Photoelectron wave function in photoionization: plane wave or Coulomb wave?

Science.gov (United States)

Gozem, Samer; Gunina, Anastasia O; Ichino, Takatoshi; Osborn, David L; Stanton, John F; Krylov, Anna I

2015-11-19

The calculation of absolute total cross sections requires accurate wave functions of the photoelectron and of the initial and final states of the system. The essential information contained in the latter two can be condensed into a Dyson orbital. We employ correlated Dyson orbitals and test approximate treatments of the photoelectron wave function, that is, plane and Coulomb waves, by comparing computed and experimental photoionization and photodetachment spectra. We find that in anions, a plane wave treatment of the photoelectron provides a good description of photodetachment spectra. For photoionization of neutral atoms or molecules with one heavy atom, the photoelectron wave function must be treated as a Coulomb wave to account for the interaction of the photoelectron with the +1 charge of the ionized core. For larger molecules, the best agreement with experiment is often achieved by using a Coulomb wave with a partial (effective) charge smaller than unity. This likely derives from the fact that the effective charge at the centroid of the Dyson orbital, which serves as the origin of the spherical wave expansion, is smaller than the total charge of a polyatomic cation. The results suggest that accurate molecular photoionization cross sections can be computed with a modified central potential model that accounts for the nonspherical charge distribution of the core by adjusting the charge in the center of the expansion.

Wigner functions of s waves

International Nuclear Information System (INIS)

Dahl, J. P.; Varro, S.; Wolf, A.; Schleich, W. P.

2007-01-01

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

Wigner functions of s waves

DEFF Research Database (Denmark)

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

2007-01-01

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

Four-body correlation embedded in antisymmetrized geminal power wave function.

Science.gov (United States)

Kawasaki, Airi; Sugino, Osamu

2016-12-28

We extend the Coleman's antisymmetrized geminal power (AGP) to develop a wave function theory that can incorporate up to four-body correlation in a region of strong correlation. To facilitate the variational determination of the wave function, the total energy is rewritten in terms of the traces of geminals. This novel trace formula is applied to a simple model system consisting of one dimensional Hubbard ring with a site of strong correlation. Our scheme significantly improves the result obtained by the AGP-configuration interaction scheme of Uemura et al. and also achieves more efficient compression of the degrees of freedom of the wave function. We regard the result as a step toward a first-principles wave function theory for a strongly correlated point defect or adsorbate embedded in an AGP-based mean-field medium.

Model wave functions for the deuteron

International Nuclear Information System (INIS)

Certov, A.; Mathelitsch, L.; Moravcsik, M.J.

1987-01-01

Model wave functions are constructed for the deuteron to facilitate the unambiguous exploration of dependencies on the percentage D state and on the small-, medium-, and large-distance parts of the deuteron wave function. The wave functions are constrained by those deuteron properties which are accurately known experimentally, and are in an analytic form which is easily integrable in expressions usually encountered in the use of such wave functions

Relativistic amplitudes in terms of wave functions

International Nuclear Information System (INIS)

Karmanov, V.A.

1978-01-01

In the framework of the invariant diagram technique which arises at the formulation of the fueld theory on the light front the question about conditions at which the relativistic amplitudes may be expressed through the wave functions is investigated. The amplitudes obtained depend on four-vector ω, determining the light front surface. The way is shown to find such values of the four-vector ω, at which the contribution of diagrams not expressed through wave functions is minimal. The investigation carried out is equivalent to the study of the dependence of amplitudes of the old-fashioned perturbation theory in the in the infinite momentum frame on direction of the infinite momentum

Analytic perturbation theory for screened Coulomb potential: full continuum wave function

International Nuclear Information System (INIS)

Bechler, A.; Ennan, Mc J.; Pratt, R.H.

1979-01-01

An analytic perturbation theory developed previously is used to find a continuum screened-Coulomb wave function characterized by definite asymptotic momentum. This wave function satisfies an inhomogeneous partial differential equation which is solved in parabolic coordinates; the solution depends on both parabolic variables. We calculate partial wave projections of this solution and show that we can choose to add a solution of the homogeneous equation such that the partial wave projections become equal to the normalized continuum radial function found previously. However, finding the unique solution with given asymptotic linear momentum will require either using boundary conditions to determine the unique needed solution of the homogeneous equation or equivalently specifying the screened-Coulomb phase-shifts. (author)

Twist-2 Light-Cone Pion Wave Function

OpenAIRE

Belyaev, V. M.; Johnson, Mikkel B.

1997-01-01

We present an analysis of the existing constraints for the twist-2 light-cone pion wave function. We find that existing information on the pion wave function does not exclude the possibility that the pion wave function attains its asymptotic form. New bounds on the parameters of the pion wave function are presented.

Wave drag as the objective function in transonic fighter wing optimization

Science.gov (United States)

Phillips, P. S.

1984-01-01

The original computational method for determining wave drag in a three dimensional transonic analysis method was replaced by a wave drag formula based on the loss in momentum across an isentropic shock. This formula was used as the objective function in a numerical optimization procedure to reduce the wave drag of a fighter wing at transonic maneuver conditions. The optimization procedure minimized wave drag through modifications to the wing section contours defined by a wing profile shape function. A significant reduction in wave drag was achieved while maintaining a high lift coefficient. Comparisons of the pressure distributions for the initial and optimized wing geometries showed significant reductions in the leading-edge peaks and shock strength across the span.

The Wave Function and Quantum Reality

International Nuclear Information System (INIS)

Gao Shan

2011-01-01

We investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributing in space, proportional to the square of the absolute value of its wave function. In a realistic interpretation, the wave function of a quantum system can be taken as a description of either a physical field or the ergodic motion of a particle. The essential difference between a field and the ergodic motion of a particle lies in the property of simultaneity; a field exists throughout space simultaneously, whereas the ergodic motion of a particle exists throughout space in a time-divided way. If the wave function is a physical field, then the mass and charge density will be distributed in space simultaneously for a charged quantum system, and thus there will exist gravitational and electrostatic self-interactions of its wave function. This not only violates the superposition principle of quantum mechanics but also contradicts experimental observations. Thus the wave function cannot be a description of a physical field but be a description of the ergodic motion of a particle. For the later there is only a localized particle with mass and charge at every instant, and thus there will not exist any self-interaction for the wave function. It is further argued that the classical ergodic models, which assume continuous motion of particles, cannot be consistent with quantum mechanics. Based on the negative result, we suggest that the wave function is a description of the quantum motion of particles, which is random and discontinuous in nature. On this interpretation, the square of the absolute value of the wave function not only gives the probability of the particle being found in certain locations, but also gives the probability of the particle being there. The suggested new interpretation of the wave function provides a natural realistic

Short time propagation of a singular wave function: Some surprising results

Science.gov (United States)

Marchewka, A.; Granot, E.; Schuss, Z.

2007-08-01

The Schrödinger evolution of an initially singular wave function was investigated. First it was shown that a wide range of physical problems can be described by initially singular wave function. Then it was demonstrated that outside the support of the initial wave function the time evolution is governed to leading order by the values of the wave function and its derivatives at the singular points. Short-time universality appears where it depends only on a single parameter—the value at the singular point (not even on its derivatives). It was also demonstrated that the short-time evolution in the presence of an absorptive potential is different than in the presence of a nonabsorptive one. Therefore, this dynamics can be harnessed to the determination whether a potential is absorptive or not simply by measuring only the transmitted particles density.

Mini wave function for the Universe

International Nuclear Information System (INIS)

Maslanka, K.

1989-01-01

The Friedman radiation filled world model can formally be treated as an oscillator with frequency determined by the cosmological constant and with an external force connected with the space curvature. The wave function for such a universe is constructed. By using Feynman's sum-over-histories method, the initial fundamental indeterminacy in the state of the universe is propagated forward in time. 5 refs. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-05-15

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

Antiferromagnetism and d-wave superconductivity in (doped) Mott insulators: A wave function approach

OpenAIRE

Weng, Z. Y.; Zhou, Y.; Muthukumar, V. N.

2003-01-01

We propose a class of wave functions that provide a unified description of antiferromagnetism and d-wave superconductivity in (doped) Mott insulators. The wave function has a Jastrow form and prohibits double occupancies. In the absence of holes, the wave function describes antiferromagnetism accurately. Off diagonal long range order develops at finite doping and the superconducting order parameter has d-wave symmetry. We also show how nodal quasiparticles and neutral spin excitations can be ...

A simple and realistic triton wave function

International Nuclear Information System (INIS)

Lomnitz-Adler, J.; Pandharipande, V.R.

1980-01-01

We propose a simple triton wave function that consists of a product of three correlation operators operating on a three-body spin-isospin state. This wave function is formally similar to that used in the recent variational theories of nuclear matter, the main difference being in the long-range behavior of the correlation operators. Variational calculations are carried out with the Reid potential, using this wave function in the so-called 'symmetrized product' and 'independent pair' forms. The triton energy and density distributions obtained with the symmetrized product wave function agree with those obtained in Faddeev and other variational calculations using harmonic oscillator states. The proposed wave function and calculational methods can be easily generalized to treat the four-nucleon α-particle. (orig.)

Configuration interaction wave functions: A seniority number approach

International Nuclear Information System (INIS)

Alcoba, Diego R.; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E.; Oña, Ofelia B.

2014-01-01

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

Configuration interaction wave functions: A seniority number approach

Energy Technology Data Exchange (ETDEWEB)

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

2014-06-21

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

Application of numerical methods to the determination of molecular wave functions

International Nuclear Information System (INIS)

Douady, Jerome

1969-01-01

A simplified SCF Method is developed. The wave function of molecular systems and spin densities in the case of free radicals are computed from geometrical data. This method, including at the beginning a delocalization of electrons over all the molecular system, two methods which clear out bonding and anti-bonding interactions have been studied and programmed: a) overlap population analysis, b) localisation of molecular orbitals. These methods have been carried out in the case of organic compounds and free radicals. (author) [fr

Determination of particle size distributions from acoustic wave propagation measurements

International Nuclear Information System (INIS)

Spelt, P.D.; Norato, M.A.; Sangani, A.S.; Tavlarides, L.L.

1999-01-01

The wave equations for the interior and exterior of the particles are ensemble averaged and combined with an analysis by Allegra and Hawley [J. Acoust. Soc. Am. 51, 1545 (1972)] for the interaction of a single particle with the incident wave to determine the phase speed and attenuation of sound waves propagating through dilute slurries. The theory is shown to compare very well with the measured attenuation. The inverse problem, i.e., the problem of determining the particle size distribution given the attenuation as a function of frequency, is examined using regularization techniques that have been successful for bubbly liquids. It is shown that, unlike the bubbly liquids, the success of solving the inverse problem is limited since it depends strongly on the nature of particles and the frequency range used in inverse calculations. copyright 1999 American Institute of Physics

On relation of momenta of structure functions of the composite systems with their simultaneous wave functions

International Nuclear Information System (INIS)

Linkevich, A.D.; Savrin, V.I.; Sanadze, V.V.; Skachkov, N.B.

1984-01-01

Calculation of hadron structure function (SF) comprising point objects is carried out. The obtained hadron SF is expressed by means of simultaneous relativistic wave functions of a composite particle. Exact calculation of hadron SF momenta in simultaneous formulation of quantum field theory off-energy surface is conducted. The given calculation of hadron SF is shown to result in their dependence on momentum transferred square (or square of total vector of energy-momentum of Compton scattering on a quark) whih is determined by the set of simultaneous hadron wave functions as bound state of quark (partons) in the considered case of non-structural quarks

Rapidity resummation for B-meson wave functions

Directory of Open Access Journals (Sweden)

Shen Yue-Long

2014-01-01

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

Boundary conditions of the exact impulse wave function

International Nuclear Information System (INIS)

Gravielle, M.; Miraglia, J.E.

1997-01-01

The behavior of the exact impulse wave function is investigated at intermediate and high impact energies. Numerical details of the wave function and its perturbative potential are reported. We conclude that the impulse wave function does not tend to the proper Coulomb asymptotic limit. For electron capture, however, it is shown that the impulse wave function produces reliable probabilities even for intermediate velocities and symmetric collision systems. copyright 1997 The American Physical Society

Riemann zeta function from wave-packet dynamics

DEFF Research Database (Denmark)

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

2010-01-01

We show that the time evolution of a thermal phase state of an anharmonic oscillator with logarithmic energy spectrum is intimately connected to the generalized Riemann zeta function zeta(s, a). Indeed, the autocorrelation function at a time t is determined by zeta (sigma + i tau, a), where sigma...... index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann zeta wave-packet dynamics using cold atoms...

Deep inelastic scattering and light-cone wave functions

International Nuclear Information System (INIS)

Belyaev, V.M.; Johnson, M.B.

1996-01-01

In the framework of light-cone QCD rules, we study the valence quark distribution function q(x B ) of a pion for moderate x B . The sum rule with the leading twist-2 wave function gives q(x B ) = φ π (x B ). Twist-4 wave functions give about 30% for x B ∼0.5. It is shown that QCD sum rule predictions, with the asymptotic pion wave function, are in good agreement with experimental data. We found that a two-hump profile for the twist-2 wave function leads to a valence quark distribution function that contradicts experimental data

On single nucleon wave functions in nuclei

International Nuclear Information System (INIS)

Talmi, Igal

2011-01-01

The strong and singular interaction between nucleons, makes the nuclear many body theory very complicated. Still, nuclei exhibit simple and regular features which are simply described by the shell model. Wave functions of individual nucleons may be considered just as model wave functions which bear little resemblance to the real ones. There is, however, experimental evidence for the reality of single nucleon wave functions. There is a simple method of constructing such wave functions for valence nucleons. It is shown that this method can be improved by considering the polarization of the core by the valence nucleon. This gives rise to some rearrangement energy which affects the single valence nucleon energy within the nucleus.

Expression of relativistic amplitudes in terms of wave functions

International Nuclear Information System (INIS)

Karmanov, V.A.

1978-01-01

The conditions under which relativistic amplitudes may be expressed in terms of the wave functions are analyzed within the framework of the invariant diagram technique which appears on formulation of field theory on the light front. The amplitudes depend on the 4-vector ω which defines the surface of the light front. A rule is formulated for the determination of those values of the 4-vector ω for which the diagram contribution, which cannot be expressed in terms of the wave functions, is minimum. The present investigation is equivalent to a study of the dependence of the amplitudes of the old fashioned perburbation theory in the infinite momentum depending on the direction of the infinite momentum

Relation between equal-time and light-front wave functions

International Nuclear Information System (INIS)

Miller, Gerald A.; Tiburzi, Brian C.

2010-01-01

The relation between equal-time and light-front wave functions is studied using models for which the four-dimensional solution of the Bethe-Salpeter wave function can be obtained. The popular prescription of defining the longitudinal momentum fraction using the instant-form free kinetic energy and third component of momentum is found to be incorrect except in the nonrelativistic limit. One may obtain light-front wave functions from rest-frame, instant-form wave functions by boosting the latter wave functions to the infinite momentum frame. Despite this difficulty, we prove a relation between certain integrals of the equal-time and light-front wave functions.

Taylor-series method for four-nucleon wave functions

International Nuclear Information System (INIS)

Sandulescu, A.; Tarnoveanu, I.; Rizea, M.

1977-09-01

Taylor-series method for transforming the infinite or finite well two-nucleon wave functions from individual coordinates to relative and c.m. coordinates, by expanding the single particle shell model wave functions around c.m. of the system, is generalized to four-nucleon wave functions. Also the connections with the Talmi-Moshinsky method for two and four harmonic oscillator wave functions are deduced. For both methods Fortran IV programs for the expansion coefficients have been written and the equivalence of corresponding expressions numerically proved. (author)

Bayesian extraction of the parton distribution amplitude from the Bethe-Salpeter wave function

Science.gov (United States)

Gao, Fei; Chang, Lei; Liu, Yu-xin

2017-07-01

We propose a new numerical method to compute the parton distribution amplitude (PDA) from the Euclidean Bethe-Salpeter wave function. The essential step is to extract the weight function in the Nakanishi representation of the Bethe-Salpeter wave function in Euclidean space, which is an ill-posed inversion problem, via the maximum entropy method (MEM). The Nakanishi weight function as well as the corresponding light-front parton distribution amplitude (PDA) can be well determined. We confirm prior work on PDA computations, which was based on different methods.

Covariance Function for Nearshore Wave Assimilation Systems

Science.gov (United States)

2018-01-30

which is applicable for any spectral wave model. The four dimensional variational (4DVar) assimilation methods are based on the mathematical ...covariance can be modeled by a parameterized Gaussian function, for nearshore wave assimilation applications , the covariance function depends primarily on...SPECTRAL ACTION DENSITY, RESPECTIVELY. ............................ 5 FIGURE 2. TOP ROW: STATISTICAL ANALYSIS OF THE WAVE-FIELD PROPERTIES AT THE

Green function for three-wave coupling problems

International Nuclear Information System (INIS)

Molevich, N E

2001-01-01

The Green function is found for three-wave coupling problems. The function was used for analysis of parametric amplification in dissipative and active media. It is shown that the parametric increment in active media can become exponential. As an example, the nonstationary stimulated scattering of electromagnetic waves by sound and temperatures waves is considered. (nonlinear optical phenomena)

Mathieu functions describing particles evolving in electromagnetic waves

Science.gov (United States)

Mihu, Denisa-Andreea; Dariescu, Marina-Aura

2017-12-01

Solutions of Klein-Gordon equation for particles moving in a standing wave configuration bring into attention an intricate and complicated category of special functions, namely the Mathieu functions. The stability of the solutions governed by the intercorrelation between Mathieu equation' parameters is discussed. For specific intervals of the wave number, the instability regime installs, pointing out the tendency of exponential growth for the oscillatory wave functions, as a consequence of parametric resonance phenomenon. The expression of the wave function allows the computation of the four-dimensional conserved current density components.

Six Impossible Things: Fractional Charge From Laughlin's Wave Function

International Nuclear Information System (INIS)

Shrivastava, Keshav N.

2010-01-01

The Laughlin's wave function is found to be the zero-energy ground state of a δ-function Hamiltonian. The finite negative value of the ground state energy which is 91 per cent of Wigner value, can be obtained only when Coulomb correlations are introduced. The Laughlin's wave function is of short range and it overlaps with that of the exact wave functions of small (number of electrons 2 or 5) systems. (i) It is impossible to obtain fractional charge from Laughlin's wave function. (ii) It is impossible to prove that the Laughlin's wave function gives the ground state of the Coulomb Hamiltonian. (iii) It is impossible to have particle-hole symmetry in the Laughlin's wave function. (iv) It is impossible to derive the value of m in the Laughlin's wave function. The value of m in ψ m can not be proved to be 3 or 5. (v) It is impossible to prove that the Laughlin's state is incompressible because the compressible states are also likely. (vi) It is impossible for the Laughlin's wave function to have spin. This effort is directed to explain the experimental data of quantum Hall effect in GaAs/AlGaAs.

Noncommuting limits of oscillator wave functions

International Nuclear Information System (INIS)

Daboul, J.; Pogosyan, G. S.; Wolf, K. B.

2007-01-01

Quantum harmonic oscillators with spring constants k > 0 plus constant forces f exhibit rescaled and displaced Hermite-Gaussian wave functions, and discrete, lower bound spectra. We examine their limits when (k, f) → (0, 0) along two different paths. When f → 0 and then k → 0, the contraction is standard: the system becomes free with a double continuous, positive spectrum, and the wave functions limit to plane waves of definite parity. On the other hand, when k → 0 first, the contraction path passes through the free-fall system, with a continuous, nondegenerate, unbounded spectrum and displaced Airy wave functions, while parity is lost. The subsequent f → 0 limit of the nonstandard path shows the dc hysteresis phenomenon of noncommuting contractions: the lost parity reappears as an infinitely oscillating superposition of the two limiting solutions that are related by the symmetry

Bayesian extraction of the parton distribution amplitude from the Bethe–Salpeter wave function

Directory of Open Access Journals (Sweden)

Fei Gao

2017-07-01

Full Text Available We propose a new numerical method to compute the parton distribution amplitude (PDA from the Euclidean Bethe–Salpeter wave function. The essential step is to extract the weight function in the Nakanishi representation of the Bethe–Salpeter wave function in Euclidean space, which is an ill-posed inversion problem, via the maximum entropy method (MEM. The Nakanishi weight function as well as the corresponding light-front parton distribution amplitude (PDA can be well determined. We confirm prior work on PDA computations, which was based on different methods.

Experimental determination of radiated internal wave power without pressure field data

Science.gov (United States)

Lee, Frank M.; Paoletti, M. S.; Swinney, Harry L.; Morrison, P. J.

2014-04-01

We present a method to determine, using only velocity field data, the time-averaged energy flux left and total radiated power P for two-dimensional internal gravity waves. Both left and P are determined from expressions involving only a scalar function, the stream function ψ. We test the method using data from a direct numerical simulation for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream function method agree to within 0.5% with results obtained using pressure and velocity data from the numerical simulation. The results for the radiated power computed from the stream function agree well with power computed from the velocity and pressure if the starting point for the stream function computation is on a solid boundary, but if a boundary point is not available, care must be taken to choose an appropriate starting point. We also test the stream function method by applying it to laboratory data for tidal flow past a knife edge, and the results are found to agree with the direct numerical simulation. The supplementary material includes a Matlab code with a graphical user interface that can be used to compute the energy flux and power from two-dimensional velocity field data.

Experimental determination of radiated internal wave power without pressure field data

International Nuclear Information System (INIS)

Lee, Frank M.; Morrison, P. J.; Paoletti, M. S.; Swinney, Harry L.

2014-01-01

We present a method to determine, using only velocity field data, the time-averaged energy flux (J) and total radiated power P for two-dimensional internal gravity waves. Both (J) and P are determined from expressions involving only a scalar function, the stream function ψ. We test the method using data from a direct numerical simulation for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream function method agree to within 0.5% with results obtained using pressure and velocity data from the numerical simulation. The results for the radiated power computed from the stream function agree well with power computed from the velocity and pressure if the starting point for the stream function computation is on a solid boundary, but if a boundary point is not available, care must be taken to choose an appropriate starting point. We also test the stream function method by applying it to laboratory data for tidal flow past a knife edge, and the results are found to agree with the direct numerical simulation. The supplementary material includes a Matlab code with a graphical user interface that can be used to compute the energy flux and power from two-dimensional velocity field data

Improved wave functions for large-N expansions

International Nuclear Information System (INIS)

Imbo, T.; Sukhatme, U.

1985-01-01

Existing large-N expansions of radial wave functions phi/sub n/,l(r) are only accurate near the minimum of the effective potential. Within the framework of the shifted 1/N expansion, we use known analytic results to motivate a simple modification so that the improved wave functions are accurate over a wide range of r and any choice of quantum numbers n and l. It is shown that these wave functions yield simple and accurate analytic expressions for certain quantities of interest in quarkonium physics

Nonstandard jump functions for radically symmetric shock waves

International Nuclear Information System (INIS)

Baty, Roy S.; Tucker, Don H.; Stanescu, Dan

2008-01-01

Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function.

Integral transform technique for meson wave functions

International Nuclear Information System (INIS)

Bakulev, A.P.; Mikhajlov, S.V.

1996-01-01

In a recent paper [1] we proposed a new approach for extracting the wave function of the π-meson φ π (x) and the masses and wave functions of its first resonances from the new QCD sum rules for nondiagonal correlators obtained in [2]. Here, we test our approach using an exactly solvable toy model as an illustrating example. We demonstrate the validity of the method and suggest a pure algebraic procedure for extracting the masses and wave functions relating to the case under investigation. We also explore the stability of the procedure under perturbations of the theoretical part of the sum rule. In application to the pion case, this results not only in the mass and wave function of the first resonance (π'), but also in the estimation of π''-mass. 17 refs., 11 figs

Simulation of wind wave growth with reference source functions

Science.gov (United States)

Badulin, Sergei I.; Zakharov, Vladimir E.; Pushkarev, Andrei N.

2013-04-01

We present results of extensive simulations of wind wave growth with the so-called reference source function in the right-hand side of the Hasselmann equation written as follows First, we use Webb's algorithm [8] for calculating the exact nonlinear transfer function Snl. Second, we consider a family of wind input functions in accordance with recent consideration [9] ( )s S = ?(k)N , ?(k) = ? ? ?- f (?). in k 0 ?0 in (2) Function fin(?) describes dependence on angle ?. Parameters in (2) are tunable and determine magnitude (parameters ?0, ?0) and wave growth rate s [9]. Exponent s plays a key role in this study being responsible for reference scenarios of wave growth: s = 4-3 gives linear growth of wave momentum, s = 2 - linear growth of wave energy and s = 8-3 - constant rate of wave action growth. Note, the values are close to ones of conventional parameterizations of wave growth rates (e.g. s = 1 for [7] and s = 2 for [5]). Dissipation function Sdiss is chosen as one providing the Phillips spectrum E(?) ~ ?5 at high frequency range [3] (parameter ?diss fixes a dissipation scale of wind waves) Sdiss = Cdissμ4w?N (k)θ(? - ?diss) (3) Here frequency-dependent wave steepness μ2w = E(?,?)?5-g2 makes this function to be heavily nonlinear and provides a remarkable property of stationary solutions at high frequencies: the dissipation coefficient Cdiss should keep certain value to provide the observed power-law tails close to the Phillips spectrum E(?) ~ ?-5. Our recent estimates [3] give Cdiss ? 2.0. The Hasselmann equation (1) with the new functions Sin, Sdiss (2,3) has a family of self-similar solutions of the same form as previously studied models [1,3,9] and proposes a solid basis for further theoretical and numerical study of wave evolution under action of all the physical mechanisms: wind input, wave dissipation and nonlinear transfer. Simulations of duration- and fetch-limited wind wave growth have been carried out within the above model setup to check its

Expansion of continuum functions on resonance wave functions and amplitudes

International Nuclear Information System (INIS)

Bang, J.; Gareev, F.A.; Gizzatkulov, M.H.; Goncharov, S.A.

