisons of the substituted atom coordinates with theoretical predictions at the MP2/aug-cc-pVTZ level of theory suggest the localized 0(+) and 0(-) wave functions of the heavier isotopes favor the C-OH and C=O forms of tropolone, respectively. The only exception occurs for the (13)C-OH and (13)C[Double Bond]O structures which correlate to the 0(-) and 0(+) states, respectively. These preferences reflect kinetic isotope effects as quantitatively verified by the calculated zero-point energy differences between members of the asymmetric atom pairs. From rotationally resolved data of the 0(+) <--0(+) and 0(-) <--0(-) bands in S(1), line-shape fits have yielded Lorentzian linewidths that differ by 12.2(16) MHz over the 19.88(4) cm(-1) interval in S(1). The fluorescence decay rates together with previously reported quantum yield data give nonradiative decay rates of 7.7(5) x 10(8) and 8.5(5) x 10(8) s(-1) for the 0(+) and 0(-) levels of the S(1) state of tropolone.

  2. Effect of the radiation reaction in classical regimes of interaction of ultra-strong electromagnetic fields with plasmas

    Science.gov (United States)

    Capdessus, R.; d'Humières, E.; Tikhonchuk, V. T.

    2013-05-01

    Radiation energy losses of electrons in ultra-intense laser fields constitute a process of major importance when considering laser-matter interaction at intensities of the order of and above 1022 W/cm2. Radiation losses can strongly modify the electron (and ion) dynamics, and are associated with intense and directional emission of high energy photons. Accounting for such effects is therefore necessary for modeling of, electron and ion acceleration and creation of secondary photon on the forthcoming ultra-high power laser facilities. To account for radiation losses in the particle-in-cell code PICLS, we have introduced the radiation friction force using a renormalized Lorentz-Abraham-Dirac model.10 Here, we present a study of the effect of radiation friction on the electron and photon energy distribution in a semi-infinite and overdense plasma. A possibillity to create a collisonless shock using an ultra intense laser field, in the context of laboratory astrophysics is discussed. The influence of the radiation reaction on the plasma dynamics is demonstrated.

  3. On the Remarkable Features of the Lower Limits of Charge and the Radiated Energy of Antennas as Predicted by Classical Electrodynamics

    Directory of Open Access Journals (Sweden)

    Vernon Cooray

    2016-05-01

    Full Text Available Electromagnetic energy radiated by antennas working in both the frequency domain and time domain is studied as a function of the charge associated with the current in the antenna. The frequency domain results, obtained under the assumption of sinusoidal current distribution, show that, for a given charge, the energy radiated within a period of oscillation increases initially with L/λ and then starts to oscillate around a steady value when L/λ > 1. The results show that for the energy radiated by the antenna to be equal to or larger than the energy of one photon, the oscillating charge in the antenna has to be equal to or larger than the electronic charge. That is, U ≥ hν or UT ≥ h ⇒ q ≥ e, where U is the energy dissipated over a period, ν is the frequency of oscillation, T is the period, h is Planck’s constant, q is the rms value of the oscillating charge, and e is the electronic charge. In the case of antennas working in the time domain, it is observed that UΔt ≥ h/4π ⇒ q ≥ e, where U is the total energy radiated, Δt is the time over which the energy is radiated, and q is the charge transported by the current. It is shown that one can recover the time–energy uncertainty principle of quantum mechanics from this time domain result. The results presented in this paper show that when quantum mechanical constraints are applied to the electromagnetic energy radiated by a finite antenna as estimated using the equations of classical electrodynamics, the electronic charge emerges as the smallest unit of free charge in nature.

  4. Classical Simulation of Quantum Fields I

    CERN Document Server

    Hirayama, T

    2005-01-01

    We study classical field theories in a background field configuration where all modes of the theory are excited, matching the zero-point energy spectrum of quantum field theory. Our construction involves elements of a theory of classical electrodynamics by Wheeler-Feynman and the theory of stochastic electrodynamics of Boyer. The nonperturbative effects of interactions in these theories can be very efficiently studied on the lattice. In $\\lambda\\phi^{4}$ theory in 1+1 dimensions we find results, in particular for mass renormalization and the critical coupling for symmetry breaking, that are in agreement with their quantum counterparts. We then study the perturbative expansion of the $n$-point Green's functions and find a loop expansion very similar to that of quantum field theory. When compared to the usual Feynman rules, we find some differences associated with particular combinations of internal lines going on-shell simultaneously.

  5. Classical simulation of quantum fields I

    Science.gov (United States)

    Hirayama, T.; Holdom, B.

    2006-10-01

    We study classical field theories in a background field configuration where all modes of the theory are excited, matching the zero-point energy spectrum of quantum field theory. Our construction involves elements of a theory of classical electrodynamics by Wheeler-Feynman and the theory of stochastic electrodynamics of Boyer. The nonperturbative effects of interactions in these theories can be very efficiently studied on the lattice. In lambda phi(4) theory in 1 + 1 dimensions, we find results, in particular, for mass renormalization and the critical coupling for symmetry breaking that are in agreement with their quantum counterparts. We then study the perturbative expansion of the n-point Green's functions and find a loop expansion very similar to that of quantum field theory. When compared to the usual Feynman rules, we find some differences associated with particular combinations of internal lines going on-shell simultaneously.

  6. Classical antiparticles

    Energy Technology Data Exchange (ETDEWEB)

    Costella, J.P.; McKellar, B.H.J.; Rawlinson, A.A.

    1997-03-01

    We review how antiparticles may be introduced in classical relativistic mechanics, and emphasize that many of their paradoxical properties can be more transparently understood in the classical than in the quantum domain. (authors). 13 refs., 1 tab.

  7. Classical antiparticles

    CERN Document Server

    Costella, J P; Rawlinson, A A; Costella, John P.; Kellar, Bruce H. J. Mc; Rawlinson, Andrew A.

    1997-01-01

    We review how antiparticles may be introduced in classical relativistic mechanics, and emphasize that many of their paradoxical properties can be more transparently understood in the classical than in the quantum domain.

  8. Methods for Estimation of Radiation Risk in Epidemiological Studies Accounting for Classical and Berkson Errors in Doses

    KAUST Repository

    Kukush, Alexander

    2011-01-16

    With a binary response Y, the dose-response model under consideration is logistic in flavor with pr(Y=1 | D) = R (1+R)(-1), R = λ(0) + EAR D, where λ(0) is the baseline incidence rate and EAR is the excess absolute risk per gray. The calculated thyroid dose of a person i is expressed as Dimes=fiQi(mes)/Mi(mes). Here, Qi(mes) is the measured content of radioiodine in the thyroid gland of person i at time t(mes), Mi(mes) is the estimate of the thyroid mass, and f(i) is the normalizing multiplier. The Q(i) and M(i) are measured with multiplicative errors Vi(Q) and ViM, so that Qi(mes)=Qi(tr)Vi(Q) (this is classical measurement error model) and Mi(tr)=Mi(mes)Vi(M) (this is Berkson measurement error model). Here, Qi(tr) is the true content of radioactivity in the thyroid gland, and Mi(tr) is the true value of the thyroid mass. The error in f(i) is much smaller than the errors in ( Qi(mes), Mi(mes)) and ignored in the analysis. By means of Parametric Full Maximum Likelihood and Regression Calibration (under the assumption that the data set of true doses has lognormal distribution), Nonparametric Full Maximum Likelihood, Nonparametric Regression Calibration, and by properly tuned SIMEX method we study the influence of measurement errors in thyroid dose on the estimates of λ(0) and EAR. The simulation study is presented based on a real sample from the epidemiological studies. The doses were reconstructed in the framework of the Ukrainian-American project on the investigation of Post-Chernobyl thyroid cancers in Ukraine, and the underlying subpolulation was artificially enlarged in order to increase the statistical power. The true risk parameters were given by the values to earlier epidemiological studies, and then the binary response was simulated according to the dose-response model.

  9. Classics Online.

    Science.gov (United States)

    Clayman, Dee L.

    1995-01-01

    Appraises several databases devoted to classical literature. Thesaurus Linguae Graecae (TLG) contains the entire extant corpus of ancient Greek literature, including works on lexicography and historiography, extending into the 15th century. Other works awaiting completion are the Database of Classical Bibliography and a CD-ROM pictorial dictionary…

  10. Classical integrability

    Science.gov (United States)

    Torrielli, Alessandro

    2016-08-01

    We review some essential aspects of classically integrable systems. The detailed outline of the sections consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schrödinger model, principal chiral field); 4. Features of classical r-matrices: Belavin-Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel’fand-Levitan-Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.

  11. Stochastic semi-classical description of sub-barrier fusion reactions

    Directory of Open Access Journals (Sweden)

    Ayik Sakir

    2011-10-01

    Full Text Available A semi-classical method that incorporates the quantum effects of the low-lying vibrational modes is applied to fusion reactions. The quantum effect is simulated by stochastic sampling of initial zero-point fluctuations of the surface modes. In this model, dissipation of the relative energy into non-collective excitations of nuclei can be included straightforwardly. The inclusion of dissipation is shown to increase the agreement with the fusion cross section data of Ni isotopes.

  12. Mode Interaction at a Triple Zero Point of O(2)-symmetric Nonlinear Systems with Two Parameters%带两个参数的O(2)对称非线性系统的三重奇异点处的分枝

    Institute of Scientific and Technical Information of China (English)

    吴微; 孟繁友

    2000-01-01

    We consider a triple zero point of nonlinear equations with O(2)-symmetry, where the Jacobian has a zero eigenvalue of geometric multiplicity one and algebraic multiplicity three, We show that this triple zero point exhibits a new bifurcation phenomenon, that is, a mode interaction of the following three paths: bifurcation points from steady-states, steadystates and rotating waves to standing waves, rotating waves and modulated rotating waves respectively.

  13. Zero-point energy of vacuum fluctuation as a candidate for dark energy versus a new conjecture of antigravity based on the modified Einstein field equation in general relativity

    CERN Document Server

    Ni, G

    2005-01-01

    In order to clarify why the zero-point energy associated with the vacuum fluctuations cannot be a candidate for the dark energy in the universe, a comparison with the Casimir effect is analyzed in some detail. A principle of epistemology is stressed that it is meaningless to talk about an absolute (isolated) thing. A relative thing can only be observed when it is changing with respect to other things. Then a new conjecture of antigravity --the repulsive force between matter and antimatter derived from the modified Einstein field equation in general relativity-- is proposed. this is due to the particle-antiparticle symmetry based on a new understanding about the essence of special relativity. Its possible consequences in the theory of cosmology are discussed briefly, including a new explanation for the accelerating universe and gamma-ray-bursts.

  14. Influence of Zero-Point Energy Correction on Effective Nucleon Mass in Derivative Coupling Models%ZM模型中零点能修正对核子有效质量的影响

    Institute of Scientific and Technical Information of China (English)

    舒崧; 李家荣

    2003-01-01

    In the light of derivative coupling models, we argue that the zero-point energy of the vacuum could not be simply thrown away at high temperature. So here the finite contribution which is temperature dependent has been separated from it and the influence of this correction on effective nucleon mass in nuclear matter has been studied.%基于ZM模型,讨论了真空零点能的贡献. 认为真空零点能不能简单地丢掉,所以零点能中与温度相关的有限部分被分离了出来,并具体讨论了在核物质中这一零点能修正对核子有效质量的影响,发现在高温时它有着非平庸的贡献.

  15. 差动变压器式位移传感器零位电压研究%Study on Zero-point Remainder Voltage of Differential Transformer Displacement Sensor

    Institute of Scientific and Technical Information of China (English)

    贾惠霞; 王健; 张娟

    2015-01-01

    The principle of the differential transformer displacement sensor is very simple,and it is very easy to realize.The measurement errors exit not only because of zero-point remainder voltage of the carrier,but also because of the circuit drift in the process of signal processing.This article was based on the principle and the signal processing of this kind of sensor,and the princi-ple of zero-point remainder voltage and the method of removing it were introduced,thus improving the certainty of measurement.The main part of null voltage was proved through MATLAB simulation and experiment,thus proving the importance of magnetic circuit symmetry in the differential transformer displacement sensor.%差动变压器式位移传感器原理简单,便于实现。但是位移传感器会产生零位电压,同时在信号处理过程中,电路漂移也会引起测量误差。文中主要基于这种传感器的工作原理和信号处理过程,阐述零位电压产生的机理和消除的方法,提高传感器的测量精度,并用MATLAB仿真和实验的方法证明零位电压产生的主要部位,进而说明差动变压器式位移传感器加工时保证磁路对称的重要性。

  16. Full dimensional (15-dimensional) quantum-dynamical simulation of the protonated water-dimer III: Mixed Jacobi-valence parametrization and benchmark results for the zero point energy, vibrationally excited states, and infrared spectrum.

    Science.gov (United States)

    Vendrell, Oriol; Brill, Michael; Gatti, Fabien; Lauvergnat, David; Meyer, Hans-Dieter

    2009-06-21

    Quantum dynamical calculations are reported for the zero point energy, several low-lying vibrational states, and the infrared spectrum of the H(5)O(2)(+) cation. The calculations are performed by the multiconfiguration time-dependent Hartree (MCTDH) method. A new vector parametrization based on a mixed Jacobi-valence description of the system is presented. With this parametrization the potential energy surface coupling is reduced with respect to a full Jacobi description, providing a better convergence of the n-mode representation of the potential. However, new coupling terms appear in the kinetic energy operator. These terms are derived and discussed. A mode-combination scheme based on six combined coordinates is used, and the representation of the 15-dimensional potential in terms of a six-combined mode cluster expansion including up to some 7-dimensional grids is discussed. A statistical analysis of the accuracy of the n-mode representation of the potential at all orders is performed. Benchmark, fully converged results are reported for the zero point energy, which lie within the statistical uncertainty of the reference diffusion Monte Carlo result for this system. Some low-lying vibrationally excited eigenstates are computed by block improved relaxation, illustrating the applicability of the approach to large systems. Benchmark calculations of the linear infrared spectrum are provided, and convergence with increasing size of the time-dependent basis and as a function of the order of the n-mode representation is studied. The calculations presented here make use of recent developments in the parallel version of the MCTDH code, which are briefly discussed. We also show that the infrared spectrum can be computed, to a very good approximation, within D(2d) symmetry, instead of the G(16) symmetry used before, in which the complete rotation of one water molecule with respect to the other is allowed, thus simplifying the dynamical problem.

  17. Lectures on classical electrodynamics

    CERN Document Server

    Englert, Berthold-Georg

    2014-01-01

    These lecture notes cover classical electrodynamics at the level of advanced undergraduates or postgraduates. There is a strong emphasis on the general features of the electromagnetic field and, in particular, on the properties of electromagnetic radiation. It offers a comprehensive and detailed, as well as self-contained, account of material that can be covered in a one-semester course for students with a solid undergraduate knowledge of basic electricity and magnetism.

  18. Classical Mechanics

    OpenAIRE

    Gallavotti, Giovanni

    2012-01-01

    This is the English version of a friendly graduate course on Classical Mechanics, containing about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. For the Spanish version, see physics/9906066

  19. The Stranger: Adventures at Zero Point

    Science.gov (United States)

    Heraud, Richard

    2013-01-01

    In one of his notebooks, Albert Camus describes, "The stranger," "The myth of Sisyphus," "Caligula" and "The misunderstanding" as pertaining to a series; a schema that suggests that if one were to write about one of these literary works, one would be writing about parts of a whole unless one also engaged…

  20. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra.

    Science.gov (United States)

    Marashdeh, Ali; Frankcombe, Terry J

    2008-06-21

    The dehydrogenation enthalpies of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski's direct method. The dehydrogenation of Ca(AlH(4))(2) is exothermic, indicating a metastable hydride. Calculations for CaAlH(5) including ZPE effects indicate that it is not stable enough for a hydrogen storage system operating near ambient conditions. The destabilized combination of LiBH(4) with CaH(2) is a promising system after ZPE-corrected enthalpy calculations. The calculations confirm that including ZPE effects in the harmonic approximation for the dehydrogenation of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) has a significant effect on the calculated reaction enthalpy. The contribution of ZPE to the dehydrogenation enthalpies of Ca(AlH(4))(2) and CaAlH(5) calculated by the direct method phonon analysis was compared to that calculated by the frozen-phonon method. The crystal structure of CaAlH(5) is presented in the more useful standard setting of P2(1)c symmetry and the phonon density of states of CaAlH(5), significantly different to other common complex metal hydrides, is rationalized.

  1. Full-dimensional quantum calculations of the dissociation energy, zero-point, and 10 K properties of H7+/D7+ clusters using an ab initio potential energy surface.

    Science.gov (United States)

    Barragán, Patricia; Pérez de Tudela, Ricardo; Qu, Chen; Prosmiti, Rita; Bowman, Joel M

    2013-07-14

    Diffusion Monte Carlo (DMC) and path-integral Monte Carlo computations of the vibrational ground state and 10 K equilibrium state properties of the H7 (+)/D7 (+) cations are presented, using an ab initio full-dimensional potential energy surface. The DMC zero-point energies of dissociated fragments H5 (+)(D5 (+))+H2(D2) are also calculated and from these results and the electronic dissociation energy, dissociation energies, D0, of 752 ± 15 and 980 ± 14 cm(-1) are reported for H7 (+) and D7 (+), respectively. Due to the known error in the electronic dissociation energy of the potential surface, these quantities are underestimated by roughly 65 cm(-1). These values are rigorously determined for first time, and compared with previous theoretical estimates from electronic structure calculations using standard harmonic analysis, and available experimental measurements. Probability density distributions are also computed for the ground vibrational and 10 K state of H7 (+) and D7 (+). These are qualitatively described as a central H3 (+)/D3 (+) core surrounded by "solvent" H2/D2 molecules that nearly freely rotate.

  2. An ab initio potential energy surface for the formic acid dimer: zero-point energy, selected anharmonic fundamental energies, and ground-state tunneling splitting calculated in relaxed 1-4-mode subspaces.

    Science.gov (United States)

    Qu, Chen; Bowman, Joel M

    2016-09-14

    We report a full-dimensional, permutationally invariant potential energy surface (PES) for the cyclic formic acid dimer. This PES is a least-squares fit to 13475 CCSD(T)-F12a/haTZ (VTZ for H and aVTZ for C and O) energies. The energy-weighted, root-mean-square fitting error is 11 cm(-1) and the barrier for the double-proton transfer on the PES is 2848 cm(-1), in good agreement with the directly-calculated ab initio value of 2853 cm(-1). The zero-point vibrational energy of 15 337 ± 7 cm(-1) is obtained from diffusion Monte Carlo calculations. Energies of fundamentals of fifteen modes are calculated using the vibrational self-consistent field and virtual-state configuration interaction method. The ground-state tunneling splitting is computed using a reduced-dimensional Hamiltonian with relaxed potentials. The highest-level, four-mode coupled calculation gives a tunneling splitting of 0.037 cm(-1), which is roughly twice the experimental value. The tunneling splittings of (DCOOH)2 and (DCOOD)2 from one to three mode calculations are, as expected, smaller than that for (HCOOH)2 and consistent with experiment.

  3. XZP + 1d and XZP + 1d-DKH basis sets for second-row elements: application to CCSD(T) zero-point vibrational energy and atomization energy calculations.

    Science.gov (United States)

    Campos, Cesar T; Jorge, Francisco E; Alves, Júlia M A

    2012-09-01

    Recently, segmented all-electron contracted double, triple, quadruple, quintuple, and sextuple zeta valence plus polarization function (XZP, X = D, T, Q, 5, and 6) basis sets for the elements from H to Ar were constructed for use in conjunction with nonrelativistic and Douglas-Kroll-Hess Hamiltonians. In this work, in order to obtain a better description of some molecular properties, the XZP sets for the second-row elements were augmented with high-exponent d "inner polarization functions," which were optimized in the molecular environment at the second-order Møller-Plesset level. At the coupled cluster level of theory, the inclusion of tight d functions for these elements was found to be essential to improve the agreement between theoretical and experimental zero-point vibrational energies (ZPVEs) and atomization energies. For all of the molecules studied, the ZPVE errors were always smaller than 0.5 %. The atomization energies were also improved by applying corrections due to core/valence correlation and atomic spin-orbit effects. This led to estimates for the atomization energies of various compounds in the gaseous phase. The largest error (1.2 kcal mol(-1)) was found for SiH(4).

  4. [Classical taxomomies].

    Science.gov (United States)

    Liubarskiĭ, G Iu

    2006-01-01

    The sequence of classic paradigms in taxonomy that partly replaced each other and partly co-exist is given as follows: the theory of "organ and organism similarity", the naturalistic theory, the descriptive theory, and the phylogenetic theory. The naturalistic classics accepted the notion of "the plan of creation". The rejection of appealing to this plan brought forth certain problems in the formulation of the purpose of taxonomy; these problems were differently solved by the descriptive and the phylogenetic classic traditions. The difficulties of the current paradigms arising from the loss of a "strong purpose", a problem to be solved by taxonomists that is to be clear and interesting to a wide range of non-professionals. The paradox of formalization led to the losing of content of the methods due to their formalization. To attract attention to taxonomy, a new "image of the results" of its work that would be interesting to the non-professionals is necessary. The co-existence of different methods of reseach applied to different groups of facts leads to the loss of integrity of the research. It is not only that the taxon becomes a hypothesis and such hypotheses multiply. The comparison of these hypotheses is problematic, because each of them is supported by its own independent scope of facts. Because of the existence of a fundamental meronotaxonomic discrepancy, taxonomic systems based on different groups of characters appear to be incomparable, being rather systems of characters than systems of taxa. Systems of characters are not directly comparable with each other; they can be compared only through appealing to taxa, but taxa themselves exist only in the form of a number of hypotheses. Consequently, each separate taxonomic approach creates its own nature, its own subject of research. Therefore, it is necessary to describe the subject of research correctly (and indicate the purpose of research), as well as to distinguish clearly between results achieved through

  5. Classical Weyl Transverse Gravity

    CERN Document Server

    Oda, Ichiro

    2016-01-01

    We study various classical aspects of the Weyl transverse (WTDiff) gravity in a general space-time dimension. First of all, we clarify a classical equivalence among three kinds of gravitational theories, those are, the conformally-invariant scalar tensor gravity, Einstein's general relativity and the WTDiff gravity via the gauge fixing procedure. Secondly, we show that in the WTDiff gravity the cosmological constant is a mere integration constant as in unimodular gravity, but it does not receive any radiative corrections unlike the unimodular gravity. A key point in this proof is to construct a covariantly conserved energy-momentum tensor, which is achieved on the basis of this equivalence relation. Thirdly, we demonstrate that the Noether current for the Weyl transformation is identically vanishing, thereby implying that the Weyl symmetry existing in both the conformally-invariant scalar tensor gravity and the WTDiff gravity is a "fake" symmetry. We find it possible to extend this proof to all matter fields,...

  6. Mechanics classical and quantum

    CERN Document Server

    Taylor, T T

    2015-01-01

    Mechanics: Classical and Quantum explains the principles of quantum mechanics via the medium of analytical mechanics. The book describes Schrodinger's formulation, the Hamilton-Jacobi equation, and the Lagrangian formulation. The author discusses the Harmonic Oscillator, the generalized coordinates, velocities, as well as the application of the Lagrangian formulation to systems that are partially or entirely electromagnetic in character under certain conditions. The book examines waves on a string under tension, the isothermal cavity radiation, and the Rayleigh-Jeans result pertaining to the e

  7. Inhomogeneous Quantum Mixmaster: from Classical toward Quantum Mechanics

    CERN Document Server

    Montani, R B G

    2006-01-01

    Starting from the Hamiltonian formulation for the inhomogeneous Mixmaster dynam- ics, we approach its quantum features through the link of the quasi-classical limit. We fix the proper operator-ordering which ensures that the WKB continuity equation overlaps the Liouville theorem as restricted to the configuration space. We describe the full quantum dynamics of the model in some details, providing a characterization of the (discrete) spectrum with analytic expressions for the limit of high occupation number. One of the main achievements of our analysis relies on the description of the ground state morphology, showing how it is characterized by a non-vanishing zero-point energy associated to the Universe anisotropy degrees of freedom

  8. Quantum calculation based on the first-principles for the zero-point vibration energy of solid helium%基于第一性原理的固氦零点振动能的量子理论计算

    Institute of Scientific and Technical Information of China (English)

    郑兴荣; 李高清; 贾利平; 孟军霞; 李杨

    2016-01-01

    Based on the First-principles, the atomic interaction energy of solid helium were calculated using ab initio calculation Hartree-Fock Self-Consistent-Field method and the atomic clusters theory in the atomic dis-tance of 1. 75-2. 60 Å. It is also obtained that the zero-point vibration frequency, the zero-point vibration energy, Gruneisen coefficient and the zero -point vibration pressure by 1stOpt software. Finally, our results were compared with the experimental results. These conclusions can be drawn that the motion of solid helium can be approximate to simple harmonic vibration in their equilibrium position;The zero-point vibration frequency of solid helium decreases with the increase of the molar volume;The proportion of the zero-point vibration energy and the total many-body interaction energy is more than 5% for solid neon, it can not be ignored and increases with the increase of the molar volume;The zero-point vibration energy decreases with the increase of the molar volume and the atomic distance;With the increase of the molar volume, Gruneisen coefficient increase, and its value is always between 1 and 2;The curve of zero-point vibration pressure has a similar tendency with the re-ported experimental results, but it is slightly smaller than the experimental results;With the increase of the molar volume, the zero-point vibration pressure contribution to the total pressure increased from 8% to 50%, and it has played an increasingly important role in the total pressure.%基于第一性原理,运用原子团簇理论和Hartree-Fock Self-Consistent-Field从头算法计算了高压固氦hcp结构在平衡位置r=1.75-2.6Å附近的原子相互作用能,并使用1stOpt软件拟合出固氦的零点振动频率,得到零点振动能、Gruneisen系数及零点振动压强,最后与实验值做了比较.结果表明:固氦晶体在其各自平衡位置附近的运动可近似为简谐振动;固氦晶体的零点振动频率随着摩尔体积的

  9. What classicality? Decoherence and Bohr's classical concepts

    CERN Document Server

    Schlosshauer, Maximilian

    2010-01-01

    Niels Bohr famously insisted on the indispensability of what he termed "classical concepts." In the context of the decoherence program, on the other hand, it has become fashionable to talk about the "dynamical emergence of classicality" from the quantum formalism alone. Does this mean that decoherence challenges Bohr's dictum and signifies a break with the Copenhagen interpretation-for example, that classical concepts do not need to be assumed but can be derived? In this paper we'll try to shine some light down the murky waters where formalism and philosophy cohabitate. To begin, we'll clarify the notion of classicality in the decoherence description. We'll then discuss Bohr's and Heisenberg's take on the quantum-classical problem and reflect on different meanings of the terms "classicality" and "classical concepts" in the writings of Bohr and his followers. This analysis will allow us to put forward some tentative suggestions for how we may better understand the relation between decoherence-induced classical...

  10. Einstein-Podolski-Rosen Paradox and Stochastic Wheeler-Feynman Absorber Theory

    OpenAIRE

    "今枝,国之助/今枝,真理"; "イマエダ,クニノスケ/イマエダ,マリ"; "Imaeda,Kuninosuke/Imaeda,Mari"

    1982-01-01

    "The basic idea of the theory developed in a previous paper : the theory of stochastic electrodynamics with classical Wheeler-Feynman absorber theory, the character of the Lorentz invariant zero point radiation and a minimum ""emitter-absorber transaction"" of Cramer extended to the case where the zero point radiation exists, has been studied."

  11. Classical mechanics without determinism

    OpenAIRE

    Nikolic, H.

    2005-01-01

    Classical statistical particle mechanics in the configuration space can be represented by a nonlinear Schrodinger equation. Even without assuming the existence of deterministic particle trajectories, the resulting quantum-like statistical interpretation is sufficient to predict all measurable results of classical mechanics. In the classical case, the wave function that satisfies a linear equation is positive, which is the main source of the fundamental difference between classical and quantum...

  12. Quantum computing classical physics.

    Science.gov (United States)

    Meyer, David A

    2002-03-15

    In the past decade, quantum algorithms have been found which outperform the best classical solutions known for certain classical problems as well as the best classical methods known for simulation of certain quantum systems. This suggests that they may also speed up the simulation of some classical systems. I describe one class of discrete quantum algorithms which do so--quantum lattice-gas automata--and show how to implement them efficiently on standard quantum computers.

  13. On the local relaxation of solid neon upon Rydberg excitation of a NO impurity: the role of the NO(A)-Ne interaction potential and zero-point quantum delocalization.

    Science.gov (United States)

    Pajón-Suárez, Pedro; Rojas-Lorenzo, Germán A; Rubayo-Soneira, Jesús; Hernández-Lamoneda, Ramón; Larrégaray, Pascal

    2009-12-31

    The local relaxation of solid neon subsequent to the impulsive excitation of the NO chromophore to its A(3s sigma) Ryberg state is investigated using molecular dynamics simulations. This study makes use of empirical NO(X,A)-Ne isotropic pair potentials as well as a recently developed ab initio triatomic potential energy surface for the excited state. The role of these interaction potentials is analyzed, including many-body effects. In particular, empirical potentials, designed to reproduce correctly both the NO X-A steady-state absorption and emission bands, are shown to lead to a good description of the subpicosecond relaxation dynamics. The 600 fs expansion of the electronic bubble fairly agrees with experimental data. This relatively long time scale with respect to solid Argon, which was previously attributed to the range of the NO(A)-Ne interaction, is presumably related to the quantum nature of the medium. The time-resolved local relaxation of the Ne solid is understandably intermediate between that of classical solids (e.g., Ar) and that of quantum solids (e.g., H(2)).