1978-01-01

To overcome difficulties encountered with wave functions of continuum spectrum (for example, in a shell model with continuum) the pole expansion (by the Mittag-Leffler theorem) of wave functions, scattering amplitudes and the Green functions with positive energies are considered. It is shown that resonance functions (the Gamov functions) form a complete set over which the continuum functions could be expanded. The general view of these expansions for final potentials and for the Coulomb repulsion potential are obtained and discussed. It is shown that the application of the method to nuclear structure calculations leads to simple algebraic equations

Improved Wave-vessel Transfer Functions by Uncertainty Modelling

DEFF Research Database (Denmark)

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

2016-01-01

This paper deals with uncertainty modelling of wave-vessel transfer functions used to calculate or predict wave-induced responses of a ship in a seaway. Although transfer functions, in theory, can be calculated to exactly reflect the behaviour of the ship when exposed to waves, uncertainty in inp...

Transient difference solutions of the inhomogeneous wave equation - Simulation of the Green's function

Science.gov (United States)

Baumeister, K. J.

1983-01-01

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Transient difference solutions of the inhomogeneous wave equation: Simulation of the Green's function

Science.gov (United States)

Baumeiste, K. J.

1983-01-01

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Calculation of the nucleon structure function from the nucleon wave function

Science.gov (United States)

Hussar, Paul E.

1993-01-01

Harmonic oscillator wave functions have played an historically important role in our understanding of the structure of the nucleon, most notably by providing insight into the mass spectra of the low-lying states. High energy scattering experiments are known to give us a picture of the nucleon wave function at high-momentum transfer and in a frame in which the nucleon is traveling fast. A simple model that crosses the twin bridges of momentum scale and Lorentz frame that separate the pictures of the nucleon wave function provided by the deep inelastic scattering data and by the oscillator model is presented.

An exponential multireference wave-function Ansatz

International Nuclear Information System (INIS)

Hanrath, Michael

2005-01-01

An exponential multireference wave-function Ansatz is formulated. In accordance with the state universal coupled-cluster Ansatz of Jeziorski and Monkhorst [Phys. Rev. A 24, 1668 (1981)] the approach uses a reference specific cluster operator. In order to achieve state selectiveness the excitation- and reference-related amplitude indexing of the state universal Ansatz is replaced by an indexing which is based on excited determinants. There is no reference determinant playing a particular role. The approach is size consistent, coincides with traditional single-reference coupled cluster if applied to a single-reference, and converges to full configuration interaction with an increasing cluster operator excitation level. Initial applications on BeH 2 , CH 2 , Li 2 , and nH 2 are reported

Charge symmetry of electron wave functions in a quantized electromagnetic wave field

Energy Technology Data Exchange (ETDEWEB)

Fedorov, M V [AN SSSR, Moscow. Fizicheskij Inst.

1975-01-01

An attempt to clear up the reasons of the electron charge symmetry violation in the quantum wave field was made in this article. For this purpose the connection between the Dirac equation and the electron wave functions in the external field with the exact equation of quantum electrodynamics is established. Attention is paid to the fact that a number of equations for single-electron wave functions can be used in the framework of the same assumptions. It permits the construction of the charge-symmetric solutions in particular.

Faddeev wave function decomposition using bipolar harmonics

International Nuclear Information System (INIS)

Friar, J.L.; Tomusiak, E.L.; Gibson, B.F.; Payne, G.L.

1981-01-01

The standard partial wave (channel) representation for the Faddeev solution to the Schroedinger equation for the ground state of 3 nucleons is written in terms of functions which couple the interacting pair and spectator angular momenta to give S, P, and D waves. For each such coupling there are three terms, one for each of the three cyclic permutations of the nucleon coordinates. A series of spherical harmonic identities is developed which allows writing the Faddeev solution in terms of a basis set of 5 bipolar harmonics: 1 for S waves; 1 for P waves; and 3 for D waves. The choice of a D-wave basis is largely arbitrary, and specific choices correspond to the decomposition schemes of Derrick and Blatt, Sachs, Gibson and Schiff, and Bolsterli and Jezak. The bipolar harmonic form greatly simplifies applications which utilize the wave function, and we specifically discuss the isoscalar charge (or mass) density and the 3 He Coulomb energy

Semiclassical initial value treatment of wave functions

International Nuclear Information System (INIS)

Kay, Kenneth G.

2010-01-01

A semiclassical initial value approximation for time-independent wave functions, previously derived for integrable systems, is rederived in a form which allows it to be applied to more general systems. The wave function is expressed as an integral over a Lagrangian manifold that is constructed by propagating trajectories from an initial manifold formed on a Poincare surface. Even in the case of bound, integrable systems, it is unnecessary to identify action-angle variables or construct quantizing tori. The approximation is numerically tested for separable and highly chaotic two-dimensional quartic oscillator systems. For the separable (but highly anharmonic) system, the accuracy of the approximation is found to be excellent: overlaps of the semiclassical wave functions with the corresponding quantum wave functions exceed 0.999. For the chaotic system, semiclassical-quantum overlaps are found to range from 0.989 to 0.994, indicating accuracy that is still very good, despite the short classical trajectories used in the calculations.

Tur\\'an type inequalities for regular Coulomb wave functions

OpenAIRE

Baricz, Árpád

2015-01-01

Tur\\'an, Mitrinovi\\'c-Adamovi\\'c and Wilker type inequalities are deduced for regular Coulomb wave functions. The proofs are based on a Mittag-Leffler expansion for the regular Coulomb wave function, which may be of independent interest. Moreover, some complete monotonicity results concerning the Coulomb zeta functions and some interlacing properties of the zeros of Coulomb wave functions are given.

Relativistic bound state wave functions

International Nuclear Information System (INIS)

Micu, L.

2005-01-01

A particular method of writing the bound state wave functions in relativistic form is applied to the solutions of the Dirac equation with confining potentials in order to obtain a relativistic description of a quark antiquark bound system representing a given meson. Concerning the role of the effective constituent in the present approach we first observe that without this additional constituent we couldn't expand the bound state wave function in terms of products of free states. Indeed, we notice that if the wave function depends on the relative coordinates only, all the expansion coefficients would be infinite. Secondly we remark that the effective constituent enabled us to give a Lorentz covariant meaning to the potential energy of the bound system which is now seen as the 4th component of a 4-momentum. On the other side, by relating the effective constituent to the quantum fluctuations of the background field which generate the binding, we provided a justification for the existence of some spatial degrees of freedom accompanying the interaction potential. These ones, which are quite unusual in quantum mechanics, in our model are the natural consequence of the the independence of the quarks and can be seen as the effect of the imperfect cancellation of the vector momenta during the quantum fluctuations. Related with all these we remark that the adequate representation for the relativistic description of a bound system is the momentum representation, because of the transparent and easy way of writing the conservation laws and the transformation properties of the wave functions. The only condition to be fulfilled is to find a suitable way to take into account the potential energy of the bound system. A particular feature of the present approach is that the confining forces are due to a kind of glue where both quarks are embedded. This recalls other bound state models where the wave function is factorized in terms of constituent wave functions and the confinement is

Study of Ion Acoustic Wave Damping through Green's Functions

DEFF Research Database (Denmark)

Hsuan, H.C.S.; Jensen, Vagn Orla

1973-01-01

Green's function analyses of ion acoustic waves in streaming plasmas show that, in general, the waves damp algebraically rather than exponentially with distance from exciter.......Green's function analyses of ion acoustic waves in streaming plasmas show that, in general, the waves damp algebraically rather than exponentially with distance from exciter....

Program for the calculation of the semiempirical radial wave functions by means of the variable Tomas-Fermi potential and for the determination of the radial integrals of the dipole transitions

International Nuclear Information System (INIS)

Kuzmitskite, L.L.

1980-01-01

The program is meant for the determination of the semiempirical radial wave functions of the positive ions and the calculation of the radial integrals of the dipole transition. The semiempirical wave functions are calculated using Tomas-Fermi potential with the variable parameter, which provides for the coincidence of the energy obtained with the ionization energy of the state under consideration. The program is written in the FORTRAN language for the BESM-6 computer

Wave function of free electron in a strong laser plasma

International Nuclear Information System (INIS)

Zhu Shitong; Shen Wenda; Guo Qizhi

1993-01-01

The wave function of free electron in a strong laser plasma is obtained by solving exactly the Dirac equation in a curved space-time with optical metric for the laser plasma. When the laser field is diminished to zero, the wave function is naturally reduced to relativistic wave function of free electron. The possible application of the wave function is discussed

Atom localization and center-of-mass wave-function determination via multiple simultaneous quadrature measurements

International Nuclear Information System (INIS)

Evers, Joerg; Qamar, Shahid; Zubairy, M. Suhail

2007-01-01

We discuss localization and center-of-mass wave-function measurement of a quantum particle using multiple simultaneous dispersive interactions of the particle with different standing-wave fields. In particular, we consider objects with an internal structure consisting of a single ground state and several excited states. The transitions between ground and the corresponding excited states are coupled to the light fields in the dispersive limit, thus giving rise to a phase shift of the light field during the interaction. We show that multiple simultaneous measurements allow both an increase in the measurement or localization precision in a single direction and the performance of multidimensional measurements or localization. Further, we show that multiple measurements may relax the experimental requirements for each individual measurement

On quantum mechanical phase-space wave functions

DEFF Research Database (Denmark)

Wlodarz, Joachim J.

1994-01-01

An approach to quantum mechanics based on the notion of a phase-space wave function is proposed within the Weyl-Wigner-Moyal representation. It is shown that the Schrodinger equation for the phase-space wave function is equivalent to the quantum Liouville equation for the Wigner distribution...... function. The relationship to the recent results by Torres-Vega and Frederick [J. Chem. Phys. 98, 3103 (1993)] is also discussed....

Improved WKB radial wave functions in several bases

International Nuclear Information System (INIS)

Durand, B.; Durand, L.; Department of Physics, University of Wisconsin, Madison, Wisconsin 53706)

1986-01-01

We develop approximate WKB-like solutions to the radial Schroedinger equation for problems with an angular momentum barrier using Riccati-Bessel, Coulomb, and harmonic-oscillator functions as basis functions. The solutions treat the angular momentum singularity near the origin more accurately in leading approximation than the standard WKB solutions based on sine waves. The solutions based on Riccati-Bessel and free Coulomb wave functions continue smoothly through the inner turning point and are appropriate for scattering problems. The solutions based on oscillator and bound Coulomb wave functions incorporate both turning points smoothly and are particularly appropriate for bound-state problems; no matching of piecewise solutions using Airy functions is necessary

Bound and scattering wave functions for a velocity-dependent Kisslinger potential for l>0

International Nuclear Information System (INIS)

Jaghoub, M.I.

2002-01-01

Using formal scattering theory, the scattering wave functions are extrapolated to negative energies corresponding to bound-state poles. It is shown that the ratio of the normalized scattering and the corresponding bound-state wave functions, at a bound-state pole, is uniquely determined by the bound-state binding energy. This simple relation is proved analytically for an arbitrary angular momentum quantum number l>0, in the presence of a velocity-dependent Kisslinger potential. The extrapolation relation is tested analytically by solving the Schroedinger equation in the p-wave case exactly for the scattering and the corresponding bound-state wave functions when the Kisslinger potential has the form of a square well. A numerical resolution of the Schroedinger equation in the p-wave case and of a square-well Kisslinger potential is carried out to investigate the range of validity of the extrapolated connection. It is found that the derived relation is satisfied best at low energies and short distances. (orig.)

Horizon wave function for single localized particles: GUP and quantum black-hole decay

International Nuclear Information System (INIS)

Casadio, Roberto; Scardigli, Fabio

2014-01-01

A localized particle in Quantum Mechanics is described by a wave packet in position space, regardless of its energy. However, from the point of view of General Relativity, if the particle's energy density exceeds a certain threshold, it should be a black hole. To combine these two pictures, we introduce a horizon wave function determined by the particle wave function in position space, which eventually yields the probability that the particle is a black hole. The existence of a minimum mass for black holes naturally follows, albeit not in the form of a sharp value around the Planck scale, but rather like a vanishing probability that a particle much lighter than the Planck mass may be a black hole. We also show that our construction entails an effective generalized uncertainty principle (GUP), simply obtained by adding the uncertainties coming from the two wave functions associated with a particle. Finally, the decay of microscopic (quantum) black holes is also described in agreement with what the GUP predicts. (orig.)

The technique of the modified hamiltonian for construction of the spin-projected wave function

International Nuclear Information System (INIS)

Tsaune, A.Ya.; Glushkov, V.N.

1991-01-01

A method is suggested to construct the wave function, which is an eigenfunction for operator S 2 . A combination of Lowdin's projection operators and the method of taking into account the orthogonality conditions in variational problems previously developed by the authors is used for determination of the spin-current wave functions component. It is shown that the suggested method gives better results for the energies that the traditional restricted Hartee-Fock scheme

Neutrino wave function and oscillation suppression

International Nuclear Information System (INIS)

Dolgov, A.D.; Lychkovskiy, O.V.; Mamonov, A.A.; Okun, L.B.; Schepkin, M.G.

2005-01-01

We consider a thought experiment, in which a neutrino is produced by an electron on a nucleus in a crystal. The wave function of the oscillating neutrino is calculated assuming that the electron is described by a wave packet. If the electron is relativistic and the spatial size of its wave packet is much larger than the size of the crystal cell, then the wave packet of the produced neutrino has essentially the same size as the wave packet of the electron. We investigate the suppression of neutrino oscillations at large distances caused by two mechanisms: (1) spatial separation of wave packets corresponding to different neutrino masses; (2) neutrino energy dispersion for given neutrino mass eigenstates. We resolve the contributions of these two mechanisms. (orig.)

Comparative study on spreading function for directional wave spectra

Digital Repository Service at National Institute of Oceanography (India)

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

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

Determination of Shear Properties in the Upper Seafloor Using Seismo-acoustic Interface Waves

Energy Technology Data Exchange (ETDEWEB)

Frivik, Svein Arne

1998-12-31

This thesis develops methods for recording and analysis of seismo-acoustic interface waves for determination of shear wave velocity as a function of depth and includes this in standard refraction seismic surveying. It investigates different techniques for estimation of dispersion characteristics of the interface waves and demonstrates that multi sensor spectral estimation techniques improve the dispersion estimates. The dispersion estimate of the fundamental interface wave mode is used as input to an object function for a model based linearized inversion. The inversion scheme provides an estimate of the shear wave velocity as a function of depth. Three field surveys were performed. Data were acquired with a standard bottom deployed refraction seismic hydrophone array containing 24 or 48 receivers, with a receiver spacing of 2.5 m. Explosive charges were used as sources. The recording time was increased from 0.5 to 8 s, compared to standard refraction seismic surveys. Shear wave velocity and shear modulus estimates were obtained from all the sites. At one of the sites, geotechnically obtained shear wave parameters were available, and a comparison between the two techniques were performed. the result of the comparison is promising and shows the potential of the technique. Although the result of applying the processing scheme to all three data sets is promising, it appears that survey parameters, like source-array spacing, receiver spacing and type of source might have been optimized for better performance. Based on this limitation, a new processing scheme and a new array configuration is proposed for surveys which integrates the recording and processing of both compressional waves and shear waves. 89 refs., 65 refs., 19 tabs.

Exploring the resonant vibration of thin plates: Reconstruction of Chladni patterns and determination of resonant wave numbers.

Science.gov (United States)

Tuan, P H; Wen, C P; Chiang, P Y; Yu, Y T; Liang, H C; Huang, K F; Chen, Y F

2015-04-01

The Chladni nodal line patterns and resonant frequencies for a thin plate excited by an electronically controlled mechanical oscillator are experimentally measured. Experimental results reveal that the resonant frequencies can be fairly obtained by means of probing the variation of the effective impedance of the exciter with and without the thin plate. The influence of the extra mass from the central exciter is confirmed to be insignificant in measuring the resonant frequencies of the present system. In the theoretical aspect, the inhomogeneous Helmholtz equation is exploited to derive the response function as a function of the driving wave number for reconstructing experimental Chladni patterns. The resonant wave numbers are theoretically identified with the maximum coupling efficiency as well as the maximum entropy principle. Substituting the theoretical resonant wave numbers into the derived response function, all experimental Chladni patterns can be excellently reconstructed. More importantly, the dispersion relationship for the flexural wave of the vibrating plate can be determined with the experimental resonant frequencies and the theoretical resonant wave numbers. The determined dispersion relationship is confirmed to agree very well with the formula of the Kirchhoff-Love plate theory.

Epicenter Location of Regional Seismic Events Using Love Wave and Rayleigh Wave Ambient Seismic Noise Green's Functions

Science.gov (United States)

Levshin, A. L.; Barmin, M. P.; Moschetti, M. P.; Mendoza, C.; Ritzwoller, M. H.

2011-12-01

We describe a novel method to locate regional seismic events based on exploiting Empirical Green's Functions (EGF) that are produced from ambient seismic noise. Elastic EGFs between pairs of seismic stations are determined by cross-correlating long time-series of ambient noise recorded at the two stations. The EGFs principally contain Rayleigh waves on the vertical-vertical cross-correlations and Love waves on the transverse-transverse cross-correlations. Earlier work (Barmin et al., "Epicentral location based on Rayleigh wave empirical Green's functions from ambient seismic noise", Geophys. J. Int., 2011) showed that group time delays observed on Rayleigh wave EGFs can be exploited to locate to within about 1 km moderate sized earthquakes using USArray Transportable Array (TA) stations. The principal advantage of the method is that the ambient noise EGFs are affected by lateral variations in structure similarly to the earthquake signals, so the location is largely unbiased by 3-D structure. However, locations based on Rayleigh waves alone may be biased by more than 1 km if the earthquake depth is unknown but lies between 2 km and 7 km. This presentation is motivated by the fact that group time delays for Love waves are much less affected by earthquake depth than Rayleigh waves; thus exploitation of Love wave EGFs may reduce location bias caused by uncertainty in event depth. The advantage of Love waves to locate seismic events, however, is mitigated by the fact that Love wave EGFs have a smaller SNR than Rayleigh waves. Here, we test the use of Love and Rayleigh wave EGFs between 5- and 15-sec period to locate seismic events based on the USArray TA in the western US. We focus on locating aftershocks of the 2008 M 6.0 Wells earthquake, mining blasts in Wyoming and Montana, and small earthquakes near Norman, OK and Dallas, TX, some of which may be triggered by hydrofracking or injection wells.

Coronary wave energy: a novel predictor of functional recovery after myocardial infarction.

Science.gov (United States)

De Silva, Kalpa; Foster, Paul; Guilcher, Antoine; Bandara, Asela; Jogiya, Roy; Lockie, Tim; Chowiencyzk, Phil; Nagel, Eike; Marber, Michael; Redwood, Simon; Plein, Sven; Perera, Divaka

2013-04-01

Revascularization after acute coronary syndromes provides prognostic benefit, provided that the subtended myocardium is viable. The microcirculation and contractility of the subtended myocardium affect propagation of coronary flow, which can be characterized by wave intensity analysis. The study objective was to determine in acute coronary syndromes whether early wave intensity analysis-derived microcirculatory (backward) expansion wave energy predicts late viability, defined by functional recovery. Thirty-one patients (58±11 years) were enrolled after non-ST elevation myocardial infarction. Regional left ventricular function and late-gadolinium enhancement were assessed by cardiac magnetic resonance imaging, before and 3 months after revascularization. The backward-traveling (microcirculatory) expansion wave was derived from wave intensity analysis of phasic coronary pressure and velocity in the infarct-related artery, whereas mean values were used to calculate hyperemic microvascular resistance. Twelve-hour troponin T, left ventricular ejection fraction, and percentage late-gadolinium enhancement mass were 1.35±1.21 µg/L, 56±11%, and 8.4±6.0%, respectively. The infarct-related artery backward-traveling (microcirculatory) expansion wave was inversely correlated with late-gadolinium enhancement infarct mass (r=-0.81; Pwave threshold of 2.8 W m(-2) s(-2)×10(5) predicted functional recovery with sensitivity and specificity of 0.91 and 0.82 (AUC 0.88). Hyperemic microvascular resistance correlated with late-gadolinium enhancement mass (r=0.48; P=0.03) but not left ventricular recovery (r=-0.34; P=0.07). The microcirculation-derived backward expansion wave is a new index that correlates with the magnitude and location of infarction, which may allow for the prediction of functional myocardial recovery. Coronary wave intensity analysis may facilitate myocardial viability assessment during cardiac catheterization.

Semiclassical multicomponent wave function

NARCIS (Netherlands)

Mostovoy, M.V.

A consistent method for obtaining the semiclassical multicomponent wave function for any value of adiabatic parameter is discussed and illustrated by examining the motion of a neutral particle in a nonuniform magnetic field. The method generalizes the Bohr-Sommerfeld quantization rule to

Computing many-body wave functions with guaranteed precision: the first-order Møller-Plesset wave function for the ground state of helium atom.

Science.gov (United States)

Bischoff, Florian A; Harrison, Robert J; Valeev, Edward F

2012-09-14

We present an approach to compute accurate correlation energies for atoms and molecules using an adaptive discontinuous spectral-element multiresolution representation for the two-electron wave function. Because of the exponential storage complexity of the spectral-element representation with the number of dimensions, a brute-force computation of two-electron (six-dimensional) wave functions with high precision was not practical. To overcome the key storage bottlenecks we utilized (1) a low-rank tensor approximation (specifically, the singular value decomposition) to compress the wave function, and (2) explicitly correlated R12-type terms in the wave function to regularize the Coulomb electron-electron singularities of the Hamiltonian. All operations necessary to solve the Schrödinger equation were expressed so that the reconstruction of the full-rank form of the wave function is never necessary. Numerical performance of the method was highlighted by computing the first-order Møller-Plesset wave function of a helium atom. The computed second-order Møller-Plesset energy is precise to ~2 microhartrees, which is at the precision limit of the existing general atomic-orbital-based approaches. Our approach does not assume special geometric symmetries, hence application to molecules is straightforward.

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

DEFF Research Database (Denmark)

Zhang, H.W.; Schäffer, Hemming Andreas

2007-01-01

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

On the construction of translationally invariant deformed wave functions

International Nuclear Information System (INIS)

Guardiola, R.

1975-01-01

Translationally invariant nuclear wave functions are constructed from deformed harmonic oscillator shell-model wave functions, with an exact projection of angular momentum quantum numbers. It is shown that the computation of matrix elements with the translationally invariant wave functions is as simple as the standard calculation, and formulae are obtained for (i) the potential energy, (ii) the kinetic energy and rms radius, and (iii) the charge form factor. (Auth.)

Wave-function reconstruction in a graded semiconductor superlattice

DEFF Research Database (Denmark)

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

2004-01-01

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

Light-front wave function of composite system with spin

International Nuclear Information System (INIS)

Karmanov, V.A.

1979-01-01

The method to construct the relativistic wave function with spin on the light front is developed. The spin structure of the deuteron wave function in relativistic range is found. The calculation methods are illustrated by the calculation of elastic pd-scattering cross section. The consideration carried out is equivalent to the solution of the problem of taking into account the spins and angular momenta in the parton wave functions in the infinite momentum frame

Quantum Chemistry on Quantum Computers: A Polynomial-Time Quantum Algorithm for Constructing the Wave Functions of Open-Shell Molecules.

Science.gov (United States)

Sugisaki, Kenji; Yamamoto, Satoru; Nakazawa, Shigeaki; Toyota, Kazuo; Sato, Kazunobu; Shiomi, Daisuke; Takui, Takeji

2016-08-18

Quantum computers are capable to efficiently perform full configuration interaction (FCI) calculations of atoms and molecules by using the quantum phase estimation (QPE) algorithm. Because the success probability of the QPE depends on the overlap between approximate and exact wave functions, efficient methods to prepare accurate initial guess wave functions enough to have sufficiently large overlap with the exact ones are highly desired. Here, we propose a quantum algorithm to construct the wave function consisting of one configuration state function, which is suitable for the initial guess wave function in QPE-based FCI calculations of open-shell molecules, based on the addition theorem of angular momentum. The proposed quantum algorithm enables us to prepare the wave function consisting of an exponential number of Slater determinants only by a polynomial number of quantum operations.

Trinucleon wave functions from separable expansions of the N-N interaction

International Nuclear Information System (INIS)

Birrell, N.D.

1976-09-01

This work is intended to determine whether a separable expansion for the N-N interaction can be used to obtain trinucleon wave functions of high quality. The expansions used in the study are the Unitary Pole expansion of Harms, Afnan and Read, and the expansion of Adhikari and Sloan. We first compare the calculation of the RSC potential Triton binding energy with the two methods, and find that the results agree quite closely. However, while it is found necessary to use t-matrix perturbation theory to obtain the UPE result, such is not the case with the ASE, thus offering a considerable improvement on the previously used method. We then proceed to calculate the L-S coupling probabilities for the wave function, and in so doing, discover a source of inaccuracy in the work of other authors. We also find that the UPE and ASE give probabilities in good agreement with one another. The calculation of the He 3 charge form factor turns out to be the most critical judge of the accuracy of the wave function. Although both expansions give quite satisfactory results for the charge form factor, those obtained with the ASE are exceptionally pleasing. We finally apply both methods to the OBEP of Holinde and Machleidt, and find that the UPE is quite unsuitable for such application. The ASE, however, once again gives very good results, indicating the high quality of the trinucleon wave function obtained with it. (author)

Hadronic wave functions and high momentum transfer interactions in quantum chromodynamics

International Nuclear Information System (INIS)

Brodsky, S.J.; Huang, T.; Lepage, G.P.

1983-01-01

This chapter emphasizes the utility of a Fock state representation of the meson and baryon wave functions as a means not only to parametrize the effects of bound state dynamics in QCD phenomena, but also to interrelate exclusive, inclusive, and higher twist processes. Discusses hadronic wave functions in QCD, measures of hadronic wave functions (form factors of composite systems, form factors of mesons, the meson distribution amplitude); large momentum transfer exclusive processes (two-photon processes); deep inelastic lepton scattering; and the phenomenology of hadronic wave functions (measures of hadron wave functions, constraints on the pion and proton valence wave function, quark jet diffraction excitation, the ''unveiling'' of the hadronic wave function and intrinsic charm). Finds that the testing ground of perturbative QCD where rigorous, definitive tests of the theory can be made can now be extended throughout a large domain of large momentum transfer exclusive and inclusive lepton, photon, and hadron reactions

Efficient and Flexible Computation of Many-Electron Wave Function Overlaps.

Science.gov (United States)

Plasser, Felix; Ruckenbauer, Matthias; Mai, Sebastian; Oppel, Markus; Marquetand, Philipp; González, Leticia

2016-03-08

A new algorithm for the computation of the overlap between many-electron wave functions is described. This algorithm allows for the extensive use of recurring intermediates and thus provides high computational efficiency. Because of the general formalism employed, overlaps can be computed for varying wave function types, molecular orbitals, basis sets, and molecular geometries. This paves the way for efficiently computing nonadiabatic interaction terms for dynamics simulations. In addition, other application areas can be envisaged, such as the comparison of wave functions constructed at different levels of theory. Aside from explaining the algorithm and evaluating the performance, a detailed analysis of the numerical stability of wave function overlaps is carried out, and strategies for overcoming potential severe pitfalls due to displaced atoms and truncated wave functions are presented.

Bohmian Conditional Wave Functions (and the status of the quantum state)

International Nuclear Information System (INIS)

Norsen, Travis

2016-01-01

The de Broglie - Bohm pilot-wave theory - uniquely among realistic candidate quantum theories - allows a straightforward and simple definition of the wave function of a subsystem of some larger system (such as the entire universe). Such sub-system wave functions are called “Conditional Wave Functions” (CWFs). Here we explain this concept and indicate the CWF's role in the Bohmian explanation of the usual quantum formalism, and then develop (and motivate) the more speculative idea that something like single-particle wave functions could replace the (ontologically problematical) universal wave function in some future, empirically adequate, pilot-wave-type theory. Throughout the presentation is pedagogical and points are illustrated with simple toy models. (paper)

Approximate scattering wave functions for few-particle continua

International Nuclear Information System (INIS)

Briggs, J.S.

1990-01-01

An operator identity which allows the wave operator for N particles interacting pairwise to be expanded as products of operators in which fewer than N particles interact is given. This identity is used to derive appproximate scattering wave functions for N-particle continua that avoid certain difficulties associated with Faddeev-type expansions. For example, a derivation is given of a scattering wave function used successfully recently to describe the three-particle continuum occurring in the electron impact ionization of the hydrogen atom

Determination of many-electron basis functions for a quantum Hall ground state using Schur polynomials

Science.gov (United States)

Mandal, Sudhansu S.; Mukherjee, Sutirtha; Ray, Koushik

2018-03-01

A method for determining the ground state of a planar interacting many-electron system in a magnetic field perpendicular to the plane is described. The ground state wave-function is expressed as a linear combination of a set of basis functions. Given only the flux and the number of electrons describing an incompressible state, we use the combinatorics of partitioning the flux among the electrons to derive the basis wave-functions as linear combinations of Schur polynomials. The procedure ensures that the basis wave-functions form representations of the angular momentum algebra. We exemplify the method by deriving the basis functions for the 5/2 quantum Hall state with a few particles. We find that one of the basis functions is precisely the Moore-Read Pfaffian wave function.

Determination of Wave Model Uncertainties used for Probabilistic Reliability Assessments of Wave Energy Devices

DEFF Research Database (Denmark)

Ambühl, Simon; Kofoed, Jens Peter; Sørensen, John Dalsgaard

2014-01-01

Wave models used for site assessments are subject to model uncertainties, which need to be quantified when using wave model results for probabilistic reliability assessments. This paper focuses on determination of wave model uncertainties. Considered are four different wave models and validation...... data is collected from published scientific research. The bias, the root-mean-square error as well as the scatter index are considered for the significant wave height as well as the mean zero-crossing wave period. Based on an illustrative generic example it is shown how the estimated uncertainties can...... be implemented in probabilistic reliability assessments....

Multiquark masses and wave functions through modified Green's function Monte Carlo method

International Nuclear Information System (INIS)

Kerbikov, B.O.; Polikarpov, M.I.; Shevchenko, L.V.

1987-01-01

The Modified Green's function Monte Carlo method (MGFMC) is used to calculate the masses and ground-state wave functions of multiquark systems in the potential model. The previously developed MGFMC is generalized in order to treat systems containing quarks with inequal masses. The obtained results are presented with the Cornell potential for the masses and the wave functions of light and heavy flavoured baryons and multiquark states (N=6, 9, 12) made of light quarks

Wave function of the Universe as a leaking system

International Nuclear Information System (INIS)

Suen, W.; Young, K.

1989-01-01

We propose a path-integral formulation for the wave function of the Universe which requires neither the Euclidean nor the conformal rotation. The boundary condition is taken to be that ''all possible boundaries are included.'' The resulting wave function in a simple model is shown to have the following properties: (i) the wave function tends to zero as the scale factor of the Universe tends to zero; (ii) in the semiclassical regime, it contains only the expanding component; (iii) it favors inflation

Wave function for harmonically confined electrons in time-dependent electric and magnetostatic fields.

Science.gov (United States)

Zhu, Hong-Ming; Chen, Jin-Wang; Pan, Xiao-Yin; Sahni, Viraht

2014-01-14

We derive via the interaction "representation" the many-body wave function for harmonically confined electrons in the presence of a magnetostatic field and perturbed by a spatially homogeneous time-dependent electric field-the Generalized Kohn Theorem (GKT) wave function. In the absence of the harmonic confinement - the uniform electron gas - the GKT wave function reduces to the Kohn Theorem wave function. Without the magnetostatic field, the GKT wave function is the Harmonic Potential Theorem wave function. We further prove the validity of the connection between the GKT wave function derived and the system in an accelerated frame of reference. Finally, we provide examples of the application of the GKT wave function.

Effect of Forcing Function on Nonlinear Acoustic Standing Waves

Science.gov (United States)

Finkheiner, Joshua R.; Li, Xiao-Fan; Raman, Ganesh; Daniels, Chris; Steinetz, Bruce

2003-01-01

Nonlinear acoustic standing waves of high amplitude have been demonstrated by utilizing the effects of resonator shape to prevent the pressure waves from entering saturation. Experimentally, nonlinear acoustic standing waves have been generated by shaking an entire resonating cavity. While this promotes more efficient energy transfer than a piston-driven resonator, it also introduces complicated structural dynamics into the system. Experiments have shown that these dynamics result in resonator forcing functions comprised of a sum of several Fourier modes. However, previous numerical studies of the acoustics generated within the resonator assumed simple sinusoidal waves as the driving force. Using a previously developed numerical code, this paper demonstrates the effects of using a forcing function constructed with a series of harmonic sinusoidal waves on resonating cavities. From these results, a method will be demonstrated which allows the direct numerical analysis of experimentally generated nonlinear acoustic waves in resonators driven by harmonic forcing functions.

Measurement of light-cone wave functions by diffractive dissociation

Energy Technology Data Exchange (ETDEWEB)

Asheri, D. [Tel Aviv Univ., School of Physics and Astronomy, Sackler Faculty of Exact Science (Israel)

2005-07-01

The measurement of the pion light-cone wave function is revisited and results for the Gegenbauer coefficients are presented. Measurements of the photon electromagnetic and hadronic wave functions are described and results are presented. (authors)

Identification and determination of solitary wave structures in nonlinear wave propagation

International Nuclear Information System (INIS)

Newman, W.I.; Campbell, D.K.; Hyman, J.M.

1991-01-01

Nonlinear wave phenomena are characterized by the appearance of ''solitary wave coherent structures'' traveling at speeds determined by their amplitudes and morphologies. Assuming that these structures are briefly noninteracting, we propose a method for the identification of the number of independent features and their respective speeds. Using data generated from an exact two-soliton solution to the Korteweg-de-Vries equation, we test the method and discuss its strengths and limitations. 41 refs., 2 figs

On wave functions of mesons involving the s-, c- and b-quarks

International Nuclear Information System (INIS)

Zhitnitskij, A.R.; Zhitnitskij, I.R.; Chernyak, V.L.

1983-01-01

The wave function components of pseudoscalar and vestor mesons which are antisymmertric with respect to permutation of the quark momenta are studied. The results are as follows: elt xsub(s)-xsub(u) > sub(K) approximately equal to 0.11 for the K meson, sub(K*) approximately equal to 0.15-C.20 for the K* meson, being a mean fraction of the longitudinal momentum transferred by the s(u) quark. The following estimates are obtained: / approximately equal to 0.20-0.25; / approximately equal to 0.8x10 -2 . The asymptotics of the K 0 -meson form factor and the etasub(c) → KK* decay width are found. Properties of the wave functions of mesons which contain a light and a heavy quark (D, B, ...) are considered. For the B 0 meson approximately equal to 0.10 is found. Arguments are given supporting nonenhancement of the amplitudes of the processes involving D mesons compared to similar K-meson amplitudes. A simple way is suggested to determine the asymptotic form of various wave functions

Wind wave source functions in opposing seas

KAUST Repository

Langodan, Sabique

2015-08-26

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

Determining the Viscosity Coefficient for Viscoelastic Wave Propagation in Rock Bars

Science.gov (United States)

Niu, Leilei; Zhu, Wancheng; Li, Shaohua; Guan, Kai

2018-05-01

Rocks with microdefects exhibit viscoelastic behavior during stress wave propagation. The viscosity coefficient of the wave can be used to characterize the attenuation as the wave propagates in rock. In this study, a long artificial bar with a readily adjustable viscosity coefficient was fabricated to investigate stress wave attenuation. The viscoelastic behavior of the artificial bar under dynamic loading was investigated, and the initial viscoelastic coefficient was obtained based on the amplitude attenuation of the incident harmonic wave. A one-dimensional wave propagation program was compiled to reproduce the time history of the stress wave measured during the experiments, and the program was well fitted to the Kelvin-Voigt model. The attenuation and dispersion of the stress wave in long artificial viscoelastic bars were quantified to accurately determine the viscoelastic coefficient. Finally, the method used to determine the viscoelastic coefficient of a long artificial bar based on the experiments and numerical simulations was extended to determine the viscoelastic coefficient of a short rock bar. This study provides a new method of determining the viscosity coefficient of rock.

Optimized Perturbation Theory for Wave Functions of Quantum Systems

International Nuclear Information System (INIS)

Hatsuda, T.; Tanaka, T.; Kunihiro, T.

1997-01-01

The notion of the optimized perturbation, which has been successfully applied to energy eigenvalues, is generalized to treat wave functions of quantum systems. The key ingredient is to construct an envelope of a set of perturbative wave functions. This leads to a condition similar to that obtained from the principle of minimal sensitivity. Applications of the method to the quantum anharmonic oscillator and the double well potential show that uniformly valid wave functions with correct asymptotic behavior are obtained in the first-order optimized perturbation even for strong couplings. copyright 1997 The American Physical Society

Conformal invariance and pion wave functions of nonleading twist

International Nuclear Information System (INIS)

Braun, V.M.; Filyanov, I.E.

1989-01-01

The restrictions are studied for the general structure of pion wave functions of twist 3 and twist 4 imposed by the conformal symmetry and the equations of motion. A systematic expansion of wave functions in the conformal spin is built and the first order corrections to asymptotic formulae are calculated by the QCD sum rule method. In particular, we have found a multiplicatively renormalizable contribution into the two-particle wave function of twist 4 which cannot be expanded in a finite set of Gegenbauer polynomials. 19 refs.; 5 figs

Surface acoustic waves and elastic constants of InN epilayers determined by Brillouin scattering

Energy Technology Data Exchange (ETDEWEB)

Jimenez-Rioboo, R.J.; Prieto, C. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid (Spain); Cusco, R.; Domenech-Amador, N.; Artus, L. [Institut Jaume Almera, Consell Superior d' Investigacions Cientifiques (CSIC), Lluis Sole i Sabaris s.n., Barcelona, Catalonia (Spain); Yamaguchi, T.; Nanishi, Y. [Faculty of Science and Engineering, Ritsumeikan University, Noji-Higashi, Kusatsu, Shiga (Japan)

2012-06-15

The surface acoustic wave velocity in InN has been experimentally determined by means of Brillouin scattering experiments on c - and m -face epilayers. From simulations based on the Green's function formalism we determine the shear elastic constants c{sub 66} and c{sub 44} and propose a complete set of elastic constants for wurtzite InN. The analysis of the sagittal and azimuthal dependence of the surface acoustic wave velocity indicates a slightly different elastic behavior of the m -face sample that basically affects the c{sub 44} elastic constant. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Nonlinear Wave-Particle Interaction: Implications for Newborn Planetary and Backstreaming Proton Velocity Distribution Functions

Science.gov (United States)

Romanelli, N.; Mazelle, C.; Meziane, K.

2018-02-01

Seen from the solar wind (SW) reference frame, the presence of newborn planetary protons upstream from the Martian and Venusian bow shocks and SW protons reflected from each of them constitutes two sources of nonthermal proton populations. In both cases, the resulting proton velocity distribution function is highly unstable and capable of giving rise to ultralow frequency quasi-monochromatic electromagnetic plasma waves. When these instabilities take place, the resulting nonlinear waves are convected by the SW and interact with nonthermal protons located downstream from the wave generation region (upstream from the bow shock), playing a predominant role in their dynamics. To improve our understanding of these phenomena, we study the interaction between a charged particle and a large-amplitude monochromatic circularly polarized electromagnetic wave propagating parallel to a background magnetic field, from first principles. We determine the number of fix points in velocity space, their stability, and their dependence on different wave-particle parameters. Particularly, we determine the temporal evolution of a charged particle in the pitch angle-gyrophase velocity plane under nominal conditions expected for backstreaming protons in planetary foreshocks and for newborn planetary protons in the upstream regions of Venus and Mars. In addition, the inclusion of wave ellipticity effects provides an explanation for pitch angle distributions of suprathermal protons observed at the Earth's foreshock, reported in previous studies. These analyses constitute a mean to evaluate if nonthermal proton velocity distribution functions observed at these plasma environments present signatures that can be understood in terms of nonlinear wave-particle processes.

General Forms of Wave Functions for Dipositronium, Ps2

Science.gov (United States)

Schrader, D.M.

2007-01-01

The consequences of particle interchange symmetry for the structure of wave functions of the states of dipositronium was recently discussed by the author [I]. In the present work, the methodology is simply explained, and the wave functions are explicitly given.

Coherent molecular transistor: control through variation of the gate wave function.

Science.gov (United States)

Ernzerhof, Matthias

2014-03-21

In quantum interference transistors (QUITs), the current through the device is controlled by variation of the gate component of the wave function that interferes with the wave function component joining the source and the sink. Initially, mesoscopic QUITs have been studied and more recently, QUITs at the molecular scale have been proposed and implemented. Typically, in these devices the gate lead is subjected to externally adjustable physical parameters that permit interference control through modifications of the gate wave function. Here, we present an alternative model of a molecular QUIT in which the gate wave function is directly considered as a variable and the transistor operation is discussed in terms of this variable. This implies that we specify the gate current as well as the phase of the gate wave function component and calculate the resulting current through the source-sink channel. Thus, we extend on prior works that focus on the phase of the gate wave function component as a control parameter while having zero or certain discrete values of the current. We address a large class of systems, including finite graphene flakes, and obtain analytic solutions for how the gate wave function controls the transistor.

Coherent molecular transistor: Control through variation of the gate wave function

International Nuclear Information System (INIS)

Ernzerhof, Matthias

2014-01-01

In quantum interference transistors (QUITs), the current through the device is controlled by variation of the gate component of the wave function that interferes with the wave function component joining the source and the sink. Initially, mesoscopic QUITs have been studied and more recently, QUITs at the molecular scale have been proposed and implemented. Typically, in these devices the gate lead is subjected to externally adjustable physical parameters that permit interference control through modifications of the gate wave function. Here, we present an alternative model of a molecular QUIT in which the gate wave function is directly considered as a variable and the transistor operation is discussed in terms of this variable. This implies that we specify the gate current as well as the phase of the gate wave function component and calculate the resulting current through the source-sink channel. Thus, we extend on prior works that focus on the phase of the gate wave function component as a control parameter while having zero or certain discrete values of the current. We address a large class of systems, including finite graphene flakes, and obtain analytic solutions for how the gate wave function controls the transistor

Collapse of the wave function models, ontology, origin, and implications

CERN Document Server

2018-01-01

This is the first single volume about the collapse theories of quantum mechanics, which is becoming a very active field of research in both physics and philosophy. In standard quantum mechanics, it is postulated that when the wave function of a quantum system is measured, it no longer follows the Schrödinger equation, but instantaneously and randomly collapses to one of the wave functions that correspond to definite measurement results. However, why and how a definite measurement result appears is unknown. A promising solution to this problem are collapse theories in which the collapse of the wave function is spontaneous and dynamical. Chapters written by distinguished physicists and philosophers of physics discuss the origin and implications of wave-function collapse, the controversies around collapse models and their ontologies, and new arguments for the reality of wave function collapse. This is an invaluable resource for students and researchers interested in the philosophy of physics and foundations of ...

Hadron-quark vertex function. Interconnection between 3D and 4D wave function

International Nuclear Information System (INIS)

Mitra, A.N.; Bhatnagar, S.

1990-01-01

Interconnection between 3D and 4D forms of Bethe-Salpeter equation (EBS) with a kernel depending on relative momenta is used to derive hadron-quark vertex function in Lorentz invariance form. The vertex function which is directly related to a 4D wave function satisfying a corresponding EBS determines the natural continuation outside mass surface for the entire momentum space and serves the basis for computing amplitudes of transitions through appropriate loop quark diagrams. Two applications (f p values for P→ll-bar and F π for n 0 +yy) are discussed briefly to illustrate this formalism. An attention is paid to the problem of complex amplitudes for quark loops with a larger number of external hadrons.A possible solution of the problem is proposed. 29 refs

The potential-free approach to the construction of the NN-wave functions

International Nuclear Information System (INIS)

Troitsky, V.E.

1984-01-01

The traditional approaches to the nonrelativistic NN-interaction use local and nonlocal potentials of the kind defined by different dynamical speculations. The wave functions are obtained then from the Schroedinger equation with the chosen potential. Here the author obtains the wave functions (scattering wave function and bound state wave function) directly from the scattering phases in the frame of a dispersion approach without use of potential. (Auth.)

The Green-function transform and wave propagation

Directory of Open Access Journals (Sweden)

Colin eSheppard

2014-11-01

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

Functionalized Nanoporous Track Etched {beta}-PVDF Membrane Electrodes for Lead (II) Determination by Square Wave Anodic Stripping Voltammetry

Energy Technology Data Exchange (ETDEWEB)

Bessbousse, H [Laboratoire des Solides Irradies, CEA-CNRS-Ecole Polytechnique, 91128 Palaiseau (France); Nadhakumar, I [School of Chemistry, University of Southampton, University Road, Southampton S017 1BJ (United Kingdom); Decker, M; Clochard, M -C; Wade, T L [Laboratoire des Solides Irradies, CEA-CNRS-Ecole Polytechnique, 91128 Palaiseau (France); Barsbay, M [Hacettepe University, Department of Chemistry, Polymer Chemistry Division, 06800 Beytepe Ankara (Turkey)

2012-09-15

Track etched functionalized nanoporous {beta}-PVDF membrane electrodes, or functionalized membrane electrodes (FME), are thin-layer cells made from poly(acrylic acid) (PAA) functionalized nanoporous {beta}-poly(vinylidene fluoride) ({beta}-PVDF) membranes with thin Au films sputtered on each side as electrodes. The Au film is thin enough that the pores of the membranes are not completely covered. The PAA functionalization is specifically localised in the walls of the nanoporous {beta}-PVDF membrane by grafting. The PAA is a cation exchange polymer that adsorbs metal ions, such as Pb{sup 2+}, from aqueous solutions concentrating the ions into the membrane. After a time the FME is transferred to an electrochemical cell for analysis. A negative potential is applied to the Au film of the FME for a set time to reduce the adsorbed ions onto the Au film working electrode. The other metalized side of the FME functions as a counter electrode. Finally, square-wave anodic stripping voltammetry (SW-ASV) is performed on the FME to determine the metal ion concentrations in the original solution. The calibration curve of charge versus log concentration has a Temkin isotherm form. The FME membranes are 9 {mu}m thick and have 40 nm diameter pores with a density of 10{sup 10} pores/cm{sup 2}. This high pore density provides a large capacity for ion adsorption. Au ingress in the pores during sputtering forms a random array of nanoelectrodes. Like surface modified electrodes for adsorptive stripping voltammetry, the pre-concentration step for the FME is performed at open circuit. The zero current intercept of the calibration for Pb{sup 2+} is 0.13 ppb ({mu}g/L) and a detection limit of 0.050 ppb based on 3S/N from blank measurements. Voltammetry (CV) and chronoapmerometry (CA) were used to characterize the system. The apparent diffusion coefficient (D) for Pb{sup 2+} in the PAA functionalized pores was determined to be 2.44 x 10{sup -7} cm{sup 2}/s and the partition coefficient (p

Simple functional-differential equations for the bound-state wave-function components

International Nuclear Information System (INIS)

Kamuntavicius, G.P.

1986-01-01

The author presents a new method of a direct derivation of differential equations for the wave-function components of identical-particles systems. The method generates in a simple manner all the possible variants of these equations. In some cases they are the differential equations of Faddeev or Yakubovskii. It is shown that the case of the bound states allows to formulate very simple equations for the components which are equivalent to the Schroedinger equation for the complete wave function. The components with a minimal antisymmetry are defined and the corresponding equations are derived. (Auth.)

The non-Gaussian joint probability density function of slope and elevation for a nonlinear gravity wave field. [in ocean surface

Science.gov (United States)

Huang, N. E.; Long, S. R.; Bliven, L. F.; Tung, C.-C.

1984-01-01

On the basis of the mapping method developed by Huang et al. (1983), an analytic expression for the non-Gaussian joint probability density function of slope and elevation for nonlinear gravity waves is derived. Various conditional and marginal density functions are also obtained through the joint density function. The analytic results are compared with a series of carefully controlled laboratory observations, and good agreement is noted. Furthermore, the laboratory wind wave field observations indicate that the capillary or capillary-gravity waves may not be the dominant components in determining the total roughness of the wave field. Thus, the analytic results, though derived specifically for the gravity waves, may have more general applications.

Sorghum cobalt analysis on not determined wave length with atomic ...

African Journals Online (AJOL)

This study was to know the better wave length on measuring cobalt content in forage sorghum hybrid (Sorghum bicolor) with an atomic absorption spectrophotometer. The analysis was on background correction mode with three wave lengths; 240.8, 240.7 (determined wave length or recommended wave length) and 240.6 ...

Consequences of wave function orthogonality for medium energy nuclear reactions

International Nuclear Information System (INIS)

Noble, J.V.