  14. Entanglement in Classical Optics

    CERN Document Server

    Ghose, Partha

    2013-01-01

    The emerging field of entanglement or nonseparability in classical optics is reviewed, and its similarities with and differences from quantum entanglement clearly pointed out through a recapitulation of Hilbert spaces in general, the special restrictions on Hilbert spaces imposed in quantum mechanics and the role of Hilbert spaces in classical polarization optics. The production of Bell-like states in classical polarization optics is discussed, and new theorems are proved to discriminate between separable and nonseparable states in classical wave optics where no discreteness is involved. The influence of the Pancharatnam phase on a classical Bell-like state is deived. Finally, to what extent classical polarization optics can be used to simulate quantum information processing tasks is also discussed. This should be of great practical importance because coherence and entanglement are robust in classical optics but not in quantum systems.

  15. Motions of Classical Charged Tachyons

    CERN Document Server

    Davidson, M P

    2001-01-01

    It is shown by numerical simulation that classical charged tachyons have self-orbiting helical solutions in a narrow neighborhood of certain discrete values for the velocity when the electromagnetic interaction is described by Feynman-Wheeler electrodynamics. The force rapidly oscillates between attractive and repulsive as a function of velocity in this neighborhood. Causal electrodynamics is also considered, and in this case it is found that when the force is attractive the tachyon loses energy to radiation. Only certain narrow ranges of velocity give attractive forces, and a geometrical derivation of these special velocities is given. Possible implications of these results for hidden variable theories of quantum mechanics are conjectured.

  16. Solar Activity and Classical Physics

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This review of solar physics emphasizes several of the more conspicuous scientific puzzles posed by contemporary observational knowledge of the magnetic activity of the Sun. The puzzles emphasize how much classical physics we have yet to learn from the Sun. The physics of solar activity is based on the principles of Newton, Maxwell, Lorentz, Boltzmann, et. al., along with the principles of radiative transfer. In the large, these principles are expressed by magnetohydrodynamics. A brief derivation of the magnetohydrodynamic induction and momentum equations is provided, with a discussion of popular misconceptions.

  17. Measurement of radiation and temperature of cathod spots in excimer laser discharge; Ekishima reza reiki hodennai ni fukumareru inkyoku kiten no kogakuteki kansoku to ondo no sokutei

    Energy Technology Data Exchange (ETDEWEB)

    Minamitani, Y.; Nakatani, H. [Mitsubishi Electric Corp., Tokyo (Japan)

    1996-08-20

    Excimer laser is used in various fields such as luminous source for steppers, annealing treatment, ablation process, nuclear fusion and so on. In this paper, the radiation timing and gas temperature of cathode spots, streamer discharges and glow discharges in KrF excimer are measured by observing the radiating spectra thereof. The following conclusions are obtained from the results of the present study. Cathode spots begin to radiate at about 20ns after the discharge initiation, then the first and second radiation peaks are observed respectively when the discharge current reversing after passing zero point and the reserved discharged current approaching zero point. Streamer discharge makes flashover between electrodes at the second radiation peak of cathode spots, while the glow discharges almost disappear when streamer discharges occurring. The temperatures of cathode spots and glow discharge as 5500K and 2600K respectively are almost constant and independent upon the discharging voltage of laser. 14 refs., 12 figs.

  18. Temperature Dependences of the Quantum-Mechanical and Semi-Classical Spectral-Line Widths and the Separation 0 of the Impact and Non-Impact Regions for an Ar-Perturbed/K-Radiator System

    Directory of Open Access Journals (Sweden)

    W. C. Kreye

    2010-01-01

    Full Text Available Quantum-mechanical and semi-classical spectral-line shapes are computed at =400, 800, and 1000 K for the line core of the 5802 Å line of the Ar-Perturbed/K-Radiator system. HWHMs ('s are measured from computed full spectral-line shapes. The final-state pseudopotential is for the 721/2 state, and the initial-state potential is for the 423/2,3/2 state. Three high-pressure (P log(—versus—log( curves, corresponding to the non-impact region, intersect a similar set of low-P, impact-region curves at intersections, 0's. Similarly, for two sets of log(—versus—log( curves, which yield intersections, 0's, where is the perturber density. These 0's and 0's separate the two regions and represent the upper limits of the impact regions. A specific validity condition for the impact region is given by the equation ≤0. From an earlier spectroscopic, Fabry-Perot paper, expt=0.021 cm−1 at =400 K and =10 torr. Two theoretical values, theor=0.025 and 0.062 cm−1 corresponding to two different pseudo-potentials, are reported. Two -dependent figures are given, in which the first shows an increase in the impact region with , based on as the basic parameter, and the second which shows a decrease in the impact region with , based on as the basic parameter.

  19. Research Directed at Developing a Classical Theory to Describe Isotope Separation of Polyatomic Molecules Illuminated by Intense Infrared Radiation. Final Report for period May 7, 1979 to September 30, 1979; Extension December 31, 1997

    Science.gov (United States)

    Lamb, W. E. Jr.

    1981-12-01

    This final report describes research on the theory of isotope separation produced by the illumination of polyatomic molecules by intense infrared laser radiation. This process is investigated by treating the molecule, sulfur hexafluoride, as a system of seven classical particles that obey the Newtonian equations of motion. A minicomputer is used to integrate these differential equations. The particles are acted on by interatomic forces, and by the time-dependent electric field of the laser. We have a very satisfactory expression for the interaction of the laser and the molecule which is compatible with infrared absorption and spectroscopic data. The interatomic potential is capable of improvement, and progress on this problem is still being made. We have made several computer runs of the dynamical behavior of the molecule using a reasonably good model for the interatomic force law. For the laser parameters chosen, we find that typically the molecule passes quickly through the resonance region into the quasi-continuum and even well into the real continuum before dissociation actually occurs. When viewed on a display terminal, the motions are exceedingly complex. As an aid to the visualization of the process, we have made a number of 16 mm movies depicting a three-dimensional representation of the motion of the seven particles. These show even more clearly the enormous complexity of the motions, and make clear the desirability of finding ways of characterizing the motion in simple ways without giving all of the numerical detail. One of the ways to do this is to introduce statistical parameters such as a temperature associated with the distribution of kinetic energies of the single particle. We have made such an analysis of our data runs, and have found favorable indications that such methods will prove useful in keeping track of the dynamical histories.

  20. Classical, Semi-classical and Quantum Noise

    CERN Document Server

    Poor, H; Scully, Marlan

    2012-01-01

    David Middleton was a towering figure of 20th Century engineering and science and one of the founders of statistical communication theory. During the second World War, the young David Middleton, working with Van Fleck, devised the notion of the matched filter, which is the most basic method used for detecting signals in noise. Over the intervening six decades, the contributions of Middleton have become classics. This collection of essays by leading scientists, engineers and colleagues of David are in his honor and reflect the wide  influence that he has had on many fields. Also included is the introduction by Middleton to his forthcoming book, which gives a wonderful view of the field of communication, its history and his own views on the field that he developed over the past 60 years. Focusing on classical noise modeling and applications, Classical, Semi-Classical and Quantum Noise includes coverage of statistical communication theory, non-stationary noise, molecular footprints, noise suppression, Quantum e...

  1. Classical and semiclassical aspects of chemical dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Gray, S.K.

    1982-08-01

    Tunneling in the unimolecular reactions H/sub 2/C/sub 2/ ..-->.. HC/sub 2/H, HNC ..-->.. HCN, and H/sub 2/CO ..-->.. H/sub 2/ + CO is studied with a classical Hamiltonian that allows the reaction coordinate and transverse vibrational modes to be considered directly. A combination of classical perturbation theory and the semiclassical WKB method allows tunneling probabilities to be obtained, and a statistical theory (RRKM) is used to construct rate constants for these reactions in the tunneling regime. In this fashion, it is found that tunneling may be important, particularly for low excitation energies. Nonadiabatic charge transfer in the reaction Na + I ..-->.. Na /sup +/ + I/sup -/ is treated with classical trajectories based on a classical Hamiltonian that is the analogue of a quantum matrix representation. The charge transfer cross section obtained is found to agree reasonably well with the exact quantum results. An approximate semiclassical formula, valid at high energies, is also obtained. The interaction of radiation and matter is treated from a classical viewpoint. The excitation of an HF molecule in a strong laser is described with classical trajectories. Quantum mechanical results are also obtained and compared to the classical results. Although the detailed structure of the pulse time averaged energy absorption cannot be reproduced classically, classical mechanics does predict the correct magnitude of energy absorption, as well as certain other qualitative features. The classical behavior of a nonrotating diatomic molecule in a strong laser field is considered further, by generating a period advance map that allows the solution over many periods of oscillation of the laser to be obtained with relative ease. Classical states are found to form beautiful spirals in phase space as time progresses. A simple pendulum model is found to describe the major qualitative features. (WHM)

  2. Lectures on Classical Integrability

    CERN Document Server

    Torrielli, Alessandro

    2016-01-01

    We review some essential aspects of classically integrable systems. The detailed outline of the lectures consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schroedinger model, principal chiral field); 4. Features of classical r-matrices: Belavin-Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel'fand-Levitan-Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.

  3. Quantum-classical crossover in electrodynamics

    CERN Document Server

    Polonyi, J

    2006-01-01

    A classical field theory is proposed for the electric current and the electromagnetic field interpolating between microscopic and macroscopic domains. It represents a generalization of the density functional for the dynamics of the current and the electromagnetic field in the quantum side of the crossover and reproduces standard classical electrodynamics on the other side. The effective action derived in the closed time path formalism and the equations of motion follow from the variational principle. The polarization of the Dirac-see can be taken into account in the quadratic approximation of the action by the introduction of the deplacement field strengths as in conventional classical electrodynamics. Decoherence appears naturally as a simple one-loop effect in this formalism. It is argued that the radiation time arrow is generated from the quantum boundary conditions in time by decoherence at the quantum-classical crossover and the Abraham-Lorentz force arises from the accelerating charge or from other char...

  4. The equilibrium classical scatter spectrum of waves

    CERN Document Server

    Guruprasad, V

    2016-01-01

    Regardless of the unspecific notions of photons as light complexes, radiation bundles or wave packets, the radiation from a single state transition is at most a single continuous wave train that starts and ends with the transition. The radiation equilibrium spectrum must be the superposition sum of the spectra of such wave trains. A classical equipartition of wave trains cannot diverge since they would be finite in number, whereas standing wave modes are by definition infinite, which had doomed Rayleigh's theory, and concern only the total radiation. Wave trains are the microscopic entities of radiation interacting with matter, that correspond to molecules in kinetic theory. Their quantization came from matter transitions in Einstein's 1917 derivation of Planck's law. The spectral scatter of wave trains by Doppler shifts, which cause the wavelength displacements in Wien's law used for the frequency dependence in Einstein's derivation, is shown to yield the shape of the Planck spectrum. A Lorentz transform pro...

  5. Fermions from classical statistics

    OpenAIRE

    2010-01-01

    We describe fermions in terms of a classical statistical ensemble. The states $\\tau$ of this ensemble are characterized by a sequence of values one or zero or a corresponding set of two-level observables. Every classical probability distribution can be associated to a quantum state for fermions. If the time evolution of the classical probabilities $p_\\tau$ amounts to a rotation of the wave function $q_\\tau(t)=\\pm \\sqrt{p_\\tau(t)}$, we infer the unitary time evolution of a quantum system of fe...

  6. Davidson and classical pragmatism

    Directory of Open Access Journals (Sweden)

    Paula Rossi

    2007-06-01

    Full Text Available In this paper I wish to trace some connections between Donald Davidson's work (1917-2003 and two major representatives of the classical pragmatist movement: Charles S. Peirce (1839-1914 and William James (1842-1910. I will start with a basic characterization of classical pragmatism; then, I shall examine certain conceptions in Peirce's and James' pragmatism, in order to establish affinities with Davidson´s thought. Finally, and bearing in mind the previous con-nections, I will reflect briefly on the relevance –often unrecognized- of classical pragmatist ideas in the context of contemporary philosophi-cal discussions.

  7. Advanced classical field theory

    CERN Document Server

    Giachetta, Giovanni; Sardanashvily, Gennadi

    2009-01-01

    Contemporary quantum field theory is mainly developed as quantization of classical fields. Therefore, classical field theory and its BRST extension is the necessary step towards quantum field theory. This book aims to provide a complete mathematical foundation of Lagrangian classical field theory and its BRST extension for the purpose of quantization. Based on the standard geometric formulation of theory of nonlinear differential operators, Lagrangian field theory is treated in a very general setting. Reducible degenerate Lagrangian theories of even and odd fields on an arbitrary smooth manifold are considered. The second Noether theorems generalized to these theories and formulated in the homology terms provide the strict mathematical formulation of BRST extended classical field theory

  8. On Noncommutative Classical Mechanics

    CERN Document Server

    Djemai, A E F

    2003-01-01

    In this work, I investigate the noncommutative Poisson algebra of classical observables corresponding to a proposed general Noncommutative Quantum Mechanics, \\cite{1}. I treat some classical systems with various potentials and some Physical interpretations are given concerning the presence of noncommutativity at large scales (Celeste Mechanics) directly tied to the one present at small scales (Quantum Mechanics) and its possible relation with UV/IR mixing.

  9. Between classical and quantum

    OpenAIRE

    2007-01-01

    The relationship between classical and quantum theory is of central importance to the philosophy of physics, and any interpretation of quantum mechanics has to clarify it. Our discussion of this relationship is partly historical and conceptual, but mostly technical and mathematically rigorous, including over 500 references. On the assumption that quantum mechanics is universal and complete, we discuss three ways in which classical physics has so far been believed to emerge from quantum physic...

  10. Quantum and Classic Brackets

    OpenAIRE

    Kisil, Vladimir V.

    2000-01-01

    We describe an $p$-mechanical (see funct-an/9405002 and quant-ph/9610016) brackets which generate quantum (commutator) and classic (Poisson) brackets in corresponding representations of the Heisenberg group. We \\emph{do not} use any kind of semiclassic approximation or limiting procedures for $\\hbar \\to 0$. Harmonic oscillator considered within the approach. Keywords: Classic and quantum mechanics, Hamilton and Heisenberg equations, Poisson brackets, commutator, Heisenberg group.

  11. Classical electromagnetism in a nutshell

    CERN Document Server

    Garg, Anupam

    2012-01-01

    This graduate-level physics textbook provides a comprehensive treatment of the basic principles and phenomena of classical electromagnetism. While many electromagnetism texts use the subject to teach mathematical methods of physics, here the emphasis is on the physical ideas themselves. Anupam Garg distinguishes between electromagnetism in vacuum and that in material media, stressing that the core physical questions are different for each. In vacuum, the focus is on the fundamental content of electromagnetic laws, symmetries, conservation laws, and the implications for phenomena such as radiation and light. In material media, the focus is on understanding the response of the media to imposed fields, the attendant constitutive relations, and the phenomena encountered in different types of media such as dielectrics, ferromagnets, and conductors. The text includes applications to many topical subjects, such as magnetic levitation, plasmas, laser beams, and synchrotrons.

  12. Noninertial zero-point fluctuations A laboratory-oriented introduction

    CERN Document Server

    Rosu, H C

    2000-01-01

    In an introductory and nonrigorous manner, the write-up of the talk extends and updates several sections of my review gr-qc/9406012, last updated in 1997. I present the recently introduced glass analogy for black holes but in order to have a more detailed picture I collected from the literature some useful material related to the violations of the fluctuation-dissipation theorem in glass physics and stationary driven systems. Nonequilibrium effective temperatures from glass irreversible thermodynamics are considered as useful and quite general concepts for noninertial quantum fluctuations, though the analogy is not fully disentangled. Next, I discuss the stationary and nonstationary scalar vacuum noises in some detail and I emphasize the radiometric nature of the Frenet invariants of the stationary worldlines, rather than sticking to the thermal interpretation of the vacuum excitations as apparent for the uniformly accelerated quantum detector. I go on with the Hacyan-Sarmiento approach for calculating electr...

  13. The Casimir effect physical manifestations of zero-point energy

    CERN Document Server

    Milton, K A

    2001-01-01

    In its simplest manifestation, the Casimir effect is a quantum force of attraction between two parallel uncharged conducting plates. More generally, it refers to the interaction - which may be either attractive or repulsive - between material bodies due to quantum fluctuations in whatever fields are relevant. It is a local version of the van der Waals force between molecules. Its sweep ranges from perhaps its being the origin of the cosmological constant to its being responsible for the confinement of quarks. This monograph develops the theory of such forces, based primarily on physically tran

  14. Classical Black Holes Are Hot

    CERN Document Server

    Curiel, Erik

    2014-01-01

    In the early 1970s it is was realized that there is a striking formal analogy between the Laws of black-hole mechanics and the Laws of classical thermodynamics. Before the discovery of Hawking radiation, however, it was generally thought that the analogy was only formal, and did not reflect a deep connection between gravitational and thermodynamical phenomena. It is still commonly held that the surface gravity of a stationary black hole can be construed as a true physical temperature and its area as a true entropy only when quantum effects are taken into account; in the context of classical general relativity alone, one cannot cogently construe them so. Does the use of quantum field theory in curved spacetime offer the only hope for taking the analogy seriously? I think the answer is `no'. To attempt to justify that answer, I shall begin by arguing that the standard argument to the contrary is not physically well founded, and in any event begs the question. Looking at the various ways that the ideas of "tempe...

  15. From Quantum to Classical in the Sky

    CERN Document Server

    Singh, Suprit

    2016-01-01

    Inflation has by-far set itself as one of the prime ideas in the current cosmological models that seemingly has an answer for every observed phenomenon in cosmology. More importantly, it serves as a bridge between the early quantum fluctuations and the present-day classical structures. Although the transition from quantum to classical is still not completely understood till date, there are two assumptions made in the inflationary paradigm in this regard: (i) the modes (metric perturbations or fluctuations) behave classically once they are well outside the Hubble radius and, (ii) once they become classical they stay classical and hence can be described by standard perturbation theory after they re-enter the Hubble radius. We critically examine these assumptions for the tensor modes of (linear) metric perturbations in a toy three stage universe with (i) inflation, (ii) radiation-dominated and (iii) late-time accelerated phases. The quantum-to-classical transition for these modes is evident from the evolution of...

  16. Discrete Classical Electromagnetic Fields

    CERN Document Server

    De Souza, M M

    1997-01-01

    The classical electromagnetic field of a spinless point electron is described in a formalism with extended causality by discrete finite transverse point-vector fields with discrete and localized point interactions. These fields are taken as a classical representation of photons, ``classical photons". They are all transversal photons; there are no scalar nor longitudinal photons as these are definitely eliminated by the gauge condition. The angular distribution of emitted photons coincides with the directions of maximum emission in the standard formalism. The Maxwell formalism and its standard field are retrieved by the replacement of these discrete fields by their space-time averages, and in this process scalar and longitudinal photons are necessarily created and added. Divergences and singularities are by-products of this averaging process. This formalism enlighten the meaning and the origin of the non-physical photons, the ones that violate the Lorentz condition in manifestly covariant quantization methods.

  17. Between classical and quantum

    CERN Document Server

    Landsman, N P

    2005-01-01

    The relationship between classical and quantum theory is of central importance to the philosophy of physics, and any interpretation of quantum mechanics has to clarify it. Our discussion of this relationship is partly historical and conceptual, but mostly technical and mathematically rigorous, including over 500 references. On the assumption that quantum mechanics is universal and complete, we discuss three ways in which classical physics has so far been believed to emerge from quantum physics, namely in the limit h -> 0 of small Planck's constant (in a finite system), in the limit of a large system, and through decoherence and consistent histores. The first limit is closely related to modern quantization theory and microlocal analysis, whereas the second involves methods of C*-algebras and the concepts of superselection sectors and macroscopic observables. In these limits, the classical world does not emerge as a sharply defined objective reality, but rather as an approximate appearance relative to certain "...

  18. Randomness: Quantum versus classical

    Science.gov (United States)

    Khrennikov, Andrei

    2016-05-01

    Recent tremendous development of quantum information theory has led to a number of quantum technological projects, e.g. quantum random generators. This development had stimulated a new wave of interest in quantum foundations. One of the most intriguing problems of quantum foundations is the elaboration of a consistent and commonly accepted interpretation of a quantum state. Closely related problem is the clarification of the notion of quantum randomness and its interrelation with classical randomness. In this short review, we shall discuss basics of classical theory of randomness (which by itself is very complex and characterized by diversity of approaches) and compare it with irreducible quantum randomness. We also discuss briefly “digital philosophy”, its role in physics (classical and quantum) and its coupling to the information interpretation of quantum mechanics (QM).

  19. Classical mechanics with Maxima

    CERN Document Server

    Timberlake, Todd Keene

    2016-01-01

    This book guides undergraduate students in the use of Maxima—a computer algebra system—in solving problems in classical mechanics. It functions well as a supplement to a typical classical mechanics textbook. When it comes to problems that are too difficult to solve by hand, computer algebra systems that can perform symbolic mathematical manipulations are a valuable tool. Maxima is particularly attractive in that it is open-source, multiple-platform software that students can download and install free of charge. Lessons learned and capabilities developed using Maxima are easily transferred to other, proprietary software.

  20. Covariantizing Classical Field Theories

    CERN Document Server

    López, Marco Castrillón

    2010-01-01

    We show how to enlarge the covariance group of any classical field theory in such a way that the resulting "covariantized" theory is 'essentially equivalent' to the original. In particular, our technique will render any classical field theory generally covariant, that is, the covariantized theory will be spacetime diffeomorphism-covariant and free of absolute objects. Our results thus generalize the well-known parametrization technique of Dirac and Kucha\\v{r}. Our constructions apply equally well to internal covariance groups, in which context they produce natural derivations of both the Utiyama minimal coupling and St\\"uckelberg tricks.

  1. Problems in classical mechanics

    CERN Document Server

    Katkar, L N

    2014-01-01

    Problems in classical mechanics presents a lucid treatment of the formulations of Lagrangian, Hamiltonian, and the Principles of Calculus of Variations etc. important for the study of modern physics. The study of classical mechanics prepares students to apply the principles and the mathematical tools to solve real life problems. The book also incorporates and discusses in detail topics such as Central Force Motion, Rigid Body Motion and Canonical Transformations. KEY FEATURES: Around 200 solved examples with complete mathematical theory Around 70 examples given as an exercise to test and develop students understanding The physical interpretation of the Hamiltonian is highlighted

  2. Classic Problems of Probability

    CERN Document Server

    Gorroochurn, Prakash

    2012-01-01

    "A great book, one that I will certainly add to my personal library."—Paul J. Nahin, Professor Emeritus of Electrical Engineering, University of New Hampshire Classic Problems of Probability presents a lively account of the most intriguing aspects of statistics. The book features a large collection of more than thirty classic probability problems which have been carefully selected for their interesting history, the way they have shaped the field, and their counterintuitive nature. From Cardano's 1564 Games of Chance to Jacob Bernoulli's 1713 Golden Theorem to Parrondo's 1996 Perplexin

  3. Classical Holographic Codes

    CERN Document Server

    Brehm, Enrico M

    2016-01-01

    In this work, we introduce classical holographic codes. These can be understood as concatenated probabilistic codes and can be represented as networks uniformly covering hyperbolic space. In particular, classical holographic codes can be interpreted as maps from bulk degrees of freedom to boundary degrees of freedom. Interestingly, they are shown to exhibit features similar to those expected from the AdS/CFT correspondence. Among these are a version of the Ryu-Takayanagi formula and intriguing properties regarding bulk reconstruction and boundary representations of bulk operations. We discuss the relation of our findings with expectations from AdS/CFT and, in particular, with recent results from quantum error correction.

  4. Learning Classical Music Club

    CERN Multimedia

    Learning Classical Music Club

    2010-01-01

    There is a new CERN Club called “Learning Classical Music at CERN”. We are aiming to give classical music lessons for different instruments (see link) for students from 5 to 100 years old. We are now ready to start our activities in the CERN barracks. We are now in the enrollment phase and hope to start lessons very soon ! Club info can be found in the list of CERN Club: http://user.web.cern.ch/user/Communication/SocialLifeActivities/Clubs/Clubs.html Salvatore Buontempo Club President

  5. Synchrotron radiation with radiation reaction

    Science.gov (United States)

    Nelson, Robert W.; Wasserman, Ira

    1991-04-01

    A rigorous discussion is presented of the classical motion of a relativistic electron in a magnetic field and the resulting electromagnetic radiation when radiation reaction is important. In particular, for an electron injected with initial energy gamma(0), a systematic perturbative solution to the Lorentz-Dirac equation of motion is developed for field strengths satisfying gamma(0) B much less than 6 x 10 to the 15th G. A particularly accurate solution to the electron orbital motion in this regime is found and it is demonstrated how lowest-order corrections can be calculated. It is shown that the total energy-loss rate corresponds to what would be found using the exact Larmor power formula without including radiation reaction. Provided that the particle energy and field strength satisfy the same contraint, it is explicitly demonstrated that the intuitive prescription for calculating the time-integrated radiation spectrum described above is correct.

  6. Strong Coupling and Classicalization

    CERN Document Server

    Dvali, Gia

    2016-01-01

    Classicalization is a phenomenon in which a theory prevents itself from entering into a strong-coupling regime, by redistributing the energy among many weakly-interacting soft quanta. In this way, the scattering process of some initial hard quanta splits into a large number of soft elementary processes. In short, the theory trades the strong coupling for a high-multiplicity of quanta. At very high energies, the outcome of such a scattering experiment is a production of soft states of high occupation number that are approximately classical. It is evident that black hole creation in particle collision at super-Planckian energies is a result of classicalization, but there is no a priory reason why this phenomenon must be limited to gravity. If the hierarchy problem is solved by classicalization, the LHC has a chance of detecting a tower of new resonances. The lowest-lying resonances must appear right at the strong coupling scale in form of short-lived elementary particles. The heavier members of the tower must b...

  7. Classical Mythology. Fourth Edition.

    Science.gov (United States)

    Morford, Mark P. O.; Lenardon, Robert J.

    Designed for students with little or no background in classical literature, this book introduces the Greek and Roman myths of creation, myths of the gods, Greek sagas and local legends, and presents contemporary theories about the myths. Drawing on Homer, Hesiod, Pindar, Vergil, and others, the book provides many translations and paraphrases of…

  8. Classical galactosaemia revisited

    NARCIS (Netherlands)

    A.M. Bosch

    2006-01-01

    Classical galactosaemia (McKusick 230400) is an: autosomal recessive disorder of galactose metabolism, caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT; EC 2.7.712). Most patients present in the neonatal period, after ingestion of galactose, with jaundice, hepatospl

  9. Classicism and Romanticism.

    Science.gov (United States)

    Huddleston, Gregory H.

    1993-01-01

    Describes one teacher's methods for introducing to secondary English students the concepts of Classicism and Romanticism in relation to pictures of gardens, architecture, music, and literary works. Outlines how the unit leads to a writing assignment based on collected responses over time. (HB)

  10. Mecanica Clasica (Classical Mechanics)

    OpenAIRE

    Rosu, H. C.

    1999-01-01

    First Internet graduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

  11. Mecanica Clasica (Classical Mechanics)

    CERN Document Server

    Rosu, H C

    1999-01-01

    First Internet undergraduate course on Classical Mechanics in Spanish (Castellano). This is about 80% of the material I covered during the January-June 1999 semester at IFUG in the Mexican city of Leon. English and Romanian versions are in (slow) progress and hopefully will be arXived. For a similar course on Quantum Mechanics, see physics/9808031

  12. Classical Mechanics Laboratory

    Science.gov (United States)

    Brosing, Juliet W.

    2006-12-01

    At Pacific University we have included a lab with our upper division Classical Mechanics class. We do a combination of physical labs (air resistance, harmonic motion, amusement park physics), Maple labs (software), and projects. Presentation of some of the labs, results and challenges with this course will be included.

  13. Children's Classics. Fifth Edition.

    Science.gov (United States)

    Jordan, Alice M.

    "Children's Classics," a 1947 article by Alice M. Jordan reprinted from "The Horn Book Magazine," examines the dynamics and appeal of some of the most famous books for young readers, including "Alice in Wonderland,""The Wind in the Willows,""Robinson Crusoe," and "Andersen's Fairy Tales." Paul Hein's annotated bibliography, a revision of Jordan's…

  14. Classical Diophantine equations

    CERN Document Server

    1993-01-01

    The author had initiated a revision and translation of "Classical Diophantine Equations" prior to his death. Given the rapid advances in transcendence theory and diophantine approximation over recent years, one might fear that the present work, originally published in Russian in 1982, is mostly superseded. That is not so. A certain amount of updating had been prepared by the author himself before his untimely death. Some further revision was prepared by close colleagues. The first seven chapters provide a detailed, virtually exhaustive, discussion of the theory of lower bounds for linear forms in the logarithms of algebraic numbers and its applications to obtaining upper bounds for solutions to the eponymous classical diophantine equations. The detail may seem stark--- the author fears that the reader may react much as does the tourist on first seeing the centre Pompidou; notwithstanding that, Sprind zuk maintainsa pleasant and chatty approach, full of wise and interesting remarks. His emphases well warrant, ...

  15. Electrodynamics classical inconsistencies

    CERN Document Server

    De Souza, M M

    1995-01-01

    The problems of Classical Electrodynamics with the electron equation of motion and with non-integrable singularity of its self-field stress tensor are well known. They are consequences, we show, of neglecting terms that are null off the charge world line but that gives a non null contribution on its world line. The self-field stress tensor of a point classical electron is integrable, there is no causality violation and no conflict with energy conservation in its equation of motion, and there is no need of any kind of renormalization nor of any change in the Maxwell's theory for this. (This is part of the paper hep-th/9510160, stripped , for simplicity, of its non-Minkowskian geometrization of causality and of its discussion about the physical meaning of the Maxwell-Faraday concept of field).