1978-01-01

In the usual models of high-energy bound-state to continuum transitions no account is taken of the orthogonality of the bound and continuum wave functions. This orthogonality induces considerable cancellations in the overlap integrals expressing the transition amplitudes for reactions such as (e,e'p), (γ,p), and (π,N), which are simply not included in the distorted-wave Born-approximation calculations which to date remain the only computationally feasible heirarchy of approximations. The object of this paper is to present a new formulation of the bound-state to continuum transition problem, based upon flux conservation, in which the orthogonality of wave functions is taken into account ab initio. The new formulation, while exact if exact wave functions are used, offers the possibility of using approximate wave functions for the continuum states without doing violence to the cancellations induced by orthogonality. The method is applied to single-particle states obeying the Schroedinger and Dirac equations, as well as to a coupled-channel model in which absorptive processes can be described in a fully consistent manner. Several types of absorption vertex are considered, and in the (π,N) case the equivalence of pseudoscalar and pseudovector πNN coupling is seen to follow directly from wave function orthogonality

A convenient analytical form for the triton wave function

International Nuclear Information System (INIS)

Hajduk, C.; Green, A.M.; Sainio, M.E.

1979-01-01

The triton wave function obtained by solving the Faddeev equations with the Reid soft core potential is parametrized in a symmetrized cluster form. As a test the 3 He charge form factor is calculated for the exact and the parametrized wave functions and reasonable agreement between the two is found. (author)

BAYESZ, S-Wave, P-Wave Resonance Level Spacing and Strength Functions

International Nuclear Information System (INIS)

Moore, M.S.

1982-01-01

A - Description of problem or function: BAYESZ calculates average s- and p-wave level spacings, strength functions, and average radiation widths of a mixed sequence of s- and p-wave resonances whose parameters are supplied as input. The code is based on two physical assumptions: 1) The neutron reduced width distribution for each open channel is a chi-squared distribution with one degree of freedom, i.e. Porter-Thomas. 2) The spacing distribution follows the Gaussian Orthogonal Ensemble. This property is used, however, only to fix the s- to p-wave level density ratio as proportional to (2J+1) with a spin cut-off correction. B - Method of solution: The method used is an extension of that described by Moore et al. in reference (1), and is based on the method of moments of a truncated Porter-Thomas distribution. C - Restrictions on the complexity of the problem: Parameters for a maximum of 500 individual resonances can be specified. This restriction can be relaxed by increasing array dimensions

ESTIMA, Neutron Width Level Spacing, Neutron Strength Function of S- Wave, P-Wave Resonances

International Nuclear Information System (INIS)

Fort, E.

1982-01-01

1 - Description of problem or function: ESTIMA calculates level spacing and neutron strength function of a mixed sequence of s- and p-wave resonances given a set of neutron widths as input parameters. Three algorithms are used, two of which calculate s-wave average parameters and assume that the reduced widths obey a Porter-Thomas distribution truncated by a minimum detection threshold. The third performs a maximum likelihood fit to a truncated chi-squared distribution of any specified number of degrees of freedom, i.e. it can be used for calculating s-wave or p-wave average parameters. Resonances of undeclared angular orbital momentum are divided into groups of probable s-wave and probable p-wave by a simple application of Bayes' Theorem. 2 - Method of solution: Three algorithms are used: i) GAMN method, based on simple moments properties of a Porter-Thomas distribution. ii) Missing Level Estimator, a simplified version of the algorithm used by the program BAYESZ. iii) ESTIMA, a maximum likelihood fit. 3 - Restrictions on the complexity of the problem: A maximum of 400 resonances is allowed in the version available from NEADB, however this restriction can be relaxed by increasing array dimensions

Determination of optimum "multi-channel surface wave method" field parameters.

Science.gov (United States)

2012-12-01

Multi-channel surface wave methods (especially the multi-channel analyses of surface wave method; MASW) are routinely used to : determine the shear-wave velocity of the subsurface to depths of 100 feet for site classification purposes. Users are awar...

Evolution of ground-state wave function in CeCoIn5 upon Cd or Sn doping

Science.gov (United States)

Chen, K.; Strigari, F.; Sundermann, M.; Hu, Z.; Fisk, Z.; Bauer, E. D.; Rosa, P. F. S.; Sarrao, J. L.; Thompson, J. D.; Herrero-Martin, J.; Pellegrin, E.; Betto, D.; Kummer, K.; Tanaka, A.; Wirth, S.; Severing, A.

2018-01-01

We present linear polarization-dependent soft-x-ray absorption spectroscopy data at the Ce M4 ,5 edges of Cd- and Sn-doped CeCoIn5. The 4 f ground-state wave functions have been determined for their superconducting, antiferromagnetic, and paramagnetic ground states. The absence of changes in the wave functions in CeCo (In1-xCdx) 5 suggests that the 4 f -conduction-electron (c f ) hybridization is not affected by global Cd doping, thus supporting the interpretation of magnetic droplets nucleating long-range magnetic order. This is contrasted by changes in the wave function due to Sn substitution. Increasing Sn in CeCo (In1-ySny) 5 compresses the 4 f orbitals into the tetragonal plane of these materials, suggesting enhanced c f hybridization with the in-plane In(1) atoms and a homogeneous altering of the electronic structure. As these experiments show, the 4 f wave functions are a very sensitive probe of small changes in the hybridization of 4 f and conduction electrons, even conveying information about direction dependencies.

Determining the near-surface current profile from measurements of the wave dispersion relation

Science.gov (United States)

Smeltzer, Benjamin; Maxwell, Peter; Aesøy, Eirik; Ellingsen, Simen

2017-11-01

The current-induced Doppler shifts of waves can yield information about the background mean flow, providing an attractive method of inferring the current profile in the upper layer of the ocean. We present measurements of waves propagating on shear currents in a laboratory water channel, as well as theoretical investigations of inversion techniques for determining the vertical current structure. Spatial and temporal measurements of the free surface profile obtained using a synthetic Schlieren method are analyzed to determine the wave dispersion relation and Doppler shifts as a function of wavelength. The vertical current profile can then be inferred from the Doppler shifts using an inversion algorithm. Most existing algorithms rely on a priori assumptions of the shape of the current profile, and developing a method that uses less stringent assumptions is a focus of this study, allowing for measurement of more general current profiles. The accuracy of current inversion algorithms are evaluated by comparison to measurements of the mean flow profile from particle image velocimetry (PIV), and a discussion of the sensitivity to errors in the Doppler shifts is presented.

Accuracy of three-body wave functions obtained with the correlation-function hyperspherical-harmonic method

International Nuclear Information System (INIS)

Haftel, M.I.; Mandelzweig, V.B.

1990-01-01

The local convergence and accuracy of wave functions obtained by direct solution of the Schroedinger equation with the help of the correlation-function hyperspherical-harmonic method are analyzed for ground and excited states of the helium atom and for the ground state of the positronium negative ion. The inclusion of the cusp conditions into the correlation function is shown to be of crucial importance, not only near the coalescence points, but also away from them. The proper inclusion of all cusps yields for the ground state of the helium atom the local wave-function accuracy of about 10 -7 for different interparticle distances. The omission of one of the cusps in the excited helium atom reduces the wave-function precision to 10 -2 near the corresponding coalescence point and to 10 -4 --10 -5 away from it

QCD Phenomenology and Light-Front Wave Functions

International Nuclear Information System (INIS)

Brodsky, St.J.

2001-01-01

A natural calculus for describing the bound-state structure of relativistic composite systems in quantum field theory is the light-front Fock expansion which encodes the properties of a hadrons in terms of a set of frame-independent n-particle wave functions. Light-front quantization in the doubly-transverse light-cone gauge has a number of remarkable advantages, including explicit unitarity, a physical Fock expansion, the absence of ghost degrees of freedom, and the decoupling properties needed to prove factorization theorems in high momentum transfer inclusive and exclusive reactions. A number of applications are discussed in these lectures, including semileptonic B decays, two-photon exclusive reactions, diffractive dissociation into jets, and deeply virtual Compton scattering. The relation of the intrinsic sea to the light-front wave functions is discussed. Light-front quantization can also be used in the Hamiltonian form to construct an event generator for high energy physics reactions at the amplitude level. The light-cone partition function, summed over exponentially-weighted light-cone energies, has simple boost properties which may be useful for studies in heavy ion collisions. I also review recent work which shows that the structure functions measured in deep inelastic lepton scattering are affected by final-state rescattering, thus modifying their connection to light-front probability distributions. In particular, the shadowing of nuclear structure functions is due to destructive interference effects from leading-twist diffraction of the virtual photon, physics not included in the nuclear light-cone wave functions. (author)

WKB wave function for many-variable systems

International Nuclear Information System (INIS)

Sakita, B.; Tzani, R.

1986-01-01

The WKB method is a non-perturbative semi-classical method in quantum mechanics. The method for a system of one degree of freedom is well known and described in standard textbooks. The method for a system with many degrees of freedom especially for quantum fields is more involved. There exist two methods: Feynman path integral and Schrodinger wave function. The Feynman path integral WKB method is essentially a stationary phase approximation for Feynman path integrals. The WKB Schrodinger wave function method is on the other hand an extension of the standard WKB to many-variable systems

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

Science.gov (United States)

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

2017-02-01

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

On the normalization of total wave function of the system of an atom and a colliding electron

International Nuclear Information System (INIS)

Nashlenas, Eh.P.; Trinkunas, G.P.

1976-01-01

The scattering of an electron by an atom is considered which causes an excitation of fine structure levels. For this purpose the wave function of a system consisting of an atom and an uncoupled electron is constructed. Boundary conditions formulated in the form of an asymptotic expression are taken into account for such a function by means of scattering amplitudes. To determine scattering amplitudes it is suggested to make use of the condition of wave function normalization into the Dirac delta function. After certain mathematical transformations the unknown relations between the scattering amplitudes are obtained. The special cases of the relations obtained are discussed. When quantum numbers of the wave functions coincide, the resulting relations express the equality of fluxes of converging and diverging waves for a certain value of the total angular momentum. In the limiting case when there are no electrons in an atom (it corresponds to elastic scattering of an electron on a potential) the relations obtained express the unitarity conditions of the scattering matrix

Classical representation of wave functions for integrable systems

International Nuclear Information System (INIS)

Kay, Kenneth G.

2004-01-01

Classical exact (CE) wave functions are certain integral representations of energy eigenfunctions that are parameterized in terms of the motion of the corresponding classical system in a semiclassically relevant way. When applied to systems for which they are not exact, such expressions serve as semiclassical approximations. Previous work identified CE wave functions for a number of specific systems and established their semiclassical usefulness. This paper explores the degree to which such representations can be found for more general systems. It is shown that CE wave functions exist, in principle, for bound states of an arbitrary integrable system that are confined to a single classically allowed region. Evidence is presented that CE representations also exist for more general states of such a system that are unbound, or that extend over more than one allowed region. The CE expressions are not unique: an innumerable variety exists for each such system. The existence proof provides a formal method for constructing CE expressions by Fourier transforming certain superpositions of energy eigenstates. The parameterization in terms of the classical motion is achieved by identifying certain quantities in these superpositions as classical action and angle variables. The semiclassical relevance of this identification is ensured by imposing some mild conditions on the coefficients in the superposition. This procedure for parameterizing exact wave functions in terms of classical variables indicates a basic relationship between the quantum and classical descriptions of states. The method of constructing CE wave functions introduced in the proof is shown to be consistent with a number of previously obtained CE formulas and is used to derive two new, closed-form, CE expressions. A simple numerical example is presented to illustrate the semiclassical application of one of these expressions and to further verify the physical significance of the classical parameterization

Acceleration rate of mitral inflow E wave: a novel transmitral doppler index for assessing diastolic function.

Science.gov (United States)

Badkoubeh, Roya Sattarzadeh; Tavoosi, Anahita; Jabbari, Mostafa; Parsa, Amir Farhang Zand; Geraeli, Babak; Saadat, Mohammad; Larti, Farnoosh; Meysamie, Ali Pasha; Salehi, Mehrdad

2016-06-10

We performed comprehensive transmitral and pulmonary venous Doppler echocardiographic studies to devise a novel index of diastolic function. This is the first study to assess the utility of the acceleration rate (AR) of the E wave of mitral inflow as a primary diagnostic modality for assessing diastolic function. Study group consisted of 84 patients (53 + 11 years) with left ventricle (LV) diastolic dysfunction and 34 healthy people (35 ± 9 years) as control group, who were referred for clinically indicated two-dimensional transthoracic echocardiogram (TTE) during 2012 and 2013 to Imam Hospital. Normal controls were defined as patients without clinical evidence of cardiac disease and had normal TTE. LV diastolic function was determined according to standardized protocol of American Society of Echocardiography (ASE). As our new parameter, AR of E wave of mitral inflow was also measured in all patients. It was represented by the slope of the line between onset of E wave and peak of it. Correlation between AR of E wave and LV diastolic function grade was measured using the Spearman correlation coefficient. Receiver operating characteristic (ROC) curve was used to determine the sensitivity and specificity of AR of E wave in diagnosing LV diastolic dysfunction in randomly selected two-thirds of population then its derived cutoff was evaluated in rest of the population. The institutional review board of the hospital approved the study protocol. All participants gave written informed consent. This investigation was in accordance with the Declaration of Helsinki. The mean value of AR was 1010 ± 420 cm/s(2) in patients whereas the mean value for the normal controls was 701 ± 210 cm/s(2). There was a strong and graded relation between AR of E wave of mitral inflow and LV diastolic function grade (Spearman P ≤0.0001, rs =0.69). ROC curve analysis revealed that AR of E wave of mitral inflow =750 cm/s(2) predicted moderate or severe LV diastolic

Regression analysis and transfer function in estimating the parameters of central pulse waves from brachial pulse wave.

Science.gov (United States)

Chai Rui; Li Si-Man; Xu Li-Sheng; Yao Yang; Hao Li-Ling

2017-07-01

This study mainly analyzed the parameters such as ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO) and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. These parameters extracted from the central pulse wave invasively measured were compared with the parameters measured from the brachial pulse waves by a regression model and a transfer function model. The accuracy of the parameters which were estimated by the regression model and the transfer function model was compared too. Our findings showed that in addition to the k value, the above parameters of the central pulse wave and the brachial pulse wave invasively measured had positive correlation. Both the regression model parameters including A_slope, DBP, SEVR and the transfer function model parameters had good consistency with the parameters invasively measured, and they had the same effect of consistency. The regression equations of the three parameters were expressed by Y'=a+bx. The SBP, PP, SV, CO of central pulse wave could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

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

Science.gov (United States)

Su, Ho-Ming; Tsai, Wei-Chung; Lin, Tsung-Hsien; Hsu, Po-Chao; Lee, Wen-Hsien; Lin, Ming-Yen; Chen, Szu-Chia; Lee, Chee-Siong; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung

2012-01-01

The P wave parameters measured by 12-lead electrocardiogram (ECG) are commonly used as noninvasive tools to assess for left atrial enlargement. There are limited studies to evaluate whether P wave parameters are independently associated with decline in renal function. Accordingly, the aim of this study is to assess whether P wave parameters are independently associated with progression to renal end point of ≥25% decline in estimated glomerular filtration rate (eGFR). This longitudinal study included 166 patients. The renal end point was defined as ≥25% decline in eGFR. We measured two ECG P wave parameters corrected by heart rate, i.e. corrected P wave dispersion (PWdisperC) and corrected P wave maximum duration (PWdurMaxC). Heart function and structure were measured from echocardiography. Clinical data, P wave parameters, and echocardiographic measurements were compared and analyzed. Forty-three patients (25.9%) reached renal end point. Kaplan-Meier curves for renal end point-free survival showed PWdisperC > median (63.0 ms) (log-rank P = 0.004) and PWdurMaxC > median (117.9 ms) (log-rank Pfunction decline.

Wave function collapse implies divergence of average displacement

OpenAIRE

Marchewka, A.; Schuss, Z.

2005-01-01

We show that propagating a truncated discontinuous wave function by Schr\\"odinger's equation, as asserted by the collapse axiom, gives rise to non-existence of the average displacement of the particle on the line. It also implies that there is no Zeno effect. On the other hand, if the truncation is done so that the reduced wave function is continuous, the average coordinate is finite and there is a Zeno effect. Therefore the collapse axiom of measurement needs to be revised.

Horizon wave-function and the quantum cosmic censorship

OpenAIRE

Casadio, RobertoDipartimento di Fisica e Astronomia, Alma Mater Università di Bologna, via Irnerio 46, Bologna, 40126, Italy; Micu, Octavian(Institute of Space Science, Bucharest, P.O. Box MG-23, Bucharest-Magurele, RO-077125, Romania); Stojkovic, Dejan(HEPCOS, Department of Physics, SUNY at Buffalo, Buffalo, NY, 14260-1500, United States)

2015-01-01

We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF) formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superxtremal case (with charge-to-mass ratio $\\alpha>1$), which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for $\\alpha^2 2$, and the uncertainty in t...

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

International Nuclear Information System (INIS)

Maydanyuk, Sergei P.

2008-01-01

In quantum cosmological models, constructed in the framework of Friedmann-Robertson-Walker metrics, a nucleation of the Universe with its further expansion is described as a tunneling transition through an effective barrier between regions with small and large values of the scale factor a at non-zero (or zero) energy. The approach for describing this tunneling consists of constructing a wave function satisfying an appropriate boundary condition. There are various ways for defining the boundary condition that lead to different estimates of the barrier penetrability and the tunneling time. In order to describe the escape from the tunneling region as accurately as possible and to construct the total wave function on the basis of its two partial solutions unambiguously, we use the tunneling boundary condition that the total wave function must represent only the outgoing wave at the point of escape from the barrier, where the following definition for the wave is introduced: the wave is represented by the wave function whose modulus changes minimally under a variation of the scale factor a. We construct a new method for a direct non-semiclassical calculation of the total stationary wave function of the Universe, analyze the behavior of this wave function in the tunneling region, near the escape point and in the asymptotic region, and estimate the barrier penetrability. We observe oscillations of the modulus of the wave function in the external region starting from the turning point which decrease with increasing of a and which are not shown in semiclassical calculations. The period of such an oscillation decreases uniformly with increasing a and can be used as a fully quantum dynamical characteristic of the expansion of the Universe. (orig.)

Probability function of breaking-limited surface elevation. [wind generated waves of ocean

Science.gov (United States)

Tung, C. C.; Huang, N. E.; Yuan, Y.; Long, S. R.

1989-01-01

The effect of wave breaking on the probability function of surface elevation is examined. The surface elevation limited by wave breaking zeta sub b(t) is first related to the original wave elevation zeta(t) and its second derivative. An approximate, second-order, nonlinear, non-Gaussian model for zeta(t) of arbitrary but moderate bandwidth is presented, and an expression for the probability density function zeta sub b(t) is derived. The results show clearly that the effect of wave breaking on the probability density function of surface elevation is to introduce a secondary hump on the positive side of the probability density function, a phenomenon also observed in wind wave tank experiments.

EDF: Computing electron number probability distribution functions in real space from molecular wave functions

Science.gov (United States)

Francisco, E.; Pendás, A. Martín; Blanco, M. A.

2008-04-01

Given an N-electron molecule and an exhaustive partition of the real space ( R) into m arbitrary regions Ω,Ω,…,Ω ( ⋃i=1mΩ=R), the edf program computes all the probabilities P(n,n,…,n) of having exactly n electrons in Ω, n electrons in Ω,…, and n electrons ( n+n+⋯+n=N) in Ω. Each Ω may correspond to a single basin (atomic domain) or several such basins (functional group). In the later case, each atomic domain must belong to a single Ω. The program can manage both single- and multi-determinant wave functions which are read in from an aimpac-like wave function description ( .wfn) file (T.A. Keith et al., The AIMPAC95 programs, http://www.chemistry.mcmaster.ca/aimpac, 1995). For multi-determinantal wave functions a generalization of the original .wfn file has been introduced. The new format is completely backwards compatible, adding to the previous structure a description of the configuration interaction (CI) coefficients and the determinants of correlated wave functions. Besides the .wfn file, edf only needs the overlap integrals over all the atomic domains between the molecular orbitals (MO). After the P(n,n,…,n) probabilities are computed, edf obtains from them several magnitudes relevant to chemical bonding theory, such as average electronic populations and localization/delocalization indices. Regarding spin, edf may be used in two ways: with or without a splitting of the P(n,n,…,n) probabilities into α and β spin components. Program summaryProgram title: edf Catalogue identifier: AEAJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5387 No. of bytes in distributed program, including test data, etc.: 52 381 Distribution format: tar.gz Programming language: Fortran 77 Computer

SCARDEC: a new technique for the rapid determination of seismic moment magnitude, focal mechanism and source time functions for large earthquakes using body-wave deconvolution

Science.gov (United States)

Vallée, M.; Charléty, J.; Ferreira, A. M. G.; Delouis, B.; Vergoz, J.

2011-01-01

Accurate and fast magnitude determination for large, shallow earthquakes is of key importance for post-seismic response and tsumami alert purposes. When no local real-time data are available, which is today the case for most subduction earthquakes, the first information comes from teleseismic body waves. Standard body-wave methods give accurate magnitudes for earthquakes up to Mw= 7-7.5. For larger earthquakes, the analysis is more complex, because of the non-validity of the point-source approximation and of the interaction between direct and surface-reflected phases. The latter effect acts as a strong high-pass filter, which complicates the magnitude determination. We here propose an automated deconvolutive approach, which does not impose any simplifying assumptions about the rupture process, thus being well adapted to large earthquakes. We first determine the source duration based on the length of the high frequency (1-3 Hz) signal content. The deconvolution of synthetic double-couple point source signals—depending on the four earthquake parameters strike, dip, rake and depth—from the windowed real data body-wave signals (including P, PcP, PP, SH and ScS waves) gives the apparent source time function (STF). We search the optimal combination of these four parameters that respects the physical features of any STF: causality, positivity and stability of the seismic moment at all stations. Once this combination is retrieved, the integration of the STFs gives directly the moment magnitude. We apply this new approach, referred as the SCARDEC method, to most of the major subduction earthquakes in the period 1990-2010. Magnitude differences between the Global Centroid Moment Tensor (CMT) and the SCARDEC method may reach 0.2, but values are found consistent if we take into account that the Global CMT solutions for large, shallow earthquakes suffer from a known trade-off between dip and seismic moment. We show by modelling long-period surface waves of these events that

Antisymmetrized four-body wave function and coexistence of single particle and cluster structures

International Nuclear Information System (INIS)

Sasakawa, T.

1979-01-01

It is shown that each Yakubovski component of the totally antisymmetric four-body wave function satisfies the same equation as the unantisymmetric wave function. In the antisymmetric total wave function, the wave functions belonging to the same kind of partition are totally antisymmetric among themselves. This leads to the coexistence of cluster models, including the single particle model as a special case of the cluster model, as a sum

9Be scattering with microscopic wave functions and the continuum-discretized coupled-channel method

Science.gov (United States)

Descouvemont, P.; Itagaki, N.

2018-01-01

We use microscopic 9Be wave functions defined in a α +α +n multicluster model to compute 9Be+target scattering cross sections. The parameter sets describing 9Be are generated in the spirit of the stochastic variational method, and the optimal solution is obtained by superposing Slater determinants and by diagonalizing the Hamiltonian. The 9Be three-body continuum is approximated by square-integral wave functions. The 9Be microscopic wave functions are then used in a continuum-discretized coupled-channel (CDCC) calculation of 9Be+208Pb and of 9Be+27Al elastic scattering. Without any parameter fitting, we obtain a fair agreement with experiment. For a heavy target, the influence of 9Be breakup is important, while it is weaker for light targets. This result confirms previous nonmicroscopic CDCC calculations. One of the main advantages of the microscopic CDCC is that it is based on nucleon-target interactions only; there is no adjustable parameter. The present work represents a first step towards more ambitious calculations involving heavier Be isotopes.

Theoretical calculation of shakeup intensities using Xa--SW wave functions

International Nuclear Information System (INIS)

Tse, J.S.; Loubriel, G.

1981-01-01

The ground and 1s core hole state molecular wave functions of CH 4 , NH 3 , H 2 O, and HF obtained from Xa--SW calculations using the touching spheres (TS) and overlapping spheres (OS) approximations are used to calculate the intensity of shakeup satellites observed in their ls core level photoelectron spectra. The sudden approximation was assumed in the calculation. In case of TS Xa--SW wave functions, the one electron overlap integral inside the intersphere was calculated via Green's theorem. For OS Xa--SW wave functions, the integration over the awkwardly shaped intersphere region was circumvented by distributing the intersphere charge into the atomic spheres according to the charge partition scheme suggested by Case and Karplus. Our results show that there are no significant differences between the shakeup energies calculated from the TS and OS approximations. However, shakeup intensities calculated from TS Xa--SW wave functions are more reliable and in better numerical agreement with experiment

A mechanistic determination of horizontal flow regime bound using void wave celerity

Energy Technology Data Exchange (ETDEWEB)

Park, J.W. [Ajou Univ., Suwon (Korea, Republic of)

1995-09-01

The two-phase flow regime boundaries in a horizontal channel has been investigated by using the behavior of the second order void wave celerities. The average two-fluid model has been constituted with closure relations for horizontally stratified and bubbly flows. A vapor phase turbulent stress model for a smooth interface geometry has been included. It is found that the second order waves (i.e., eigenvalues) propagate in opposite direction with almost the same speed when the liquid phase is stationary. Using the well-posedness limit of the two-phase system, the dispersed-stratified flow regime boundary has been modeled. Two-phase Froude number has been theoretically found to be a convenient parameter in quantifying the flow regime boundary as a function of the void fraction. It is found that interaction between void wave celerities become stronger as the two-phase Froude number is reduced. This result should be interpreted as that gravity and the relative velocity are key parameters in determining flow regime boundaries in a horizontal flow. The influence of the vapor phase turbulent stress found to stabilize the flow stratification. This study clearly shows that the average two-fluid model is very effective for a mechanistic determination of horizontal flow regimes if appropriate closure relations are developed.

A mechanistic determination of horizontal flow regime bound using void wave celerity

International Nuclear Information System (INIS)

Park, J.W.

1995-01-01

The two-phase flow regime boundaries in a horizontal channel has been investigated by using the behavior of the second order void wave celerities. The average two-fluid model has been constituted with closure relations for horizontally stratified and bubbly flows. A vapor phase turbulent stress model for a smooth interface geometry has been included. It is found that the second order waves (i.e., eigenvalues) propagate in opposite direction with almost the same speed when the liquid phase is stationary. Using the well-posedness limit of the two-phase system, the dispersed-stratified flow regime boundary has been modeled. Two-phase Froude number has been theoretically found to be a convenient parameter in quantifying the flow regime boundary as a function of the void fraction. It is found that interaction between void wave celerities become stronger as the two-phase Froude number is reduced. This result should be interpreted as that gravity and the relative velocity are key parameters in determining flow regime boundaries in a horizontal flow. The influence of the vapor phase turbulent stress found to stabilize the flow stratification. This study clearly shows that the average two-fluid model is very effective for a mechanistic determination of horizontal flow regimes if appropriate closure relations are developed

Wave functions constructed from an invariant sum over histories satisfy constraints

International Nuclear Information System (INIS)

Halliwell, J.J.; Hartle, J.B.

1991-01-01

Invariance of classical equations of motion under a group parametrized by functions of time implies constraints between canonical coordinates and momenta. In the Dirac formulation of quantum mechanics, invariance is normally imposed by demanding that physical wave functions are annihilated by the operator versions of these constraints. In the sum-over-histories quantum mechanics, however, wave functions are specified, directly, by appropriate functional integrals. It therefore becomes an interesting question whether the wave functions so specified obey the operator constraints of the Dirac theory. In this paper, we show for a wide class of theories, including gauge theories, general relativity, and first-quantized string theories, that wave functions constructed from a sum over histories are, in fact, annihilated by the constraints provided that the sum over histories is constructed in a manner which respects the invariance generated by the constraints. By this we mean a sum over histories defined with an invariant action, invariant measure, and an invariant class of paths summed over

Irregular wave functions of a hydrogen atom in a uniform magnetic field

Science.gov (United States)

Wintgen, D.; Hoenig, A.

1989-01-01

The highly excited irregular wave functions of a hydrogen atom in a uniform magnetic field are investigated analytically, with wave function scarring by periodic orbits considered quantitatively. The results obtained confirm that the contributions of closed classical orbits to the spatial wave functions vanish in the semiclassical limit. Their disappearance, however, is slow. This discussion is illustrated by numerical examples.

Response functions of free mass gravitational wave antennas

Science.gov (United States)

Estabrook, F. B.

1985-01-01

The work of Gursel, Linsay, Spero, Saulson, Whitcomb and Weiss (1984) on the response of a free-mass interferometric antenna is extended. Starting from first principles, the earlier work derived the response of a 2-arm gravitational wave antenna to plane polarized gravitational waves. Equivalent formulas (generalized slightly to allow for arbitrary elliptical polarization) are obtained by a simple differencing of the '3-pulse' Doppler response functions of two 1-arm antennas. A '4-pulse' response function is found, with quite complicated angular dependences for arbitrary incident polarization. The differencing method can as readily be used to write exact response functions ('3n+1 pulse') for antennas having multiple passes or more arms.

A particular inverse problem for Schroedinger discrete equation in two and higher dimensions under apriori information of wave functions

International Nuclear Information System (INIS)

Pavlus, M.

1997-01-01

The entire potential and the rest of wave functions are determined in parallelepiped domain if the entire discrete spectrum and the apriori information about the wave functions on one side of parallelepiped are given. Formulation for solving the Schroedinger discrete equation in two and higher dimensions is proposed and new formulas are derived for their solution. Two examples for a 2D case and one example for a 3D case are demonstrated

Impact of interfacial imperfection on transverse wave in a functionally graded piezoelectric material structure with corrugated boundaries

Science.gov (United States)

Kumar Singh, Abhishek; Kumar, Santan; Kumari, Richa

2018-03-01

The propagation behavior of Love-type wave in a corrugated functionally graded piezoelectric material layered structure has been taken into account. Concretely, the layered structure incorporates a corrugated functionally graded piezoelectric material layer imperfectly bonded to a functionally graded piezoelectric material half-space. An analytical treatment has been employed to determine the dispersion relation for both cases of electrically open condition and electrically short condition. The phase velocity of the Love-type wave has been computed numerically and its dependence on the wave number has been depicted graphically for a specific type of corrugated boundary surfaces for both said conditions. The crux of the study lies in the fact that the imperfect bonding of the interface, the corrugated boundaries present in the layer, and the material properties of the layer and the half-space strongly influence the phase velocity of the Love-type wave. It can be remarkably noted that the imperfect bonding of the interface reduces the phase velocity of the Love-type wave significantly. As a special case of the problem, it is noticed that the procured dispersion relation for both cases of electrically open and electrically short conditions is in accordance with the classical Love wave equation.

Central Arterial Function Measured by Non-invasive Pulse Wave Analysis is Abnormal in Patients with Duchenne Muscular Dystrophy.

Science.gov (United States)

Ryan, Thomas D; Parent, John J; Gao, Zhiqian; Khoury, Philip R; Dupont, Elizabeth; Smith, Jennifer N; Wong, Brenda; Urbina, Elaine M; Jefferies, John L

2017-08-01

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutation of dystrophin. Cardiovascular involvement includes dilated cardiomyopathy. Non-invasive assessment of vascular function has not been evaluated in DMD. We hypothesize arterial wave reflection is abnormal in patients with DMD. Pulse wave analysis was performed on DMD patients with a SphygmoCor SCOR-PVx System to determine central blood pressure and augmentation index (AIx) as an assessment of arterial wave reflection. Results were compared to a control group. A total of 43 patients with DMD were enrolled, and compared to 43 normal controls. Central systolic blood pressure was lower, while both AIx-75 (7.8 ± 9.6% vs. 2.1 ± 10.4%, p 0.01, DMD vs. normal) and AIx-not corrected (16.8 ± 10.1% vs. -3.6 ± 10.9, p wave reflection when compared to normal controls, which may represent increased arterial stiffness. Overall there appears to be no effect on ventricular systolic function, however the long-term consequence in this group is unknown. Further study is required to determine the mechanism of these differences, which may be related to the effects of systemic steroids or the role of dystrophin in vascular function.

Period functions for Maass wave forms and cohomology

CERN Document Server

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

2015-01-01

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

Evolution of wave function in a dissipative system

Science.gov (United States)

Yu, Li-Hua; Sun, Chang-Pu

1994-01-01

For a dissipative system with Ohmic friction, we obtain a simple and exact solution for the wave function of the system plus the bath. It is described by the direct product in two independent Hilbert space. One of them is described by an effective Hamiltonian, the other represents the effect of the bath, i.e., the Brownian motion, thus clarifying the structure of the wave function of the system whose energy is dissipated by its interaction with the bath. No path integral technology is needed in this treatment. The derivation of the Weisskopf-Wigner line width theory follows easily.

Wave number determination of Pc 1-2 mantle waves considering He++ ions: A Cluster study

Science.gov (United States)

Grison, B.; Escoubet, C. P.; Santolík, O.; Cornilleau-Wehrlin, N.; Khotyaintsev, Y.

2014-09-01

The present case study concerns narrowband electromagnetic emission detected in the distant cusp region simultaneously with upgoing plasma flows. The wave properties match the usual properties of the Pc 1-2 mantle waves: small angle between the wave vector and the magnetic field line, left-hand polarization, and propagation toward the ionosphere. We report here the first direct wave vector measurement of these waves (about 1.2 × 10- 2 rad/km) through multi spacecraft analysis using the three magnetic components and, at the same time, through single spacecraft analysis based on the refractive index analysis using the three magnetic components and two electric components. The refractive index analysis offers a simple way to estimate wave numbers in this frequency range. Numerical calculations are performed under the observed plasma conditions. The obtained results show that the ion distribution functions are unstable to ion cyclotron instability at the observed wave vector value, due to the large ion temperature anisotropy. We thus show that these electromagnetic ion cyclotron (EMIC) waves are amplified in the distant cusp region. The Poynting flux of the waves is counterstreaming with respect to the plasma flow. This sense of propagation is consistent with the time necessary to amplify the emissions to the observed level. We point out the role of the wave damping at the He++ gyrofrequency to explain that such waves cannot be observed from the ground at the cusp foot print location.

Correlated wave functions for three-particle systems with Coulomb interaction - The muonic helium atom

Science.gov (United States)

Huang, K.-N.

1977-01-01

A computational procedure for calculating correlated wave functions is proposed for three-particle systems interacting through Coulomb forces. Calculations are carried out for the muonic helium atom. Variational wave functions which explicitly contain interparticle coordinates are presented for the ground and excited states. General Hylleraas-type trial functions are used as the basis for the correlated wave functions. Excited-state energies of the muonic helium atom computed from 1- and 35-term wave functions are listed for four states.

Longitudinal wave function control in single quantum dots with an applied magnetic field

Science.gov (United States)

Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A.; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

2015-01-01

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots. PMID:25624018

Longitudinal wave function control in single quantum dots with an applied magnetic field.

Science.gov (United States)

Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

2015-01-27

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots.

Wave function continuity and the diagonal Born-Oppenheimer correction at conical intersections.

Science.gov (United States)

Meek, Garrett A; Levine, Benjamin G

2016-05-14

We demonstrate that though exact in principle, the expansion of the total molecular wave function as a sum over adiabatic Born-Oppenheimer (BO) vibronic states makes inclusion of the second-derivative nonadiabatic energy term near conical intersections practically problematic. In order to construct a well-behaved molecular wave function that has density at a conical intersection, the individual BO vibronic states in the summation must be discontinuous. When the second-derivative nonadiabatic terms are added to the Hamiltonian, singularities in the diagonal BO corrections (DBOCs) of the individual BO states arise from these discontinuities. In contrast to the well-known singularities in the first-derivative couplings at conical intersections, these singularities are non-integrable, resulting in undefined DBOC matrix elements. Though these singularities suggest that the exact molecular wave function may not have density at the conical intersection point, there is no physical basis for this constraint. Instead, the singularities are artifacts of the chosen basis of discontinuous functions. We also demonstrate that continuity of the total molecular wave function does not require continuity of the individual adiabatic nuclear wave functions. We classify nonadiabatic molecular dynamics methods according to the constraints placed on wave function continuity and analyze their formal properties. Based on our analysis, it is recommended that the DBOC be neglected when employing mixed quantum-classical methods and certain approximate quantum dynamical methods in the adiabatic representation.

Discrete expansions of continuum wave functions

International Nuclear Information System (INIS)

Bang, J.; Ershov, S.N.; Gareev, F.A.; Kazacha, G.S.

1980-01-01

Different methods of expanding continuum wave functions in terms of discrete basis sets are discussed. The convergence properties of these expansions are investigated, both from a mathematical and a numerical point of view, for the case of potentials of Woods-Saxon and square well type. (orig.)

Linear density response function in the projector augmented wave method

DEFF Research Database (Denmark)

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

2011-01-01

We present an implementation of the linear density response function within the projector-augmented wave method with applications to the linear optical and dielectric properties of both solids, surfaces, and interfaces. The response function is represented in plane waves while the single...... functions of Si, C, SiC, AlP, and GaAs compare well with previous calculations. While optical properties of semiconductors, in particular excitonic effects, are generally not well described by ALDA, we obtain excellent agreement with experiments for the surface loss function of graphene and the Mg(0001...

Order in large and chaos in small components of nuclear wave functions

International Nuclear Information System (INIS)

Soloviev, V.G.

1992-06-01

An investigation of the order and chaos of the nuclear excited states has shown that there is order in the large and chaos in the small quasiparticle or phonon components of the nuclear wave functions. The order-to-chaos transition is treated as a transition from the large to the small components of the nuclear wave function. The analysis has shown that relatively large many-quasiparticle components of the wave function at an excitation energy (4-8)MeV may exist. The large many-quasiparticle components of the wave functions of the neutron resonances are responsible for enhanced E1-, M1- and E2-transition probabilities from neutron resonance to levels lying (1-2)MeV below them. (author)

Performance of wave function and density functional methods for water hydrogen bond spin-spin coupling constants.

Science.gov (United States)

García de la Vega, J M; Omar, S; San Fabián, J

2017-04-01

Spin-spin coupling constants in water monomer and dimer have been calculated using several wave function and density functional-based methods. CCSD, MCSCF, and SOPPA wave functions methods yield similar results, specially when an additive approach is used with the MCSCF. Several functionals have been used to analyze their performance with the Jacob's ladder and a set of functionals with different HF exchange were tested. Functionals with large HF exchange appropriately predict 1 J O H , 2 J H H and 2h J O O couplings, while 1h J O H is better calculated with functionals that include a reduced fraction of HF exchange. Accurate functionals for 1 J O H and 2 J H H have been tested in a tetramer water model. The hydrogen bond effects on these intramolecular couplings are additive when they are calculated by SOPPA(CCSD) wave function and DFT methods. Graphical Abstract Evaluation of the additive effect of the hydrogen bond on spin-spin coupling constants of water using WF and DFT methods.

Experimentally determined profiles of fast wave current drive on DIII-D

International Nuclear Information System (INIS)

Forest, C.B.; Petty, C.C.; Baity, F.W.; Chiu, S.C.; deGrassie, J.S.; Groebner, R.J.; Ikezi, H.; Jaeger, E.F.; Kupfer, K.; Murakami, M.; Pinsker, R.I.; Prater, R.; Rice, B.W.; Wade, M.R.; Whyte, D.G.

1996-01-01

Profiles of non-inductive current driven by fast waves have been determined for reversed-shear DIII-D discharges. Both the current profile and toroidal electric field profile are determined from time sequences of equilibrium reconstructions [C. B. Forest et al., Phys. Rev. Lett. 73, 2224 (1994)]. Using this information, the measured current profile has been separated into inductive and non-inductive portions. By comparing similar discharges with co and counter antenna phasings and similar fast wave power, the portion of the total non-inductive current driven by fast waves was determined. The experimentally determined profiles of FWCD are in general agreement with theoretical predictions. Specifically, 135 kA was driven by 1.4 MW of rf power with a profile peaked inside ρ=2. copyright 1996 American Institute of Physics

Special software for computing the special functions of wave catastrophes

Directory of Open Access Journals (Sweden)

Andrey S. Kryukovsky

2015-01-01

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

Hartree-Fock implementation using a Laguerre-based wave function for the ground state and correlation energies of two-electron atoms.

Science.gov (United States)

King, Andrew W; Baskerville, Adam L; Cox, Hazel

2018-03-13

An implementation of the Hartree-Fock (HF) method using a Laguerre-based wave function is described and used to accurately study the ground state of two-electron atoms in the fixed nucleus approximation, and by comparison with fully correlated (FC) energies, used to determine accurate electron correlation energies. A variational parameter A is included in the wave function and is shown to rapidly increase the convergence of the energy. The one-electron integrals are solved by series solution and an analytical form is found for the two-electron integrals. This methodology is used to produce accurate wave functions, energies and expectation values for the helium isoelectronic sequence, including at low nuclear charge just prior to electron detachment. Additionally, the critical nuclear charge for binding two electrons within the HF approach is calculated and determined to be Z HF C =1.031 177 528.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

Inverse Schroedinger equation and the exact wave function

International Nuclear Information System (INIS)

Nakatsuji, Hiroshi

2002-01-01

Using the inverse of the Hamiltonian, we introduce the inverse Schroedinger equation (ISE) that is equivalent to the ordinary Schroedinger equation (SE). The ISE has the variational principle and the H-square group of equations as the SE has. When we use a positive Hamiltonian, shifting the energy origin, the inverse energy becomes monotonic and we further have the inverse Ritz variational principle and cross-H-square equations. The concepts of the SE and the ISE are combined to generalize the theory for calculating the exact wave function that is a common eigenfunction of the SE and ISE. The Krylov sequence is extended to include the inverse Hamiltonian, and the complete Krylov sequence is introduced. The iterative configuration interaction (ICI) theory is generalized to cover both the SE and ISE concepts and four different computational methods of calculating the exact wave function are presented in both analytical and matrix representations. The exact wave-function theory based on the inverse Hamiltonian can be applied to systems that have singularities in the Hamiltonian. The generalized ICI theory is applied to the hydrogen atom, giving the exact solution without any singularity problem

Diagonal Born-Oppenheimer correction for coupled-cluster wave-functions

Science.gov (United States)

Shamasundar, K. R.

2018-06-01

We examine how geometry-dependent normalisation freedom of electronic wave-functions affects extraction of a meaningful diagonal Born-Oppenheimer correction (DBOC) to the ground-state Born-Oppenheimer potential energy surface (PES). By viewing this freedom as a kind of gauge-freedom, it is shown that DBOC and the resulting associated mass-dependent adiabatic PES are gauge-invariant quantities. A sum-over-states (SOS) formula for DBOC which explicitly exhibits this invariance is derived. A biorthogonal formulation suitable for DBOC computations using standard unnormalised coupled-cluster (CC) wave-functions is presented. This is shown to lead to a biorthogonal version of SOS formula with similar properties. On this basis, different computational schemes for evaluating DBOC using approximate CC wave-functions are derived. One of this agrees with the formula used in the current literature. The connection to adiabatic-to-diabatic transformations in non-adiabatic dynamics is explored and complications arising from biorthogonal nature of CC theory are identified.

Convergence of repeated quantum nondemolition measurements and wave-function collapse

International Nuclear Information System (INIS)

Bauer, Michel; Bernard, Denis

2011-01-01

Motivated by recent experiments on quantum trapped fields, we give a rigorous proof that repeated indirect quantum nondemolition (QND) measurements converge to the collapse of the wave function as predicted by the postulates of quantum mechanics for direct measurements. We also relate the rate of convergence toward the collapsed wave function to the relative entropy of each indirect measurement, a result which makes contact with information theory.

Construction of Bethe Salpeter wave functions and applications in QCD

International Nuclear Information System (INIS)

Gromes, D.

1993-01-01

We suggest an ansatz for the Bethe Salpeter wave function which is strictly covariant, obeys the spectrum conditions, and has the correct non relativistic limit. As a first simple application we present a wave function for the pion. It contains two parameters, one of them being the quark mass. The decay constant and the form factor derived from this are in excellent agreement with the data. (orig.)

Comultiplication in ABCD algebra and scalar products of Bethe wave functions

International Nuclear Information System (INIS)

Mikhailov, A.

1995-01-01

The representation of scalar products of Bethe wave functions in terms of dual fields, plays an important role in the theory of completely integrable models. The proof is based on the explicit expression for the open-quotes seniorclose quotes coefficient, which was guessed in the Izergin paper and then proved to satisfy some recurrent relations, which determine it unambiguously. In this paper we present an alternative proof based on direct computation. It uses the operation of comultiplication in the ABCD-algebra

Possibility to determine the radius of accretion disk by gravitational waves

International Nuclear Information System (INIS)

Sotani, H; Saijo, M

2007-01-01

We investigate gravitational waves from a dust disk around a Schwarzschild black hole to focus on whether we can extract any of its physical properties from a direct detection of gravitational waves. We adopt a black hole perturbation approach in a time domain, which is a satisfactory approximation to illustrate a dust disk in a supermassive black hole. We find that we can determine the radius of the disk by using the power spectrum of gravitational waves and that our method to extract the radius works for a disk of arbitrary density distribution. Therefore we believe a possibility exists for determining the radius of the disk from a direct observation of gravitational waves detected by the Laser Interferometer Space Antenna

The deuteron bound state wave function with tensor forces

International Nuclear Information System (INIS)

Takemasa, Tadashi

1991-01-01

A FORTRAN program named DEUTERON is developed to calculate the binding energy and wave function of a deuteron, when the interaction between two nucleons is described in terms of central, tensor, spin-orbit, and quadratic LS potentials with or without a hard core. An important use of the program is to provide the deuteron wave function required in nuclear reaction calculations involving a deuteron. Also, this program may be employed in nuclear Hartree-Fock calculations using an effective nucleon-nucleon interaction with a tensor component. (author)

Functional estimation of kidneys after extracorporeal shock wave therapy (ESWL) by clearance

International Nuclear Information System (INIS)

Sydow, K.; Kirschner, P.; Brien, G.; Buchali, K.; Frenzel, R.

1991-01-01

35 patients were scintiscanned with 99m-Tc-DTPA to determine the effects of extracorporeal shock waves used to desintegrate renal concrements may have on the patients renal function. The therapy was conducted using a standard Lithostar unit (Siemens) (20 patients) and an additional overtable module (15 patients). Functional scintigraphy was performed using a gamma camera before lithotripsy, and on the first day after it. Further control investigations were performed one or two weeks later and two till six months later. In both groups most of the patients developed temporary restrictions in renal function, some of them irreversible restrictions. Functional losses were found to be less severe with the use of the overtable module than with the standard Lithostar unit. (orig.) [de

Extracting a shape function for a signal with intra-wave frequency modulation.

Science.gov (United States)

Hou, Thomas Y; Shi, Zuoqiang

2016-04-13

In this paper, we develop an effective and robust adaptive time-frequency analysis method for signals with intra-wave frequency modulation. To handle this kind of signals effectively, we generalize our data-driven time-frequency analysis by using a shape function to describe the intra-wave frequency modulation. The idea of using a shape function in time-frequency analysis was first proposed by Wu (Wu 2013 Appl. Comput. Harmon. Anal. 35, 181-199. (doi:10.1016/j.acha.2012.08.008)). A shape function could be any smooth 2π-periodic function. Based on this model, we propose to solve an optimization problem to extract the shape function. By exploring the fact that the shape function is a periodic function with respect to its phase function, we can identify certain low-rank structure of the signal. This low-rank structure enables us to extract the shape function from the signal. Once the shape function is obtained, the instantaneous frequency with intra-wave modulation can be recovered from the shape function. We demonstrate the robustness and efficiency of our method by applying it to several synthetic and real signals. One important observation is that this approach is very stable to noise perturbation. By using the shape function approach, we can capture the intra-wave frequency modulation very well even for noise-polluted signals. In comparison, existing methods such as empirical mode decomposition/ensemble empirical mode decomposition seem to have difficulty in capturing the intra-wave modulation when the signal is polluted by noise. © 2016 The Author(s).

Comparison of Regression Analysis and Transfer Function in Estimating the Parameters of Central Pulse Waves from Brachial Pulse Wave.

Science.gov (United States)

Chai, Rui; Xu, Li-Sheng; Yao, Yang; Hao, Li-Ling; Qi, Lin

2017-01-01

This study analyzed ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO), and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. Invasively measured parameters were compared with parameters measured from brachial pulse waves by regression model and transfer function model. Accuracy of parameters estimated by regression and transfer function model, was compared too. Findings showed that k value, central pulse wave and brachial pulse wave parameters invasively measured, correlated positively. Regression model parameters including A_slope, DBP, SEVR, and transfer function model parameters had good consistency with parameters invasively measured. They had same effect of consistency. SBP, PP, SV, and CO could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

Semi-analytical Karhunen-Loeve representation of irregular waves based on the prolate spheroidal wave functions

Science.gov (United States)

Lee, Gibbeum; Cho, Yeunwoo

2018-01-01

A new semi-analytical approach is presented to solving the matrix eigenvalue problem or the integral equation in Karhunen-Loeve (K-L) representation of random data such as irregular ocean waves. Instead of direct numerical approach to this matrix eigenvalue problem, which may suffer from the computational inaccuracy for big data, a pair of integral and differential equations are considered, which are related to the so-called prolate spheroidal wave functions (PSWF). First, the PSWF is expressed as a summation of a small number of the analytical Legendre functions. After substituting them into the PSWF differential equation, a much smaller size matrix eigenvalue problem is obtained than the direct numerical K-L matrix eigenvalue problem. By solving this with a minimal numerical effort, the PSWF and the associated eigenvalue of the PSWF differential equation are obtained. Then, the eigenvalue of the PSWF integral equation is analytically expressed by the functional values of the PSWF and the eigenvalues obtained in the PSWF differential equation. Finally, the analytically expressed PSWFs and the eigenvalues in the PWSF integral equation are used to form the kernel matrix in the K-L integral equation for the representation of exemplary wave data such as ordinary irregular waves. It is found that, with the same accuracy, the required memory size of the present method is smaller than that of the direct numerical K-L representation and the computation time of the present method is shorter than that of the semi-analytical method based on the sinusoidal functions.