  16. Injuries in classical ballet

    Directory of Open Access Journals (Sweden)

    Adriana Coutinho de Azevedo Guimarães

    2008-06-01

    Full Text Available This study aimed to elucidate what injuries are most likely to occur due to classical ballet practice. The research used national and international bibliography. The bibliography analysis indicated that technical and esthetical demands lead to a practice of non-anatomical movements, causing the ballet dancer to suffer from a number of associated lesions. Most of the injuries are caused by technical mistakes and wrong training. Troubles in children are usually due to trying to force external rotation at hip level and to undue use of point ballet slippers. The commonest lesions are in feet and ankles, followed by knees and hips. The rarest ones are in the upper limbs. These injuries are caused by exercise excess, by repetitions always in the same side and by wrong and early use of point slippers. The study reached the conclusion that incorrect application of classical ballet technique predisposes the dancers to characteristic injuries.

  17. Classical and statistical thermodynamics

    CERN Document Server

    Rizk, Hanna A

    2016-01-01

    This is a text book of thermodynamics for the student who seeks thorough training in science or engineering. Systematic and thorough treatment of the fundamental principles rather than presenting the large mass of facts has been stressed. The book includes some of the historical and humanistic background of thermodynamics, but without affecting the continuity of the analytical treatment. For a clearer and more profound understanding of thermodynamics this book is highly recommended. In this respect, the author believes that a sound grounding in classical thermodynamics is an essential prerequisite for the understanding of statistical thermodynamics. Such a book comprising the two wide branches of thermodynamics is in fact unprecedented. Being a written work dealing systematically with the two main branches of thermodynamics, namely classical thermodynamics and statistical thermodynamics, together with some important indexes under only one cover, this treatise is so eminently useful.

  18. Randomness: quantum versus classical

    CERN Document Server

    Khrennikov, Andrei

    2015-01-01

    Recent tremendous development of quantum information theory led to a number of quantum technological projects, e.g., quantum random generators. This development stimulates a new wave of interest in quantum foundations. One of the most intriguing problems of quantum foundations is elaboration of a consistent and commonly accepted interpretation of quantum state. Closely related problem is clarification of the notion of quantum randomness and its interrelation with classical randomness. In this short review we shall discuss basics of classical theory of randomness (which by itself is very complex and characterized by diversity of approaches) and compare it with irreducible quantum randomness. The second part of this review is devoted to the information interpretation of quantum mechanics (QM) in the spirit of Zeilinger and Brukner (and QBism of Fuchs et al.) and physics in general (e.g., Wheeler's "it from bit") as well as digital philosophy of Chaitin (with historical coupling to ideas of Leibnitz). Finally, w...

  19. Computation in Classical Mechanics

    CERN Document Server

    Timberlake, Todd

    2007-01-01

    There is a growing consensus that physics majors need to learn computational skills, but many departments are still devoid of computation in their physics curriculum. Some departments may lack the resources or commitment to create a dedicated course or program in computational physics. One way around this difficulty is to include computation in a standard upper-level physics course. An intermediate classical mechanics course is particularly well suited for including computation. We discuss the ways we have used computation in our classical mechanics courses, focusing on how computational work can improve students' understanding of physics as well as their computational skills. We present examples of computational problems that serve these two purposes. In addition, we provide information about resources for instructors who would like to include computation in their courses.

  20. Concepts of classical optics

    CERN Document Server

    Strong, John

    2004-01-01

    An intermediate course in optics, this volume explores both experimental and theoretical concepts, offering practical knowledge of geometrical optics that will enhance students' comprehension of any relevant applied science. Its exposition of the concepts of classical optics is presented with a minimum of mathematical detail but presumes some knowledge of calculus, vectors, and complex numbers.Subjects include light as wave motion; superposition of wave motions; electromagnetic waves; interaction of light and matter; velocities and scattering of light; polarized light and dielectric boundarie

  1. Revisiting a Classic

    Science.gov (United States)

    Rogers, Ibram

    2008-01-01

    As a 26-year-old English teacher in 1958, Chinua Achebe had no idea that the book he was writing would become a literary classic, not only in Africa but also throughout the world. He could only try to articulate the feelings he had for his countrymen and women. Achebe had a burning desire to tell the true story of Africa and African humanity. The…

  2. Gravitational radiation resistance, radiation damping and field fluctuations

    Science.gov (United States)

    Schaefer, G.

    1981-03-01

    Application is made of two different generalized fluctuation-dissipation theorems and their derivations to the calculation of the gravitational quadrupole radiation resistance using the radiation-reaction force given by Misner, Thorne and Wheeler and the usual tidal force on one hand and the tidal force and the free gravitational radiation field on the other hand. The quantum-mechanical version (including thermal generalizations) of the well known classical quadrupole radiation damping formula is obtained as a function of the radiation resistance.

  3. Classical Trace Anomaly

    OpenAIRE

    Farhoudi, M.

    1995-01-01

    We seek an analogy of the mathematical form of the alternative form of Einstein's field equations for Lovelock's field equations. We find that the price for this analogy is to accept the existence of the trace anomaly of the energy-momentum tensor even in classical treatments. As an example, we take this analogy to any generic second order Lagrangian and exactly derive the trace anomaly relation suggested by Duff. This indicates that an intrinsic reason for the existence of such a relation sh...

  4. The classical task

    DEFF Research Database (Denmark)

    Gillis, Steven; Souman, Agnita; Dhollander, Sim

    -year-olds to 9-year-olds. The experiment was also administered with a control group of adults. Procedure: The procedure consists of a classical set-up in which the subjects are shown pictures of objects. On presenting each object, the test leader says: "Here is a X (name of the object)". The next...... articulated: Prediction 1: a global analysis of the plural forms provided by the subjects is expected to show an increase of the correct responses as children grow older. Prediction 2: As to suffix selection, we expect that the plural of nouns selecting a fully predictable suffix will be more readily mastered...

  5. A Classic Through Eternity

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    FIVE years ago, an ancient Chinese air was beamed to outer space as a PR exercise. To humankind, music is a universal language, so the tune seemed an ideal medium for communication with extraterrestrial intelligence. So far there has been no response, but it is believed that the tune will play for a billion years, and eventually be heard and understood. The melody is called High Mountain and Flowing Stream, and it is played on the guqin, a seven-stringed classical musical instrument similar to the zither.

  6. On Classical Ideal Gases

    Directory of Open Access Journals (Sweden)

    Laurent Chusseau

    2013-02-01

    Full Text Available We show that the thermodynamics of ideal gases may be derived solely from the Democritean concept of corpuscles moving in vacuum plus a principle of simplicity, namely that these laws are independent of the laws of motion, aside from the law of energy conservation. Only a single corpuscle in contact with a heat bath submitted to a z and t-invariant force is considered. Most of the end results are known but the method appears to be novel. The mathematics being elementary, the present paper should facilitate the understanding of the ideal gas law and of classical thermodynamics even though not-usually-taught concepts are being introduced.

  7. Semi-classical Electrodynamics

    Science.gov (United States)

    Lestone, John

    2016-03-01

    Quantum electrodynamics is complex and its associated mathematics can appear overwhelming for those not trained in this field. We describe semi-classical approaches that can be used to obtain a more intuitive physical feel for several QED processes including electro-statics, Compton scattering, pair annihilation, the anomalous magnetic moment, and the Lamb shift, that could be taught easily to undergraduate students. Any physicist who brings their laptop to the talk will be able to build spread sheets in less than 10 minutes to calculate g/2 =1.001160 and a Lamb shift of 1057 MHz.

  8. Classical cytogenetics: karyotyping techniques.

    Science.gov (United States)

    Bates, Steven E

    2011-01-01

    Classical cytogenetics by karyotyping has been utilized in clinical research laboratories for more than 50 years and remains the key method used in the stem cell laboratory to assess the genetic stability of stem cell cultures. It is currently the most readily accessible method for detecting chromosomal abnormalities in pluripotent stem cell cultures. This chapter will describe (1) how to prepare a culture to maximize the number of metaphase cells, (2) how to prepare slides containing chromosome spreads (3) methods used to stain chromosomes, and (4) how to interpret the cytogenetic report.

  9. Probability representation of classical states

    NARCIS (Netherlands)

    Man'ko, OV; Man'ko, [No Value; Pilyavets, OV

    2005-01-01

    Probability representation of classical states described by symplectic tomograms is discussed. Tomographic symbols of classical observables which are functions on phase-space are studied. Explicit form of kernel of commutative star-product of the tomographic symbols is obtained.

  10. Features of Low Energy Classical Bremsstrahlung From Neutral Atoms.

    Science.gov (United States)

    Florescu, A.; Obolensky, O. I.; Pratt, R. H.

    2002-05-01

    We study classical bremsstrahlung from neutral atoms and investigate the features characteristic for the low incident energy region. These features include oscillations in the energy dependence of the bremsstrahlung cross section and structures in the asymmetry parameter of radiation. We use soft-photon limit results to elucidate the physical origins of the features. We show that there is a correspondence between classical and quantum results [1]. In both cases the features result from the suppression of contributions to the radiation from certain angular momenta at certain energies. In quantum mechanics this corresponds to zeroes in certain radiation matrix elements. In the classical case the lack of contribution from some interval of angular momentum is caused by behaviors of elastic electron scattering in screened potentials. [1] A. Florescu, O. I. Obolensky, C. D. Shaffer, and R. H. Pratt 2001 AIP Conference Proceedings 576, 60-64.

  11. Classical Trajectories and Quantum Spectra

    Science.gov (United States)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  12. Wave-particle duality in classical mechanics

    Science.gov (United States)

    Davydov, Alexander Y.

    2012-05-01

    Until recently, wave-particle duality has been thought of as quantum principle without a counterpart in classical physics. This belief was challenged after (i) finding that average dynamics of a classical particle in a strong inhomogeneous oscillating field resembles that of a quantum object and (ii) experimental discovery of "walkers" - macroscopic droplets that bounce on a vertically vibrating bath of the same fluid and can self-propel via interaction with the surface waves they generate. This paper exposes a new family of objects that can display both particle and wave features all together while strictly obeying laws of the Newtonian mechanics. In contrast to the previously known duality examples in classical physics, oscillating field or constant inflow of energy are not required for their existence. These objects behave deterministically provided that all their degrees of freedom are known to an observer. If, however, some degrees of freedom are unknown, an observer can describe such objects only probabilistically and they manifest weird features similar to that of quantum particles. We show new classical counterparts of such quantum phenomena as particle interference, tunneling, above-barrier reflection, trapping on top of a barrier, and spontaneous emission of radiation. In the light of these findings, we hypothesize that quantum mechanics may emerge as approximation from a more profound theory on a deeper level.

  13. Effective dynamics of a classical point charges

    CERN Document Server

    Polonyi, Janos

    2013-01-01

    The effective Lagrangian of a point charge is derived by eliminating the electromagnetic field within the framework of the classical closed time path formalism. The short distance singularity of the electromagnetic field is regulated by an UV cutoff. The Abraham-Lorentz force is recovered and its similarity to anomalies is underlined. The full cutoff-dependent linearized equation of motion is obtained, no runaway trajectories are found but the effective dynamics shows acausality if the cutoff is beyond the classical charge radius. The strength of the radiation reaction force displays a pole in its cutoff-dependence in a manner reminiscent of the Landau-pole of perturbative QED. Similarity between the dynamical breakdown of the time reversal invariance and dynamical symmetry breaking is pointed out.

  14. Perspective: Quantum or classical coherence?

    Science.gov (United States)

    Miller, William H

    2012-06-07

    Some coherence effects in chemical dynamics are described correctly by classical mechanics, while others only appear in a quantum treatment--and when these are observed experimentally it is not always immediately obvious whether their origin is classical or quantum. Semiclassical theory provides a systematic way of adding quantum coherence to classical molecular dynamics and thus provides a useful way to distinguish between classical and quantum coherence. Several examples are discussed which illustrate both cases. Particularly interesting is the situation with electronically non-adiabatic processes, where sometimes whether the coherence effects are classical or quantum depends on what specific aspects of the process are observed.

  15. Mechanical Systems, Classical Models

    CERN Document Server

    Teodorescu, Petre P

    2009-01-01

    This third volume completes the Work Mechanical Systems, Classical Models. The first two volumes dealt with particle dynamics and with discrete and continuous mechanical systems. The present volume studies analytical mechanics. Topics like Lagrangian and Hamiltonian mechanics, the Hamilton-Jacobi method, and a study of systems with separate variables are thoroughly discussed. Also included are variational principles and canonical transformations, integral invariants and exterior differential calculus, and particular attention is given to non-holonomic mechanical systems. The author explains in detail all important aspects of the science of mechanics, regarded as a natural science, and shows how they are useful in understanding important natural phenomena and solving problems of interest in applied and engineering sciences. Professor Teodorescu has spent more than fifty years as a Professor of Mechanics at the University of Bucharest and this book relies on the extensive literature on the subject as well as th...

  16. Grassmannization of classical models

    CERN Document Server

    Pollet, Lode; Prokof'ev, Nikolay V; Svistunov, Boris V

    2016-01-01

    Applying Feynman diagrammatics to non-fermionic strongly correlated models with local constraints might seem generically impossible for two separate reasons: (i) the necessity to have a Gaussian (non-interacting) limit on top of which the perturbative diagrammatic expansion is generated by Wick's theorem, and (ii) the Dyson's collapse argument implying that the expansion in powers of coupling constant is divergent. We show that for arbitrary classical lattice models both problems can be solved/circumvented by reformulating the high-temperature expansion (more generally, any discrete representation of the model) in terms of Grassmann integrals. Discrete variables residing on either links, plaquettes, or sites of the lattice are associated with the Grassmann variables in such a way that the partition function (and correlations) of the original system and its Grassmann-field counterpart are identical. The expansion of the latter around its Gaussian point generates Feynman diagrams. A proof-of-principle implement...

  17. Classical and quantum cosmology

    CERN Document Server

    Calcagni, Gianluca

    2017-01-01

    This comprehensive textbook is devoted to classical and quantum cosmology, with particular emphasis on modern approaches to quantum gravity and string theory and on their observational imprint. It covers major challenges in theoretical physics such as the big bang and the cosmological constant problem. An extensive review of standard cosmology, the cosmic microwave background, inflation and dark energy sets the scene for the phenomenological application of all the main quantum-gravity and string-theory models of cosmology. Born of the author's teaching experience and commitment to bridging the gap between cosmologists and theoreticians working beyond the established laws of particle physics and general relativity, this is a unique text where quantum-gravity approaches and string theory are treated on an equal footing. As well as introducing cosmology to undergraduate and graduate students with its pedagogical presentation and the help of 45 solved exercises, this book, which includes an ambitious bibliography...

  18. Classical and quantum electrodynamics and the B(3) field

    CERN Document Server

    Evans, Myron W

    2001-01-01

    It is well known that classical electrodynamics is riddled with internal inconsistencies springing from the fact that it is a linear, Abelian theory in which the potentials are unphysical. This volume offers a self-consistent hypothesis which removes some of these problems, as well as builds a framework on which linear and nonlinear optics are treated as a non-Abelian gauge field theory based on the emergence of the fundamental magnetizing field of radiation, the B(3) field. Contents: Interaction of Electromagnetic Radiation with One Fermion; The Field Equations of Classical O (3) b Electrodyn

  19. Citation classics in epilepsy

    Directory of Open Access Journals (Sweden)

    Maryann Wilson

    2013-01-01

    Full Text Available BACKGROUND: The impact of a scientific article is proportional to the citations it has received. In this study, we set out to identify the most cited works in epileptology in order to evaluate research trends in this field. METHODS: According to the Web of Science database, articles with more than 400 citations qualify as "citation classics". We conducted a literature search on the ISI Web of Science bibliometric database for scientific articles relevant to epilepsy. RESULTS: We retrieved 67 highly cited articles (400 or more citations, which were published in 31 journals: 17 clinical studies, 42 laboratory studies, 5 reviews and 3 classification articles. Clinical studies consisted of epidemiological analyses (n=3, studies on the clinical phenomenology of epilepsy (n=5 – including behavioral and prognostic aspects – and articles focusing on pharmacological (n=6 and non-pharmacological (n=3 treatment. The laboratory studies dealt with genetics (n=6, animal models (n=27, and neurobiology (n=9 – including both neurophysiology and neuropathology studies. The majority (61% of citation classics on epilepsy were published after 1986, possibly reflecting the expansion of research interest in laboratory studies driven by the development of new methodologies, specifically in the fields of genetics and animal models. Consequently, clinical studies were highly cited both before and after the mid 80s, whilst laboratory researches became widely cited after 1990. CONCLUSIONS: Our study indicates that the main drivers of scientific impact in the field of epileptology have increasingly become genetic and neurobiological studies, along with research on animal models of epilepsy. These articles are able to gain the highest numbers of citations in the time span of a few years and suggest potential directions for future research.

  20. Classical Fourier analysis

    CERN Document Server

    Grafakos, Loukas

    2014-01-01

    The main goal of this text is to present the theoretical foundation of the field of Fourier analysis on Euclidean spaces. It covers classical topics such as interpolation, Fourier series, the Fourier transform, maximal functions, singular integrals, and Littlewood–Paley theory. The primary readership is intended to be graduate students in mathematics with the prerequisite including satisfactory completion of courses in real and complex variables. The coverage of topics and exposition style are designed to leave no gaps in understanding and stimulate further study. This third edition includes new Sections 3.5, 4.4, 4.5 as well as a new chapter on “Weighted Inequalities,” which has been moved from GTM 250, 2nd Edition. Appendices I and B.9 are also new to this edition.  Countless corrections and improvements have been made to the material from the second edition. Additions and improvements include: more examples and applications, new and more relevant hints for the existing exercises, new exercises, and...

  1. Extended symmetrical classical electrodynamics.

    Science.gov (United States)

    Fedorov, A V; Kalashnikov, E G

    2008-03-01

    In this paper, we discuss a modification of classical electrodynamics in which "ordinary" point charges are absent. The modified equations contain additional terms describing the induced charges and currents. The densities of the induced charges and currents depend on the vector k and the vectors of the electromagnetic field, E and B . It is shown that the vectors E and B can be defined in terms of two four-potentials and the components of k are the components of a four-tensor of the third rank. The Lagrangian of the modified electrodynamics is defined. The conditions are derived at which only one four-potential determines the behavior of the electromagnetic field. It is also shown that static modified electrodynamics can describe the electromagnetic field in the inner region of an electric monopole. In the outer region of the electric monopole the electric field is governed by the Maxwell equations. It follows from boundary conditions at the interface between the inner and outer regions of the monopole that the vector k has a discrete spectrum. The electric and magnetic fields, energy, and angular momentum of the monopole are found for different eigenvalues of k .

  2. Grassmannization of classical models

    Science.gov (United States)

    Pollet, Lode; Kiselev, Mikhail N.; Prokof'ev, Nikolay V.; Svistunov, Boris V.

    2016-11-01

    Applying Feynman diagrammatics to non-fermionic strongly correlated models with local constraints might seem generically impossible for two separate reasons: (i) the necessity to have a Gaussian (non-interacting) limit on top of which the perturbative diagrammatic expansion is generated by Wick’s theorem, and (ii) Dyson’s collapse argument implying that the expansion in powers of coupling constant is divergent. We show that for arbitrary classical lattice models both problems can be solved/circumvented by reformulating the high-temperature expansion (more generally, any discrete representation of the model) in terms of Grassmann integrals. Discrete variables residing on either links, plaquettes, or sites of the lattice are associated with the Grassmann variables in such a way that the partition function (as well as all correlation functions) of the original system and its Grassmann-field counterpart are identical. The expansion of the latter around its Gaussian point generates Feynman diagrams. Our work paves the way for studying lattice gauge theories by treating bosonic and fermionic degrees of freedom on equal footing.

  3. Time, classical and quantum

    Science.gov (United States)

    Aniello, P.; Ciaglia, F. M.; Di Cosmo, F.; Marmo, G.; Pérez-Pardo, J. M.

    2016-10-01

    We propose a new point of view regarding the problem of time in quantum mechanics, based on the idea of replacing the usual time operator T with a suitable real-valued function T on the space of physical states. The proper characterization of the function T relies on a particular relation with the dynamical evolution of the system rather than with the infinitesimal generator of the dynamics (Hamiltonian). We first consider the case of classical hamiltonian mechanics, where observables are functions on phase space and the tools of differential geometry can be applied. The idea is then extended to the case of the unitary evolution of pure states of finite-level quantum systems by means of the geometric formulation of quantum mechanics. It is found that T is a function on the space of pure states which is not associated with any self-adjoint operator. The link between T and the dynamical evolution is interpreted as defining a simultaneity relation for the states of the system with respect to the dynamical evolution itself. It turns out that different dynamical evolutions lead to different notions of simultaneity, i.e., the notion of simultaneity is a dynamical notion.

  4. Classical competing risks

    CERN Document Server

    Crowder, Martin J

    2001-01-01

    If something can fail, it can often fail in one of several ways and sometimes in more than one way at a time. There is always some cause of failure, and almost always, more than one possible cause. In one sense, then, survival analysis is a lost cause. The methods of Competing Risks have often been neglected in the survival analysis literature. Written by a leading statistician, Classical Competing Risks thoroughly examines the probability framework and statistical analysis of data of Competing Risks. The author explores both the theory of the subject and the practicalities of fitting the models to data. In a coherent, self-contained, and sequential account, the treatment moves from the bare bones of the Competing Risks setup and the associated likelihood functions through survival analysis using hazard functions. It examines discrete failure times and the difficulties of identifiability, and concludes with an introduction to the counting-process approach and the associated martingale theory.With a dearth of ...

  5. Classics in radio astronomy

    CERN Document Server

    Sullivan, Woodruff Turner

    1982-01-01

    Radio techniques were the nrst to lead astronomy away from the quiescent and limited Universe revealed by traditional observations at optical wave­ lengths. In the earliest days of radio astronomy, a handful of radio physicists and engineers made one startling discovery after another as they opened up the radio sky. With this collection of classic papers and the extensive intro­ ductory material, the reader can experience these exciting discoveries, as well as understand the developing techniques and follow the motivations which prompted the various lines of inquiry. For instance he or she will follow in detail the several attempts to detect radio waves from the sun at the turn of the century; the unravelling by Jansky of a "steady hiss type static"; the incredible story of Reber who built a 9 meter dish in his backyard in 1937 and then mapped the Milky Way; the vital discoveries by Hey and colleagues of radio bursts from the Sun and of a discrete source in the constellation of Cygnus; the development of re...

  6. Thermal radiation heat transfer

    CERN Document Server

    Howell, John R; Mengüç, M Pinar

    2011-01-01

    Providing a comprehensive overview of the radiative behavior and properties of materials, the fifth edition of this classic textbook describes the physics of radiative heat transfer, development of relevant analysis methods, and associated mathematical and numerical techniques. Retaining the salient features and fundamental coverage that have made it popular, Thermal Radiation Heat Transfer, Fifth Edition has been carefully streamlined to omit superfluous material, yet enhanced to update information with extensive references. Includes four new chapters on Inverse Methods, Electromagnetic Theory, Scattering and Absorption by Particles, and Near-Field Radiative Transfer Keeping pace with significant developments, this book begins by addressing the radiative properties of blackbody and opaque materials, and how they are predicted using electromagnetic theory and obtained through measurements. It discusses radiative exchange in enclosures without any radiating medium between the surfaces-and where heat conduction...

  7. The classic: Bone morphogenetic protein.

    Science.gov (United States)

    Urist, Marshall R; Strates, Basil S

    2009-12-01

    This Classic Article is a reprint of the original work by Marshall R. Urist and Basil S. Strates, Bone Morphogenetic Protein. An accompanying biographical sketch of Marshall R. Urist, MD is available at DOI 10.1007/s11999-009-1067-4; a second Classic Article is available at DOI 10.1007/s11999-009-1069-2; and a third Classic Article is available at DOI 10.1007/s11999-009-1070-9. The Classic Article is copyright 1971 by Sage Publications Inc. Journals and is reprinted with permission from Urist MR, Strates BS. Bone morphogenetic protein. J Dent Res. 1971;50:1392-1406.

  8. Innovation: the classic traps.

    Science.gov (United States)

    Kanter, Rosabeth Moss

    2006-11-01

    Never a fad, but always in or out of fashion, innovation gets rediscovered as a growth enabler every half dozen years. Too often, though, grand declarations about innovation are followed by mediocre execution that produces anemic results, and innovation groups are quietly disbanded in cost-cutting drives. Each managerial generation embarks on the same enthusiastic quest for the next new thing. And each generation faces the same vexing challenges- most of which stem from the tensions between protecting existing revenue streams critical to current success and supporting new concepts that may be crucial to future success. In this article, Harvard Business School professor Rosabeth Moss Kanter reflects on the four major waves of innovation enthusiasm she's observed over the past 25 years. She describes the classic mistakes companies make in innovation strategy, process, structure, and skills assessment, illustrating her points with a plethora of real-world examples--including AT&T Worldnet, Timberland, and Ocean Spray. A typical strategic blunder is when managers set their hurdles too high or limit the scope of their innovation efforts. Quaker Oats, for instance, was so busy in the 1990s making minor tweaks to its product formulas that it missed larger opportunities in distribution. A common process mistake is when managers strangle innovation efforts with the same rigid planning, budgeting, and reviewing approaches they use in their existing businesses--thereby discouraging people from adapting as circumstances warrant. Companies must be careful how they structure fledgling entities alongside existing ones, Kanter says, to avoid a clash of cultures and agendas--which Arrow Electronics experienced in its attempts to create an online venture. Finally, companies commonly undervalue and underinvest in the human side of innovation--for instance, promoting individuals out of innovation teams long before their efforts can pay off. Kanter offers practical advice for avoiding

  9. Fundamental Elements and Interactions of Nature: A Classical Unification Theory

    Directory of Open Access Journals (Sweden)

    Tianxi Zhang

    2010-04-01

    Full Text Available A classical unification theory that completely unifies all the fundamental interactions of nature is developed. First, the nature is suggested to be composed of the following four fundamental elements: mass, radiation, electric charge, and color charge. All known types of matter or particles are a combination of one or more of the four fundamental elements. Photons are radiation; neutrons have only mass; protons have both mass and electric charge; and quarks contain mass, electric charge, and color charge. The nature fundamental interactions are interactions among these nature fundamental elements. Mass and radiation are two forms of real energy. Electric and color charges are considered as two forms of imaginary energy. All the fundamental interactions of nature are therefore unified as a single interaction between complex energies. The interaction between real energies is the gravitational force, which has three types: mass-mass, mass-radiation, and radiation-radiation interactions. Calculating the work done by the mass-radiation interaction on a photon derives the Einsteinian gravitational redshift. Calculating the work done on a photon by the radiation-radiation interaction derives a radiation redshift, which is much smaller than the gravitational redshift. The interaction between imaginary energies is the electromagnetic (between electric charges, weak (between electric and color charges, and strong (between color charges interactions. In addition, we have four imaginary forces between real and imaginary energies, which are mass-electric charge, radiation-electric charge, mass-color charge, and radiation-color charge interactions. Among the four fundamental elements, there are ten (six real and four imaginary fundamental interactions. This classical unification theory deepens our understanding of the nature fundamental elements and interactions, develops a new concept of imaginary energy for electric and color charges, and provides a

  10. Fundamental Elements and Interactions of Nature: A Classical Unification Theory

    Directory of Open Access Journals (Sweden)

    Zhang T. X.

    2010-04-01

    Full Text Available A classical unification theory that completely unifies all the fundamental interactions of nature is developed. First, the nature is suggested to be composed of the following four fundamental elements: mass, radiation, electric charge, and color charge. All known types of matter or particles are a combination of one or more of the four fundamental elements. Photons are radiation; neutrons have only mass; protons have both mass and electric charge; and quarks contain mass, electric charge, and color charge. The nature fundamental interactions are interactions among these nature fundamental elements. Mass and radiation are two forms of real energy. Electric and color charges are con- sidered as two forms of imaginary energy. All the fundamental interactions of nature are therefore unified as a single interaction between complex energies. The interac- tion between real energies is the gravitational force, which has three types: mass-mass, mass-radiation, and radiation-radiation interactions. Calculating the work done by the mass-radiation interaction on a photon derives the Einsteinian gravitational redshift. Calculating the work done on a photon by the radiation-radiation interaction derives a radiation redshift, which is much smaller than the gravitational redshift. The interaction between imaginary energies is the electromagnetic (between electric charges, weak (between electric and color charges, and strong (between color charges interactions. In addition, we have four imaginary forces between real and imaginary energies, which are mass-electric charge, radiation-electric charge, mass-color charge, and radiation- color charge interactions. Among the four fundamental elements, there are ten (six real and four imaginary fundamental interactions. This classical unification theory deep- ens our understanding of the nature fundamental elements and interactions, develops a new concept of imaginary energy for electric and color charges, and provides a

  11. A Classical Framework for Nonlocality and Entanglement

    CERN Document Server

    Groessing, Gerhard; Pascasio, Johannes Mesa; Schwabl, Herbert

    2012-01-01

    Based on our model of quantum systems as emerging from the coupled dynamics between oscillating "bouncers" and the space-filling zero-point field, a sub-quantum account of nonlocal correlations is given. This is explicitly done for the example of the "double two-slit" variant of two-particle interferometry. However, it is also shown that the entanglement in two-particle interferometry is only a natural consequence of the fact that already a "single" two-slit experiment can be described on a sub-quantum level with the aid of "entangling currents" of a generally nonlocal nature.