Double photoionization of helium: A new correlated double continuum wave function

Energy Technology Data Exchange (ETDEWEB)

Macri, P.A.; Kornberg, M.A.; Miraglia, J.E. [Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina). Inst. de Astron. y Fisica del Espacio; Garibotti, C.R.; Gasaneo, G.; Colavecchia, F.D. [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, 8400 S.C. de Bariloche, Rio Negro (Argentina)

1997-10-01

In this work we discuss the failures and goodness of using the product of two and three Coulomb waves to represent the double-continuum wave function of two electrons in the field of an ion. Furthermore, we present a new wave function for the double continuum, which takes into account the non-diagonal part of the kinetic energy. It satisfies the correct boundary conditions for large particle separations, and treats the electronic interaction in a more realistic way than the previously enunciated models. (orig.). 14 refs.

On the interpretation of wave function overlaps in quantum dots

DEFF Research Database (Denmark)

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

2011-01-01

The spontaneous emission rate of excitons strongly confined in quantum dots (QDs) is proportional to the overlap integral of electron and hole envelope wave functions. A common and intuitive interpretation of this result is that the spontaneous emission rate is proportional to the probability...... that the electron and the hole are located at the same point or region in space, i.e., they must coincide spatially to recombine. Here, we show that this interpretation is not correct even loosely speaking. By general mathematical considerations we compare the envelope wave function overlap, the exchange overlap...... integral, and the probability of electrons and holes coinciding, and find that the frequency dependence of the envelope wave function overlap integral is very different from that expected from the common interpretation. We show that these theoretical considerations lead to predictions for measurements. We...

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-08-15

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

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

International Nuclear Information System (INIS)

Ritboon, Atirach; Daengngam, Chalongrat; Pengpan, Teparksorn

2016-01-01

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

Variational Optimization of the Second-Order Density Matrix Corresponding to a Seniority-Zero Configuration Interaction Wave Function.

Science.gov (United States)

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

2015-09-08

We perform a direct variational determination of the second-order (two-particle) density matrix corresponding to a many-electron system, under a restricted set of the two-index N-representability P-, Q-, and G-conditions. In addition, we impose a set of necessary constraints that the two-particle density matrix must be derivable from a doubly occupied many-electron wave function, i.e., a singlet wave function for which the Slater determinant decomposition only contains determinants in which spatial orbitals are doubly occupied. We rederive the two-index N-representability conditions first found by Weinhold and Wilson and apply them to various benchmark systems (linear hydrogen chains, He, N2, and CN(-)). This work is motivated by the fact that a doubly occupied many-electron wave function captures in many cases the bulk of the static correlation. Compared to the general case, the structure of doubly occupied two-particle density matrices causes the associate semidefinite program to have a very favorable scaling as L(3), where L is the number of spatial orbitals. Since the doubly occupied Hilbert space depends on the choice of the orbitals, variational calculation steps of the two-particle density matrix are interspersed with orbital-optimization steps (based on Jacobi rotations in the space of the spatial orbitals). We also point to the importance of symmetry breaking of the orbitals when performing calculations in a doubly occupied framework.

Sum rules for baryonic vertex functions and the proton wave function in QCD

International Nuclear Information System (INIS)

Lavelle, M.J.

1985-01-01

We consider light-cone sum rules for vertex functions involving baryon-meson couplings. These sum rules relate the non-perturbative, and experimentally known, coupling constants to the moments of the wave function of the proton state. Our results for these moments are consistent with those obtained from QCD sum rules for two-point functions. (orig.)

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

Energy Technology Data Exchange (ETDEWEB)

Tolezani, Elaine Cristina; Costa-Hong, Valéria, E-mail: hong.valeria@gmail.com; Correia, Gustavo; Mansur, Alfredo José; Drager, Luciano Ferreira; Bortolotto, Luiz Aparecido [Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

2014-11-15

Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior{sup ®} device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure related to the carotid functional measure

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

International Nuclear Information System (INIS)

Tolezani, Elaine Cristina; Costa-Hong, Valéria; Correia, Gustavo; Mansur, Alfredo José; Drager, Luciano Ferreira; Bortolotto, Luiz Aparecido

2014-01-01

Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior ® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure related to the carotid functional measure. The

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

Directory of Open Access Journals (Sweden)

Elaine Cristina Tolezani

2014-11-01

Full Text Available Background: Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. Objective: To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. Methods: This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. Results: The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01 and triglycerides (p = 0.02; intima-media thickness, to age (p < 0.01; diameter, to creatinine (p = 0.03 and age (p = 0.02; relative distensibility, to age (p < 0.01 and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively. Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01 and with relative distensibility (p < 0.01, while diameter showed a positive correlation with distensibility (p = 0.03. Conclusion: In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic

Excitation spectra and wave functions of quasiparticle bound states in bilayer Rashba superconductors

Energy Technology Data Exchange (ETDEWEB)

Higashi, Yoichi, E-mail: higashiyoichi@ms.osakafu-u.ac.jp [Department of Mathematical Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan); Nagai, Yuki [CCSE, Japan Atomic Energy Agency, 178-4-4, Wakashiba, Kashiwa, Chiba 277-0871 (Japan); Yoshida, Tomohiro [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Kato, Masaru [Department of Mathematical Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531 (Japan); Yanase, Youichi [Department of Physics, Niigata University, Niigata 950-2181 (Japan)

2015-11-15

Highlights: • We focus on the pair-density wave state in bilayer Rashba superconductors. • The zero energy Bogoliubov wave functions are localized at the edge and vortex core. • We investigate the excitation spectra of edge and vortex bound states. - Abstract: We study the excitation spectra and the wave functions of quasiparticle bound states at a vortex and an edge in bilayer Rashba superconductors under a magnetic field. In particular, we focus on the quasiparticle states at the zero energy in the pair-density wave state in a topologically non-trivial phase. We numerically demonstrate that the quasiparticle wave functions with zero energy are localized at both the edge and the vortex core if the magnetic field exceeds the critical value.

Wind wave source functions in opposing seas

KAUST Repository

Langodan, Sabique; Cavaleri, Luigi; Viswanadhapalli, Yesubabu; Hoteit, Ibrahim

2015-01-01

that the currently available wave model source functions may not properly represent the evolution of the local fields that appear to be characterized by a less effective wind input and an enhanced white-capping. We propose and test a possible simple solution

Wave function for time-dependent harmonically confined electrons in a time-dependent electric field.

Science.gov (United States)

Li, Yu-Qi; Pan, Xiao-Yin; Sahni, Viraht

2013-09-21

The many-body wave function of a system of interacting particles confined by a time-dependent harmonic potential and perturbed by a time-dependent spatially homogeneous electric field is derived via the Feynman path-integral method. The wave function is comprised of a phase factor times the solution to the unperturbed time-dependent Schrödinger equation with the latter being translated by a time-dependent value that satisfies the classical driven equation of motion. The wave function reduces to that of the Harmonic Potential Theorem wave function for the case of the time-independent harmonic confining potential.

Ab initio calculation atomics ground state wave function for interactions Ion- Atom

International Nuclear Information System (INIS)

Shojaee, F.; Bolori zadeh, M. A.

2007-01-01

Ab initio calculation atomics ground state wave function for interactions Ion- Atom Atomic wave function expressed in a Slater - type basis obtained within Roothaan- Hartree - Fock for the ground state of the atoms He through B. The total energy is given for each atom.

Gravity induced wave function collapse

Science.gov (United States)

Gasbarri, G.; Toroš, M.; Donadi, S.; Bassi, A.

2017-11-01

Starting from an idea of S. L. Adler [in Quantum Nonlocality and Reality: 50 Years of Bell's Theorem, edited by M. Bell and S. Gao (Cambridge University Press, Cambridge, England 2016)], we develop a novel model of gravity induced spontaneous wave function collapse. The collapse is driven by complex stochastic fluctuations of the spacetime metric. After deriving the fundamental equations, we prove the collapse and amplification mechanism, the two most important features of a consistent collapse model. Under reasonable simplifying assumptions, we constrain the strength ξ of the complex metric fluctuations with available experimental data. We show that ξ ≥10-26 in order for the model to guarantee classicality of macro-objects, and at the same time ξ ≤10-20 in order not to contradict experimental evidence. As a comparison, in the recent discovery of gravitational waves in the frequency range 35 to 250 Hz, the (real) metric fluctuations reach a peak of ξ ˜10-21.

Microscopy of electronic wave function

International Nuclear Information System (INIS)

Harb, M.

2010-01-01

This work of thesis aims to visualize, on a position sensitive detector, the spatial oscillations of slow electrons (∼ meV) emitted by a threshold photoionization in the presence of an external electric field. The interference figure obtained represents the square magnitude of electronic wavefunction. This fundamental work allows us to have access to the electronic dynamics and thus to highlight several quantum mechanisms that occur at the atomic scale (field Coulomb, electron/electron interaction..). Despite the presence an electronic core in Li atom, we have succeeded, experimentally and for the first time, in visualizing the wave function associated with the quasi-discrete Stark states coupled to the ionization continuum. Besides, using simulations of wave packet propagation, based on the 'Split-operator' method, we have conducted a comprehensive study of the H, Li and Cs atoms while revealing the significant effects of the Stark resonances. A very good agreement, on and off resonances, was obtained between simulated and experimental results. In addition, we have developed a generalized analytical model to understand deeply the function of VMI (Velocity-Map Imaging) spectrometer. This model is based on the paraxial approximation; it is based on matrix optics calculation by making an analogy between the electronic trajectory and the light beam. An excellent agreement was obtained between the model predictions and the experimental results. (author)

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

Science.gov (United States)

Wapenaar, Kees

2017-06-01

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

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

Science.gov (United States)

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

2016-07-12

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

The extended hyperbolic function method and exact solutions of the long-short wave resonance equations

International Nuclear Information System (INIS)

Shang Yadong

2008-01-01

The extended hyperbolic functions method for nonlinear wave equations is presented. Based on this method, we obtain a multiple exact explicit solutions for the nonlinear evolution equations which describe the resonance interaction between the long wave and the short wave. The solutions obtained in this paper include (a) the solitary wave solutions of bell-type for S and L, (b) the solitary wave solutions of kink-type for S and bell-type for L, (c) the solitary wave solutions of a compound of the bell-type and the kink-type for S and L, (d) the singular travelling wave solutions, (e) periodic travelling wave solutions of triangle function types, and solitary wave solutions of rational function types. The variety of structure to the exact solutions of the long-short wave equation is illustrated. The methods presented here can also be used to obtain exact solutions of nonlinear wave equations in n dimensions

A comprehensive analysis of molecule-intrinsic quasi-atomic, bonding, and correlating orbitals. I. Hartree-Fock wave functions

International Nuclear Information System (INIS)

West, Aaron C.; Schmidt, Michael W.; Gordon, Mark S.; Ruedenberg, Klaus

2013-01-01

Through a basis-set-independent web of localizing orbital-transformations, the electronic wave function of a molecule is expressed in terms of a set of orbitals that reveal the atomic structure and the bonding pattern of a molecule. The analysis is based on resolving the valence orbital space in terms of an internal space, which has minimal basis set dimensions, and an external space. In the internal space, oriented quasi-atomic orbitals and split-localized molecular orbitals are determined by new, fast localization methods. The density matrix between the oriented quasi-atomic orbitals as well as the locations of the split-localized orbitals exhibit atomic populations and inter-atomic bonding patterns. A correlation-adapted quasi-atomic basis is determined in the external orbital space. The general formulations are specified in detail for Hartree-Fock wave functions. Applications to specific molecules exemplify the general scheme

Addendum to foundations of multidimensional wave field signal theory: Gaussian source function

Directory of Open Access Journals (Sweden)

Natalie Baddour

2018-02-01

Full Text Available Many important physical phenomena are described by wave or diffusion-wave type equations. Recent work has shown that a transform domain signal description from linear system theory can give meaningful insight to multi-dimensional wave fields. In N. Baddour [AIP Adv. 1, 022120 (2011], certain results were derived that are mathematically useful for the inversion of multi-dimensional Fourier transforms, but more importantly provide useful insight into how source functions are related to the resulting wave field. In this short addendum to that work, it is shown that these results can be applied with a Gaussian source function, which is often useful for modelling various physical phenomena.

Addendum to foundations of multidimensional wave field signal theory: Gaussian source function

Science.gov (United States)

Baddour, Natalie

2018-02-01

Many important physical phenomena are described by wave or diffusion-wave type equations. Recent work has shown that a transform domain signal description from linear system theory can give meaningful insight to multi-dimensional wave fields. In N. Baddour [AIP Adv. 1, 022120 (2011)], certain results were derived that are mathematically useful for the inversion of multi-dimensional Fourier transforms, but more importantly provide useful insight into how source functions are related to the resulting wave field. In this short addendum to that work, it is shown that these results can be applied with a Gaussian source function, which is often useful for modelling various physical phenomena.

Shear wave velocity model beneath CBJI station West Java, Indonesia from joint inversion of teleseismic receiver functions and surface wave dispersion

Science.gov (United States)

Simanungkalit, R. H.; Anggono, T.; Syuhada; Amran, A.; Supriyanto

2018-03-01

Earthquake signal observations around the world allow seismologists to obtain the information of internal structure of the Earth especially the Earth’s crust. In this study, we used joint inversion of receiver functions and surface wave group velocities to investigate crustal structure beneath CBJI station in West Java, Indonesia. Receiver function were calculated from earthquakes with magnitude more than 5 and at distance 30°-90°. Surface wave group velocities were calculated using frequency time analysis from earthquakes at distance of 30°- 40°. We inverted shear wave velocity model beneath the station by conducting joint inversion from receiver functions and surface wave dispersions. We suggest that the crustal thickness beneath CBJI station, West Java, Indonesia is about 35 km.

Shock Wave Propagation in Functionally Graded Mineralized Tissue

Science.gov (United States)

Nelms, Matthew; Hodo, Wayne; Livi, Ken; Browning, Alyssa; Crawford, Bryan; Rajendran, A. M.

2017-06-01

In this investigation, the effects of shock wave propagation in bone-like biomineralized tissue was investigated. The Alligator gar (Atractosteus spatula) exoskeleton is comprised of many disparate scales that provide a biological analog for potential design of flexible protective material systems. The gar scale is identified as a two-phase, (1) hydroxyapatite mineral and (2) collagen protein, biological composite with two distinct layers where a stiff, ceramic-like ganoine overlays a soft, highly ductile ganoid bone. Previous experimentations has shown significant softening under compressive loading and an asymmetrical stress-strain response for analogous mineralized tissues. The structural features, porosity, and elastic modulus were determined from high-resolution scanning electron microscopy, 3D micro-tomography, and dynamic nanoindentation experiments to develop an idealized computational model for FE simulations. The numerical analysis employed Gurson's yield criterion to determine the influence of porosity and pressure on material strength. Functional gradation of elastic moduli and certain structural features, such as the sawtooth interface, are explicitly modeled to study the plate impact shock profile for a full 3-D analysis using ABAQUS finite element software.

The wave function behavior of the open topological string partition function on the conifold

International Nuclear Information System (INIS)

Kashani-Poor, Amir-Kian

2007-01-01

We calculate the topological string partition function to all genus on the conifold, in the presence of branes. We demonstrate that the partition functions for different brane backgrounds (smoothly connected along a quantum corrected moduli space) can be interpreted as the same wave function in different polarizations. This behavior has a natural interpretation in the Chern-Simons target space description of the topological theory. Our detailed analysis however indicates that non-perturbatively, a modification of real Chern-Simons theory is required to capture the correct target space theory of the topological string. We perform our calculations in the framework of a free fermion representation of the open topological string, demonstrating that this framework extends beyond the simple C 3 geometry. The notion of a fermionic brane creation operator arises in this setting, and we study to what extent the wave function properties of the partition function can be extended to this operator

Embedding beyond electrostatics-The role of wave function confinement.

Science.gov (United States)

Nåbo, Lina J; Olsen, Jógvan Magnus Haugaard; Holmgaard List, Nanna; Solanko, Lukasz M; Wüstner, Daniel; Kongsted, Jacob

2016-09-14

We study excited states of cholesterol in solution and show that, in this specific case, solute wave-function confinement is the main effect of the solvent. This is rationalized on the basis of the polarizable density embedding scheme, which in addition to polarizable embedding includes non-electrostatic repulsion that effectively confines the solute wave function to its cavity. We illustrate how the inclusion of non-electrostatic repulsion results in a successful identification of the intense π → π(∗) transition, which was not possible using an embedding method that only includes electrostatics. This underlines the importance of non-electrostatic repulsion in quantum-mechanical embedding-based methods.

A combined wave distribution function and stability analysis of Viking particle and low-frequency wave data

International Nuclear Information System (INIS)

Oscarsson, T.E.; Roennmark, K.G.

1990-01-01

In this paper the authors present an investigation of low-frequency waves observed on auroral field lines below the acceleration region by the Swedish satellite Viking. The measured frequency spectra are peaked at half the local proton gyrofrequency, and the waves are observed in close connection with precipitating electrons. In order to obtain information about the distribution of wave energy in wave vector space, they reconstruct the wave distribution function (WDF) from observed spectral densities. They use a new scheme that allows them to reconstruct simultaneously the WDF over a broad frequency band. The method also makes it possible to take into account available particle observations as well as Doppler shifts caused by the relative motion between the plasma and the satellite. The distribution of energy in wave vector space suggested by the reconstructed WDF is found to be consistent with what is expected from a plasma instability driven by the observed precipitating electrons. Furthermore, by using UV images obtained on Viking, they demonstrate that the wave propagation directions indicated by the reconstructed WDFs are consistent with a simple model of the presumed wave source in the electron precipitation region

Angular momentum projection of cranked PNC wave function

International Nuclear Information System (INIS)

Han Yong

2000-01-01

In studying the properties of nuclear higher-spin states, not only the K-mixture needed to be taken into account, but also the Coriolis interaction (the cranking term) should be introduced. The cranking term breaks the time reversal symmetry, and the projection of the single-particle angular momentum on the intrinsic symmetric axis is no longer a good quantum number. This makes the theoretical calculation somewhat complicated. However, considering some intrinsic symmetry in a nucleus, it is not very difficult to apply the angular momentum projection technique to the PNC wave functions including the cranking components (the cranked PNC wave functions). The fundamental expressions for calculating the nuclear energy spectra and the electromagnetic properties are deduced and evaluated in theory, consequently the feasibility of actualizing the present scheme is made clear

Mantle upwelling beneath Madagascar: evidence from receiver function analysis and shear wave splitting

Science.gov (United States)

Paul, Jonathan D.; Eakin, Caroline M.

2017-07-01

Crustal receiver functions have been calculated from 128 events for two three-component broadband seismomenters located on the south coast (FOMA) and in the central High Plateaux (ABPO) of Madagascar. For each station, crustal thickness and V p / V s ratio were estimated from H- κ plots. Self-consistent receiver functions from a smaller back-azimuthal range were then selected, stacked and inverted to determine shear wave velocity structure as a function of depth. These results were corroborated by guided forward modeling and by Monte Carlo error analysis. The crust is found to be thinner (39 ± 0.7 km) beneath the highland center of Madagascar compared to the coast (44 ± 1.6 km), which is the opposite of what would be expected for crustal isostasy, suggesting that present-day long wavelength topography is maintained, at least in part, dynamically. This inference of dynamic support is corroborated by shear wave splitting analyses at the same stations, which produce an overwhelming majority of null results (>96 %), as expected for vertical mantle flow or asthenospheric upwelling beneath the island. These findings suggest a sub-plate origin for dynamic support.

Fredholm determinant representation of quantum correlation function for Sine-Gordon at special value of coupling constant

International Nuclear Information System (INIS)

Itoyama, H.; Korepin, V.E.; Thacker, H.B.

1992-01-01

In this paper, correlation functions of the Sine-Gordon model (which is equivalent of the Massive-Thirring model) are considered at the free fermion point. The authors derive a determinant formula for local correlation functions of the Sine-Gordon model, starting form Bethe ansatz wave function. Kernel of integral operator is trigonometric version of the one for Impenetrable Bosons

N-representability of the Jastrow wave function pair density of the lowest-order.

Science.gov (United States)

Higuchi, Katsuhiko; Higuchi, Masahiko

2017-08-08

Conditions for the N-representability of the pair density (PD) are needed for the development of the PD functional theory. We derive sufficient conditions for the N-representability of the PD that is calculated from the Jastrow wave function within the lowest order. These conditions are used as the constraints on the correlation function of the Jastrow wave function. A concrete procedure to search the suitable correlation function is also presented.

Third-order non-Coulomb correction to the S-wave quarkonium wave functions at the origin

International Nuclear Information System (INIS)

Beneke, M.; Kiyo, Y.; Schuller, K.

2008-01-01

We compute the third-order correction to the S-wave quarkonium wave functions |ψ n (0)| 2 at the origin from non-Coulomb potentials in the effective non-relativistic Lagrangian. Together with previous results on the Coulomb correction and the ultrasoft correction computed in a companion paper, this completes the third-order calculation up to a few unknown matching coefficients. Numerical estimates of the new correction for bottomonium and toponium are given

Analytical evaluation of integrals over Coulomb wave functions

International Nuclear Information System (INIS)

Nesbet, R.K.

1988-01-01

Indefinite integrals of products of Coulomb wave functions over the interval (r, ∞) can be evaluated by conversion to continued fractions. Examples are given of normalization and dipole transition integrals required in photoionization calculations. (orig.)

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

DEFF Research Database (Denmark)

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

2016-01-01

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

Trial wave functions for a composite Fermi liquid on a torus

Science.gov (United States)

Fremling, M.; Moran, N.; Slingerland, J. K.; Simon, S. H.

2018-01-01

We study the two-dimensional electron gas in a magnetic field at filling fraction ν =1/2 . At this filling the system is in a gapless state which can be interpreted as a Fermi liquid of composite fermions. We construct trial wave functions for the system on a torus, based on this idea, and numerically compare these to exact wave functions for small systems found by exact diagonalization. We find that the trial wave functions give an excellent description of the ground state of the system, as well as its charged excitations, in all momentum sectors. We analyze the dispersion of the composite fermions and the Berry phase associated with dragging a single fermion around the Fermi surface and comment on the implications of our results for the current debate on whether composite fermions are Dirac fermions.

Spectral and partial-wave decomposition of time-dependent wave functions on a grid: Photoelectron spectra of H and H2+ in electromagnetic fields

International Nuclear Information System (INIS)

Nikolopoulos, L. A. A.; Kjeldsen, T. K.; Madsen, L. B.

2007-01-01

We present a method for spectral (bound and continuum) and partial-wave analysis of a three-dimensional time-dependent wave function, defined on a grid, without projecting onto the field-free eigenstates of the system. The method consists of propagating the time-dependent Schroedinger equation to obtain its autocorrelation function C(t)= after the end of the interaction, at time T, of the system with an external time-dependent field. The Fourier spectrum of this correlation function is directly related to the expansion coefficients of the wave function on the field-free bound and continuum energy eigenstates of the system. By expanding on a spherical harmonics basis we show how to calculate the contribution of the various partial waves to the total photoelectron energy spectrum

Delta function excitation of waves in the earth's ionosphere

Science.gov (United States)

Vidmar, R. J.; Crawford, F. W.; Harker, K. J.

1983-01-01

Excitation of the earth's ionosphere by delta function current sheets is considered, and the temporal and spatial evolution of wave packets is analyzed for a two-component collisional F2 layer. Approximations of an inverse Fourier-Laplace transform via saddle point methods provide plots of typical wave packets. These illustrate cold plasma wave theory and may be used as a diagnostic tool since it is possible to relate specific features, e.g., the frequency of a modulation envelope, to plasma parameters such as the electron cyclotron frequency. It is also possible to deduce the propagation path length and orientation of a remote radio beacon.

Symmetry analysis of many-body wave functions, with applications to the nuclear shell model

International Nuclear Information System (INIS)

Novoselsky, A.; Katriel, J.

1995-01-01

The weights of the different permutational symmetry components of a nonsymmetry-adapted many-particle wave function are evaluated in terms of the expectation values of the symmetric-group class sums. This facilitates the evaluation of the weights without the construction of a complete set of symmetry adapted functions. Subspace projection operators are introduced, to be used when prior knowledge about the symmetry-species composition of a wave function is available. The permutational weight analysis of a recursively angular-momentum coupled (shell model) wave function is presented as an illustration

Horizon wave-function and the quantum cosmic censorship

Directory of Open Access Journals (Sweden)

Roberto Casadio

2015-07-01

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

Prospects for determination of thermal history after inflation with future gravitational wave detectors

International Nuclear Information System (INIS)

Kuroyanagi, Sachiko; Nakayama, Kazunori; Saito, Shun

2011-01-01

Thermal history of the Universe between inflation and big-bang nucleosynthesis has not yet been revealed observationally. It will be probed by the detection of primordial gravitational waves generated during inflation, which contain information on the reheating temperature as well as the equation of state of the Universe after inflation. Based on the Fisher information formalism, we examine how accurately the tensor-to-scalar ratio and reheating temperature after inflation can be simultaneously determined with space-based gravitational wave detectors such as the DECI-hertz Interferometer Gravitational-wave Observatory and the Big-Bang Observer. We show that the reheating temperature is best determined if it is around 10 7 GeV for tensor-to-scalar ratio of around 0.1, and explore the detectable parameter space. We also find that equation of state of the early Universe can be also determined accurately enough to distinguish different equation-of-state parameters if the inflationary gravitational waves are successfully detected. Thus, future gravitational wave detectors provide a unique and promising opportunity to reveal the thermal history of the Universe around 10 7 GeV.