  12. Potential theory of radiation

    Science.gov (United States)

    Chiu, Huei-Huang

    1989-01-01

    A theoretical method is being developed by which the structure of a radiation field can be predicted by a radiation potential theory, similar to a classical potential theory. The introduction of a scalar potential is justified on the grounds that the spectral intensity vector is irrotational. The vector is also solenoidal in the limits of a radiation field in complete radiative equilibrium or in a vacuum. This method provides an exact, elliptic type equation that will upgrade the accuracy and the efficiency of the current CFD programs required for the prediction of radiation and flow fields. A number of interesting results emerge from the present study. First, a steady state radiation field exhibits an optically modulated inverse square law distribution character. Secondly, the unsteady radiation field is structured with two conjugate scalar potentials. Each is governed by a Klein-Gordon equation with a frictional force and a restoring force. This steady potential field structure and the propagation of radiation potentials are consistent with the well known results of classical electromagnetic theory. The extension of the radiation potential theory for spray combustion and hypersonic flow is also recommended.

  13. Operator Formulation of Classical Mechanics.

    Science.gov (United States)

    Cohn, Jack

    1980-01-01

    Discusses the construction of an operator formulation of classical mechanics which is directly concerned with wave packets in configuration space and is more similar to that of convential quantum theory than other extant operator formulations of classical mechanics. (Author/HM)

  14. Dynamical Symmetries in Classical Mechanics

    Science.gov (United States)

    Boozer, A. D.

    2012-01-01

    We show how symmetries of a classical dynamical system can be described in terms of operators that act on the state space for the system. We illustrate our results by considering a number of possible symmetries that a classical dynamical system might have, and for each symmetry we give examples of dynamical systems that do and do not possess that…

  15. Teaching and Demonstrating Classical Conditioning.

    Science.gov (United States)

    Sparrow, John; Fernald, Peter

    1989-01-01

    Discusses classroom demonstrations of classical conditioning and notes tendencies to misrepresent Pavlov's procedures. Describes the design and construction of the conditioner that is used for demonstrating classical conditioning. Relates how students experience conditioning, generalization, extinction, discrimination, and spontaneous recovery.…

  16. Classic writings on instructional technology

    NARCIS (Netherlands)

    Ely, Donald P.; Plomp, Tjeerd

    1996-01-01

    This paper describes the selection process of 17 articles for inclusion in the book, "Classic Writings on Instructional Technology." The book brings together original "classic" educational technology articles into one volume to document the history of the field through its literature. It is also an

  17. COMPETITION: CLASSICAL VERSUS NEOCLASSICAL VIEW

    OpenAIRE

    Mihaela Cornelia Sandu

    2013-01-01

    Competition is an important element from economical theory. Over time it has experienced several definitions and classifications much of them being contradictory. In this paper I will make a parallel between classical and neoclassical point of view according to competition. Keywords. Competition; neoclassical theory; classical theory; monopolistic; perfect competition.

  18. Classic African American Children's Literature

    Science.gov (United States)

    McNair, Jonda C.

    2010-01-01

    The purpose of this article is to assert that there are classic African American children's books and to identify a sampling of them. The author presents multiple definitions of the term classic based on the responses of children's literature experts and relevant scholarship. Next, the manner in which data were collected and analyzed in regard to…

  19. Classical Music Fan Chen Li

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The heyday of Beijing’s classical music beganin 1993, when top-quality sound equipment andrecords were imported. Also in that year, BeijingMusic Radio presented a classical music programtitled "Fan’s Club" and founded the "Music and

  20. Classical approach in quantum physics

    CERN Document Server

    Solov'ev, Evgeni A

    2010-01-01

    The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom recently discovered with the help of Poincar$\\acute{\\mathrm{e}}$ section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treating as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semicla...

  1. Classical dynamics a modern perspective

    CERN Document Server

    Sudarshan, Ennackal Chandy George

    2016-01-01

    Classical dynamics is traditionally treated as an early stage in the development of physics, a stage that has long been superseded by more ambitious theories. Here, in this book, classical dynamics is treated as a subject on its own as well as a research frontier. Incorporating insights gained over the past several decades, the essential principles of classical dynamics are presented, while demonstrating that a number of key results originally considered only in the context of quantum theory and particle physics, have their foundations in classical dynamics.Graduate students in physics and practicing physicists will welcome the present approach to classical dynamics that encompasses systems of particles, free and interacting fields, and coupled systems. Lie groups and Lie algebras are incorporated at a basic level and are used in describing space-time symmetry groups. There is an extensive discussion on constrained systems, Dirac brackets and their geometrical interpretation. The Lie-algebraic description of ...

  2. Classical Knowledge for Quantum Security

    CERN Document Server

    D'Hondt, Ellie

    2008-01-01

    We propose a decision procedure for analysing security of quantum cryptographic protocols, combining a classical algebraic rewrite system for knowledge with an operational semantics for quantum distributed computing. As a test case, we use our procedure to reason about security properties of a recently developed quantum secret sharing protocol that uses graph states. We analyze three different scenarios based on the safety assumptions of the classical and quantum channels and discover the path of an attack in the presence of an adversary. The epistemic analysis that leads to this and similar types of attacks is purely based on our classical notion of knowledge.

  3. Quantum localization of Classical Mechanics

    CERN Document Server

    Batalin, Igor A

    2016-01-01

    Quantum localization of classical mechanics within the BRST-BFV and BV (or field-antifield) quantization methods are studied. It is shown that a special choice of gauge fixing functions (or BRST-BFV charge) together with the unitary limit leads to Hamiltonian localization in the path integral of the BRST-BFV formalism. In turn, we find that a special choice of gauge fixing functions being proportional to extremals of an initial non-degenerate classical action together with a very special solution of the classical master equation result in Lagrangian localization in the partition function of the BV formalism.

  4. Quantum localization of classical mechanics

    Science.gov (United States)

    Batalin, Igor A.; Lavrov, Peter M.

    2016-07-01

    Quantum localization of classical mechanics within the BRST-BFV and BV (or field-antifield) quantization methods are studied. It is shown that a special choice of gauge fixing functions (or BRST-BFV charge) together with the unitary limit leads to Hamiltonian localization in the path integral of the BRST-BFV formalism. In turn, we find that a special choice of gauge fixing functions being proportional to extremals of an initial non-degenerate classical action together with a very special solution of the classical master equation result in Lagrangian localization in the partition function of the BV formalism.

  5. The Wigner representation of classical mechanics, quantization and classical limit

    Energy Technology Data Exchange (ETDEWEB)

    Bolivar, A.O. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    2001-08-01

    Starting from the Liouvillian formulation of classical physics it is possible by means of a Fourier transform to introduce the Wigner representation and to derive an operator structure to classical mechanisms. The importance of this new representation lies on the fact that it turns out to be suitable route to establish a general method of quantization directly from the equations of motion without alluding to the existence of Hamiltonian and Lagrangian functions. Following this approach we quantize only the motion of a Browian particle with non-linear friction in the Markovian approximation - the thermal bath may be quantum or classical -, thus when the bath is classically described we obtain a master equation which reduces to Caldeira-Legget equation for the linear friction case, and when the reservoir is quantum we get an equation reducing to the one found by Caldeira et al. By neglecting the environmental influence we show that the system can be approximately described by equations of motion in terms of wave function, such as the Schrodinger-Langevin equation and equations of the Caldirola-Kanai type. Finally to make the present study self-consistent we evaluate the classical limit of these dynamical equations employing a new classical limiting method h/2{pi} {yields} 0. (author)

  6. Semi-classical Universe Near Initial Singularity

    CERN Document Server

    ,

    2009-01-01

    The properties of the quantum universe on extremely small spacetime scales are studied in the semi-classical approach to the well-defined quantum model. It is shown that near the initial cosmological singularity point quantum gravity effects ~ h exhibit themselves in the form of additional matter source with the negative pressure and the equation of state as for ultrastiff matter. The analytical solution of the equations of theory of gravity, in which matter is represented by the radiation and additional matter source of quantum nature, is found. It is shown that in the stage of the evolution of the universe, when quantum corrections ~ h dominate over the radiation, the geometry of the universe is described by the metric which is conformal to a metric of a unit four-sphere in a five-dimensional Euclidean flat space. In the radiation dominated era the metric is found to be conformal to a unit hyperboloid embedded in a five-dimensional Lorentz-signatured flat space. The origin of the universe can be interpreted...

  7. Synchrotron radiation from massless charge

    Directory of Open Access Journals (Sweden)

    D.V. Gal'tsov

    2015-07-01

    Full Text Available Classical radiation power from an accelerated massive charge diverges in the zero-mass limit, while some authors suggest that strictly massless charge does not radiate at all. On the other hand, the regularized classical radiation reaction force, though looking odd, is non-zero and finite. To clarify this controversy, we consider radiation problem in massless scalar quantum electrodynamics in the external magnetic field. In this framework, synchrotron radiation is found to be non-zero, finite, and essentially quantum. Its spectral distribution is calculated using Schwinger's proper time technique for ab initio massless particle of zero spin. Provided E2≫eH, the maximum in the spectrum is shown to be at ħω=E/3, and the average photon energy is 4E/9. The normalized spectrum is universal, depending neither on E nor on H. Quantum nature of radiation makes classical radiation reaction equation meaningless for massless charge. Classical theory is reliable only as providing the low-frequency part of the true quantum radiation spectrum.

  8. New perspectives on classical electromagnetism

    OpenAIRE

    Cote, Paul J.

    2009-01-01

    The fallacies associated with the gauge concept in electromagnetism are illustrated. A clearer and more valid formulation of the basics of classical electromagnetism is provided by recognizing existing physical constraints as well as the physical reality of the vector potential.

  9. Soundscape of classical Chinese garden

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    With deep humanized connotation,the classical Chinese garden uses human intuitive sensation and personal poetic observation to express natural sound phenomena.It differs from the rational modern soundscape in western countries.

  10. Invariants from classical field theory

    CERN Document Server

    Diaz, Rafael

    2007-01-01

    We introduce a method that generates invariant functions from classical field theories depending on external parameters. We apply our method to several field theories such as abelian BF, Chern-Simons and 2-dimensional Yang-Mills theory.

  11. From Classical to Quantum Transistor

    OpenAIRE

    Sanjeev Kumar

    2009-01-01

    In this article the classical transistor and the basic physics underlying the operation of single electron transistor are presented; a brief history of transistor and current technological issues are discussed.

  12. From Classical to Quantum Transistor

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2009-05-01

    Full Text Available In this article the classical transistor and the basic physics underlying the operation of single electron transistor are presented; a brief history of transistor and current technological issues are discussed.

  13. Classical Mechanics and Symplectic Integration

    DEFF Research Database (Denmark)

    Nordkvist, Nikolaj; Hjorth, Poul G.

    2005-01-01

    Content: Classical mechanics: Calculus of variations, Lagrange’s equations, Symmetries and Noether’s theorem, Hamilton’s equations, cannonical transformations, integrable systems, pertubation theory. Symplectic integration: Numerical integrators, symplectic integrators, main theorem on symplectic...

  14. Electrostatics interactions in classical simulations.

    Science.gov (United States)

    Cisneros, G Andrés; Babin, Volodymyr; Sagui, Celeste

    2013-01-01

    Electrostatic interactions are crucial for both the accuracy and performance of atomistic biomolecular simulations. In this chapter we review well-established methods and current developments aiming at efficiency and accuracy. Specifically, we review the classical Ewald summations, particle-particle particle-method particle-method Ewald algorithms, multigrid, fast multipole, and local methods. We also highlight some recent developments targeting more accurate, yet classical, representation of the molecular charge distribution.

  15. Classical Transitions for Flux Vacua

    CERN Document Server

    Deskins, J Tate; Yang, I-Sheng

    2012-01-01

    We present the simplest model for classical transitions in flux vacua. A complex field with a spontaneously broken U(1) symmetry is embedded in $M_2\\times S_1$. We numerically construct different winding number vacua, the vortices interpolating between them, and simulate the collisions of these vortices. We show that classical transitions are generic at large boosts, independent of whether or not vortices miss each other in the compact $S_1$.

  16. New Perspective on Classical Electromagnetism

    Science.gov (United States)

    2013-04-01

    R. Feynman , R. Leighton, and M. Sands, The Feynman Lectures in Physics vol II (Addison-Wesley, Reading, MA, 1964). 6. W.K.H. Panofsky and M...of the basics of classical electromagnetism is provided by recognizing a previously overlooked law of induction as well as the physical reality of the...classical electromagnetism is provided by recognizing a previously overlooked law of induction as well as the physical reality of the vector potential

  17. Semi-classical beam cooling in an intense laser pulse

    CERN Document Server

    Yoffe, Samuel R; Noble, Adam; Jaroszynski, Dino A

    2014-01-01

    We present a novel technique for studying the evolution of a particle distribution using single particle dynamics such that the distribution can be accurately reconstructed using fewer particles than existing approaches. To demonstrate this, the Landau-Lifshiftz description of radiation reaction is adapted into a semi-classical model, for which the Vlasov equation is intractable. Collision between an energetic electron bunch and high-intensity laser pulses are then compared using the two theories. Reduction in beam cooling is observed for the semi-classical case.

  18. Testing single-parameter classical standpoint cosmology

    CERN Document Server

    Chew, Geoffrey Foucar

    1995-01-01

    Experimental tests of homogeneous-universe classical standpoint cosmology are proposed after presentation of conceptual considerations that encourage this radical departure from the standard model. Among predictions of the new model are standpoint age equal to Hubble time, energy-density parameter \\Omega_0 = 2 - \\sqrt{2} =.586, and relations between redshift, Hubble-scale distribution of matter and galaxy luminosity and angular diameter. These latter relations coincide with those of the standard model for zero deceleration. With eye to further tests, geodesics of the non-Riemannian standpoint metric are explicitly given. Although a detailed thermodynamic ``youthful-standpoint'' approximation remains to be developed (for particle mean free path small on standpoint scale), standpoint temperature depending only on standpoint age is a natural concept, paralleling energy density and redshift that perpetuates thermal spectrum for cosmic background radiation. Prospects for primordial nucleosynthesis are promising.

  19. Snow Line Localization in Classical Protoplanetary Disks

    Science.gov (United States)

    Blevins, S.

    2014-04-01

    Protoplanetary disks are volatile-rich environments capable of producing the essential conditions that make planet formation viable. Establishing a molecular inventory of dominant volatile species, such as water, in the planet-forming zones surrounding young, solar-type stars elevates our understanding of the chemistry involved with planet formation, composition and disk evolution. For this study we measure the water vapor content and determine the location of the condensation front, or snow line, for four classical disks selected for the strong water emission present in their mid-infrared spectra. To accomplish this we combine deep Herschel PACS observations with high resolution Spitzer IRS spectra to create molecular maps comprised of water lines with excitation temperatures that trace the disks' surfaces from 1-100 AU. We use two-dimensional, axisymmetric radiative transfer modeling to retrieve the disks' dust structures and the RADLite raytracer to render model spectra for each disk. A simple step function is used to define the abundance structure and the model spectra are fit to the observed water lines. Preliminary results will be discussed, including the inner disk chemical content, snow line radius and fractional water vapor abundances for the classical disk RNO 90.

  20. The structure of the classical cosmological singularity

    Science.gov (United States)

    Tipler, Frank J.

    The existence of an all-encompassing initial classical cosmological singularity is established: it is shown that if: (1) global hyperbolicity, (2) the timelike convergence condition, and (3) all past-directed nonspacelike geodesics start to reconverge within a compact region in the causal past of the present-day earth, then all timelike curves in the past have a finite proper time length less than a universal constant L. It is argued that an analogue of this predicted cosmological singularity should exist even when quantum effects are taken into account. In particular, in a closed Friedmann radiation-filled universe quantized via the ADM method, the R = 0 singularity still exists and influences wave packet evolution at all times. Furthermore, quantum effects can in most cases eliminate curvature singularities only by introducing singularities in the universal action; most classical closed universes have finite action if and only if they begin and end in curvature singularities. Finally, the two basic ways of studying the structure of cosmological singularities are reviewed: completion methods (e.g., the c-boundary construction), and approach methods (e.g., analyzing metric behavior in a synchronous coordinate system).

  1. Classical-field model of the hydrogen atom

    Science.gov (United States)

    Rashkovskiy, Sergey A.

    2017-02-01

    It is shown that all of the basic properties of the hydrogen atom can be consistently described in terms of classical electrodynamics if instead of considering the electron to be a particle, we consider an electrically charged classical wave field—an "electron wave"—which is held by the electrostatic field of the proton. It is shown that quantum mechanics must be considered not as a theory of particles but as a classical field theory in the spirit of classical electrodynamics. In this case, we are not faced with difficulties in interpreting the results of the theory. In the framework of classical electrodynamics, all of the well-known regularities of the spontaneous emission of the hydrogen atom are obtained, which is usually derived in the framework of quantum electrodynamics. It is shown that there are no discrete states and discrete energy levels of the atom: the energy of the atom and its states change continuously. An explanation of the conventional corpuscular-statistical interpretation of atomic phenomena is given. It is shown that this explanation is only a misinterpretation of continuous deterministic processes. In the framework of classical electrodynamics, the nonlinear Schrödinger equation is obtained, which accounts for the inverse action of self-electromagnetic radiation of the electron wave and completely describes the spontaneous emissions of an atom.

  2. Hermeneutic reading of classic texts.

    Science.gov (United States)

    Koskinen, Camilla A-L; Lindström, Unni Å

    2013-09-01

    The purpose of this article is to broaden the understandinfg of the hermeneutic reading of classic texts. The aim is to show how the choice of a specific scientific tradition in conjunction with a methodological approach creates the foundation that clarifies the actual realization of the reading. This hermeneutic reading of classic texts is inspired by Gadamer's notion that it is the researcher's own research tradition and a clearly formulated theoretical fundamental order that shape the researcher's attitude towards texts and create the starting point that guides all reading, uncovering and interpretation. The researcher's ethical position originates in a will to openness towards what is different in the text and which constantly sets the researcher's preunderstanding and research tradition in movement. It is the researcher's attitude towards the text that allows the text to address, touch and arouse wonder. Through a flexible, lingering and repeated reading of classic texts, what is different emerges with a timeless value. The reading of classic texts is an act that may rediscover and create understanding for essential dimensions and of human beings' reality on a deeper level. The hermeneutic reading of classic texts thus brings to light constantly new possibilities of uncovering for a new envisioning and interpretation for a new understanding of the essential concepts and phenomena within caring science.

  3. Does classical liberalism imply democracy?

    Directory of Open Access Journals (Sweden)

    David Ellerman

    2015-12-01

    Full Text Available There is a fault line running through classical liberalism as to whether or not democratic self-governance is a necessary part of a liberal social order. The democratic and non-democratic strains of classical liberalism are both present today—particularly in the United States. Many contemporary libertarians and neo-Austrian economists represent the non-democratic strain in their promotion of non-democratic sovereign city-states (start-up cities or charter cities. We will take the late James M. Buchanan as a representative of the democratic strain of classical liberalism. Since the fundamental norm of classical liberalism is consent, we must start with the intellectual history of the voluntary slavery contract, the coverture marriage contract, and the voluntary non-democratic constitution (or pactum subjectionis. Next we recover the theory of inalienable rights that descends from the Reformation doctrine of the inalienability of conscience through the Enlightenment (e.g. Spinoza and Hutcheson in the abolitionist and democratic movements. Consent-based governments divide into those based on the subjects’ alienation of power to a sovereign and those based on the citizens’ delegation of power to representatives. Inalienable rights theory rules out that alienation in favor of delegation, so the citizens remain the ultimate principals and the form of government is democratic. Thus the argument concludes in agreement with Buchanan that the classical liberal endorsement of sovereign individuals acting in the marketplace generalizes to the joint action of individuals as the principals in their own organizations.

  4. No Return to Classical Reality

    CERN Document Server

    Jennings, David

    2015-01-01

    At a fundamental level, the classical picture of the world is dead, and has been dead now for almost a century. Pinning down exactly which quantum phenomena are responsible for this has proved to be a tricky and controversial question, but a lot of progress has been made in the past few decades. We now have a range of precise statements showing that whatever the ultimate laws of Nature are, they cannot be classical. In this article, we review results on the fundamental phenomena of quantum theory that cannot be understood in classical terms. We proceed by first granting quite a broad notion of classicality, describe a range of quantum phenomena (such as randomness, discreteness, the indistinguishability of states, measurement-uncertainty, measurement-disturbance, complementarity, noncommutativity, interference, the no-cloning theorem, and the collapse of the wave-packet) that do fall under its liberal scope, and then finally describe some aspects of quantum physics that can never admit a classical understandi...

  5. Classical approach in atomic physics

    Science.gov (United States)

    Solov'ev, E. A.

    2011-12-01

    The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of a hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom discovered with the help of Poincaré section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treated as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormgroup symmetry, criterion of accuracy and so on are reviewed as well.

  6. Classical approach in atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Solov' ev, E.A. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2011-12-15

    The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of a hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom discovered with the help of Poincare section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treated as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormalization group symmetry, criterion of accuracy and so on are reviewed as well. (author)

  7. Population in the classic economics

    Directory of Open Access Journals (Sweden)

    Adnan Doğruyol

    2013-02-01

    Full Text Available Growth subject in economics is an important factor of development. Classic economics ecole indicates the population as main variable which tender of growth. On the other hand T. R. Malthus is known as economist who regards population as a problem and brings up it among the classical economists. However, Adam Smith is an intellectual who discussed population problem earlier on the classic economics theory. According to Adam Smith one of the main factors that realise the growth is labour. In addition to population made it established. The aim of this study is analyzing the mental relationship between Malthus whose name has been identified with relation between population-growth and Smith who discussed this subject first time but put it off on process of theorisation.

  8. Optimum Onager: The Classical Mechanics of a Classical Siege Engine

    Science.gov (United States)

    Denny, Mark

    2009-01-01

    The onager is a throwing weapon of classical antiquity, familiar to both the ancient Greeks and Romans. Here we analyze the dynamics of onager operation and derive the optimum angle for launching a projectile to its maximum range. There is plenty of scope for further considerations about increasing onager range, and so by thinking about how this…

  9. Overview of Classical Swine Fever (Hog Cholera, Classical Swine fever)

    Science.gov (United States)

    Classical swine fever is a contagious often fatal disease of pigs clinically characterized by high body temperature, lethargy, yellowish diarrhea, vomits and purple skin discoloration of ears, lower abdomen and legs. It was first described in the early 19th century in the USA. Later, a condition i...

  10. Ice and water droplets on graphite: A comparison of quantum and classical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez, Rafael, E-mail: ramirez@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid (Spain); Singh, Jayant K. [Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, 64287 Darmstadt (Germany); Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Müller-Plathe, Florian; Böhm, Michael C. [Eduard-Zintl-Institut für Anorganische und Physikalische Chemie and Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, 64287 Darmstadt (Germany)

    2014-11-28

    Ice and water droplets on graphite have been studied by quantum path integral and classical molecular dynamics simulations. The point-charge q-TIP4P/F potential was used to model the interaction between flexible water molecules, while the water-graphite interaction was described by a Lennard-Jones potential previously used to reproduce the macroscopic contact angle of water droplets on graphite. Several energetic and structural properties of water droplets with sizes between 10{sup 2} and 10{sup 3} molecules were analyzed in a temperature interval of 50–350 K. The vibrational density of states of crystalline and amorphous ice drops was correlated to the one of ice Ih to assess the influence of the droplet interface and molecular disorder on the vibrational properties. The average distance of covalent OH bonds is found 0.01 Å larger in the quantum limit than in the classical one. The OO distances are elongated by 0.03 Å in the quantum simulations at 50 K. Bond distance fluctuations are large as a consequence of the zero-point vibrations. The analysis of the H-bond network shows that the liquid droplet is more structured in the classical limit than in the quantum case. The average kinetic and potential energy of the ice and water droplets on graphite has been compared with the values of ice Ih and liquid water as a function of temperature. The droplet kinetic energy shows a temperature dependence similar to the one of liquid water, without apparent discontinuity at temperatures where the droplet is solid. However, the droplet potential energy becomes significantly larger than the one of ice or water at the same temperature. In the quantum limit, the ice droplet is more expanded than in a classical description. Liquid droplets display identical density profiles and liquid-vapor interfaces in the quantum and classical limits. The value of the contact angle is not influenced by quantum effects. Contact angles of droplets decrease as the size of the water droplet

  11. Diffraction radiation from relativistic particles

    CERN Document Server

    Potylitsyn, Alexander Petrovich; Strikhanov, Mikhail Nikolaevich; Tishchenko, Alexey Alexandrovich

    2010-01-01

    This book deals with diffraction radiation, which implies the boundary problems of electromagnetic radiation theory. Diffraction radiation is generated when a charged particle moves in a vacuum near a target edge. Diffraction radiation of non-relativistic particles is widely used to design intense emitters in the cm wavelength range. Diffraction radiation from relativistic charged particles is important for noninvasive beam diagnostics and design of free electron lasers based on Smith-Purcell radiation which is diffraction radiation from periodic structures. Different analytical models of diffraction radiation and results of recent experimental studies are presented in this book. The book may also serve as guide to classical electrodynamics applications in beam physics and electrodynamics. It can be of great use for young researchers to develop skills and for experienced scientists to obtain new results.

  12. Classical planning and causal implicatures

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Benotti, Luciana

    In this paper we motivate and describe a dialogue manager (called Frolog) which uses classical planning to infer causal implicatures. A causal implicature is a type of Gricean relation implicature, a highly context dependent form of inference. As we shall see, causal implicatures are important...... to generate clarification requests"; as a result we can model task-oriented dialogue as an interactive process locally structured by negotiation of the underlying task. We give several examples of Frolog-human dialog, discuss the limitations imposed by the classical planning paradigm, and indicate...

  13. Comparing classical and quantum equilibration

    CERN Document Server

    Malabarba, Artur S L; Short, Anthony J

    2016-01-01

    By using a physically-relevant and theory independent definition of measurement-based equilibration, we show quantitatively that equilibration is easier for quantum systems than for classical systems, in the situation where the initial state of the system is completely known (pure state). This shows that quantum equilibration is a fundamental, nigh unavoidable, aspect of physical systems, while classical equilibration relies on experimental ignorance. When the state is not completely known, a mixed state, this framework also shows quantum equilibration requires weaker conditions.

  14. Principal bundles the classical case

    CERN Document Server

    Sontz, Stephen Bruce

    2015-01-01

    This introductory graduate level text provides a relatively quick path to a special topic in classical differential geometry: principal bundles.  While the topic of principal bundles in differential geometry has become classic, even standard, material in the modern graduate mathematics curriculum, the unique approach taken in this text presents the material in a way that is intuitive for both students of mathematics and of physics. The goal of this book is to present important, modern geometric ideas in a form readily accessible to students and researchers in both the physics and mathematics communities, providing each with an understanding and appreciation of the language and ideas of the other.

  15. Quantum teleportation without classical channel

    Science.gov (United States)

    Al Amri, M.; Li, Zheng-Hong; Zubairy, M. Suhail

    2016-11-01

    For the first time, we show how quantum teleportation can be achieved without the assistance of classical channels. Our protocol does not need any pre-established entangled photon pairs beforehand. Just by utilizing quantum Zeno effect and couterfactual communication idea, we can achieve two goals; entangling a photon and an atom and also disentangling them by non-local interaction. Information is completely transferred from atom to photon with controllable disentanglement processes. More importantly, there is no need to confirm teleportation results via classical channels.

  16. Superradiance of a subwavelength array of independent classical nonlinear emitters

    CERN Document Server

    Nefedkin, N E; Zyablovsky, A A; Pukhov, A A; Vinogradov, A P; Lisyansky, A A

    2015-01-01

    We suggest a mechanism for the emergence of a superradiance burst in a subwavelength array of nonlinear classical emitters. We assume that the emitters interact via their common field of radiative response and that they may have an arbitrary distribution of initially phases. We show that only if this distribution is not uniform, a non-zero field of radiative response arises leading to a superradiance burst. Although this field cannot synchronize the emitters, it forces fast oscillations of a classical nonlinear emitter to have long-period envelopes. Constructive interference in the envelopes creates a large dipole moment of the array which results in a superradiance pulse. The intensity of the superradiance is proportional to the squared number of the emitters, which envelopes participate in the fluctuation.

  17. Khan's the physics of radiation therapy

    CERN Document Server

    Khan, Faiz M

    2014-01-01

    Expand your understanding of the physics and practical clinical applications of advanced radiation therapy technologies with Khan's The Physics of Radiation Therapy, 5th edition, the book that set the standard in the field. This classic full-color text helps the entire radiation therapy team-radiation oncologists, medical physicists, dosimetrists, and radiation therapists-develop a thorough understanding of 3D conformal radiotherapy (3D-CRT), stereotactic radiosurgery (SRS), high dose-rate remote afterloaders (HDR), intensity modulated radiation therapy (IMRT), image-guided radiation therapy (

  18. Classical limits of boot-rotation symmetric spacetimes

    CERN Document Server

    Kofron, David

    2010-01-01

    Boost-rotation symmetric spacetimes are exceptional as they are the only exact asymptotically flat solutions to the Einstein equations describing spatially bounded sources ("point-like" particles, black holes) undergoing non-trivial motion ("uniform acceleration") with radiation. We construct the Newtonian limit of these spacetimes: it yields fields of uniformly accelerated sources in classical mechanics. We also study the special-relativistic limit of the charged rotating C-metric and so find accelerating electromagnetic magic field.