Exact Time-Dependent Wave Functions of a Confined Time-Dependent Harmonic Oscillator with Two Moving Boundaries

International Nuclear Information System (INIS)

Lo, C.F.

2009-01-01

By applying the standard analytical techniques of solving partial differential equations, we have obtained the exact solution in terms of the Fourier sine series to the time-dependent Schroedinger equation describing a quantum one-dimensional harmonic oscillator of time-dependent frequency confined in an infinite square well with the two walls moving along some parametric trajectories. Based upon the orthonormal basis of quasi-stationary wave functions, the exact propagator of the system has also been analytically derived. Special cases like (i) a confined free particle, (ii) a confined time-independent harmonic oscillator, and (iii) an aging oscillator are examined, and the corresponding time-dependent wave functions are explicitly determined. Besides, the approach has been extended to solve the case of a confined generalized time-dependent harmonic oscillator for some parametric moving boundaries as well. (general)

Effect of single-particle splitting in the exact wave function of the isovectorial pairing Hamiltonian

International Nuclear Information System (INIS)

Lerma H, S.

2010-01-01

The structure of the exact wave function of the isovectorial pairing Hamiltonian with nondegenerate single-particle levels is discussed. The way that the single-particle splittings break the quartet condensate solution found for N=Z nuclei in a single degenerate level is established. After a brief review of the exact solution, the structure of the wave function is analyzed and some particular cases are considered where a clear interpretation of the wave function emerges. An expression for the exact wave function in terms of the isospin triplet of pair creators is given. The ground-state wave function is analyzed as a function of pairing strength, for a system of four protons and four neutrons. For small and large values of the pairing strength a dominance of two-pair (quartets) scalar couplings is found, whereas for intermediate values enhancements of the nonscalar couplings are obtained. A correlation of these enhancements with the creation of Cooper-like pairs is observed.

On the asymptotic evolution of finite energy Airy wave functions.

Science.gov (United States)

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

2015-06-15

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

Probing α-particle wave functions using (rvec d,α) reactions

International Nuclear Information System (INIS)

Crosson, E.R.; Lemieux, S.K.; Ludwig, E.J.; Thompson, W.J.; Bisenberger, M.; Hertenberger, R.; Hofer, D.; Kader, H.; Schiemenz, P.; Graw, G.; Eiro, A.M.; Santos, F.D.

1993-01-01

Wave functions of the α particle corresponding to different S- and D-state deuteron-deuteron overlaps, left-angle dd|α right-angle, were investigated using exact finite-range distorted-wave Born-approximation (DWBA) analyses of (rvec d,α) reactions. Cross sections, vector, and tensor-analyzing powers were measured for (rvec d,α) reactions populating the lowest J π =7 + state in 56 Co at bombarding energies E d of 16 and 22 MeV, the lowest 7 + state in 48 Sc at E d =16 MeV, and the lowest 7 + state in 46 Sc at E d =22 MeV. We find that DWBA analyses of tensor-analyzing powers produce satisfactory agreement with the data and that A xx is especially sensitive to the D-state component of α-particle wave functions generated by different realistic nucleon-nucleon interactions

Calculating scattering matrices by wave function matching

International Nuclear Information System (INIS)

Zwierzycki, M.; Khomyakov, P.A.; Starikov, A.A.; Talanana, M.; Xu, P.X.; Karpan, V.M.; Marushchenko, I.; Brocks, G.; Kelly, P.J.; Xia, K.; Turek, I.; Bauer, G.E.W.

2008-01-01

The conductance of nanoscale structures can be conveniently related to their scattering properties expressed in terms of transmission and reflection coefficients. Wave function matching (WFM) is a transparent technique for calculating transmission and reflection matrices for any Hamiltonian that can be represented in tight-binding form. A first-principles Kohn-Sham Hamiltonian represented on a localized orbital basis or on a real space grid has such a form. WFM is based upon direct matching of the scattering-region wave function to the Bloch modes of ideal leads used to probe the scattering region. The purpose of this paper is to give a pedagogical introduction to WFM and present some illustrative examples of its use in practice. We briefly discuss WFM for calculating the conductance of atomic wires, using a real space grid implementation. A tight-binding muffin-tin orbital implementation very suitable for studying spin-dependent transport in layered magnetic materials is illustrated by looking at spin-dependent transmission through ideal and disordered interfaces. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Quasiparticle Green's function theory of the Josephson effect in chiral p-wave superconductor/diffusive normal metal/chiral p-wave superconductor junctions

NARCIS (Netherlands)

Sawa, Y.; Yokoyama, T.; Tanaka, Y.; Golubov, Alexandre Avraamovitch

2007-01-01

We study the Josephson effect in chiral p-wave superconductor/diffusive normal metal (DN)/chiral p-wave superconductor (CP/DN/CP) junctions using quasiclassical Green's function formalism with proper boundary conditions. The px+ipy-wave symmetry of superconducting order parameter is chosen which is

Projected potential profiles across interfaces obtained by reconstructing the exit face wave function from through focal series

International Nuclear Information System (INIS)

Bhattacharyya, Somnath; Koch, Christoph T.; Ruehle, Manfred

2006-01-01

An iterative method for reconstructing the exit face wave function from a through focal series of transmission electron microscopy image line profiles across an interface is presented. Apart from high-resolution images recorded with small changes in defocus, this method works also well for a large defocus range as used for Fresnel imaging. Using the phase-object approximation the projected electrostatic as well as the absorptive potential profiles across an interface are determined from this exit face wave function. A new experimental image alignment procedure was developed in order to align images with large relative defocus shift. The performance of this procedure is shown to be superior to other image alignment procedures existing in the literature. The reconstruction method is applied to both simulated and experimental images

Double-continuum wave functions and double-photoionization cross sections of two-electron systems

International Nuclear Information System (INIS)

Tiwary, S.N.

1996-09-01

The present review briefly presents the growing experimental as well as theoretical interests in recent years in the double-continuum wave functions and double-photoionization cross sections of two-electron systems. The validity of existing double-continuum wave functions is analyzed and the importance of electronic correlations in both the initial as well as final states wave functions involved in the transition amplitude for double-photoionization process is demonstrated. At present, we do not have comprehensive and practical double-continuum wave functions which account the full correlation of two-electron in the continuum. Basic difficulties in making accurate theoretical calculations of double ionization by a single high energy photon especially in the vicinity of the threshold, where the correlation plays an important role, are discussed. Illuminating, illustrative and representative examples are presented in order to show the present status and the progress in this field. Future challenges and directions, in high-precision double-photoionization cross sections calculations, have been discussed and suggested. (author). 133 refs, 9 figs

On propagation of axisymmetric waves in pressurized functionally graded elastomeric hollow cylinders

Science.gov (United States)

Wu, Bin; Su, Yipin; Liu, Dongying; Chen, Weiqiu; Zhang, Chuanzeng

2018-05-01

Soft materials can be designed with a functionally graded (FG) property for specific applications. Such material inhomogeneity can also be found in many soft biological tissues whose functionality is only partly understood to date. In this paper, we analyze the axisymmetric guided wave propagation in a pressurized FG elastomeric hollow cylinder. The cylinder is subjected to a combined action of axial pre-stretch and pressure difference applied to the inner and outer cylindrical surfaces. We consider both torsional waves and longitudinal waves propagating in the FG cylinder made of incompressible isotropic elastomer, which is characterized by the Mooney-Rivlin strain energy function but with the material parameters varying with the radial coordinate in an affine way. The pressure difference generates an inhomogeneous deformation field in the FG cylinder, which dramatically complicates the superimposed wave problem described by the small-on-large theory. A particularly efficient approach is hence employed which combines the state-space formalism for the incremental wave motion with the approximate laminate or multi-layer technique. Dispersion relations for the two types of axisymmetric guided waves are then derived analytically. The accuracy and convergence of the proposed approach is validated numerically. The effects of the pressure difference, material gradient, and axial pre-stretch on both the torsional and the longitudinal wave propagation characteristics are discussed in detail through numerical examples. It is found that the frequency of axisymmetric waves depends nonlinearly on the pressure difference and the material gradient, and an increase in the material gradient enhances the capability of the pressure difference to adjust the wave behavior in the FG cylinder. This work provides a theoretical guidance for characterizing FG soft materials by in-situ ultrasonic nondestructive evaluation and for designing tunable waveguides via material tailoring along

Geometrical Determinants of Neuronal Actin Waves.

Science.gov (United States)

Tomba, Caterina; Braïni, Céline; Bugnicourt, Ghislain; Cohen, Floriane; Friedrich, Benjamin M; Gov, Nir S; Villard, Catherine

2017-01-01

Hippocampal neurons produce in their early stages of growth propagative, actin-rich dynamical structures called actin waves. The directional motion of actin waves from the soma to the tip of neuronal extensions has been associated with net forward growth, and ultimately with the specification of neurites into axon and dendrites. Here, geometrical cues are used to control actin wave dynamics by constraining neurons on adhesive stripes of various widths. A key observable, the average time between the production of consecutive actin waves, or mean inter-wave interval (IWI), was identified. It scales with the neurite width, and more precisely with the width of the proximal segment close to the soma. In addition, the IWI is independent of the total number of neurites. These two results suggest a mechanistic model of actin wave production, by which the material conveyed by actin waves is assembled in the soma until it reaches the threshold leading to the initiation and propagation of a new actin wave. Based on these observations, we formulate a predictive theoretical description of actin wave-driven neuronal growth and polarization, which consistently accounts for different sets of experiments.

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

Energy Technology Data Exchange (ETDEWEB)

Franz Gross, Alfred Stadler

2010-09-01

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

Nodal structure and phase shifts of zero-incident-energy wave functions: Multiparticle single-channel scattering

International Nuclear Information System (INIS)

Iwinski, Z.R.; Rosenberg, L.; Spruch, L.

1986-01-01

For potential scattering, with delta/sub L/(k) the phase shift modulo π for an incident wave number k, Levinson's theorem gives delta/sub L/(0)-delta/sub L/(infinity) in terms of N/sub L/, the number of bound states of angular momentum L, for delta/sub L/(k) assumed to be a continuous function of k. N/sub L/ also determines the number of nodes of the zero-energy wave function u/sub L/(r). A knowledge of the nodal structure and of the absolute value of delta/sub L/(0) is very useful in theoretical studies of low-energy potential scattering. Two preliminary attempts, one formal and one ''physical,'' are made to extend the above results to single-channel scattering by a compound system initially in its ground state. The nodal structure will be of greater interest to us here than an extension of Levinson's theorem

Two-body Schrödinger wave functions in a plane-wave basis via separation of dimensions

Science.gov (United States)

Jerke, Jonathan; Poirier, Bill

2018-03-01

Using a combination of ideas, the ground and several excited electronic states of the helium atom and the hydrogen molecule are computed to chemical accuracy—i.e., to within 1-2 mhartree or better. The basic strategy is very different from the standard electronic structure approach in that the full two-electron six-dimensional (6D) problem is tackled directly, rather than starting from a single-electron Hartree-Fock approximation. Electron correlation is thus treated exactly, even though computational requirements remain modest. The method also allows for exact wave functions to be computed, as well as energy levels. From the full-dimensional 6D wave functions computed here, radial distribution functions and radial correlation functions are extracted—as well as a 2D probability density function exhibiting antisymmetry for a single Cartesian component. These calculations support a more recent interpretation of Hund's rule, which states that the lower energy of the higher spin-multiplicity states is actually due to reduced screening, rather than reduced electron-electron repulsion. Prospects for larger systems and/or electron dynamics applications appear promising.

Wave resistance calculation method combining Green functions based on Rankine and Kelvin source

Directory of Open Access Journals (Sweden)

LI Jingyu

2017-12-01

Full Text Available [Ojectives] At present, the Boundary Element Method(BEM of wave-making resistance mostly uses a model in which the velocity distribution near the hull is solved first, and the pressure integral is then calculated using the Bernoulli equation. However,the process of this model of wave-making resistance is complex and has low accuracy.[Methods] To address this problem, the present paper deduces a compound method for the quick calculation of ship wave resistance using the Rankine source Green function to solve the hull surface's source density, and combining the Lagally theorem concerning source point force calculation based on the Kelvin source Green function so as to solve the wave resistance. A case for the Wigley model is given.[Results] The results show that in contrast to the thin ship method of the linear wave resistance theorem, this method has higher precision, and in contrast to the method which completely uses the Kelvin source Green function, this method has better computational efficiency.[Conclusions] In general, the algorithm in this paper provides a compromise between precision and efficiency in wave-making resistance calculation.

Determination of surface tension coefficient of liquids by diffraction of light on capillary waves

International Nuclear Information System (INIS)

Nikolić, D; Nešić, Lj

2012-01-01

This paper describes a simple technique for determining the coefficient of the surface tension of liquids, based on laser light diffraction on capillary waves. Capillary waves of given frequency are created by an exciter needle acting on the surface of liquid and represent a reflective diffraction grating, the constant of which (the wavelength of capillary waves) can be determined based on a known incidence angle of light (grazing angle). We obtain the coefficient of the surface tension of liquids by applying the dispersion relation for capillary waves and analyze the difficulties that arise when setting up and conducting the experiment in detail. (paper)

Meson wave functions in 2-dim QCD

International Nuclear Information System (INIS)

Hildebrandt, S.; Visnjic, V.

1977-07-01

We consider the eigenvalue problem of 't Hooft for the meson spectrum in 2-dim QCD by defining some alternative formulations whose equivalence we prove. Hence we are able to prove that the spectrum is discrete and of finite multiplicity and to derive bounds (upper and lower) for the eigenvalues (ground state, with state and n → infinitely state). We prove that the functions are analytic and use this to carry out explicit numerical calculations of the wave functions for various values of the quark masses and to recalculate the meson spectrum. (orig.) [de

Influence of wetting layer wave functions on carrier capture in quantum dots

DEFF Research Database (Denmark)

Markussen, Troels; Kristensen, Philip; Tromborg, Bjarne

2005-01-01

This work numerically solves the effective mass Schrodinger equation and shows that the capture times are strongly influenced by details of the continuum states not accounted for by the approximate wave functions. Results show that calculations of capture time for phonon mediated carrier capture...... from a wetting layer into a quantum dot depend critically on the approximations used for the wetting layer wave functions....

Determination of wave direction using an orbital following buoy

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, A.A.; Almeida, A.M.; Vaithiyanathan, R.; Vethamony, P.

Software has been developed in FORTRAN language using a personal computer for the determination of wave direction from time series measurements of heave, pitch and roll of an orbital following buoy. The method of digital band pass filtering describ...

Application of the generalized multi structural (GMS) wave function to photoelectron spectra and electron scattering processes

International Nuclear Information System (INIS)

Nascimento, M.A.C. do

1992-01-01

A Generalized Multi Structural (GMS) wave function is presented which combines the advantages of the SCF-MO and VB models, preserving the classical chemical structures but optimizing the orbitals in a self-consistent way. This wave function is particularly suitable to treat situations where the description of the molecular state requires localized wave functions. It also provides a very convenient way of treating the electron correlation problem, avoiding large CI expansions. The final wave functions are much more compact and easier to interpret than the ones obtained by the conventional methods, using orthogonal orbitals. Applications of the GMS wave function to the study of the photoelectron spectra of the trans-glyoxal molecule and to electron impact excitation processes in the nitrogen molecule are presented as an illustration of the method. (author)

Electronic structure and correlated wave functions of a few electron quantum dots

Energy Technology Data Exchange (ETDEWEB)

Sako, Tokuei [Laboratory of Physics, College of Science and Technology, Nihon University, 7-24-1 Narashinodai, Funabashi, Chiba 274-8501 (Japan); Ishida, Hiroshi [College of Humanities and Sciences, Nihon University, Tokyo 156-8550 (Japan); Fujikawa, Kazuo [Institute of Quantum Science, College of Science and Technology, Nihon University, Chiyoda-ku, Tokyo 101-8308 (Japan)

2015-01-22

The energy spectra and wave functions of a few electrons confined by a quasi-one-dimensional harmonic and anharmonic potentials have been studied by using a full configuration interaction method employing a Cartesian anisotropic Gaussian basis set. The energy spectra are classified into three regimes of the strength of confinement, namely, large, medium and small. The polyad quantum number defined by a total number of nodes in the wave functions is shown to be a key ingredient to interpret the energy spectra for the whole range of the confinement strength. The nodal pattern of the wave functions exhibits normal modes for the harmonic confining potential, indicating collective motions of electrons. These normal modes are shown to undergo a transition to local modes for an anharmonic potential with large anharmonicity.

Some Remarks on the Accuracy of Wave Resistance Determination From Wave Measurements along a Parallel Cut

OpenAIRE

Moriconi, Alessandro; Lalli, Francesco; Di Felice, Fabio; Esposito, Pier Giorgio; Piscopia, Rodolfo

1998-01-01

In the present work some of the main error sources in the wave pattern resistance determination were investigated. The experimental data obtained at the Italian Ship Model Basin (longitudinal wave profiles generated by the steady motion of the Series 60 model and a hard chine Catamaran) were analyzed. It was found that, within the range of Froude numbers tested (.225 ≤ Fr ≤ .345 for the Series 60 and .5 ≤ Fr ≤ 1 for the Catamaran) two sources of uncertainty play a sign...

Quantitative determination of glycyrrhizinic acid by square-wave

Directory of Open Access Journals (Sweden)

Aneta Dimitrovska

2003-06-01

Full Text Available Novel adsorptive stripping square-wave voltammetric method as well as a new high-pressure liquid chromatographic method for direct determination of glycyrrhizinic acid in dosage pharmaceutical preparation, used against virus infections, have been developed. Glycyrrhizinic acid is an electrochemically active compound, which undergoes irreversible reduction on a mercury electrode surface in an aqueous medium. Its redox properties were studied thoroughly by means of square-wave voltammetry, as one of the most advanced electroanalytical technique. The voltammetric response depends mainly on the pH of the medium, composition of the supporting electrolyte, as well as the parameters of the excitement signal. It was also observed that the voltammetric properties strongly depend on the accumulation time and potential, revealing significant adsorption of glycyrrhizinic acid onto the mercury electrode surface. Upon this feature, an adsorptive stripping voltammetric method for quantitative determination of glycyrrhizinic acid was developed. A simple, sensitive and precise reversed phase HPLC method with photodiode array UV detection has also been developed, mainly for comparison and conformation of the results obtained with the voltammetric method.

The puzzling entanglement of Schroedinger's wave function

International Nuclear Information System (INIS)

Ghirardi, G.C.; Rimini, A.; Weber, T.

1987-05-01

A brief review of the conceptual difficulties met by the quantum formalism is presented. The main attempts to overcome these difficulties are considered and their limitations are pointed out. A recent proposal based on the assumption of the occurrence of a specific type of wave function collapse is discussed and its consequences for the above-mentioned problems are analyzed. (author). 28 refs

Asymptotic form of three-body (dtμ)+ and (ddμ)+ wave functions

International Nuclear Information System (INIS)

Kino, Y.; Shimamura, I.; Armour, E.A.G.; Kamimura, M.

1996-01-01

In order to investigate a discrepancy between existing literature values for the normalization constant in the asymptotic form of three-body wave functions for (DTμ) + , we report the results of a new calculation of the normalization constants for this system as well as the related system (DDμ) + . These were obtained by fitting to accurate variational wave functions with special care being taken to describe the long-range behavior. (orig.)

Direct Determination of Wavenumbers of ULF Waves Using the Cluster Multipoint and Multicomponent Measurements

Science.gov (United States)

Grison, B.; Escoubet, C.; Santolik, O.; Cornilleau-Wehrlin, N.

2013-12-01

The wavenumber is a key parameter to understand the physics of the interactions between the electromagnetic waves and the ionized particles in space plasmas. Search-coil magnetometers and electric antennas measure time series of both magnetic and electric field fluctuations, respectively. The fleet of four Cluster spacecraft made possible to determine the full wave vector and even to differentiate the waves present at the same frequency in the spacecraft frame through various techniques: k-filtering analysis, wave telescope, phase differentiating method. However the fleet configuration (inter-spacecraft separation, tetrahedron elongation and planarity) limit the possibilities to use these techniques. From single spacecraft measurements, assumptions concerning the wave mode -and thus, concerning the physical processes- are usually required to derive the corresponding wavenumber. Using three orthogonal magnetic components and two electric antennas, it is possible to estimate n/Z where n is the refractive index and Z the transfer function of the interface between the plasma and the electric antennas. For ULF waves we assume Z=1 and we thus obtain the wavenumber. We test this hypothesis on a case where the spacecraft are in a close configuration in the distant cusp region and where we are able to apply the k-filtering analysis, too. The results obtained by multispacecraft and multicomponents analysis are close to each other and permit us to precise the value of Z. We test this procedure on several events (in various regions of the magnetosphere) in order to get more precise wave number measurements from the single spacecraft analysis. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7-SPACE-2010-1) under grant agreement n. 284520 (MAARBLE).

Determining the speed of sound in the air by sound wave interference

Science.gov (United States)

Silva, Abel A.

2017-07-01

Mechanical waves propagate through material media. Sound is an example of a mechanical wave. In fluids like air, sound waves propagate through successive longitudinal perturbations of compression and decompression. Audible sound frequencies for human ears range from 20 to 20 000 Hz. In this study, the speed of sound v in the air is determined using the identification of maxima of interference from two synchronous waves at frequency f. The values of v were correct to 0 °C. The experimental average value of {\\bar{ν }}\\exp =336 +/- 4 {{m}} {{{s}}}-1 was found. It is 1.5% larger than the reference value. The standard deviation of 4 m s-1 (1.2% of {\\bar{ν }}\\exp ) is an improved value by the use of the concept of the central limit theorem. The proposed procedure to determine the speed of sound in the air aims to be an academic activity for physics classes of scientific and technological courses in college.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Science.gov (United States)

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

2016-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Hégely, Bence; Nagy, Péter R.; Kállay, Mihály, E-mail: kallay@mail.bme.hu [MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest (Hungary); Ferenczy, György G. [Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, H-1117 Budapest (Hungary); Department of Biophysics and Radiation Biology, Semmelweis University, Tűzoltó u. 37-47, H-1094 Budapest (Hungary)

2016-08-14

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

Determination of wave direction from linear and polygonal arrays

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, A.A; Gouveia, A; Nagarajan, R.

documentation of Borgman (1974) in case of linear arrays; and the second issue being the failure of Esteva (1976, 1977) to correctly determine wave directions over the design range 25 to 7 sec of his polygonal array. This paper presents requisite documentation...

Rayleigh wave behavior in functionally graded magneto-electro-elastic material

Science.gov (United States)

Ezzin, Hamdi; Mkaoir, Mohamed; Amor, Morched Ben

2017-12-01

Piezoelectric-piezomagnetic functionally graded materials, with a gradual change of the mechanical and electromagnetic properties have greatly applying promises. Based on the ordinary differential equation and stiffness matrix methods, a dynamic solution is presented for the propagation of the wave on a semi-infinite piezomagnetic substrate covered with a functionally graded piezoelectric material (FGPM) layer. The materials properties are assumed to vary in the direction of the thickness according to a known variation law. The phase and group velocity of the Rayleigh wave is numerically calculated for the magneto-electrically open and short cases, respectively. The effect of gradient coefficients on the phase velocity, group velocity, coupled magneto-electromechanical factor, on the stress fields, the magnetic potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the hetero-structure PZT-5A/CoFe2O4; the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Rayleigh wave propagation behavior.

Investigation of Ion Acoustic Waves in Collisionless Plasmas

DEFF Research Database (Denmark)

Christoffersen, G. B.; Jensen, Vagn Orla; Michelsen, Poul

1974-01-01

The Green's functions for the linearized ion Vlasov equation with a given boundary value are derived. The propagation properties of ion acoustic waves are calculated by performing convolution integrals over the Green's functions. For Te/Ti less than about 3 it is concluded that the collective...... interaction is very weak and that the propagation properties are determined almost completely by freely streaming ions. The wave damping, being due to phase mixing, is determined by the width of the perturbed distribution function rather than by the slope of the undisturbed distribution function at the phase...

Watt-Level Continuous-Wave Emission from a Bi-Functional Quantum Cascade Laser/Detector

Science.gov (United States)

2017-04-18

cally authorized by the U.S. Government may violate any copyrights that exist in this work. Watt-level continuous- wave emission from a bi- functional ... wave bi- functional devices, opens the perspective of on-chip dual comb spectroscopy. Also for discrete sens- ing setups, one can switch to lasers...seas.harvard.edu Abstract Bi- functional active regions, capable of light generation and detection at the same wavelength, allow a straightforward realization of

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

Science.gov (United States)

Wu, Hau-Tieng; Wu, Han-Kuei; Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang; Tsai, Tung-Hu; Chang, Hen-Hong

2016-01-01

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

Overlap integrals of model wave functions of 4He and 3He,3H nuclei

International Nuclear Information System (INIS)

Voloshin, N.I.; Levshin, E.B.; Fursa, A.D.