  19. Teaching Classical Mechanics Using Smartphones

    Science.gov (United States)

    Chevrier, Joel; Madani, Laya; Ledenmat, Simon; Bsiesy, Ahmad

    2013-01-01

    A number of articles published in this column have dealt with topics in classical mechanics. This note describes some additional examples employing a smartphone and the new software iMecaProf. Steve Jobs presented the iPhone as "perfect for gaming." Thanks to its microsensors connected in real time to the numerical world, physics…

  20. Supersymmetric classical mechanics: free case

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, R. de Lima [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]|[Paraiba Univ., Cajazeiras, PB (Brazil). Dept. de Ciencias Exatas e da Natureza]. E-mail: rafael@cfp.ufpb.br; Almeida, W. Pires de [Paraiba Univ., Cajazeiras, PB (Brazil). Dept. de Ciencias Exatas e da Natureza; Fonseca Neto, I. [Paraiba Univ., Campina Grande, PB (Brazil). Dept. de Fisica

    2001-06-01

    We present a review work on Supersymmetric Classical Mechanics in the context of a Lagrangian formalism, with N = 1-supersymmetry. We show that the N = 1 supersymmetry does not allow the introduction of a potencial energy term depending on a single commuting supercoordinate, {phi}(t;{theta}). (author)

  1. Agglomeration Economies in Classical Music

    DEFF Research Database (Denmark)

    Borowiecki, Karol Jan

    2015-01-01

    This study investigates agglomeration effects for classical music production in a wide range of cities for a global sample of composers born between 1750 and 1899. Theory suggests a trade-off between agglomeration economies (peer effects) and diseconomies (peer crowding). I test this hypothesis...

  2. Classical and quantum Coulomb crystals

    CERN Document Server

    Bonitz, M; Baumgartner, H; Henning, C; Filinov, A; Block, D; Arp, O; Piel, A; Kading, S; Ivanov, Y; Melzer, A; Fehske, H; Filinov, V

    2008-01-01

    Strong correlation effects in classical and quantum plasmas are discussed. In particular, Coulomb (Wigner) crystallization phenomena are reviewed focusing on one-component non-neutral plasmas in traps and on macroscopic two-component neutral plasmas. The conditions for crystal formation in terms of critical values of the coupling parameters and the distance fluctuations and the phase diagram of Coulomb crystals are discussed.

  3. Classical Syllogisms in Logic Teaching

    DEFF Research Database (Denmark)

    Øhrstrøm, Peter; Sandborg-Petersen, Ulrik; Thorvaldsen, Steinar

    2013-01-01

    This paper focuses on the challenges of introducing classical syllogisms in university courses in elementary logic and human reasoning. Using a program written in Prolog+CG, some empirical studies have been carried out involving three groups of students in Denmark; one group of philosophy student...

  4. On classical and quantum liftings

    CERN Document Server

    Accardi, L; Kossakowski, A; Matsuoka, T; Ohya, M

    2011-01-01

    We analyze the procedure of lifting in classical stochastic and quantum systems. It enables one to `lift' a state of a system into a state of `system+reservoir'. This procedure is important both in quantum information theory and the theory of open systems. We illustrate the general theory of liftings by a particular class related to so called circulant states.

  5. Relative Clauses in Classical Nahuatl

    Science.gov (United States)

    Langacker, Ronald W.

    1975-01-01

    Jane Rosenthal's paper on relative clauses in Classical Nahuatl is discussed, and it is argued that she misses an important generalization. An alternative analysis to a class of relative pronouns and new rules for the distribution of relative pronouns are proposed. (SC)

  6. On Classical and Quantum Cryptography

    CERN Document Server

    Volovich, I V; Volovich, Ya.I.

    2001-01-01

    Lectures on classical and quantum cryptography. Contents: Private key cryptosystems. Elements of number theory. Public key cryptography and RSA cryptosystem. Shannon`s entropy and mutual information. Entropic uncertainty relations. The no cloning theorem. The BB84 quantum cryptographic protocol. Security proofs. Bell`s theorem. The EPRBE quantum cryptographic protocol.

  7. Minimum signals in classical physics

    Institute of Scientific and Technical Information of China (English)

    邓文基; 许基桓; 刘平

    2003-01-01

    The bandwidth theorem for Fourier analysis on any time-dependent classical signal is shown using the operator approach to quantum mechanics. Following discussions about squeezed states in quantum optics, the problem of minimum signals presented by a single quantity and its squeezing is proposed. It is generally proved that all such minimum signals, squeezed or not, must be real Gaussian functions of time.

  8. Classical and molecular genetic mapping

    Science.gov (United States)

    A brief history of classical genetic mapping in soybean [Glycine max (L.) Merr.] is described. Detailed descriptions are given of the development of molecular genetic linkage maps based upon various types of DNA markers Like many plant and animal species, the first molecular map of soybean was bas...

  9. Classical Music as Enforced Utopia

    Science.gov (United States)

    Leech-Wilkinson, Daniel

    2016-01-01

    In classical music composition, whatever thematic or harmonic conflicts may be engineered along the way, everything always turns out for the best. Similar utopian thinking underlies performance: performers see their job as faithfully carrying out their master's (the composer's) wishes. The more perfectly they represent them, the happier the…

  10. Radiation Protection

    Science.gov (United States)

    ... EPA United States Environmental Protection Agency Search Search Radiation Protection Share Facebook Twitter Google+ Pinterest Contact Us Radiation Protection Document Library View and download EPA radiation ...

  11. No return to classical reality

    Science.gov (United States)

    Jennings, David; Leifer, Matthew

    2016-01-01

    At a fundamental level, the classical picture of the world is dead, and has been dead now for almost a century. Pinning down exactly which quantum phenomena are responsible for this has proved to be a tricky and controversial question, but a lot of progress has been made in the past few decades. We now have a range of precise statements showing that whatever the ultimate laws of nature are, they cannot be classical. In this article, we review results on the fundamental phenomena of quantum theory that cannot be understood in classical terms. We proceed by first granting quite a broad notion of classicality, describe a range of quantum phenomena (such as randomness, discreteness, the indistinguishability of states, measurement-uncertainty, measurement-disturbance, complementarity, non-commutativity, interference, the no-cloning theorem and the collapse of the wave-packet) that do fall under its liberal scope, and then finally describe some aspects of quantum physics that can never admit a classical understanding - the intrinsically quantum mechanical aspects of nature. The most famous of these is Bell's theorem, but we also review two more recent results in this area. Firstly, Hardy's theorem shows that even a finite-dimensional quantum system must contain an infinite amount of information, and secondly, the Pusey-Barrett-Rudolph theorem shows that the wave function must be an objective property of an individual quantum system. Besides being of foundational interest, results of this sort now find surprising practical applications in areas such as quantum information science and the simulation of quantum systems.

  12. Does classical mechanics always adequately describe "classical physical reality"

    CERN Document Server

    Shemi-zadeh, V E

    2002-01-01

    The article is dedicated to discussion of irreversibility and foundation of statistical mechanics "from the first principles". Taking into account infinitesimal and, as it seems, neglectful for classical mechanics fluctuations of the physical vacuum, makes a deterministic motion of unstable dynamic systems is broken ("spontaneous determinism breaking", "spontaneous stochastization"). Vacuum fluctuations play part of the trigger, starting the powerful mechanism of exponent instability. The motion of the dynamic systems becomes irreversible and stochastic. Classical mechanics turns out to be applicable only for a small class of stable dynamic systems with zero Kolmogorov-Sinay entropy $h=0$. For alternative "Stochastic mechanics" there are corresponding equations of motion and Master Equation, describing irreversible evolution of the initial distribution function to equilibrium state.

  13. Why Can We Copy Classical Information?

    Institute of Scientific and Technical Information of China (English)

    SHEN Yao; HAO Liang; LONG Gui-Lu

    2011-01-01

    It is pointed out that the noncloning theorem in quantum mechanics also holds for unknown state in linear classical physics. The apparent capability of copying of a classical state is essentially the capability of perfect measurement in classical physics. The difference in copying between quantum and classical physics is the difference in measurement between the two theories. A classical copying process is the combined action of measurement of an unknown state and the preparation of this state onto another system. Hence perfect measurability in classical physics enables the copying of a classical state.

  14. Radiation sickness

    Science.gov (United States)

    ... radiation. There are two basic types of radiation: ionizing and nonionizing. Nonionizing radiation comes in the form of light, radio waves, microwaves and radar. This kind of radiation usually ...

  15. Radiation enteritis

    Science.gov (United States)

    Radiation enteropathy; Radiation-induced small bowel injury; Post-radiation enteritis ... Radiation therapy uses high-powered x-rays, particles, or radioactive seeds to kill cancer cells. The therapy ...

  16. Radiation Therapy

    Science.gov (United States)

    ... the area is stitched shut. Another treatment, called proton-beam radiation therapy , focuses the radiation on the ... after radiation treatment ends. Sore mouth and tooth decay. If you received radiation therapy to the head ...

  17. Radiation dosimetry.

    OpenAIRE

    Cameron, J

    1991-01-01

    This article summarizes the basic facts about the measurement of ionizing radiation, usually referred to as radiation dosimetry. The article defines the common radiation quantities and units; gives typical levels of natural radiation and medical exposures; and describes the most important biological effects of radiation and the methods used to measure radiation. Finally, a proposal is made for a new radiation risk unit to make radiation risks more understandable to nonspecialists.

  18. Teaching Classical Mechanics using Smartphones

    CERN Document Server

    Chevrier, Joel; Ledenmat, Simon; Bsiesy, Ahmad

    2012-01-01

    Using a personal computer and a smartphone, iMecaProf is a software that provides a complete teaching environment for practicals associated to a Classical Mechanics course. iMecaProf proposes a visual, real time and interactive representation of data transmitted by a smartphone using the formalism of Classical Mechanics. Using smartphones is more than using a set of sensors. iMecaProf shows students that important concepts of physics they here learn, are necessary to control daily life smartphone operations. This is practical introduction to mechanical microsensors that are nowadays a key technology in advanced trajectory control. First version of iMecaProf can be freely downloaded. It will be tested this academic year in Universit\\'e Joseph Fourier (Grenoble, France)

  19. Classical Equations for Quantum Systems

    CERN Document Server

    Gell-Mann, Murray; Gell-Mann, Murray; Hartle, James B.

    1993-01-01

    The origin of the phenomenological deterministic laws that approximately govern the quasiclassical domain of familiar experience is considered in the context of the quantum mechanics of closed systems such as the universe as a whole. We investigate the requirements for coarse grainings to yield decoherent sets of histories that are quasiclassical, i.e. such that the individual histories obey, with high probability, effective classical equations of motion interrupted continually by small fluctuations and occasionally by large ones. We discuss these requirements generally but study them specifically for coarse grainings of the type that follows a distinguished subset of a complete set of variables while ignoring the rest. More coarse graining is needed to achieve decoherence than would be suggested by naive arguments based on the uncertainty principle. Even coarser graining is required in the distinguished variables for them to have the necessary inertia to approach classical predictability in the presence of t...

  20. Classical databases and knowledge organization

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2015-01-01

    This paper considers classical bibliographic databases based on the Boolean retrieval model (such as MEDLINE and PsycInfo). This model is challenged by modern search engines and information retrieval (IR) researchers, who often consider Boolean retrieval a less efficient approach. The paper...... examines this claim and argues for the continued value of Boolean systems, which suggests two further considerations: (1) the important role of human expertise in searching (expert searchers and “information literate” users) and (2) the role of library and information science and knowledge organization (KO......) in the design and use of classical databases. An underlying issue is the kind of retrieval system for which one should aim. Warner’s (2010) differentiation between the computer science traditions and an older library-oriented tradition seems important; the former aim to transform queries automatically...

  1. From classical to quantum physics

    CERN Document Server

    Stehle, Philip

    2017-01-01

    Suitable for lay readers as well as students, this absorbing survey explores the twentieth-century transition from classical to quantum physics. Author Philip Stehle traces the shift in the scientific worldview from the work of Galileo, Newton, and Darwin to the modern-day achievements of Max Planck, Albert Einstein, Ernest Rutherford, Niels Bohr, and others of their generation. His insightful overview examines not only the history of quantum physics but also the ways that progress in the discipline changed our understanding of the physical world and forces of nature. This chronicle of the second revolution in the physical sciences conveys the excitement and suspense that new developments produced in the scientific community. The narrative ranges from the classical physics of the seventeenth-century to the emergence of quantum mechanics with the entrance of the electron, the rise of relativity theory, the development of atomic theory, and the recognition of wave-particle duality. Relevant mathematical details...

  2. A Companion to Classical Receptions

    Directory of Open Access Journals (Sweden)

    A. De Villiers

    2012-03-01

    Full Text Available This recent addition to the excellent Blackwell Companions series looks at the various forms of classical reception currently being researched as well as those deemed to have future importance. The diversity and volume of the themes and approaches contained in this book are truly impressive. As Hardwick and Stray state in their introduction, this collection “has been constructed on the basis that the activators of reception are many and varied and that we all gain from encountering examples from outside our own immediate areas of knowledge” (p. 4. Throughout the book they stay true to this motto and traditional approaches to classical reception are not given prominence over more recent (sometimes contentious approaches such as film studies, cultural politics and photography. The same goes for the various cultures involved and there is even a chapter on Greek drama in South Africa.

  3. Quantum Models of Classical World

    Directory of Open Access Journals (Sweden)

    Petr Hájíček

    2013-02-01

    Full Text Available This paper is a review of our recent work on three notorious problems of non-relativistic quantum mechanics: realist interpretation, quantum theory of classical properties, and the problem of quantum measurement. A considerable progress has been achieved, based on four distinct new ideas. First, objective properties are associated with states rather than with values of observables. Second, all classical properties are selected properties of certain high entropy quantum states of macroscopic systems. Third, registration of a quantum system is strongly disturbed by systems of the same type in the environment. Fourth, detectors must be distinguished from ancillas and the states of registered systems are partially dissipated and lost in the detectors. The paper has two aims: a clear explanation of all new results and a coherent and contradiction-free account of the whole quantum mechanics including all necessary changes of its current textbook version.

  4. Classical Corrections in String Cosmology

    CERN Document Server

    Brustein, Ram; Brustein, Ram; Madden, Richard

    1999-01-01

    An important element in a model of non-singular string cosmology is a phase in which classical corrections saturate the growth of curvature in a deSitter-like phase with a linearly growing dilaton (an `algebraic fixed point'). As the form of the classical corrections is not well known, here we look for evidence, based on a suggested symmetry of the action, scale factor duality and on conformal field theory considerations, that they can produce this saturation. It has previously been observed that imposing scale factor duality on the $O(\\alpha')$ corrections is not compatible with fixed point behavior. Here we present arguments that these problems persist to all orders in $\\alpha'$. We also present evidence for the form of a solution to the equations of motion using conformal perturbation theory, examine its implications for the form of the effective action and find novel fixed point structure.

  5. The Planck Blackbody Spectrum Follows from the Structure of Relativistic Spacetime

    CERN Document Server

    Boyer, Timothy H

    2016-01-01

    Here we show that within classical physics, the Planck blackbody spectrum can be derived directly from the structure of relativistic spacetime. In noninertial frames, thermal radiation at positive temperature is connected directly to zero-point radiation whose spectrum follows from the geodesic structure of the spacetime. The connection between zero-point radiation and thermal radiation at postive temperature is through a time-dilating conformal transformation in the noninertial frame. Transferring the spectrum back to Minskowski spacetime, the Planck spectrum is obtained.

  6. Potential Theory in Classical Electrodynamics

    CERN Document Server

    Engelhardt, Wolfgang

    2012-01-01

    In Maxwell's classical theory of electrodynamics the fields are frequently expressed by potentials in order to facilitate the solution of the first order system of equations. This method obscures, however, that there exists an inconsistency between Faraday's law of induction and Maxwell's flux law. As a consequence of this internal contradiction there is neither gauge invariance, nor exist unique solutions in general. It is also demonstrated that inhomogeneous wave equations cannot be solved by retarded integrals.

  7. Semi-classical signal analysis

    CERN Document Server

    Laleg-Kirati, Taous-Meriem; Sorine, Michel

    2010-01-01

    This study introduces a new signal analysis method called SCSA, based on a semi-classical approach. The main idea in the SCSA is to interpret a pulse-shaped signal as a potential of a Schr\\"odinger operator and then to use the discrete spectrum of this operator for the analysis of the signal. We present some numerical examples and the first results obtained with this method on the analysis of arterial blood pressure waveforms.

  8. Quantum manifolds with classical limit

    CERN Document Server

    Hohmann, Manuel; Wohlfarth, Mattias N R

    2008-01-01

    We propose a mathematical model of quantum spacetime as an infinite-dimensional manifold locally homeomorphic to an appropriate Schwartz space. This extends and unifies both the standard function space construction of quantum mechanics and the manifold structure of spacetime. In this picture we demonstrate that classical spacetime emerges as a finite-dimensional manifold through the topological identification of all quantum points with identical position expectation value. We speculate on the possible relevance of this geometry to quantum field theory and gravity.

  9. Semi-classical signal analysis

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2012-09-30

    This study introduces a new signal analysis method, based on a semi-classical approach. The main idea in this method is to interpret a pulse-shaped signal as a potential of a Schrödinger operator and then to use the discrete spectrum of this operator for the analysis of the signal. We present some numerical examples and the first results obtained with this method on the analysis of arterial blood pressure waveforms. © 2012 Springer-Verlag London Limited.

  10. Synchrotron radiation from massless charge

    CERN Document Server

    Gal'tsov, D V

    2015-01-01

    Classical radiation power from an accelerated massive charge diverges in the zero-mass limit, while some general arguments suggest that strictly massless charge does not not radiate at all. On the other hand, the regularized classical radiation reaction force, though looking odd, is non-zero and finite. To clarify this controversy, we consider radiation problem in massless scalar quantum electrodynamics in the external magnetic field. In this framework, synchrotron radiation is found to be non-zero, finite, and essentially quantum. Its spectral distribution is calculated using Schwinger's proper time technique for {\\em ab initio} massless particle of zero spin. Provided $E^2\\gg eH$, the maximum in the spectrum is shown to be at $\\hbar \\omega=E/3$, and the average photon energy is $4E/9$. The normalized spectrum is universal, depending neither on $E$ nor on $H$. Quantum nature of radiation makes classical radiation reaction equation meaningless for massless charge. Our results are consistent with the view (sup...

  11. Radiative Bulk Viscosity

    CERN Document Server

    Chen, X

    2001-01-01

    Viscous resistance to changes in the volume of a gas arises when different degrees of freedom have different relaxation times. Collisions tend to oppose the resulting departures from equilibrium and, in so doing, generate entropy. Even for a classical gas of hard spheres, when the mean free paths or mean flight times of constituent particles are long, we find a nonvanishing bulk viscosity. Here we apply a method recently used to uncover this result for a classical rarefied gas to radiative transfer theory and derive an expression for the radiative stress tensor for a gray medium with absorption and Thomson scattering. We determine the transport coefficients through the calculation of the comoving entropy generation. When scattering dominates absorption, the bulk viscosity becomes much larger than either the shear viscosity or the thermal conductivity.

  12. Quantum-Classical Correspondence: Dynamical Quantization and the Classical Limit

    Energy Technology Data Exchange (ETDEWEB)

    Turner, L [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2004-11-12

    In only 150 pages, not counting appendices, references, or the index, this book is one author's perspective of the massive theoretical and philosophical hurdles in the no-man's-land separating the classical and quantum domains of physics. It ends with him emphasizing his own theoretical contribution to this area. In his own words, he has attempted to answer: 1. How can we obtain the quantum dynamics of open systems initially described by the equations of motion of classical physics (quantization process) 2. How can we retrieve classical dynamics from the quantum mechanical equations of motion by means of a classical limiting process (dequantization process). However, this monograph seems overly ambitious. Although the publisher's description refers to this book as an accessible entre, we find that this author scrambles too hastily over the peaks of information that are contained in his large collection of 272 references. Introductory motivating discussions are lacking. Profound ideas are glossed over superficially and shoddily. Equations morph. But no new convincing understanding of the physical world results. The author takes the viewpoint that physical systems are always in interaction with their environment and are thus not isolated and, therefore, not Hamiltonian. This impels him to produce a method of quantization of these stochastic systems without the need of a Hamiltonian. He also has interest in obtaining the classical limit of the quantized results. However, this reviewer does not understand why one needs to consider open systems to understand quantum-classical correspondence. The author demonstrates his method using various examples of the Smoluchowski form of the Fokker--Planck equation. He then renders these equations in a Wigner representation, uses what he terms an infinitesimality condition, and associates with a constant having the dimensions of an action. He thereby claims to develop master equations, such as the Caldeira

  13. Quantum Transitions Between Classical Histories: Bouncing Cosmologies

    CERN Document Server

    Hartle, James

    2015-01-01

    In a quantum theory of gravity spacetime behaves classically when quantum probabilities are high for histories of geometry and field that are correlated in time by the Einstein equation. Probabilities follow from the quantum state. This quantum perspective on classicality has important implications: (a) Classical histories are generally available only in limited patches of the configuration space on which the state lives. (b) In a given patch states generally predict relative probabilities for an ensemble of possible classical histories. (c) In between patches classical predictability breaks down and is replaced by quantum evolution connecting classical histories in different patches. (d) Classical predictability can break down on scales well below the Planck scale, and with no breakdown in the classical equations of motion. We support and illustrate (a)-(d) by calculating the quantum transition across the de Sitter like throat connecting asymptotically classical, inflating histories in the no-boundary quantu...

  14. Classical and quantum dynamics from classical paths to path integrals

    CERN Document Server

    Dittrich, Walter

    2016-01-01

    Graduate students who want to become familiar with advanced computational strategies in classical and quantum dynamics will find here both the fundamentals of a standard course and a detailed treatment of the time-dependent oscillator, Chern-Simons mechanics, the Maslov anomaly and the Berry phase, to name a few. Well-chosen and detailed examples illustrate the perturbation theory, canonical transformations, the action principle and demonstrate the usage of path integrals. This new edition has been revised and enlarged with chapters on quantum electrodynamics, high energy physics, Green’s functions and strong interaction.

  15. Intuitionism vs. classicism a mathematical attack on classical logic

    CERN Document Server

    Haverkamp, Nick

    2015-01-01

    In the early twentieth century, the Dutch mathematician L.E.J. Brouwer launched a powerful attack on the prevailing mathematical methods and theories. He developed a new kind of constructive mathematics, called intuitionism, which seems to allow for a rigorous refutation of widely accepted mathematical assumptions including fundamental principles of classical logic. Following an intense mathematical debate esp. in the 1920s, Brouwer's revolutionary criticism became a central philosophical concern in the 1970s, when Michael Dummett tried to substantiate it with meaning-theoretic considerations.

  16. The Relation between Classical and Quantum Electrodynamics

    Directory of Open Access Journals (Sweden)

    Mario Bacelar Valente

    2011-01-01

    Full Text Available Quantum electrodynamics presents intrinsic limitations in the description of physical processes that make it impossible to recover from it the type of description we have in classical electrodynamics. Hence one cannot consider classical electrodynamics as reducing to quantum electrodynamics and being recovered from it by some sort of limiting procedure. Quantum electrodynamics has to be seen not as an more fundamental theory, but as an upgrade of classical electrodynamics, which permits an extension of classical theory to the description of phenomena that, while being related to the conceptual framework of the classical theory, cannot be addressed from the classical theory.

  17. RESONANCE RADIATION OF SUBMERGED INFINITE CYLINDRICAL SHELL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The resonance sound radiation from submerged infinite elastic cylindrical shell, excited by internal harmonic line force, is investigated. The shell radiation power is presented in terms of resonant modal radiation derived from resonance radiation theory (RRT). The resonance radiation formulae are derived from classical Rayleigh normal mode solution, which are useful for understanding the mechanism of sound radiation from submerged shells. As an example, numerical calculation of a thin steel cylindrical shell is done by using these two methods. It seems that the results of RRT solutions are in good agreement with that of Rayleigh normal mode solutions.

  18. Radiation damping in real time.

    Science.gov (United States)

    Mendes, A C; Takakura, F I

    2001-11-01

    We study the nonequilibrium dynamics of a charge interacting with its own radiation, which originates the radiation damping. The real-time equation of motion for the charge and the associated Langevin equation is found in classical limit. The equation of motion for the charge allows one to obtain the frequency-dependent coefficient of friction. In the lowest order we find that although the coefficient of static friction vanishes, there is dynamical dissipation represented by a non-Markovian dissipative kernel.

  19. Classical Optics and its Applications

    Science.gov (United States)

    Mansuripur, Masud

    2009-02-01

    Preface; Introduction; 1. Abbe's sine condition; 2. Fourier optics; 3. Effect of polarization on diffraction in systems of high numerical aperture; 4. Gaussian beam optics; 5. Coherent and incoherent imaging; 6. First-order temporal coherence in classical optics; 7. The Van Cittert-Zernike theorem; 8. Partial polarization, Stokes parameters, and the Poincarè Sphere; 9. Second-order coherence and the Hanbury Brown - Twiss experiment; 10. What in the world are surface plasmons?; 11. Surface plasmon polaritons on metallic surfaces; 12. The Faraday effecy; 13. The magneto-optical Kerr effect; 14. The Sagnac interferometer; 15. Fabry-Perot etalons in polarized light; 16. The Ewald-Oseen extinction theorem; 17. Reciprocity in classical Linear optics; 18. Optical pulse compression; 19. The uncertainty principle in classical optics; 20. Omni-directional dielectric mirrors; 21. Optical vortices; 22. Geometric-optical rays, Poynting's vector, and field momenta; 23. Doppler shift, stellar aberration, and convection of light by moving Media; 24. Diffraction gratings; 25. Diffractive optical elements; 26. The talbot effect; 27. Some quirks of total internal reflection; 28. Evanescent coupling; 29. Internal and external conical refraction; 30. Transmission of light through small elliptical apertures; 31. The method of Fox and Li; 32. The beam propagation method; 33. Launching light into a Fiber; 34. The optics of demiconductor fiode Laser; 35. Michelson's dtellar interferometer; 36. Bracewell's interferometric telescope; 37. Scanning optical microscopy; 38. Zernike's method of phase contrast; 39. Polarization microscopy; 40. Nomarski's differential interference contrast microscope; 41. The Van Leeuwenhoek microscope; 42. Projection photolithography; 43. Interaction of light with subwavelength structures; 44 The Ronchi test; 45. The Shack-Hartmann Wavefront sensor; 46. Ellipsometry; 47. Holography and holographic interferometry; 48. Self-focusing in non-linear optical media; 49

  20. Classical trajectories and quantum tunneling

    CERN Document Server

    Ivlev, B I

    2003-01-01

    The problem of inter-band tunneling in a semiconductor (Zener breakdown) in a nonstationary and homogeneous electric field is solved exactly. Using the exact analytical solution, the approximation based on classical trajectories is studied. A new mechanism of enhanced tunneling through static non-one-dimensional barriers is proposed in addition to well known normal tunneling solely described by a trajectory in imaginary time. Under certain conditions on the barrier shape and the particle energy, the probability of enhanced tunneling is not exponentially small even for non-transparent barriers, in contrast to the case of normal tunneling.

  1. Classical databases and knowledge organization

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2015-01-01

    examines this claim and argues for the continued value of Boolean systems, which suggests two further considerations: (1) the important role of human expertise in searching (expert searchers and “information literate” users) and (2) the role of library and information science and knowledge organization (KO......) in the design and use of classical databases. An underlying issue is the kind of retrieval system for which one should aim. Warner’s (2010) differentiation between the computer science traditions and an older library-oriented tradition seems important; the former aim to transform queries automatically...

  2. Lectures on classical differential geometry

    CERN Document Server

    Struik, Dirk J

    1988-01-01

    Elementary, yet authoritative and scholarly, this book offers an excellent brief introduction to the classical theory of differential geometry. It is aimed at advanced undergraduate and graduate students who will find it not only highly readable but replete with illustrations carefully selected to help stimulate the student's visual understanding of geometry. The text features an abundance of problems, most of which are simple enough for class use, and often convey an interesting geometrical fact. A selection of more difficult problems has been included to challenge the ambitious student.Writ

  3. The revision of classical stock model

    Institute of Scientific and Technical Information of China (English)

    YE Bai-qing; WANG Hong-li

    2001-01-01

    On the basis of the analysis of classical stock model, according to th e limitation of the model, the article puts forward the revision of classical mo del and enforces the applicability of the stock model.

  4. The revision of classical stock model

    Institute of Scientific and Technical Information of China (English)

    叶柏青; 王洪利

    2001-01-01

    On the basis of the analysis of classical stock model, according to the limitation of the model, the article puts forward the revision of classical model and enforces the applicability of the stock model.

  5. Higgs Triplet Model with Classically Conformal Invariance

    CERN Document Server

    Okada, Hiroshi; Yagyu, Kei

    2015-01-01

    We discuss an extension of the minimal Higgs triplet model with a classically conformal invariance and with a gauged $U(1)_{B-L}$ symmetry. In our scenario, tiny masses of neutrinos are generated by a hybrid contribution from the type-I and type-II seesaw mechanisms. The shape of the Higgs potential at low energies is determined by solving one-loop renormalization group equations for all the scalar quartic couplings with a set of initial values of parameters at the Planck scale. We find a successful set of the parameters in which the $U(1)_{B-L}$ symmetry is radiatively broken via the Coleman-Weinberg mechanism at the ${\\cal O}$(10) TeV scale, and the electroweak symmetry breaking is also triggered by the $U(1)_{B-L}$ breaking. Under this configuration, we can predict various low energy observables such as the mass spectrum of extra Higgs bosons, and the mixing angles. Furthermore, using these predicted mass parameters, we obtain upper limits on Yukawa couplings among an isospin triplet Higgs field and lepton...

  6. Seven Steps Towards the Classical World

    OpenAIRE

    Allori, Valia; Dürr, Detlef; Goldstein, Shelly; Zanghí, Nino

    2001-01-01

    Classical physics is about real objects, like apples falling from trees, whose motion is governed by Newtonian laws. In standard Quantum Mechanics only the wave function or the results of measurements exist, and to answer the question of how the classical world can be part of the quantum world is a rather formidable task. However, this is not the case for Bohmian mechanics, which, like classical mechanics, is a theory about real objects. In Bohmian terms, the problem of the classical limit be...

  7. About the modern house - and the classical

    DEFF Research Database (Denmark)

    Hauberg, Jørgen

    2010-01-01

    In text and illustrations describes the classical house and the classical city, represented by Andrea Palladio (1508-80), and the modern house, the modern city and building task, represented by Le Corbusier (1857-1965).......In text and illustrations describes the classical house and the classical city, represented by Andrea Palladio (1508-80), and the modern house, the modern city and building task, represented by Le Corbusier (1857-1965)....

  8. A theoretical approach to room acoustic simulations based on a radiative transfer model

    DEFF Research Database (Denmark)

    Ruiz-Navarro, Juan-Miguel; Jacobsen, Finn; Escolano, José;

    2010-01-01

    A theoretical approach to room acoustic simulations based on a radiative transfer model is developed by adapting the classical radiative transfer theory from optics to acoustics. The proposed acoustic radiative transfer model expands classical geometrical room acoustic modeling algorithms by inco...

  9. Overuse injuries in classical ballet.

    Science.gov (United States)

    Khan, K; Brown, J; Way, S; Vass, N; Crichton, K; Alexander, R; Baxter, A; Butler, M; Wark, J

    1995-05-01

    Successful management of classical ballet dancers with overuse injuries requires an understanding of the art form, precise knowledge of anatomy and awareness of certain conditions. Turnout is the single most fundamental physical attribute in classical ballet and 'forcing turnout' frequently contributes to overuse injuries. Common presenting conditions arising from the foot and ankle include problems at the first metatarsophalangeal joint, second metatarsal stress fractures, flexor hallucis longus tendinitis and anterior and posterior ankle impingement syndromes. Persistent shin pain in dancers is often due to chronic compartment syndrome, stress fracture of the posteromedial or anterior tibia. Knee pain can arise from patellofemoral syndrome, patellar tendon insertional pathologies, or a combination of both. Hip and back problems are also prevalent in dancers. To speed injury recovery of dancers, it is important for the sports medicine team to cooperate fully. This permits the dancer to benefit from accurate diagnosis, technique correction where necessary, the full range of manual therapies to joint and soft tissue, appropriate strengthening programmes and maintenance of dance fitness during any time out of class with Pilates-based exercises and nutrition advice. Most overuse ballet conditions respond well to a combination of conservative therapies. Those dancers that do require surgical management still depend heavily on ballet-specific rehabilitation for a complete recovery.

  10. Classical equations for quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Gell-Mann, M. (Theoretical Astrophysics Group (T-6), Los Alamos National Laboratory, Los Alamos, New Mexico 87545) (United States) (Santa Fe Institute, 1660 Old Pecos Trail, Santa Fe, New Mexico 87501); Hartle, J.B. (Department of Physics, University of California enSanta Barbara, Santa Barbara, (California) 93106)

    1993-04-15

    The origin of the phenomenological deterministic laws that approximately govern the quasiclassical domain of familiar experience is considered in the context of the quantum mechanics of closed systems such as the universe as a whole. A formulation of quantum mechanics is used that predicts probabilities for the individual members of a set of alternative coarse-grained histories that [ital decohere], which means that there is negligible quantum interference between the individual histories in the set. We investigate the requirements for coarse grainings to yield decoherent sets of histories that are quasiclassical, i.e., such that the individual histories obey, with high probability, effective classical equations of motion interrupted continually by small fluctuations and occasionally by large ones. We discuss these requirements generally but study them specifically for coarse grainings of the type that follows a distinguished subset of a complete set of variables while ignoring the rest. More coarse graining is needed to achieve decoherence than would be suggested by naive arguments based on the uncertainty principle. Even coarser graining is required in the distinguished variables for them to have the necessary inertia to approach classical predictability in the presence of the noise consisting of the fluctuations that typical mechanisms of decoherence produce. We describe the derivation of phenomenological equations of motion explicitly for a particular class of models.

  11. Physiological characteristics of classical ballet.

    Science.gov (United States)

    Schantz, P G; Astrand, P O

    1984-10-01

    The aerobic and anaerobic energy yield during professional training sessions ("classes") of classical ballet as well as during rehearsed and performed ballets has been studied by means of oxygen uptake, heart rate, and blood lactate concentration determinations on professional ballet dancers from the Royal Swedish Ballet in Stockholm. The measured oxygen uptake during six different normal classes at the theatre averaged about 35-45% of the maximal oxygen uptake, and the blood lactate concentration averaged 3 mM (N = 6). During 10 different solo parts of choreographed dance (median length = 1.8 min) representative for moderately to very strenuous dance, an average oxygen uptake (measured during the last minute) of 80% of maximum and blood lactate concentration of 10 mM was measured (N = 10). In addition, heart rate registrations from soloists in different ballets during performance and final rehearsals frequently indicated a high oxygen uptake relative to maximum and an average blood lactate concentration of 11 mM (N = 5). Maximal oxygen uptake, determined in 1971 (N = 11) and 1983 (N = 13) in two different groups of dancers, amounted to on the average 51 and 56 ml X min-1 X kg-1 for the females and males, respectively. In conclusion, classical ballet is a predominantly intermittent type of exercise. In choreographed dance each exercise period usually lasts only a few minutes, but can be very demanding energetically, while during the dancers' basic training sessions, the energy yield is low.

  12. Fluctuations in classical sum rules.

    Science.gov (United States)

    Elton, John R; Lakshminarayan, Arul; Tomsovic, Steven

    2010-10-01

    Classical sum rules arise in a wide variety of physical contexts. Asymptotic expressions have been derived for many of these sum rules in the limit of long orbital period (or large action). Although sum-rule convergence may well be exponentially rapid for chaotic systems in a global phase-space sense with time, individual contributions to the sums may fluctuate with a width which diverges in time. Our interest is in the global convergence of sum rules as well as their local fluctuations. It turns out that a simple version of a lazy baker map gives an ideal system in which classical sum rules, their corrections, and their fluctuations can be worked out analytically. This is worked out in detail for the Hannay-Ozorio sum rule. In this particular case the rate of convergence of the sum rule is found to be governed by the Pollicott-Ruelle resonances, and both local and global boundaries for which the sum rule may converge are given. In addition, the width of the fluctuations is considered and worked out analytically, and it is shown to have an interesting dependence on the location of the region over which the sum rule is applied. It is also found that as the region of application is decreased in size the fluctuations grow. This suggests a way of controlling the length scale of the fluctuations by considering a time dependent phase-space volume, which for the lazy baker map decreases exponentially rapidly with time.

  13. The physics of radiation therapy

    CERN Document Server

    Khan, Faiz M

    2009-01-01

    Dr. Khan's classic textbook on radiation oncology physics is now in its thoroughly revised and updated Fourth Edition. It provides the entire radiation therapy team—radiation oncologists, medical physicists, dosimetrists, and radiation therapists—with a thorough understanding of the physics and practical clinical applications of advanced radiation therapy technologies, including 3D-CRT, stereotactic radiotherapy, HDR, IMRT, IGRT, and proton beam therapy. These technologies are discussed along with the physical concepts underlying treatment planning, treatment delivery, and dosimetry. This Fourth Edition includes brand-new chapters on image-guided radiation therapy (IGRT) and proton beam therapy. Other chapters have been revised to incorporate the most recent developments in the field. This edition also features more than 100 full-color illustrations throughout.

  14. The dynamics of the H(+) + D(2) reaction: a comparison of quantum mechanical wavepacket, quasi-classical and statistical-quasi-classical results.

    Science.gov (United States)

    Jambrina, P G; Aoiz, F J; Bulut, N; Smith, Sean C; Balint-Kurti, G G; Hankel, M

    2010-02-01

    A detailed study of the proton exchange reaction H(+) + D(2)(v = 0, j = 0) --> HD + D(+) on its ground 1(1)A' potential energy surface has been carried out using 'exact' close-coupled quantum mechanical wavepacket (WP-EQM), quasi-classical trajectory (QCT), and statistical quasi-classical trajectory (SQCT) calculations for a range of collision energies starting from the reaction threshold to 1.3 eV. The WP-EQM calculations include all total angular momenta up to J(max) = 50, and therefore the various dynamical observables are converged up to 0.6 eV. It has been found that it is necessary to include all Coriolis couplings to obtain reliable converged results. Reaction probabilities obtained using the different methods are thoroughly compared as a function of the total energy for a series of J values. Comparisons are also made of total reaction cross sections as function of the collision energy, and rate constants. In addition, opacity functions, integral cross sections (ICS) and differential cross sections (DCS) are presented at 102 meV, 201.3 meV and 524.6 meV collision energy. The agreement between the three sets of results is only qualitative. The QCT calculations fail to describe the overall reactivity and most of the dynamical observables correctly. At low collision energies, the QCT method is plagued by the lack of conservation of zero point energy, whilst at higher collision energies and/or total angular momenta, the appearance of an effective repulsive potential associated with the centrifugal motion "over" the well causes a substantial decrease of the reactivity. In turn, the statistical models overestimate the reactivity over the whole range of collision energies as compared with the WP-EQM method. Specifically, at sufficiently high collision energies the reaction cannot be deemed to be statistical and important dynamical effects seem to be present. In general the WP-EQM results lie in between those obtained using the QCT and SQCT methods. One of the main

  15. Self compensation of classical non abelian charge

    OpenAIRE

    Bartnik, E. A.

    2009-01-01

    A new classical, non singular solution with arbitrarily low energy is found for SU(2) non abelian fields in the presence of a static charge. Physically it means that a classical charge coupled to any SU(N) non abelian gauge field will develop a pure gauge field, carrying no energy, that will completely screen it - there are no visible classical non abelian charges.

  16. Quantum-classical hybrid dynamics - a summary

    CERN Document Server

    Elze, Hans-Thomas

    2013-01-01

    A summary of a recently proposed description of quantum-classical hybrids is presented, which concerns quantum and classical degrees of freedom of a composite object that interact directly with each other. This is based on notions of classical Hamiltonian mechanics suitably extended to quantum mechanics.

  17. Collection of problems in classical mechanics

    CERN Document Server

    Kotkin, G L; ter Haar, D

    1971-01-01

    Collection of Problems in Classical Mechanics presents a set of problems and solutions in physics, particularly those involving mechanics. The coverage of the book includes 13 topics relevant to classical mechanics, such as integration of one-dimensional equations of motion; the Hamiltonian equations of motion; and adiabatic invariants. The book will be of great use to physics students studying classical mechanics.

  18. Radiation Therapy

    Science.gov (United States)

    Radiation therapy is a cancer treatment. It uses high doses of radiation to kill cancer cells and stop them from ... half of all cancer patients receive it. The radiation may be external, from special machines, or internal, ...

  19. Classical static final state of collapse with supertranslation memory

    CERN Document Server

    Compère, Geoffrey

    2016-01-01

    The Kerr metric models the final classical black hole state after gravitational collapse of matter and radiation. Any stationary metric which is close to the Kerr metric has been proven to be diffeomorphic to it. Now, finite supertranslation diffeomorphisms are symmetries which map solutions to inequivalent solutions, as illustrated by the classical memory effect. Such diffeomorphisms generate conserved superrotation charges. The final state of gravitational collapse is therefore parameterized by its mass, angular momentum and supertranslation field, signaled by its conserved superrotation charges. In this paper, we first derive the angle-dependent energy conservation law relating the asymptotic value of the supertranslation field of the final state to the details of the collapse and subsequent evolution of the system. We then generate the static solution with an asymptotic supertranslation field and we study some of its properties. The deviation from the Schwarzschild metric could therefore be predicted on a...

  20. Radiation dosimetry

    CERN Document Server

    Hine, Gerald J; Hine, Gerald J

    1956-01-01

    Radiation Dosimetry focuses on the advancements, processes, technologies, techniques, and principles involved in radiation dosimetry, including counters and calibration and standardization techniques. The selection first offers information on radiation units and the theory of ionization dosimetry and interaction of radiation with matter. Topics include quantities derivable from roentgens, determination of dose in roentgens, ionization dosimetry of high-energy photons and corpuscular radiations, and heavy charged particles. The text then examines the biological and medical effects of radiation,

  1. Inflation and classical scale invariance

    CERN Document Server

    Racioppi, Antonio

    2014-01-01

    BICEP2 measurement of primordial tensor modes in CMB suggests that cosmological inflation is due to a slowly rolling inflaton taking trans-Planckian values and provides further experimental evidence for the absence of large $M_{\\rm P}$ induced operators. We show that classical scale invariance solves the problem and allows for a remarkably simple scale-free inflaton model without any gauge group. Due to trans-Planckian inflaton values and VEVs, a dynamically induced Coleman-Weinberg-type inflaton potential of the model can predict tensor-to-scalar ratio $r$ in a large range. Precise determination of $r$ in future experiments will allow to test the proposed field-theoretic framework.

  2. Theoretical physics 1 classical mechanics

    CERN Document Server

    Nolting, Wolfgang

    2016-01-01

    This textbook offers a clear and comprehensive introduction to classical mechanics, one of the core components of undergraduate physics courses. The book starts with a thorough introduction to the mathematical tools needed, to make this textbook self-contained for learning. The second part of the book introduces the mechanics of the free mass point and details conservation principles. The third part expands the previous to mechanics of many particle systems. Finally the mechanics of the rigid body is illustrated with rotational forces, inertia and gyroscope movement. Ideally suited to undergraduate students in their first year, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful German editions, the eight volumes of this series...

  3. A Classical Model of Gravitation

    Directory of Open Access Journals (Sweden)

    Wagener P.

    2008-07-01

    Full Text Available A classical model of gravitation is proposed with time as an independent coordinate. The dynamics of the model is determined by a proposed Lagrangian. Applying the canonical equations of motion to its associated Hamiltonian gives conservation equa- tions of energy, total angular momentum and the z component of the angular momen- tum. These lead to a Keplerian orbit in three dimensions, which gives the observed values of perihelion precession and bending of light by a massive object. An expression for gravitational redshift is derived by accepting the local validity of special relativity at all points in space. Exact expressions for the GEM relations, as well as their associated Lorentz-type force, are derived. An expression for Mach’s Principle is also derived.

  4. A course in classical physics

    CERN Document Server

    Bettini, Alessandro

    This first volume covers the mechanics of point particles, gravitation, extended systems (starting from the two-body system), the basic concepts of relativistic mechanics and the mechanics of rigid bodies and fluids. The four-volume textbook, which covers electromagnetism, mechanics, fluids and thermodynamics, and waves and light, is designed to reflect the typical syllabus during the first two years of a calculus-based university physics program. Throughout all four volumes, particular attention is paid to in-depth clarification of conceptual aspects, and to this end the historical roots of the principal concepts are traced. Writings by the founders of classical mechanics, G. Galilei and I. Newton, are reproduced, encouraging students to consult them. Emphasis is also consistently placed on the experimental basis of the concepts, highlighting the experimental nature of physics. Whenever feasible at the elementary level, concepts relevant to more advanced courses in modern physics are included. Each chapter b...

  5. Classical mechanics of nonconservative systems.

    Science.gov (United States)

    Galley, Chad R

    2013-04-26

    Hamilton's principle of stationary action lies at the foundation of theoretical physics and is applied in many other disciplines from pure mathematics to economics. Despite its utility, Hamilton's principle has a subtle pitfall that often goes unnoticed in physics: it is formulated as a boundary value problem in time but is used to derive equations of motion that are solved with initial data. This subtlety can have undesirable effects. I present a formulation of Hamilton's principle that is compatible with initial value problems. Remarkably, this leads to a natural formulation for the Lagrangian and Hamiltonian dynamics of generic nonconservative systems, thereby filling a long-standing gap in classical mechanics. Thus, dissipative effects, for example, can be studied with new tools that may have applications in a variety of disciplines. The new formalism is demonstrated by two examples of nonconservative systems: an object moving in a fluid with viscous drag forces and a harmonic oscillator coupled to a dissipative environment.

  6. Introducing Newton and classical physics

    CERN Document Server

    Rankin, William

    2002-01-01

    The rainbow, the moon, a spinning top, a comet, the ebb and flood of the oceans ...a falling apple. There is only one universe and it fell to Isaac Newton to discover its secrets. Newton was arguably the greatest scientific genius of all time, and yet he remains a mysterious figure. Written and illustrated by William Rankin, "Introducting Newton and Classical Physics" explains the extraordinary ideas of a man who sifted through the accumulated knowledge of centuries, tossed out mistaken beliefs, and single-handedly made enormous advances in mathematics, mechanics and optics. By the age of 25, entirely self-taught, he had sketched out a system of the world. Einstein's theories are unthinkable without Newton's founding system. He was also a secret heretic, a mystic and an alchemist, the man of whom Edmund Halley said "Nearer to the gods may no man approach!". This is an ideal companion volume to "Introducing Einstein".

  7. Scientific Realism and Classical Physics

    CERN Document Server

    Singh, Virendra

    2008-01-01

    We recount the successful long career of classical physics, from Newton to Einstein, which was based on the philosophy of scientific realism. Special emphasis is given to the changing status and number of ontological entitities and arguments for their necessity at any time. Newton, initially, began with (i) point particles, (ii) aether, (iii) absolute space and (iv) absolute time. The electromagnetic theory of Maxwell and Faraday introduced `fields' as a new ontological entity not reducible to earlier ones. Their work also unified electricity, magnetism and optics. Repeated failure to observe the motion of earth through aether led Einstein to modify the Newtonian absolute space and time concepts to a fused Minkowski space-time and the removal of aether from basic ontological entities in his special theory of relativity. Later Einstein in his attempts to give a local theory of gravitation was led to further modify flat Minkowski space-time to the curved Riemannian space time. This reduced gravitational phenome...

  8. Classical scattering from oscillating targets

    Energy Technology Data Exchange (ETDEWEB)

    Papachristou, P.K.; Diakonos, F.K.; Constantoudis, V.; Schmelcher, P.; Benet, L

    2002-12-30

    We study planar classical scattering from an oscillating heavy target whose dynamics defines a five-dimensional phase space. Although the system possesses no periodic orbits, and thus topological chaos is not present, the scattering functions display a variety of structures on different time scales. These structures are due to scattering events with a strong energy transfer from the projectile to the moving disk resulting in low-velocity peaks. We encounter initial conditions for which the projectile exhibits infinitely many bounces with the oscillating disk. Our numerical investigations are supported by analytical results on a specific model with a simple time-law. The observed properties possess universal character for scattering off oscillating targets.

  9. Classic ballet dancers postural patterns

    Directory of Open Access Journals (Sweden)

    Joseani Paulini Neves Simas

    2008-06-01

    Full Text Available The aim of this study was to evaluate classic ballet practice and its influence on postural patterns and (a identify the most frequent postural changes; (b determine the postural pattern; (c verify the existence of association of practice time and postural changes. The investigation was carried out in two stages: one, description in which 106 dancers participated; the other, causal comparative in which 50 dancers participated; and (a questionnaire; (b a checkerboard; (c postural chart; (d measure tape; (e camera and (f pedoscope were used as instrument. Descriptive and inferential statistics was used for analysis. The results revealed the most frequent postural changes such as hyperlordosis, unleveled shoulders and pronated ankles. Ballet seems to have negative implications in the postural development , affecting especially the vertebral spine, trunk and feet. The practice time was not a parameter to indicate the increase in postural changes. In conclusion, ballet may be associated with postural changes and determining a characteristic postural pattern.

  10. GALK inhibitors for classic galactosemia.

    Science.gov (United States)

    Lai, Kent; Boxer, Matthew B; Marabotti, Anna

    2014-06-01

    Classic galactosemia is an inherited metabolic disease for which, at present, no therapy is available apart from galactose-restricted diet. However, the efficacy of the diet is questionable, since it is not able to prevent the insurgence of chronic complications later in life. In addition, it is possible that dietary restriction itself could induce negative side effects. Therefore, there is a need for an alternative therapeutic approach that can avert the manifestation of chronic complications in the patients. In this review, the authors describe the development of a novel class of pharmaceutical agents that target the production of a toxic metabolite, galactose-1-phosphate, considered as the main culprit for the cause of the complications, in the patients.

  11. Hydrogen Beyond the Classic Approximation

    CERN Document Server

    Scivetti, I

    2003-01-01

    The classical nucleus approximation is the most frequently used approach for the resolution of problems in condensed matter physics.However, there are systems in nature where it is necessary to introduce the nuclear degrees of freedom to obtain a correct description of the properties.Examples of this, are the systems with containing hydrogen.In this work, we have studied the resolution of the quantum nuclear problem for the particular case of the water molecule.The Hartree approximation has been used, i.e. we have considered that the nuclei are distinguishable particles.In addition, we have proposed a model to solve the tunneling process, which involves the resolution of the nuclear problem for configurations of the system away from its equilibrium position

  12. From classical to quantum fields

    CERN Document Server

    Baulieu, Laurent; Sénéor, Roland

    2017-01-01

    Quantum Field Theory has become the universal language of most modern theoretical physics. This introductory textbook shows how this beautiful theory offers the correct mathematical framework to describe and understand the fundamental interactions of elementary particles. The book begins with a brief reminder of basic classical field theories, electrodynamics and general relativity, as well as their symmetry properties, and proceeds with the principles of quantisation following Feynman's path integral approach. Special care is used at every step to illustrate the correct mathematical formulation of the underlying assumptions. Gauge theories and the problems encountered in their quantisation are discussed in detail. The last chapters contain a full description of the Standard Model of particle physics and the attempts to go beyond it, such as grand unified theories and supersymmetry. Written for advanced undergraduate and beginning graduate students in physics and mathematics, the book could also serve as a re...

  13. SYNCHROTRON RADIATION SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    HULBERT,S.L.; WILLIAMS,G.P.

    1998-07-01

    Synchrotron radiation is a very bright, broadband, polarized, pulsed source of light extending from the infrared to the x-ray region. It is an extremely important source of Vacuum Ultraviolet radiation. Brightness is defined as flux per unit area per unit solid angle and is normally a more important quantity than flux alone particularly in throughput limited applications which include those in which monochromators are used. It is well known from classical theory of electricity and magnetism that accelerating charges emit electromagnetic radiation. In the case of synchrotron radiation, relativistic electrons are accelerated in a circular orbit and emit electromagnetic radiation in a broad spectral range. The visible portion of this spectrum was first observed on April 24, 1947 at General Electric's Schenectady facility by Floyd Haber, a machinist working with the synchrotron team, although the first theoretical predictions were by Lienard in the latter part of the 1800's. An excellent early history with references was presented by Blewett and a history covering the development of the utilization of synchrotron radiation was presented by Hartman. Synchrotron radiation covers the entire electromagnetic spectrum from the infrared region through the visible, ultraviolet, and into the x-ray region up to energies of many 10's of kilovolts. If the charged particles are of low mass, such as electrons, and if they are traveling relativistically, the emitted radiation is very intense and highly collimated, with opening angles of the order of 1 milliradian. In electron storage rings there are three possible sources of synchrotron radiation; dipole (bending) magnets; wigglers, which act like a sequence of bending magnets with alternating polarities; and undulators, which are also multi-period alternating magnet systems but in which the beam deflections are small resulting in coherent interference of the emitted light.

  14. Gastrointestinal Health in Classic Galactosemia.

    Science.gov (United States)

    Shaw, Kelly A; Mulle, Jennifer G; Epstein, Michael P; Fridovich-Keil, Judith L

    2016-07-01

    Classic galactosemia (CG) is an autosomal recessive disorder of galactose metabolism that affects approximately 1/50,000 live births in the USA. Following exposure to milk, which contains large quantities of galactose, affected infants may become seriously ill. Early identification by newborn screening with immediate dietary galactose restriction minimizes or prevents the potentially lethal acute symptoms of CG. However, more than half of individuals with CG still experience long-term complications including cognitive disability, behavioral problems, and speech impairment. Anecdotal reports have also suggested frequent gastrointestinal (GI) problems, but this outcome has not been systematically addressed. In this study we explored the prevalence of GI symptoms among 183 children and adults with CG (cases) and 190 controls. Cases reported 4.5 times more frequent constipation (95% CI 1.8-11.5) and 4.2 times more frequent nausea (95% CI 1.2-15.5) than controls. Cases with genotypes predicting residual GALT activity reported less frequent constipation than cases without predicted GALT activity but this difference was not statistically significant. Because the rigor of dietary galactose restriction varies among individuals with galactosemia, we further tested whether GI symptoms associated with diet in infancy. Though constipation was almost four times as common among cases reporting a more restrictive diet in infancy, this difference was not statistically significant. These data confirm that certain GI symptoms are more common in classic galactosemia compared to controls and suggest that future studies should investigate associations with residual GALT activity and dietary galactose restriction in early life.

  15. Hilbert space theory of classical electrodynamics

    Indian Academy of Sciences (India)

    RAJAGOPAL A K; GHOSE PARTHA

    2016-06-01

    Classical electrodynamics is reformulated in terms of wave functions in the classical phase space of electrodynamics, following the Koopman–von Neumann–Sudarshan prescription for classical mechanics on Hilbert spaces sans the superselection rule which prohibits interference effects in classical mechanics. This is accomplished by transforming from a set of commutingobservables in one Hilbert space to another set of commuting observables in a larger Hilbert space. This is necessary to clarify the theoretical basis of the much recent work on quantum-like features exhibited by classical optics. Furthermore, following Bondar et al, {\\it Phys. Rev.} A 88, 052108 (2013), it is pointed out that quantum processes that preserve the positivity or nonpositivity of theWigner function can be implemented by classical optics. This may be useful in interpreting quantum information processing in terms of classical optics.

  16. The dissociative chemisorption of methane on Ni(100) and Ni(111): classical and quantum studies based on the reaction path Hamiltonian.

    Science.gov (United States)

    Mastromatteo, Michael; Jackson, Bret

    2013-11-21

    Electronic structure methods based on density functional theory are used to construct a reaction path Hamiltonian for CH4 dissociation on the Ni(100) and Ni(111) surfaces. Both quantum and quasi-classical trajectory approaches are used to compute dissociative sticking probabilities, including all molecular degrees of freedom and the effects of lattice motion. Both approaches show a large enhancement in sticking when the incident molecule is vibrationally excited, and both can reproduce the mode specificity observed in experiments. However, the quasi-classical calculations significantly overestimate the ground state dissociative sticking at all energies, and the magnitude of the enhancement in sticking with vibrational excitation is much smaller than that computed using the quantum approach or observed in the experiments. The origin of this behavior is an unphysical flow of zero point energy from the nine normal vibrational modes into the reaction coordinate, giving large values for reaction at energies below the activation energy. Perturbative assumptions made in the quantum studies are shown to be accurate at all energies studied.

  17. Current status and potential perspectives in classical radiotherapy technology

    Directory of Open Access Journals (Sweden)

    Dabić-Stanković Kata M.

    2004-01-01

    Full Text Available Introduction and potentials of classical radiotherapy After purchase of radiotherapy equipment in 2003, classic radiation therapy in Serbia will reach the highest world level. In order to define the highest standards in radiation technology, we analyzed the current status and potential perspectives of radiation therapy. Technological levels of radiotherapy in developed countries An analysis of present situation in the USA, assumed as the most developed in the world, was done. Available data, collected in the last 3 years (equipment assortment, therapy modalities, workload and manpower for 284 radiotherapy centers, out of potential 2050, were analyzed. Results were presented as crude percentage and mached to point current status. Results of analysis and discussion The analysis showed that CLINAC accelerators are the most popular (82.7%, as well as, ADAC (43.7% and Focus (CMS (27.4% systems for therapy planning. Movement towards virtual simulation is evident (59.3%, although classic ”simulation” is not fully eliminated from the radiotherapy chain. The most popular brachytherapy afterloader is Microselectron HDR (71%. About 64.4% centers use IMPAC communication/verification/record system that seems more open than Varis. All centers practice modern radiotherapy modalities and techniques (CFRT, IMRT, SRS/SRT, TBI, IORT, IVBHRT, HDR BHRT, etc.. CT and MRI availability is out of question, but PET is available in 3% of centers, however this percentage is rapidly growing. Up to 350 new patients per year are treated by one accelerator (about 35 pts. a day. Centers are relatively small and utilize 2-3 accelerators on average. Average FTE staffing norm is 4 radiation oncologists, 2-3 medical radiotherapy physicists, about 3 certified medical dosimetrists and about 6 radiotherapy technologists. Technological aspects and conclusion In the past 5 years relative stagnation in classic radiotherapy has been observed. In spite of substantial investments in

  18. Workshop I – Black holes and compact objects: Classical aspects

    Indian Academy of Sciences (India)

    B S Ramachandra; C V Vishveshwara

    2000-10-01

    This is a summary of the papers presented in session W1 on the papers submitted to the workshop I on the classical aspects of black holes and compact objects were classified into three categories: (i) theoretical aspects; (ii) astrophysical aspects; (iii) gravitational radiation. The three sessions were devoted each to one of the above categories. The chairmen of the workshop were J Bičák, Charles University, Prague (Czech Republic) and C V Vishveshwara, Indian Institute of Astrophysics, India.

  19. Quantum remnants in the classical limit

    Energy Technology Data Exchange (ETDEWEB)

    Kowalski, A.M., E-mail: kowalski@fisica.unlp.edu.ar [Instituto de Física (IFLP-CCT-Conicet), Universidad Nacional de La Plata, C.C. 727, 1900 La Plata (Argentina); Comision de Investigaciones Científicas (CIC) (Argentina); Plastino, A., E-mail: plastino@fisica.unlp.edu.ar [Instituto de Física (IFLP-CCT-Conicet), Universidad Nacional de La Plata, C.C. 727, 1900 La Plata (Argentina); Argentina' s National Research Council (CONICET) (Argentina); SThAR, EPFL Innovation Park, Lausanne (Switzerland)

    2016-09-16

    We analyze here the common features of two dynamical regimes: a quantum and a classical one. We deal with a well known semi-classic system in its route towards the classical limit, together with its purely classic counterpart. We wish to ascertain i) whether some quantum remnants can be found in the classical limit and ii) the details of the quantum-classic transition. The so-called mutual information is the appropriate quantifier for this task. Additionally, we study the Bandt–Pompe's symbolic patterns that characterize dynamical time series (representative of the semi-classical system under scrutiny) in their evolution towards the classical limit. - Highlights: • We investigate the classical limit (CL) of a well known semi classical model. • The study is made by reference to the Bandt Pompe symbolic approach. • The number and type of associated symbols changes as one proceeds towards the CL. • We ascertain which symbols pertaining to the quantum zone remain in the CL.

  20. Religious ecstasy in classical Sufism

    Directory of Open Access Journals (Sweden)

    Göran Ogén

    1982-01-01

    Full Text Available The purpose of this essay is to shed some light on the phenomenon of religious ecstasy as met within Islamic mysticism and there particularly during its classical period. In this case, the expression "classical Sufism" refers to the period of Sufi history from about 850 A.D. until circa 1100 A.D. In the Sufi vocabulary there is even a rather differentiated terminology concerning these ecstatic experiences or states; whether different descriptions of one and the same experience are involved or whether the terms actually describe different experiences is a question that we must set aside for the present. There are, however, Sufis expressing the opinion that these different states of mind are based on one single experience in spite of the difference in terms. A generic term for these experiences or states is not to be found in the Sufi terminology however, so the problem of which of these phenomena must be present in order for ecstasy to be evidenced—or which of them would be sufficient— does not therefore arise for the Sufis. So instead of speaking of religious ecstasy in general, they either refer to the single specific terms in question or else use the plural of one of the words employed to designate one of the terms we include in "religious ecstasy". They thus speak of "ecstasies", mawagid from the singular form wagd—if one should at all attempt a translation of this plural. This plural is a genuine Sufi construction and does not otherwise seem to occur in the Arabic language, except as a later borrowing. Psalmody based on the Koranic vocabulary remains the main procedure for putting oneself in ecstasy. If we add 'and listening to psalmody', we then obtain a fairly satisfactory picture of the external conditions for the Sufis' ecstasy until the eleventh century, when various innovations begin to appear. As far as the darwiš-dance is concerned, it is not until the thirteenth century with Rumi that it becomes transformed from an expression

  1. Blackbody radiation: rosetta stone of heat bath models

    Science.gov (United States)

    O'Connell, R. F.

    2007-06-01

    The radiation field can be regarded as a collection of independent harmonic oscillators and, as such, constitutes a heat bath. Moreover, the known form of its interaction with charged particles provides a "rosetta stone" for deciding on and interpreting the correct interaction for the more general case of a quantum particle in an external potential and coupled to an arbitrary heat bath. In particular, combining QED with the machinery of stochastic physics, enables the usual scope of applications to be widened. We discuss blackbody radiation effects on: the equation of motion of a radiating electron (obtaining an equation of motion which is free from runaway solutions), anomalous diffusion, the spreading of a Gaussian wave packet, and decoherence effects due to zero-point oscillations. In addition, utilizing a formula we obtained for the free energy of an oscillator in a heat bath, enables us to determine all the quantum thermodynamic functions of interest (particularly in the areas of quantum information and nanophysics where small systems are involved) and from which we obtain temperature dependent Lamb shifts, quantum effects on the entropy at low temperature and implications for Nernst's law.

  2. Stability of the hydrogen atom of classical electrodynamics

    CERN Document Server

    De Luca, J

    2004-01-01

    We study the stability of the circular orbits of the electromagnetic two-body problem of classical electrodynamics. We introduce the concept of resonant dissipation, i.e. a motion that radiates the center-of-mass energy while the interparticle distance performs bounded oscillations about a metastable orbit. The stability mechanism is established by the existence of a quartic resonant constant generated by the stiff eigenvalues of the linear stability problem. This constant bounds the particles together during the radiative recoil. The condition of resonant dissipation predicts angular momenta for the metastable orbits in reasonable agreement with the Bohr atom. The principal result is that the emission lines agree with the predictions of quantum electrodynamics (QED) with 1 percent average error even up to the $40^{th}$ line. Our angular momenta depend logarithmically on the mass of the heavy body, such that the deuterium and the muonium atoms have essentially the same angular momenta, in agreement with QED. ...

  3. Classical topology and quantum states

    Indian Academy of Sciences (India)

    A P Balachandran

    2001-02-01

    Any two infinite-dimensional (separable) Hilbert spaces are unitarily isomorphic. The sets of all their self-adjoint operators are also therefore unitarily equivalent. Thus if all self-adjoint operators can be observed, and if there is no further major axiom in quantum physics than those formulated for example in Dirac’s ‘quantum mechanics’, then a quantum physicist would not be able to tell a torus from a hole in the ground. We argue that there are indeed such axioms involving observables with smooth time evolution: they contain commutative subalgebras from which the spatial slice of spacetime with its topology (and with further refinements of the axiom, its - and ∞ - structures) can be reconstructed using Gel’fand–Naimark theory and its extensions. Classical topology is an attribute of only certain quantum observables for these axioms, the spatial slice emergent from quantum physics getting progressively less differentiable with increasingly higher excitations of energy and eventually altogether ceasing to exist. After formulating these axioms, we apply them to show the possibility of topology change and to discuss quantized fuzzy topologies. Fundamental issues concerning the role of time in quantum physics are also addressed.

  4. Pembrolizumab in classical Hodgkin's lymphoma.

    Science.gov (United States)

    Maly, Joseph; Alinari, Lapo

    2016-09-01

    Pembrolizumab is a humanized monoclonal antibody directed against programmed cell death protein 1 (PD-1), a key immune-inhibitory molecule expressed on T cells and implicated in CD4+ T-cell exhaustion and tumor immune-escape mechanisms. Classical Hodgkin's lymphoma (cHL) is a unique B-cell malignancy in the sense that malignant Reed-Sternberg (RS) cells represent a small percentage of cells within an extensive immune cell infiltrate. PD-1 ligands are upregulated on RS cells as a consequence of both chromosome 9p24.1 amplification and Epstein-Barr virus infection and by interacting with PD-1 promote an immune-suppressive effect. By augmenting antitumor immune response, pembrolizumab and nivolumab, another monoclonal antibody against PD-1, have shown significant activity in patients with relapsed/refractory cHL as well as an acceptable toxicity profile with immune-related adverse events that are generally manageable. In this review, we explore the rationale for targeting PD-1 in cHL, review the clinical trial results supporting the use of checkpoint inhibitors in this disease, and present future directions for investigation in which this approach may be used.

  5. Relaxation properties in classical diamagnetism

    Science.gov (United States)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  6. THE BUREAUCRATIC PHENOMENON: CLASSICAL CONCEPTS

    Directory of Open Access Journals (Sweden)

    Дама Ибрагима

    2013-09-01

    Full Text Available Aim of this article - to analyze Hegel and Karl Marx’s classic bureaucracy theories and also Max Weber’s concept of rational bureaucracy and its development in the works of Herbert Simon, Robert Merton, Peter Blau and Michel Crozier. It shows that the above listed researchers only undertook a change of terminology within the same theoretical tradition. The article describes different approaches to the bureaucratic system of administrative schools of the late 1950s and early 1980s. Major conclusions in the article include the following: administering the state apparatus consists in the organization of government on the basis of regulated rights, mandatory procedures that are invoked to ensure balance in the interest of man and society; bad effectiveness of government, infringement of the rights and freedoms of the individual is the result of dysfunction in the state apparatus; the struggle against it can be carried out with the help of administrative, economical and legal methods.DOI: http://dx.doi.org/10.12731/2218-7405-2013-6-45

  7. Classical electrodynamics. Lecture and exercises of electromagnetism; Electrodynamique classique. Cours et exercices d'electromagnetisme

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, J.D. [Berkeley University, California (United States)

    2001-07-01

    This book is the French translation of the last revised edition of the original version published by John Wiley and Sons under the title 'Classical electrodynamics 3. Edition'. It covers the physics and classical mathematics necessary to understand electromagnetic fields in materials and at surfaces and interfaces. It emphasizes the unity of electric and magnetic phenomena both in their physical basis and the mode of their mathematical description. It develops and utilizes a number of tools in mathematical physics, and presents now material on the interaction of relativistic charged particles with electromagnetic fields and other areas. First published in 1962, and again in 1974; the third edition incorporates the slight drifts in emphasis and applications that have occurred in the past twenty years. Content: introduction to electrostatics; boundary-value problems in electrostatics; multipoles, electrostatics of macroscopic media, dielectrics; magneto-statics, Faraday's law, quasi-static fields; Maxwell equations, macroscopic electromagnetism, conservation laws; plane electromagnetic waves and wave propagation; waveguides, resonant cavities, and optical fibers; radiating systems, multipole fields and radiation; scattering and diffraction; special theory of relativity; dynamics of relativistic particles and electromagnetic fields; collisions, energy loss, and scattering of charged particles, Cherenkov and transition radiation; radiation by moving charges; Bremsstrahlung, method of virtual quanta, radiative beta processes; radiation damping, classical models of charged particles. (J.S.)

  8. Structure of classical affine and classical affine fractional W-algebras

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Uhi Rinn, E-mail: uhrisu1@math.snu.ac.kr [Department of Mathematical Sciences, Seoul National University, GwanAkRo 1, Gwanak-Gu, Seoul 151-747 (Korea, Republic of)

    2015-01-15

    We introduce a classical BRST complex (See Definition 3.2.) and show that one can construct a classical affine W-algebra via the complex. This definition clarifies that classical affine W-algebras can be considered as quasi-classical limits of quantum affine W-algebras. We also give a definition of a classical affine fractional W-algebra as a Poisson vertex algebra. As in the classical affine case, a classical affine fractional W-algebra has two compatible λ-brackets and is isomorphic to an algebra of differential polynomials as a differential algebra. When a classical affine fractional W-algebra is associated to a minimal nilpotent, we describe explicit forms of free generators and compute λ-brackets between them. Provided some assumptions on a classical affine fractional W-algebra, we find an infinite sequence of integrable systems related to the algebra, using the generalized Drinfel’d and Sokolov reduction.

  9. Locking classical correlation in quantum states

    CERN Document Server

    Di Vincenzo, D P; Leung, D; Smolin, J A; Terhal, B M; Vincenzo, David Di; Horodecki, Michal; Leung, Debbie; Smolin, John; Terhal, Barbara

    2003-01-01

    We show that there exist bipartite quantum states which contain large hidden classical correlation that can be unlocked by a disproportionately small amount of classical communication. In particular, there are $(2n+1)$-qubit states for which a one bit message doubles the optimal classical mutual information between measurement results on the subsystems, from $n/2$ bits to $n$ bits. States exhibiting this behavior need not be entangled. We study the range of states exhibiting this phenomenon and bound its magnitude.

  10. Classical information capacity of superdense coding

    CERN Document Server

    Bowen, G H

    2001-01-01

    Classical communication through quantum channels may be enhanced by sharing entanglement. Superdense coding allows the encoding, and transmission, of up to two classical bits of information in a single qubit. In this paper, the maximum classical channel capacity for states that are not maximally entangled is derived. Particular schemes are then shown to attain this capacity, firstly for pairs of qubits, and secondly for pairs of qutrits.

  11. Digital Classics Outside the Echo-Chamber

    OpenAIRE

    Bodard, Gabriel; Romanello, Matteo

    2016-01-01

    This volume, edited by the organizers of the “Digital Classicist” seminars series, presents research in classical studies, digital classics and digital humanities, bringing together scholarship that addresses the impact of the study of classical antiquity through computational methods on audiences such as scientists, heritage professionals, students and the general public. Within this context, chapters tackle particular aspects, from epigraphy, papyrology and manuscripts, via Greek language, ...

  12. On the tomographic description of classical fields

    CERN Document Server

    Ibort, A; Man'ko, V I; Marmo, G; Simoni, A; Sudarshan, E C G; Ventriglia, F

    2012-01-01

    After a general description of the tomographic picture for classical systems, a tomographic description of free classical scalar fields is proposed both in a finite cavity and the continuum. The tomographic description is constructed in analogy with the classical tomographic picture of an ensemble of harmonic oscillators. The tomograms of a number of relevant states such as the canonical distribution, the classical counterpart of quantum coherent states and a new family of so called Gauss--Laguerre states, are discussed. Finally the Liouville equation for field states is described in the tomographic picture offering an alternative description of the dynamics of the system that can be extended naturally to other fields.

  13. Classical Fields and the Quantum Concept

    CERN Document Server

    De Souza, M M

    1996-01-01

    We do a critical review of the Faraday-Maxwell concept of classical field and of its quantization process. With the hindsight knowledge of the essentially quantum character of the interactions, we use a naive classical model of field, based on exchange of classical massless particles, for a comparative and qualitative analysis of the physical content of the Coulomb's and Gauss's laws. It enlightens the physical meaning of a field singularity and of a static field. One can understand the problems on quantizing a classical field but not the hope of quantizing the gravitational field right from General Relativity.

  14. Seven Steps Towards the Classical World

    CERN Document Server

    Allori, V; Goldstein, S; Zanghì, N; Allori, Valia; Goldstein, Shelly; Zangh\\'{\\i}, Nino

    2001-01-01

    Classical physics is about real objects, like apples falling from trees, whose motion is governed by Newtonian laws. In standard Quantum Mechanics only the wave function or the results of measurements exist, and to answer the question of how the classical world can be part of the quantum world is a rather formidable task. However, this is not the case for Bohmian mechanics, which, like classical mechanics, is a theory about real objects. In Bohmian terms, the problem of the classical limit becomes very simple: when do the Bohmian trajectories look Newtonian?

  15. Primitive Ontology and the Classical World

    Science.gov (United States)

    Allori, Valia

    In this chapter, I present the common structure of quantum theories with a primitive ontology (PO), and discuss in what sense the classical world emerges from quantum theories as understood in this framework. In addition, I argue that the PO approach is better at analyzing the classical limit than the rival wave function ontology approach or any other approach in which the classical world is non-reductively "emergent:" even if the classical limit within this framework needs to be fully developed, the difficulties are technical rather than conceptual, while this is not true for the alternatives.

  16. Limitations on Cloning in Classical Mechanics

    OpenAIRE

    Fenyes, Aaron

    2010-01-01

    In this paper, we show that a result precisely analogous to the traditional quantum no-cloning theorem holds in classical mechanics. This classical no-cloning theorem does not prohibit classical cloning, we argue, because it is based on a too-restrictive definition of cloning. Using a less popular, more inclusive definition of cloning, we give examples of classical cloning processes. We also prove that a cloning machine must be at least as complicated as the object it is supposed to clone.

  17. Non-classical dispersive shock waves in shallow water

    Science.gov (United States)

    Sprenger, Patrick; Hoefer, Mark

    2016-11-01

    A classical model for shallow water waves with strong surface tension is the Kawahara equation, which is the Korteweg-de Vries (KdV) including a fifth order derivative term. A particular problem of interest to these types of equations is step initial data, known as the Riemann problem, which results in a shock in finite time. Unlike classical shock waves, where a discontinuity is resolved by dissipation, the dispersive regularization results in the discontinuity resolved as a dispersive shock wave (DSW). When parameter choices result in non-convex dispersion, three distinct dynamic regimes are observed that can be characterized solely by the amplitude of the initial step. For small jumps, a perturbed KdV DSW with positive polarity and orientation is generated, accompanied by small amplitude radiation from an embedded solitary wave leading edge, termed a radiating DSW. For moderate jumps, a crossover regime is observed with waves propagating forward and backward from the sharp transition region. For sufficiently large jumps, a new type of DSW is observed we term a translating DSW were a partial, non-monotonic, negative solitary wave at the trailing edge is connected to an interior nonlinear periodic wave and exhibits features common to both dissipative and dispersive shock waves.

  18. Perturbative quantization of Yang-Mills theory with classical double as gauge algebra

    CERN Document Server

    Ruiz, F Ruiz

    2015-01-01

    Perturbative quantization of Yang-Mills theory with a gauge algebra given by the classical double of a semisimple Lie algebra is considered. The classical double of a real Lie algebra is a nonsemisimple real Lie algebra that admits a nonpositive definite invariant metric, the indefiniteness of the metric suggesting an apparent lack of unitarity. It is shown that the theory is UV divergent at one loop and that there are no radiative corrections at higher loops. One-loop UV divergences are removed through renormalization of the coupling constant, thus introducing a renormalization scale. The terms in the classical action that would spoil unitarity are proved to be cohomologically trivial with respect to the Slavnov-Taylor operator that controls gauge invariance for the quantum theory. Hence they do not contribute gauge invariant radiative corrections to the quantum effective action and the theory is unitary.

  19. Perturbative quantization of Yang-Mills theory with classical double as gauge algebra

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Ruiz, F. [Universidad Complutense de Madrid, Departamento de Fisica Teorica I, Madrid (Spain)

    2016-02-15

    Perturbative quantization of Yang-Mills theory with a gauge algebra given by the classical double of a semisimple Lie algebra is considered. The classical double of a real Lie algebra is a nonsemisimple real Lie algebra that admits a nonpositive definite invariant metric, the indefiniteness of the metric suggesting an apparent lack of unitarity. It is shown that the theory is UV divergent at one loop and that there are no radiative corrections at higher loops. One-loop UV divergences are removed through renormalization of the coupling constant, thus introducing a renormalization scale. The terms in the classical action that would spoil unitarity are proved to be cohomologically trivial with respect to the Slavnov-Taylor operator that controls gauge invariance for the quantum theory. Hence they do not contribute gauge invariant radiative corrections to the quantum effective action and the theory is unitary. (orig.)

  20. Radiation in Particle Simulations

    Energy Technology Data Exchange (ETDEWEB)

    More, R; Graziani, F; Glosli, J; Surh, M

    2010-11-19

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of megabars to thousands of gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known. The second method expands the electromagnetic field in normal modes (planewaves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion. The third method is a hybrid molecular dynamics/Monte Carlo (MD/MC) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions. The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc. This approach is inspired by the virial expansion method of equilibrium statistical mechanics. Using a combination of these methods we believe it is possible to do atomic-scale particle

  1. Radiation Therapy: Professions in Radiation Therapy

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Professions in Radiation Therapy Radiation Oncologist Therapeutic Medical Physicist Radiation Therapist Dosimetrist Radiation Oncology Nurse Social Worker Dietitian Radiation Oncologist Radiation oncologists are physicians who oversee the ...

  2. Factors Influencing the Learning of Classical Mechanics.

    Science.gov (United States)

    Champagne, Audrey B.; And Others

    1980-01-01

    Describes a study investigating the combined effect of certain variables on student achievement in classical mechanics. The purpose was to (1) describe preinstructional knowledge and skills; (2) correlate these variables with the student's success in learning classical mechanics; and (3) develop hypothesis about relationships between these…

  3. Classical and Quantum-Mechanical State Reconstruction

    Science.gov (United States)

    Khanna, F. C.; Mello, P. A.; Revzen, M.

    2012-01-01

    The aim of this paper is to present the subject of state reconstruction in classical and in quantum physics, a subject that deals with the experimentally acquired information that allows the determination of the physical state of a system. Our first purpose is to explain a method for retrieving a classical state in phase space, similar to that…

  4. On entanglement-assisted classical capacity

    Science.gov (United States)

    Holevo, A. S.

    2002-09-01

    We give a modified proof of the recent result of C. H. Bennett, P. W. Shor, J. A. Smolin, and A. V. Thapliyal concerning entanglement-assisted classical capacity of a quantum channel and discuss the relation between entanglement-assisted and unassisted classical capacities.

  5. Classical Conditioning: Eliciting the Right Response.

    Science.gov (United States)

    Tauber, Robert T.

    1990-01-01

    Classical conditioning is responsible for students' positive and negative feelings, whether directed toward subject matter, peers, teachers, or education in general. This article explains how educators can use classical conditioning principles (such as reinforcement, extinction, and paired stimuli) to create an anxiety-free learning environment.…

  6. Classical Music, liveness and digital technologies

    DEFF Research Database (Denmark)

    Steijn, Arthur

    2014-01-01

    Performances of classical composition music have seen a decline in their audiences for some years. Does the classical concert ritual scare people off? This notion has spurred off a development of design concepts directed at rethinking concert rituals in order to create new audience experiences. T...

  7. Isomorphic Formulae in Classical Propositional Logic

    CERN Document Server

    Dosen, K

    2009-01-01

    Isomorphism between formulae is defined with respect to categories formalizing equality of deductions in classical propositional logic and in the multiplicative fragment of classical linear propositional logic caught by proof nets. This equality is motivated by generality of deductions. Characterizations are given for pairs of isomorphic formulae, which lead to decision procedures for this isomorphism.

  8. Why Do We See a Classical World?

    CERN Document Server

    Roemer, Hartmann

    2011-01-01

    From a general abstract system theoretical perspective, a quantum-like system description in the spirit of a generalized quantum theory may appear to be simpler and more natural than a classically inspired description. We investigate the reasons why we nevertheless conceive ourselves embedded into a classically structured world.

  9. Classical Swine Fever Virus-Rluc Replicons

    DEFF Research Database (Denmark)

    Risager, Peter Christian; Belsham, Graham J.; Rasmussen, Thomas Bruun

    Classical swine fever virus (CSFV) is the etiologic agent of the severe porcine disease, classical swine fever. Unraveling the molecular determinants of efficient replication is crucial for gaining proper knowledge of the pathogenic traits of this virus. Monitoring the replication competence within...

  10. Milgram's Obedience Study: A Contentious Classic Reinterpreted

    Science.gov (United States)

    Griggs, Richard A.

    2017-01-01

    Given the many older criticisms of Milgram's obedience study and the more damning recent criticisms based on analyses of materials available in the Milgram archives at Yale, this study has become a contentious classic. Yet, current social psychology textbooks present it as an uncontentious classic, with no coverage of the recent criticisms and…

  11. Converting Projects from STK Classic to STK

    Energy Technology Data Exchange (ETDEWEB)

    Foucar, James G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    The version of STK (Sierra ToolKit) that has long been provided with Trilinos is no longer supported by the core develop- ment team. With the introduction of a the new STK library into Trilinos, the old STK has been renamed to stk classic. This document contains a rough guide of how to port a stk classic code to STK.

  12. Classical decoherence in a nanomechanical resonator

    Science.gov (United States)

    Maillet, O.; Vavrek, F.; Fefferman, A. D.; Bourgeois, O.; Collin, E.

    2016-07-01

    Decoherence is an essential mechanism that defines the boundary between classical and quantum behaviours, while imposing technological bounds for quantum devices. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. But decoherence can also be thought of in a purely classical context, as the loss of phase coherence in the classical phase space. Indeed the bridge between quantum and classical physics is under intense investigation, using, in particular, classical nanomechanical analogues of quantum phenomena. In the present work, by separating pure dephasing from dissipation, we quantitatively model the classical decoherence of a mechanical resonator: through the experimental control of frequency fluctuations, we engineer artificial dephasing. Building on the fruitful analogy introduced between spins/quantum bits and nanomechanical modes, we report on the methods available to define pure dephasing in these systems, while demonstrating the intrinsic almost-ideal properties of silicon nitride beams. These experimental and theoretical results, at the boundary between classical nanomechanics and quantum information fields, are prerequisite in the understanding of decoherence processes in mechanical devices, both classical and quantum.

  13. New Classical and New Keynesian Macroeconomics.

    Science.gov (United States)

    Vane, Howard; Snowdon, Brian

    1992-01-01

    Summarizes underlying tenets and policy implications of new classical and new Keynesian macroeconomics. Compares new approaches with orthodox Keynesian and monetarist schools of thought. Identifies the fundamental difference between new classical and new Keynesian models as the assumption regarding the speed of wage and price adjustment following…

  14. Introducing quantum effects in classical theories

    CERN Document Server

    Fabris, J C; Rodrigues, D C; Daouda, M H

    2015-01-01

    In this paper, we explore two different ways of implementing quantum effects in a classical structure. The first one is through an external field. The other one is modifying the classical conservation laws. In both cases, the consequences for the description of the evolution of the universe are discussed.

  15. Classical transport in disordered systems

    Science.gov (United States)

    Papaioannou, Antonios

    This thesis reports on the manifestation of structural disorder on molecular transport and it consists of two parts. Part I discusses the relations between classical transport and the underlying structural complexity of the system. Both types of molecular diffusion, namely Gaussian and non- Gaussian are presented and the relevant time regimes are discussed. In addition the concept of structural universality is introduced and connected with the diffusion metrics. One of the most robust techniques for measuring molecular mean square displacements is magnetic resonance. This method requires encoding and subsequently reading out after an experimentally controlled time, a phase φ to the spins using magnetic field gradients. The main limitation for probing short diffusion lengths L(t) ˜ 1micro m with magnetic resonance is the requirement to encode and decode the phase φ in very short time intervals. Therefore, to probe such displacements a special probe was developed equipped with a gradient coil capable of delivering magnetic field gradients of approximately 90 G/cmA . The design of the probe is reported. Part I also includes a discussion of experiments of transport in two qualitatively different disordered phantoms and reports on a direct observation of universality in one-dimension. The results reveal the universal power law scaling of the diffusion coefficient at the long-time regime and illustrate the essence of structural universality by experimentally determining the structure correlation function of the phantoms. In addition, the scaling of the diffusive permeability of the phantoms with respect to the pore size is investigated. Additional work presented includes a detailed study of adsorption of methane gas in Vycor disordered glass. The techniques described in Part I of this thesis are widely used for measuring structural parameters of porous media, such as the surface-to-volume ratio or diffusive permeability. Part II of this thesis discusses the

  16. Spectral properties of Compton inverse radiation: Application of Compton beams

    CERN Document Server

    Bulyak, Eugene

    2013-01-01

    Compton inverse radiation emitted due to backscattering of laser pulses off the relativistic electrons possesses high spectral density and high energy of photons - in hard x-ray up to gamma-ray energies - because of short wavelength of laser radiation as compared with the classical electromagnetic devices such as undulators. In this report, the possibility of such radiation to monochromatization by means of collimation is studied. Two approaches have been considered for the description of the spectral-angular density of Compton radiation based on the classical field theory and on the quantum electrodynamics. As is shown, both descriptions produce similar total spectra. On the contrary, angular distribution of the radiation is different: the classical approach predicted a more narrow radiation cone. Also proposed and estimated is a method of the `electronic' monochromatization based on the electronic subtraction of the two images produced by the electron beams with slightly different energies. A `proof-of-prin...

  17. Nonlinear acoustics in a dispersive continuum: Random waves, radiation pressure, and quantum noise

    Science.gov (United States)

    Cabot, M. A.

    The nonlinear interaction of sound with sound is studied using dispersive hydrodynamics which derived from a variational principle and the assumption that the internal energy density depends on gradients of the mass density. The attenuation of sound due to nonlinear interaction with a background is calculated and is shown to be sensitive to both the nature of the dispersion and decay bandwidths. The theoretical results are compared to those of low temperature helium experiments. A kinetic equation which described the nonlinear self-inter action of a background is derived. When a Deybe-type cutoff is imposed, a white noise distribution is shown to be a stationary distribution of the kinetic equation. The attenuation and spectrum of decay of a sound wave due to nonlinear interaction with zero point motion is calculated. In one dimension, the dispersive hydrodynamic equations are used to calculate the Langevin and Rayleigh radiation pressures of wave packets and solitary waves.

  18. Quantum Communication Attacks on Classical Cryptographic Protocols

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre

    In the literature on cryptographic protocols, it has been studied several times what happens if a classical protocol is attacked by a quantum adversary. Usually, this is taken to mean that the adversary runs a quantum algorithm, but communicates classically with the honest players. In several cases......, one can show that the protocol remains secure even under such an attack. However, there are also cases where the honest players are quantum as well, even if the protocol uses classical communication. For instance, this is the case when classical multiparty computation is used as a “subroutine......” in quantum multiparty computation. Furthermore, in the future, players in a protocol may employ quantum computing simply to improve efficiency of their local computation, even if the communication is supposed to be classical. In such cases, it no longer seems clear that a quantum adversary must be limited...

  19. [Heavy particle radiation therapy].

    Science.gov (United States)

    Lozares, S; Mañeru, F; Pellejero, S

    2009-01-01

    The characteristics of radiation formed by heavy particles make it a highly useful tool for therapeutic use. Protons, helium nuclei or carbon ions are being successfully employed in radiotherapy installations throughout the world. This article sets out the physical and technological foundations that make these radiation particles suitable for attacking white volume, as well as the different ways of administering treatment. Next, the main clinical applications are described, which show the therapeutic advantages in some of the pathologies most widely employed in proton and hadron therapy centres at present. Under continuous study, the clinical use of heavy particles appears to be an enormously promising path of advance in comparison with classical technologies, both in tumour coverage and in reducing dosages in surrounding tissue.

  20. Experimental proposal for testing the Emergence of Environment Induced (EIN) Classical Selection rules with Biological Systems

    CERN Document Server

    Durt, Thomas

    2010-01-01

    According to the so-called Quantum Darwinist approach, the emergence of "classical islands" from a quantum background is assumed to obey a (selection) principle of maximal information. We illustrate this idea by considering the coupling of two oscillators (modes). As our approach suggests that the classical limit could have emerged throughout a long and progressive Evolution mechanism, it is likely that primitive living organisms behave in a "more quantum", "less classical" way than more evolved ones. This brings us to seriously consider the possibility to measure departures from classicality exhibited by biological systems. We describe an experimental proposal the aimed at revealing the presence of entanglement in the biophotonic radiation emitted by biological sources.

  1. Illusory flow in radiation from accelerating charge

    Energy Technology Data Exchange (ETDEWEB)

    Biro, Tamas S.; Szendi, Zsuzsanna [RMI, WIGNER Research Centre for Physics, Budapest (Hungary); Schram, Zsolt [University of Debrecen, Department of Theoretical Physics, Debrecen (Hungary); MTA-DE Particle Physics Research Group, Debrecen (Hungary)

    2014-03-15

    In this paper we analyze the classical electromagnetic radiation of an accelerating point charge moving on a straight line trajectory. Depending on the duration of accelerations, rapidity distributions of photons emerge, resembling the ones obtained in the framework of hydrodynamical models by Landau or Bjorken. Detectable differences between our approach and spectra obtained from hydrodynamical models occur at high transverse momenta due to classical wave interference phenomena included in our model. (orig.)

  2. Effects of interaction on the properties of spiral galaxies. II. Isolated galaxies: The zero point

    Science.gov (United States)

    Márquez, I.; Moles, M.

    1999-04-01

    We analyse the properties of a sample of 22 bright isolated spiral galaxies on the basis of Johnson B,V,I images and optical rotation curves. The fraction of early morphological types in our sample of isolated galaxies (or in other samples of non-interacting spiral galaxies) appears to be smaller than in samples including interacting systems. The overall morphological aspect is regular and symmetric, but all the galaxies present non-axisymmetric components in the form of bars or rings. We find that the color indices become bluer towards the outer parts and that their central values are well correlated with the total colors. The properties of the bulges span a larger range than those of the disks, that thus are more alike between them. None of the galaxies shows a truncated, type II disk profile. It is found that the relation between surface brightness and size for the bulges, the Kormendy relation, is tighter when only isolated galaxies are considered. We find a similar relation for the disk parameters with an unprecedented low scatter. A Principal Component Analysis of the measured parameters shows that 2 eigenvectors suffice to explain more than 95 % of the total variance. These are, as found for other samples including spiral galaxies in different environmental situations, a scale parameter given by the mass or, equivalently, the luminosity or the size; and a form parameter given by the bulge to disk luminosity ratio, B/D, or, equivalently, by the gradient of the solid-body rotation region of the rotation curve, the G-parameter. We report here a tight correlation between G and B/D for our sample of isolated spirals that could be used as a new distance indicator. Based on data obtained at the 1.5m telescope of the Estacion de Observacion de Calar Alto, Instituto Geografico Nacional, which is jointly operated by the Instituto Geografico Nacional and the Consejo Superior de Investigaciones Cientificas through the Instituto de Astrofisica de Andalucia

  3. Thermodynamic Stability of Boron : The Role of Defects and Zero Point Motion

    NARCIS (Netherlands)

    Setten, Michiel J. van; Uijttewaal, Matthé A.; Wijs, Gilles A. de; Groot, Robert A. de

    2007-01-01

    Its low weight, high melting point, and large degree of hardness make elemental boron a technologically interesting material. The large number of allotropes, mostly containing over a hundred atoms in the unit cell, and their difficult characterization challenge both experimentalists and theoretician

  4. Thermodynamic stability of boron : The role of defects and zero point motion

    NARCIS (Netherlands)

    van Setten, Michiel J.; Uijttewaal, Matthe A.; de Wijs, Gilles A.; de Groot, Robert A.

    2007-01-01

    Its low weight, high melting point, and large degree of hardness make elemental boron a technologically interesting material. The large number of allotropes, mostly containing over a hundred atoms in the unit cell, and their difficult characterization challenge both experimentalists and theoretician

  5. Approximating zero points of accretive operators with compact domains in general Banach spaces

    Directory of Open Access Journals (Sweden)

    Miyake Hiromichi

    2005-01-01

    Full Text Available We prove strong convergence theorems of Mann's type and Halpern's type for resolvents of accretive operators with compact domains and apply these results to find fixed points of nonexpansive mappings in Banach spaces.

  6. Classical microscopic theory of dispersion, emission and absorption of light in dielectrics. Classical microscopic theory of dielectric susceptibility

    Science.gov (United States)

    Carati, Andrea; Galgani, Luigi

    2014-10-01

    This paper is a continuation of a recent one in which, apparently for the first time, the existence of polaritons in ionic crystals was proven in a microscopic electrodynamic theory. This was obtained through an explicit computation of the dispersion curves. Here the main further contribution consists in studying electric susceptibility, from which the spectrum can be inferred. We show how susceptibility is obtained by the Green-Kubo methods of Hamiltonian statistical mechanics, and give for it a concrete expression in terms of time-correlation functions. As in the previous paper, here too we work in a completely classical framework, in which the electrodynamic forces acting on the charges are all taken into account, both the retarded forces and the radiation reaction ones. So, in order to apply the methods of statistical mechanics, the system has to be previously reduced to a Hamiltonian one. This is made possible in virtue of two global properties of classical electrodynamics, namely, the Wheeler-Feynman identity and the Ewald resummation properties, the proofs of which were already given for ordered system. The second contribution consists in formulating the theory in a completely general way, so that in principle it applies also to disordered systems such as glasses, or liquids or gases, provided the two general properties mentioned above continue to hold. A first step in this direction is made here by providing a completely general proof of the Wheeler-Feynman identity, which is shown to be the counterpart of a general causality property of classical electrodynamics. Finally it is shown how a line spectrum can appear at all in classical systems, as a counterpart of suitable stability properties of the motions, with a broadening due to a coexistence of chaoticity. The relevance of some recent results of the theory of dynamical systems in this connection is also pointed out.

  7. Driven topological systems in the classical limit

    Science.gov (United States)

    Duncan, Callum W.; Öhberg, Patrik; Valiente, Manuel

    2017-03-01

    Periodically driven quantum systems can exhibit topologically nontrivial behavior, even when their quasienergy bands have zero Chern numbers. Much work has been conducted on noninteracting quantum-mechanical models where this kind of behavior is present. However, the inclusion of interactions in out-of-equilibrium quantum systems can prove to be quite challenging. On the other hand, the classical counterpart of hard-core interactions can be simulated efficiently via constrained random walks. The noninteracting model, proposed by Rudner et al. [Phys. Rev. X 3, 031005 (2013), 10.1103/PhysRevX.3.031005], has a special point for which the system is equivalent to a classical random walk. We consider the classical counterpart of this model, which is exact at a special point even when hard-core interactions are present, and show how these quantitatively affect the edge currents in a strip geometry. We find that the interacting classical system is well described by a mean-field theory. Using this we simulate the dynamics of the classical system, which show that the interactions play the role of Markovian, or time-dependent disorder. By comparing the evolution of classical and quantum edge currents in small lattices, we find regimes where the classical limit considered gives good insight into the quantum problem.

  8. Fluctuations of wavefunctions about their classical average

    CERN Document Server

    Bénet, L; Hernandez-Saldana, H; Izrailev, F M; Leyvraz, F; Seligman, T H

    2003-01-01

    Quantum-classical correspondence for the average shape of eigenfunctions and the local spectral density of states are well-known facts. In this paper, the fluctuations of the quantum wavefunctions around the classical value are discussed. A simple random matrix model leads to a Gaussian distribution of the amplitudes whose width is determined by the classical shape of the eigenfunction. To compare this prediction with numerical calculations in chaotic models of coupled quartic oscillators, we develop a rescaling method for the components. The expectations are broadly confirmed, but deviations due to scars are observed. This effect is much reduced when both Hamiltonians have chaotic dynamics.

  9. Classical Gravitational Interactions and Gravitational Lorentz Force

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In quantum gauge theory of gravity, the gravitational field is represented by gravitational gauge field.The field strength of gravitational gauge field has both gravitoelectric component and gravitomagnetic component. In classical level, gauge theory of gravity gives classical Newtonian gravitational interactions in a relativistic form. Besides,it gives gravitational Lorentz force, which is the gravitational force on a moving object in gravitomagnetic field The direction of gravitational Lorentz force is not the same as that of classical gravitational Newtonian force. Effects of gravitational Lorentz force should be detectable, and these effects can be used to discriminate gravitomagnetic field from ordinary electromagnetic magnetic field.

  10. A Classical Introduction to Galois Theory

    CERN Document Server

    Newman, Stephen C

    2012-01-01

    This book provides an introduction to Galois theory and focuses on one central theme - the solvability of polynomials by radicals. Both classical and modern approaches to the subject are described in turn in order to have the former (which is relatively concrete and computational) provide motivation for the latter (which can be quite abstract). The theme of the book is historically the reason that Galois theory was created, and it continues to provide a platform for exploring both classical and modern concepts. This book examines a number of problems arising in the area of classical mathematic

  11. Effective Privacy Amplification for Secure Classical Communications

    CERN Document Server

    Horvath, Tamas; Scheuer, Jacob

    2011-01-01

    We study the effectiveness of privacy amplification for classical key-distribution schemes. We find that, unlike quantum key distribution schemes, the high fidelity of the raw key in classical systems allow the users to always sift a secure shorter key, given that they have an upper bound of eavesdropper probability to correctly guess the exchanged key-bits. We establish the number of privacy amplification iterations needed to achieve information leak of 10^-8 in several classical systems and highlight the inherent tradeoff between the number of iterations and the security of the raw key.

  12. Classical dynamics of particles and systems

    CERN Document Server

    Marion, Jerry B

    1965-01-01

    Classical Dynamics of Particles and Systems presents a modern and reasonably complete account of the classical mechanics of particles, systems of particles, and rigid bodies for physics students at the advanced undergraduate level. The book aims to present a modern treatment of classical mechanical systems in such a way that the transition to the quantum theory of physics can be made with the least possible difficulty; to acquaint the student with new mathematical techniques and provide sufficient practice in solving problems; and to impart to the student some degree of sophistication in handl

  13. Classical thermodynamics of non-electrolyte solutions

    CERN Document Server

    Van Ness, H C

    1964-01-01

    Classical Thermodynamics of Non-Electrolyte Solutions covers the historical development of classical thermodynamics that concerns the properties of vapor and liquid solutions of non-electrolytes. Classical thermodynamics is a network of equations, developed through the formal logic of mathematics from a very few fundamental postulates and leading to a great variety of useful deductions. This book is composed of seven chapters and begins with discussions on the fundamentals of thermodynamics and the thermodynamic properties of fluids. The succeeding chapter presents the equations of state for

  14. Fluctuations of wavefunctions about their classical average

    Energy Technology Data Exchange (ETDEWEB)

    Benet, L [Centro Internacional de Ciencias, Ciudad Universitaria, Chamilpa, Cuernavaca (Mexico); Flores, J [Centro Internacional de Ciencias, Ciudad Universitaria, Chamilpa, Cuernavaca (Mexico); Hernandez-Saldana, H [Centro Internacional de Ciencias, Ciudad Universitaria, Chamilpa, Cuernavaca (Mexico); Izrailev, F M [Centro Internacional de Ciencias, Ciudad Universitaria, Chamilpa, Cuernavaca (Mexico); Leyvraz, F [Centro Internacional de Ciencias, Ciudad Universitaria, Chamilpa, Cuernavaca (Mexico); Seligman, T H [Centro Internacional de Ciencias, Ciudad Universitaria, Chamilpa, Cuernavaca (Mexico)

    2003-02-07

    Quantum-classical correspondence for the average shape of eigenfunctions and the local spectral density of states are well-known facts. In this paper, the fluctuations of the quantum wavefunctions around the classical value are discussed. A simple random matrix model leads to a Gaussian distribution of the amplitudes whose width is determined by the classical shape of the eigenfunction. To compare this prediction with numerical calculations in chaotic models of coupled quartic oscillators, we develop a rescaling method for the components. The expectations are broadly confirmed, but deviations due to scars are observed. This effect is much reduced when both Hamiltonians have chaotic dynamics.

  15. Classical realizability in the CPS target language

    DEFF Research Database (Denmark)

    Frey, Jonas

    2016-01-01

    Motivated by considerations about Krivine's classical realizability, we introduce a term calculus for an intuitionistic logic with record types, which we call the CPS target language. We give a reformulation of the constructions of classical realizability in this language, using the categorical...... techniques of realizability triposes and toposes. We argue that the presentation of classical realizability in the CPS target language simplifies calculations in realizability toposes, in particular it admits a nice presentation of conjunction as intersection type which is inspired by Girard's ludics....

  16. Classical Statistical Mechanics and Landau Damping

    OpenAIRE

    1997-01-01

    We study the retarded response function in scalar $\\phi^4$-theory at finite temperature. We find that in the high-temperature limit the imaginary part of the self-energy is given by the classical theory to leading order in the coupling. In particular the plasmon damping rate is a purely classical effect to leading order, as shown by Aarts and Smit. The dominant contribution to Landau damping is given by the propagation of classical fields in a heat bath of non-interacting fields.

  17. Applying classical geometry intuition to quantum spin

    Science.gov (United States)

    Durfee, Dallin S.; Archibald, James L.

    2016-09-01

    Using concepts of geometric orthogonality and linear independence, we logically deduce the form of the Pauli spin matrices and the relationships between the three spatially orthogonal basis sets of the spin-1/2 system. Rather than a mathematically rigorous derivation, the relationships are found by forcing expectation values of the different basis states to have the properties we expect of a classical, geometric coordinate system. The process highlights the correspondence of quantum angular momentum with classical notions of geometric orthogonality, even for the inherently non-classical spin-1/2 system. In the process, differences in and connections between geometrical space and Hilbert space are illustrated.

  18. Deduction of Lorentz Transformations from Classical Thermodynamics

    Directory of Open Access Journals (Sweden)

    Angela M. Ares de Parga

    2015-01-01

    Full Text Available The Lorentz transformations are obtained by assuming that the laws of classical thermodynamics are invariant under changes of inertial reference frames. As Maxwell equations are used in order to deduce a wave equation that shows the constancy of the speed of light, by means of the laws of classical thermodynamics, the invariance of the Carnot cycle is deduced under reference frame changes. Starting with this result and the blackbody particle number density in a rest frame, the Lorentz transformations are obtained. A discussion about the universality of classical thermodynamics is given.

  19. Bohmian measures and their classical limit

    KAUST Repository

    Markowich, Peter

    2010-09-01

    We consider a class of phase space measures, which naturally arise in the Bohmian interpretation of quantum mechanics. We study the classical limit of these so-called Bohmian measures, in dependence on the scale of oscillations and concentrations of the sequence of wave functions under consideration. The obtained results are consequently compared to those derived via semi-classical Wigner measures. To this end, we shall also give a connection to the theory of Young measures and prove several new results on Wigner measures themselves. Our analysis gives new insight on oscillation and concentration effects in the semi-classical regime. © 2010 Elsevier Inc.

  20. Radiation in Particle Simulations

    Energy Technology Data Exchange (ETDEWEB)

    More, R M; Graziani, F R; Glosli, J; Surh, M

    2009-06-15

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known (section 3). The second method expands the electromagnetic field in normal modes (plane-waves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion (section 4). The third method is a hybrid MD/MC (molecular dynamics/Monte Carlo) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions (section 5). The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc.(section 6). This approach is inspired by the Virial expansion method of equilibrium statistical mechanics.

  1. Quantum radiation by electrons in lasers and the Unruh effect

    CERN Document Server

    Schützhold, Ralf

    2010-01-01

    In addition to the Larmor radiation known from classical electrodynamics, electrons in a laser field may emit pairs of entangled photons -- which is a pure quantum effect. We investigate this quantum effect and discuss why it is suppressed in comparison with the classical Larmor radiation (which is just Thomson backscattering of the laser photons). Further, we provide an intuitive explanation of this process (in a simplified setting) in terms of the Unruh effect.

  2. Atoms, Radiation, and Radiation Protection

    CERN Document Server

    Turner, James E

    2007-01-01

    Atoms, Radiation, and Radiation Protection offers professionals and advanced students a comprehensive coverage of the major concepts that underlie the origins and transport of ionizing radiation in matter. Understanding atomic structure and the physical mechanisms of radiation interactions is the foundation on which much of the current practice of radiological health protection is based. The work covers the detection and measurement of radiation and the statistical interpretation of the data. The procedures that are used to protect man and the environment from the potential harmful effects of

  3. A classical case of the Gasul phenomenon.

    Science.gov (United States)

    Sabnis, Girish R; Phadke, Milind S; Kerkar, Prafulla G

    2016-02-01

    This case demonstrates the development of secondary infundibular stenosis in a 10-year-old male child with documented large non-restrictive perimembranous ventricular septal defect in infancy - the classical Gasul phenomenon.

  4. The Zoology of the classical islamic culture

    DEFF Research Database (Denmark)

    Provencal, Philippe; Aarab, Ahmed

    2014-01-01

    This article brings a survey of research on the science of zoology in the Classical Arabic/Islamic Culture as revealed in texts on this subject written in Classical Arabic from the second half of the 8th century to the 15th century A.D. In the light of recent research and by use of examples from ...... the Arabic texts themselves, a new evaluation on the scientific content of these texts will be proposed.......This article brings a survey of research on the science of zoology in the Classical Arabic/Islamic Culture as revealed in texts on this subject written in Classical Arabic from the second half of the 8th century to the 15th century A.D. In the light of recent research and by use of examples from...

  5. Chaos in effective classical and quantum dynamics

    CERN Document Server

    Casetti, L; Modugno, M; Casetti, Lapo; Gatto, Raoul; Modugno, Michele

    1998-01-01

    We investigate the dynamics of classical and quantum N-component phi^4 oscillators in presence of an external field. In the large N limit the effective dynamics is described by two-degree-of-freedom classical Hamiltonian systems. In the classical model we observe chaotic orbits for any value of the external field, while in the quantum case chaos is strongly suppressed. A simple explanation of this behaviour is found in the change in the structure of the orbits induced by quantum corrections. Consistently with Heisenberg's principle, quantum fluctuations are forced away from zero, removing in the effective quantum dynamics a hyperbolic fixed point that is a major source of chaos in the classical model.

  6. Classical and quantum wormholes with tachyon field

    Institute of Scientific and Technical Information of China (English)

    高长军; 沈有根

    2003-01-01

    The wormhole equations are presented in the presence of tachyon field. Specializing at some values of ω (the ratio of pressure to energy density), we find a family of classical and quantum wormhole solutions.

  7. A new supersymmetric classical Boussinesq equation

    Institute of Scientific and Technical Information of China (English)

    Zhang Meng-Xia; Liu Qing-Ping; Wang Juan; Wu Ke

    2008-01-01

    In this paper,we obtain a supersymmetric generalization for the classical Boussinesq equation.We show that the supersymmetric equation system passes the Painlevé test and we also calculate its one- and two-soliton solutions.

  8. Classical algebra its nature, origins, and uses

    CERN Document Server

    Cooke, Roger L

    2008-01-01

    This insightful book combines the history, pedagogy, and popularization of algebra to present a unified discussion of the subject. Classical Algebra provides a complete and contemporary perspective on classical polynomial algebra through the exploration of how it was developed and how it exists today. With a focus on prominent areas such as the numerical solutions of equations, the systematic study of equations, and Galois theory, this book facilitates a thorough understanding of algebra and illustrates how the concepts of modern algebra originally developed from classical algebraic precursors. This book successfully ties together the disconnect between classical and modern algebraand provides readers with answers to many fascinating questions that typically go unexamined, including: What is algebra about? How did it arise? What uses does it have? How did it develop? What problems and issues have occurred in its history? How were these problems and issues resolved? The author answers these questions and more,...

  9. Rough sets: the classical and extended views

    Institute of Scientific and Technical Information of China (English)

    ZIARKO Wojciech

    2008-01-01

    The article is a comprehensive review of two major approaches to rough set theory: the classic rough setmodel introduced by Pawlak and the probabilistic approaches. The classic model is presented as a staging ground to the discussion of two varieties of the probabilistic approach, i.e. of the variable precision and Bayesian rough set models. Both of these models extend the classic model to deal with stochastic interactions while preserving the basicideas of the original rough set theory, such as set approximations, data dependencies, reducts etc. The probabilistic models are able to handle weaker data interactions than the classic model, thus extending the applicability of the rough set paradigm. The extended models are presented in considerable detail with some illustrative examples.

  10. Observable Signatures of a Classical Transition

    CERN Document Server

    Johnson, Matthew C

    2015-01-01

    Eternal inflation arising from a potential landscape predicts that our universe is one realization of many possible cosmological histories. One way to access different cosmological histories is via the nucleation of bubble universes from a metastable false vacuum. Another way to sample different cosmological histories is via classical transitions, the creation of pocket universes through the collision between bubbles. Using relativistic numerical simulations, we examine the possibility of observationally determining if our observable universe resulted from a classical transition. We find that classical transitions produce spatially infinite, approximately open Friedman-Robertson-Walker universes. The leading set of observables in the aftermath of a classical transition are negative spatial curvature and a contribution to the Cosmic Microwave Background temperature quadrupole. The level of curvature and magnitude of the quadrupole are dependent on the position of the observer, and we determine the possible ran...

  11. Hermite polynomials and quasi-classical asymptotics

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S. Twareque, E-mail: twareque.ali@concordia.ca [Department of Mathematics and Statistics, Concordia University, Montréal, Québec H3G 1M8 (Canada); Engliš, Miroslav, E-mail: englis@math.cas.cz [Mathematics Institute, Silesian University in Opava, Na Rybníčku 1, 74601 Opava, Czech Republic and Mathematics Institute, Žitná 25, 11567 Prague 1 (Czech Republic)

    2014-04-15

    We study an unorthodox variant of the Berezin-Toeplitz type of quantization scheme, on a reproducing kernel Hilbert space generated by the real Hermite polynomials and work out the associated quasi-classical asymptotics.

  12. Classical enhancement of quantum vacuum fluctuations

    CERN Document Server

    De Lorenci, V A

    2016-01-01

    We propose a mechanism for the enhancement of vacuum fluctuations by means of a classical field. The basic idea is that if an observable quantity depends quadratically upon a quantum field, such as the electric field, then the application of a classical field produces a cross term between the classical and quantum fields. This cross term may be significantly larger than the purely quantum part, but also undergoes fluctuations driven by the quantum field. We illustrate this effect in a model for lightcone fluctuations involving pulses in a nonlinear dielectric. Vacuum electric field fluctuations produce fluctuations in the speed of a probe pulse, and form an analog model for quantum gravity effects. If the material has a nonzero third-order susceptibility, then the fractional light speed fluctuations are proportional to the square of the fluctuating electric field. Hence the application of a classical electric field can enhance the speed fluctuations. We give an example where this enhancement can be an increas...

  13. Classics in the Classroom: Great Expectations Fulfilled.

    Science.gov (United States)

    Pearl, Shela

    1986-01-01

    Describes how an English teacher in a Queens, New York, ghetto school introduced her grade nine students to Charles Dickens's "Great Expectations." Focuses on students' responses, which eventually became enthusiastic, and discusses the use of classics within the curriculum. (KH)

  14. Classical and quantum resonances for hyperbolic surfaces

    OpenAIRE

    Guillarmou, Colin; Hilgert, Joachim; Weich, Tobias

    2016-01-01

    For compact and for convex co-compact oriented hyperbolic surfaces, we prove an explicit correspondence between classical Ruelle resonant states and quantum resonant states, except at negative integers where the correspondence involves holomorphic sections of line bundles.

  15. Ambiguities in Quantizing a Classical System

    CERN Document Server

    Redmount, I H; Young, K; Redmount, Ian; Suen, Wai-Mo; Young, Kenneth

    1999-01-01

    One classical theory, as determined by an equation of motion or set of classical trajectories, can correspond to many unitarily {\\em in}equivalent quantum theories upon canonical quantization. This arises from a remarkable ambiguity, not previously investigated, in the construction of the classical (and hence the quantized) Hamiltonian or Lagrangian. This ambiguity is illustrated for systems with one degree of freedom: An arbitrary function of the constants of motion can be introduced into this construction. For example, the nonrelativistic and relativistic free particles follow identical classical trajectories, but the Hamiltonians or Lagrangians, and the canonically quantized versions of these descriptions, are inequivalent. Inequivalent descriptions of other systems, such as the harmonic oscillator, are also readily obtained.

  16. Secure quantum communication using classical correlated channel

    Science.gov (United States)

    Costa, D.; de Almeida, N. G.; Villas-Boas, C. J.

    2016-10-01

    We propose a secure protocol to send quantum information from one part to another without a quantum channel. In our protocol, which resembles quantum teleportation, a sender (Alice) and a receiver (Bob) share classical correlated states instead of EPR ones, with Alice performing measurements in two different bases and then communicating her results to Bob through a classical channel. Our secure quantum communication protocol requires the same amount of classical bits as the standard quantum teleportation protocol. In our scheme, as in the usual quantum teleportation protocol, once the classical channel is established in a secure way, a spy (Eve) will never be able to recover the information of the unknown quantum state, even if she is aware of Alice's measurement results. Security, advantages, and limitations of our protocol are discussed and compared with the standard quantum teleportation protocol.

  17. Equilibration properties of classical integrable field theories

    Science.gov (United States)

    De Luca, Andrea; Mussardo, Giuseppe

    2016-06-01

    We study the equilibration properties of classical integrable field theories at a finite energy density, with a time evolution that starts from initial conditions far from equilibrium. These classical field theories may be regarded as quantum field theories in the regime of high occupation numbers. This observation permits to recover the classical quantities from the quantum ones by taking a proper \\hslash \\to 0 limit. In particular, the time averages of the classical theories can be expressed in terms of a suitable version of the LeClair-Mussardo formula relative to the generalized Gibbs ensemble. For the purposes of handling time averages, our approach provides a solution of the problem of the infinite gap solutions of the inverse scattering method.

  18. Classical geometry from the quantum Liouville theory

    CERN Document Server

    Hadasz, L; Piatek, M; Hadasz, Leszek; Jaskolski, Zbigniew; Piatek, Marcin

    2005-01-01

    Zamolodchikov's recursion relations are used to analyze the existence and approximations to the classical conformal block in the case of four parabolic weights. Strong numerical evidence is found that the saddle point momenta arising in the classical limit of the DOZZ quantum Liouville theory are simply related to the geodesic length functions of the hyperbolic geometry on the 4-punctured Riemann sphere. Such relation provides new powerful methods for both numerical and analytical calculations of these functions. The consistency conditions for the factorization of the 4-point classical Liouville action in different channels are numerically verified. The factorization yields efficient numerical methods to calculate the 4-point classical action and, by the Polyakov conjecture, the accessory parameters of the Fuchsian uniformization of the 4-punctured sphere.

  19. Classical geometry from the quantum Liouville theory

    Energy Technology Data Exchange (ETDEWEB)

    Hadasz, Leszek [M. Smoluchowski Institute of Physics, Jagellonian University, Reymonta 4, 30-059 Cracow (Poland)]. E-mail: hadasz@th.if.uj.edu.pl; Jaskolski, Zbigniew [Institute of Theoretical Physics, University of WrocIaw, pl. M. Borna, 950-204 WrocIaw (Poland)]. E-mail: jask@ift.uni.wroc.pl; Piatek, Marcin [Institute of Theoretical Physics, University of WrocIaw, pl. M. Borna, 950-204 WrocIaw (Poland)]. E-mail: piatek@ift.uni.wroc.pl

    2005-09-26

    Zamolodchikov's recursion relations are used to analyze the existence and approximations to the classical conformal block in the case of four parabolic weights. Strong numerical evidence is found that the saddle point momenta arising in the classical limit of the DOZZ quantum Liouville theory are simply related to the geodesic length functions of the hyperbolic geometry on the 4-punctured Riemann sphere. Such relation provides new powerful methods for both numerical and analytical calculations of these functions. The consistency conditions for the factorization of the 4-point classical Liouville action in different channels are numerically verified. The factorization yields efficient numerical methods to calculate the 4-point classical action and, by the Polyakov conjecture, the accessory parameters of the Fuchsian uniformization of the 4-punctured sphere.

  20. Vacuum polarization and Hawking radiation

    Science.gov (United States)

    Rahmati, Shohreh

    Quantum gravity is one of the interesting fields in contemporary physics which is still in progress. The purpose of quantum gravity is to present a quantum description for spacetime at 10-33cm or find the 'quanta' of gravitational interaction.. At present, the most viable theory to describe gravitational interaction is general relativity which is a classical theory. Semi-classical quantum gravity or quantum field theory in curved spacetime is an approximation to a full quantum theory of gravity. This approximation considers gravity as a classical field and matter fields are quantized. One interesting phenomena in semi-classical quantum gravity is Hawking radiation. Hawking radiation was derived by Stephen Hawking as a thermal emission of particles from the black hole horizon. In this thesis we obtain the spectrum of Hawking radiation using a new method. Vacuum is defined as the possible lowest energy state which is filled with pairs of virtual particle-antiparticle. Vacuum polarization is a consequence of pair creation in the presence of an external field such as an electromagnetic or gravitational field. Vacuum polarization in the vicinity of a black hole horizon can be interpreted as the cause of the emission from black holes known as Hawking radiation. In this thesis we try to obtain the Hawking spectrum using this approach. We re-examine vacuum polarization of a scalar field in a quasi-local volume that includes the horizon. We study the interaction of a scalar field with the background gravitational field of the black hole in the desired quasi-local region. The quasi-local volume is a hollow cylinder enclosed by two membranes, one inside the horizon and one outside the horizon. The net rate of particle emission can be obtained as the difference of the vacuum polarization from the outer boundary and inner boundary of the cylinder. Thus we found a new method to derive Hawking emission which is unitary and well defined in quantum field theory.