1990-01-01

Overlap integrals of wave functions 4 He nucleus and 3 He and 3 H nuclei are calculated. Two types of model wave functions are used to describe the structure of nuclei. The wace function is taken as a product of the one-particle Gaussian functions of the Gaussian type in the second case

Strong Measurements Give a Better Direct Measurement of the Quantum Wave Function.

Science.gov (United States)

Vallone, Giuseppe; Dequal, Daniele

2016-01-29

Weak measurements have thus far been considered instrumental in the so-called direct measurement of the quantum wave function [4J. S. Lundeen, Nature (London) 474, 188 (2011).]. Here we show that a direct measurement of the wave function can be obtained by using measurements of arbitrary strength. In particular, in the case of strong measurements, i.e., those in which the coupling between the system and the measuring apparatus is maximum, we compared the precision and the accuracy of the two methods, by showing that strong measurements outperform weak measurements in both for arbitrary quantum states in most cases. We also give the exact expression of the difference between the original and reconstructed wave function obtained by the weak measurement approach; this will allow one to define the range of applicability of such a method.

Experimental study on p-wave neutron strength functions for light nuclei

International Nuclear Information System (INIS)

Koester, L.; Waschkowski, W.; Meier, J.; Rau, G.; Salehi, M.

1988-01-01

Broad energy distributions in fast neutron beams have been achieved by appropriate filtering of the 236 U fission radiation provided from the RENT converter facility at the FRM research reactor. Transmission measurements in such beams result in average cross sections to which resonance reactions and shape elastic scattering contribute. We used a silicon (124.5 cm) filtered beam with a median energy of 143 keV (width 20 keV) and beams with 1.3 MeV (0.55 to 3 MeV) and 2.1 MeV (1 to 5.5 MeV) obtained through different filter combinations of lead and polyethylene. The relative high energies and the broad spectra made it possible to determine experimentally the contributions of s- and p-wave resonance reactions to the average cross section even for light nuclei. Using the three different beams we determined the average cross sections for the elements in the mass region A = 9 to 65. Analysing the measured cross sections by means of the R matrix formalism provided a complete set of p-wave strength functions and distant level parameters. Moreover, single particle shell effects in the cross sections were observed. In conclusion we obtained information on the 2P and the 3S size resonances and about the validity of the optical model for neutron reactions with light nuclei. (orig.)

Genetic determinants of P wave duration and PR segment

NARCIS (Netherlands)

Verweij, Niek; Mateo Leach, Irene; van den Boogaard, Malou; van Veldhuisen, Dirk J.; Christoffels, Vincent M.; Hillege, Hans L.; van Gilst, Wiek H.; Barnett, Phil; de Boer, Rudolf A.; van der Harst, Pim

2014-01-01

The PR interval on the ECG reflects atrial depolarization and atrioventricular nodal delay which can be partially differentiated by P wave duration and PR segment, respectively. Genome-wide association studies have identified several genetic loci for PR interval, but it remains to be determined

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

Science.gov (United States)

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

1980-01-01

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

Coordinate asymptotics of the (3→3) wave functions for a three charged particle system

International Nuclear Information System (INIS)

Merkur'ev, S.P.

1977-01-01

Coordinate asymptotics of the (3 → 3) wave functions for three particles system with Coulomb interaction in the scattering problem is plotted. (3 → 3) and (3 → 2) process cases are considered, when the particles are not connected at the initial state. For coordinate asymptotics plotting the basis functions are used which meet Schroedinger equation in the eikonal approximation. The wave functions coordinate asymptotics plotting method is described far from special directions. Wave function asymptotical form is studied in the range of special directions and (3 → 3) scattering amplitude singularities are described. All data are given in accordance with the system with 2 charged particles only. The model in question is of special interest because of the described ppn system the studying of which is of great importance in nuclear physics. Final formulae are discussed for the most general case of three charged particles. Boundary problems for Schroedinger equation are shown to give the only way of definition for the (3 → 3) wave functions. It is pointed out that in special directions wave function coordinate asymptotics is presented with accuracy that gives the possibility to set such a boundary problem

P-wave dispersion: relationship to left ventricular function in sickle cell anaemia.

Science.gov (United States)

Oguanobi, N I; Onwubere, B J; Ike, S O; Anisiuba, B C; Ejim, E C; Ibegbulam, O G

2011-01-01

The prognostic implications of P-wave dispersion in patients with a variety of cardiac disease conditions are increasingly being recognised. The relationship between P-wave dispersion and left ventricular function in sickle cell anaemia is unknown. This study was aimed at evaluating the relationship between P-wave dispersion and left ventricular function in adult Nigerian sickle cell anaemia patients. Between February and August 2007, a total of 62 sickle cell anaemia patients (aged 18-44 years; mean 28.27 ± 5.58) enrolled in the study. These were drawn from patients attending the adult sickle cell clinic of the University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu. An equal number of age- and gender-matched normal subjects served as controls. All the participants were evaluated with electrocardiography and echocardiography. P-wave dispersion was defined as the difference between the maximum and minimum P-wave duration measured in a 12-lead electrocardiogram. P-wave duration and P-wave dispersion were significantly higher in patients than in controls. Significant correlation was demonstrated between P-wave dispersion and age in the patients (r = 0.387; p = 0.031). A comparison of subsets of sickle cell anaemia patients and controls with comparable haematocrit values (30-35%) showed significantly higher P-wave duration and P-wave dispersion in the patients than in the controls. The P-wave duration in patients and controls, respectively, was 111.10 ± 14.53 ms and 89.14 ± 16.45 ms (t = 3.141; p = 0.006). P-wave dispersion was 64.44 ± 15.86 ms in the patients and 36.43 ± 10.35 ms in the controls (t = 2.752; p = 0.013). Significant negative correlation was found between P-wave dispersion and left ventricular transmitral E/A ratio (r = -0.289; p = 0.023). These findings suggest that P-wave dispersion could be useful in the evaluation of sickle cell patients with left ventricular diastolic dysfunction. Further prospective studies are recommended to evaluate

Cranked cluster wave function for molecular states

International Nuclear Information System (INIS)

Horiuchi, Hisashi; Yabana, Kazuhiro; Wada, Takahiro.

1986-01-01

Construction of the cranked cluster wave function is discussed by focussing on three problems; the self-consistency between the potential and the density distribution, the properties of the rotational angular frequency which is strongly influenced by the inter-cluster Pauli principle and by the parity projection, and the spin alignment along the rotation axis with the resulting structure-change of the molecular state. (author)

Phase function of a spherical particle when scattering an inhomogeneous electromagnetic plane wave

DEFF Research Database (Denmark)

Frisvad, Jeppe Revall

2018-01-01

of the complex hypergeometric function 2F1 for every term of a series expansion. In this work, I develop a simpler solution based on associated Legendre functions with argument zero. It is similar to the solution for homogeneous plane waves but with new explicit expressions for the angular dependency of the far......In absorbing media, electromagnetic plane waves are most often inhomogeneous. Existing solutions for the scattering of an inhomogeneous plane wave by a spherical particle provide no explicit expressions for the scattering components. In addition, current analytical solutions require evaluation......-field scattering components, that is, the phase function. I include recurrence formulae for practical evaluation and provide numerical examples to evaluate how well the new expressions match previous work in some limiting cases. The predicted difference in the scattering phase function due to inhomogeneity...

Wave Intensity Analysis of Right Ventricular Function during Pulsed Operation of Rotary Left Ventricular Assist Devices.

Science.gov (United States)

Bouwmeester, J Christopher; Park, Jiheum; Valdovinos, John; Bonde, Pramod

2018-05-29

Changing the speed of left ventricular assist devices (LVADs) cyclically may be useful to restore aortic pulsatility; however, the effects of this pulsation on right ventricular (RV) function are unknown. This study investigates the effects of direct ventricular interaction by quantifying the amount of wave energy created by RV contraction when axial and centrifugal LVADs are used to assist the left ventricle. In 4 anesthetized pigs, pressure and flow were measured in the main pulmonary artery and wave intensity analysis was used to identify and quantify the energy of waves created by the RV. The axial pump depressed the intensity of waves created by RV contraction compared with the centrifugal pump. In both pump designs, there were only minor and variable differences between the continuous and pulsed operation on RV function. The axial pump causes the RV to contract with less energy compared with a centrifugal design. Diminishing the ability of the RV to produce less energy translates to less pressure and flow produced, which may lead to LVAD-induced RV failure. The effects of pulsed LVAD operation on the RV appear to be minimal during acute observation of healthy hearts. Further study is necessary to uncover the effects of other modes of speed modulation with healthy and unhealthy hearts to determine if pulsed operation will benefit patients by reducing LVAD complications.

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

CERN Document Server

Gao, Shan

2017-01-01

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

Wave function analysis of type-II self-assembled quantum dot structures using magneto-optics

International Nuclear Information System (INIS)

Godoy, Marcio Peron Franco de; Nakaema, Marcelo K.K.; Gomes, Paulo F.; Iikawa, Fernando; Brasil, Maria Jose S.P.; Bortoleto, Jose Roberto R.; Cotta, Monica A.; Ribeiro, Evaldo; Medeiros-Ribeiro, Gilberto; Marques, Gilmar E.; Bittencourt, A.C.R.

2004-01-01

Full text: Recently, self-assembled quantum dots have attracted considerable attention for their potential for device applications. Type II interface, in particular, present interesting properties due to the space separation of the carriers. One of the carriers is confined at the lower band gap layer and the other remains at the barrier layers and is only localized by the Coulomb attraction. An essential information for using type II quantum wells and quantum dots on technological applications is the localization of the carrier wave function, which is an experimentally difficult parameter to be measured. Some techniques have been proposed to map the wave functions in quantum dots such as magneto-tunneling spectroscopy and near- field scanning optical microscopy. These techniques involve however a very complex experimental apparatus and sample processing. The magneto-exciton transition can be used as an alternative tool to investigate the exciton wave function distribution, since this distribution has a strong influence on the diamagnetic shift and Zeeman splitting. In this work, we present magneto-optical studies of In P/GaAs type II self-assembled quantum dots, where the electron is strongly confined at the In P, while the hole is weakly localized at the GaAs barrier due to the Coulombic attraction from the electrons. This scenery is very distinct from type I systems. The weaker hole confinement should alter the valence band mixing resulting in a different valence band contribution on the Zeeman splitting as compared to type I systems. Based on the results of the magneto-exciton emission from the wetting layer and from the individual dots, we obtained interesting results concerning the wave function distribution in our system. We discuss the localization of the hole wave function along the growth direction based on the measured Zeeman splitting and the in-plane wave function distribution, based on the observed diamagnetic shift. A remarkable result is that the

Description of the nucleon wave function as a sum of well-chosen Gaussian functions

International Nuclear Information System (INIS)

Roux, C.; Silvestre-Brac, B.

1995-01-01

We study in detail the possibility of describing the nucleon (three quark-system) wave function as a superposition of Gaussian functions. A Faddeev treatment including 8 amplitudes is performed and taken as reference for the exact values. Several approximations are proposed and compared carefully to the exact solutions. Three different potentials have been tested and several observables are considered. (author)

Fourier Transform Ultrasound Spectroscopy for the determination of wave propagation parameters.

Science.gov (United States)

Pal, Barnana

2017-01-01

The reported results for ultrasonic wave attenuation constant (α) in pure water show noticeable inconsistency in magnitude. A "Propagating-Wave" model analysis of the most popular pulse-echo technique indicates that this is a consequence of the inherent wave propagation characteristics in a bounded medium. In the present work Fourier Transform Ultrasound Spectroscopy (FTUS) is adopted to determine ultrasonic wave propagation parameters, the wave number (k) and attenuation constant (α) at 1MHz frequency in tri-distilled water at room temperature (25°C). Pulse-echo signals obtained under same experimental conditions regarding the exciting input signal and reflecting boundary wall of the water container for various lengths of water columns are captured. The Fast Fourier Transform (FFT) components of the echo signals are taken to compute k, α and r, the reflection constant at the boundary, using Oak Ridge and Oxford method. The results are compared with existing literature values. Copyright © 2016 Elsevier B.V. All rights reserved.

Variation of wave speed determined by the PU-loop with proximity to a reflection site.

Science.gov (United States)

Li, Ye; Borlotti, Alessandra; Parker, Kim H; Khir, Ashraf W

2011-01-01

Wave speed is directly related to arterial distensibility and is widely used by clinicians to assess arterial stiffness. The PU-loop method for determining wave speed is based on the water hammer equation for flow in flexible tubes and artery using the method of characteristics. This technique determines wave speed using simultaneous measurements of pressure and velocity at a single point. The method shows that during the early part of systole, the relationship between pressure and velocity is generally linear, and the initial slope of the PU-loop is proportional to wave speed. In this work, we designed an in-vitro experiment to investigate the effect of proximity to a reflection site on the wave speed determined by the PU-loop through varying the distance between the measurement and reflection sites. Measurements were made in a flexible tube with a reflection site at the distal end formed by joining the tube to another tube with a different diameter and material properties. Six different flexible tubes were used to generate both positive and negative reflection coefficients of different magnitudes. We found that the wave speed determined by the PU-loop did not change when the measurement site was far from the reflection site but did change as the distance to the reflection site decreased. The calculated wave speed increased with positive reflections and decreased with negative reflections. The magnitude of the change in wave speed at a fixed distance from the reflection site increased with increasing the value of the reflection coefficient.

Direct fragmentation of quarkonia including Fermi motion using light-cone wave function

Energy Technology Data Exchange (ETDEWEB)

Nobary, M.A. Gomshi [Razi University, Department of Physics, Faculty of Science, Kermanshah (Iran); A.E.O.I., Center for Theoretical Physics and Mathematics, Tehran (Iran); Javadi, B. [Razi University, Department of Physics, Faculty of Science, Kermanshah (Iran)

2005-07-01

We investigate the effect of Fermi motion on the direct fragmentation of the J/{psi} and {upsilon} states employing a light-cone wave function. Consistent with such a wave function we set up the kinematics of a heavy quark fragmenting into quarkonia such that the Fermi motion of the constituents splits into a longitudinal as well as a transverse direction and thus calculate the fragmentation functions for these states. In the framework of our investigation, we estimate that the fragmentation probabilities of J/{psi} and {upsilon} may increase at least up to 14 percent when including this degree of freedom. (orig.)

Lithosphere structure in Madagascar as revealed from receiver functions and surface waves analysis.

Science.gov (United States)

Rindraharisaona, E. J.; Tilmann, F. J.; Yuan, X.; Dreiling, J.; Priestley, K. F.; Barruol, G.; Wysession, M. E.

2017-12-01

The geological history of Madagascar makes it an ideal place to study the lithospheric structure and its evolution. It comprises Archean to Proterozoic units on the central eastern part, which is surrounded by a Triassic to Jurassic basin formation in the west and Cretaceous volcanics along the coasts. Quaternary volcanic rocks have been embedded in crystalline and sedimentary rocks. The aim of the present work is to characterize the crustal structure and determine the imprint of the dominant geodynamic events that have affected Madagascar: the Pan-African orogeny, the breakup of Gondwanaland and Neogene tectonic activity. From 2011 to 2014 different temporary seismic arrays were deployed in Madagascar. We based the current study mostly on SELASOMA project, which is composed of 50 seismic stations that were installed traversing southern Madagascar from the west to the east, sampling the different geological units. To measured seismic dispersion curves, one a wide period ranges using ambient noise, Rayleigh and Love surface waves. To compute the average crustal Vp/Vs ratio internal crustal structure and discontinuities in the mantle, we use both P- and S-waves receiver functions. To better resolve of the crustal structure, we jointly inverted P-wave receiver functions and Rayleigh wave group velocity.The crustal extension during the Carboniferous to Cenozoic has thinned the igneous crust down to 15 km in the western Morondava basin by removing much of the lower crust, while the thickness of the upper crust is nearly identical in the sedimentary basin and under Proterozoic and Archaean rocks of the eastern two thirds of Southern Madagascar. In general, the Archean crust is thicker than the Proterozoic, because mafic component is missing in the Proterozoic domain while it forms the bottom of the Archean crust. The lithosphere thickness in the southern part of Madagascar is estimated to be between 90 and 125 km.

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

Directory of Open Access Journals (Sweden)

Hau-Tieng Wu

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

Inelastic electron scattering as an indicator of clustering in wave functions

International Nuclear Information System (INIS)

1998-01-01

While the shell model is the most fundamental of nuclear structure models, states in light nuclei also have been described successfully in terms of clusters. Indeed, Wildemuth and Tang have shown a correspondence between the cluster and shell models, the clusters arising naturally as correlations out of the shell model Hamiltonian. For light nuclei, the cluster model reduces the many-body problem to a few-body one, with interactions occurring between the clusters. These interactions involve particle exchanges, since the nucleons may still be considered somewhat freely moving, with their motion not strictly confined to the clusters themselves. Such is the relation of the cluster model to the shell model. For a realistic shell model then, one may expect some evidence of clustering in the wave functions for those systems in which the cluster model is valid. The results obtained using the multi-ℎωshell model wave functions are closer in agreement with experiment than the results obtained using the 0ℎωwave functions. Yet in all cases, that level of agreement is not good, with the calculations underpredicting the measured values by at least a factor of two. This indicates that the shell model wave functions do not exhibit clustering behavior, which is expected to manifest itself at small momentum transfer. The exception is the transition to the 7 - /2 state in 7 Li, for which the value obtained from the γ-decay width is in agreement with the value obtained from the MK3W and (0 + 2 + 4)ℎωshell model calculations

Joint resummation for pion wave function and pion transition form factor

Energy Technology Data Exchange (ETDEWEB)

Li, Hsiang-nan [Institute of Physics, Academia Sinica,Academia Rd., Taipei, Taiwan 115 (China); Department of Physics, National Cheng-Kung University,University Rd., Tainan, Taiwan 701 (China); Department of Physics, National Tsing-Hua University,Kuang-Fu Rd., Hsinchu, Taiwan 300 (China); Shen, Yue-Long [College of Information Science and Engineering, Ocean University of China,Songling Rd, Qingdao, Shandong 266100 (China); Wang, Yu-Ming [Institut für Theoretische Teilchenphysik und Kosmologie RWTH Aachen,Physikzentrum Otto-Blumenthal-Straße, D-52056 Aachen (Germany); Physik Department T31, Technische Universität München,James-Franck-Straße, D-85748 Garching (Germany)

2014-01-03

We construct an evolution equation for the pion wave function in the k{sub T} factorization formalism, whose solution sums the mixed logarithm ln xln k{sub T} to all orders, with x (k{sub T}) being a parton momentum fraction (transverse momentum). This joint resummation induces strong suppression of the pion wave function in the small x and large b regions, b being the impact parameter conjugate to k{sub T}, and improves the applicability of perturbative QCD to hard exclusive processes. The above effect is similar to those from the conventional threshold resummation for the double logarithm ln{sup 2} x and the conventional k{sub T} resummation for ln{sup 2} k{sub T}. Combining the evolution equation for the hard kernel, we are able to organize all large logarithms in the γ{sup ∗}π{sup 0}→γ scattering, and to establish a scheme-independent k{sub T} factorization formula. It will be shown that the significance of next-to-leading-order contributions and saturation behaviors of this process at high energy differ from those under the conventional resummations. It implies that QCD logarithmic corrections to a process must be handled appropriately, before its data are used to extract a hadron wave function. Our predictions for the involved pion transition form factor, derived under the joint resummation and the input of a non-asymptotic pion wave function with the second Gegenbauer moment a{sub 2}=0.05, match reasonably well the CLEO, BaBar, and Belle data.

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

Energy Technology Data Exchange (ETDEWEB)

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

1996-07-01

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

Four-body wave function of π3He-system at the threshold energy

International Nuclear Information System (INIS)

Pupyshev, V.V.; Rakityanskij, S.A.

1985-01-01

On the basis of approximate four-body equations the wave function of π 3 He-system is calculated at zero kinetic energy of the pion. In the case when distances between all four particles are comparable with the nucleus size a strong distortion of the wave function of (3N)-subsystem caused by the presence of the pion is found. The calculated four-body function is represented in a semianalytical form, which makes it possible to apply it in different calculations

Wave equations on a de Sitter fiber bundle. [Semiclassical wave function, bundle space, L-S coupling

Energy Technology Data Exchange (ETDEWEB)

Drechsler, W [Max-Planck-Institut fuer Physik und Astrophysik, Muenchen (F.R. Germany)

1975-01-01

A gauge theory of strong interaction is developed based on fields defined on a fiber bundle. The structural group of the bundle is taken to be the Lsub(4,1) de Sitter group. An internal variable xi, varying in the fiber over a space-time point x, is introduced as a means to describe - with the help of a semiclassical wave function psi(x,xi) defined on the bundle space - the internal structure of extended hadrons in a framework using differential geometric techniques. Three basic nonlinear wave equations for psi(x,xi) are established which are of integro-differential type. The nonlinear coupling terms in these de Sitter gauge invariant equations represent physically a generalized spin orbit coupling or a generalized spin coupling for the motion taking place in the fiber. The motivation for using a bigger space for the definition of hadronic matter wave functions as well as the implications of this geometric approach to strong interaction physics is discussed in detail, in particular with respect to the problem of hadronic constituents. The proposed fiber bundle formalism allows a dynamical description of extended structures for hadrons without implying the necessity of introducing any constituents.

Shear Wave Elastography of the Spleen for Monitoring Transjugular Intrahepatic Portosystemic Shunt Function: A Pilot Study.

Science.gov (United States)

Gao, Jing; Zheng, Xiao; Zheng, Yuan-Yi; Zuo, Guo-Qing; Ran, Hai-Tao; Auh, Yong Ho; Waldron, Levi; Chan, Tiffany; Wang, Zhi-Gang

2016-05-01

To assess the feasibility of splenic shear wave elastography in monitoring transjugular intrahepatic portosystemic shunt (TIPS) function. We measured splenic shear wave velocity (SWV), main portal vein velocity (PVV), and splenic vein velocity (SVV) in 33 patients 1 day before and 3 days to 12 months after TIPS placement. We also measured PVV, SVV, and SWV in 10 of 33 patients with TIPS dysfunction 1 day before and 3 to 6 days after TIPS revision. Analyses included differences in portosystemic pressure gradient (PPG), PVV, SVV, and mean SWV before and after TIPS procedures; comparison of median SWV before and after TIPS procedures; differences in PVV, SVV, and SWV before and at different times up to 12 months after TIPS placement; accuracy of PVV, SVV, and SWV in determining TIPS dysfunction; and correlation between PPG and SWV. During 12 months of follow-up, 23 of 33 patients had functioning TIPS, and 10 had TIPS dysfunction. The median SWV was significantly different before and after primary TIPS placement (3.60 versus 3.05 m/s; P = .005), as well as before and after revision (3.73 versus 3.06 m/s; P = .003). The PPG, PVV, and SVV were also significantly different before and after TIPS placement and revision (P function and determining TIPS dysfunction. © 2016 by the American Institute of Ultrasound in Medicine.

An innovative method for automatic determination of time of arrival for Lamb waves excited by impact events

Science.gov (United States)

Zhu, Junxiao; Parvasi, Seyed Mohammad; Ho, Siu Chun Michael; Patil, Devendra; Ge, Maochen; Li, Hongnan; Song, Gangbing

2017-05-01

Lamb waves have great potential as a diagnostic tool in the application of structural health monitoring. Propagation properties of Lamb waves are affected by the state of the structure that the waves are traveling upon. Thus Lamb waves can carry information about the structure as they travel across a structure. However, the dispersive, multimodal and attenuation characteristics of Lamb waves make it difficult to determine the time of arrival of Lamb waves. To deal with these characteristics, an innovative method to automatically determine the time of arrival for impact-induced Lamb waves without human intervention is proposed in this paper. Lead zirconate titanate sensors mounted on the surface of an aluminum plate were used to measure the Lamb waves excited by an impact. The time of arrival was determined based on wavelet decomposition, Hilbert transform and statistics (Grubbs’ test and maximum likelihood estimation). Both of numerical analysis and physical measurements have verified the accuracy of this method for impacts on an aluminum plate.

Schmidt decomposition for non-collinear biphoton angular wave functions

International Nuclear Information System (INIS)

Fedorov, M V

2015-01-01

Schmidt modes of non-collinear biphoton angular wave functions are found analytically. The experimentally realizable procedure for their separation is described. Parameters of the Schmidt decomposition are used to evaluate the degree of the biphoton's angular entanglement. (paper)

Non-dipolar gauge links for transverse-momentum-dependent pion wave functions

International Nuclear Information System (INIS)

Wang, Y.M.

2016-01-01

I discuss the factorization-compatible definitions of transverse-momentum-dependent (TMD) pion wave functions which are fundamental theory inputs entering QCD factorization formulae for many hard exclusive processes. I will first demonstrate that the soft subtraction factor introduced to remove both rapidity and pinch singularities can be greatly reduced by making the maximal use of the freedom to construct the Wilson-line paths when defining the TMD wave functions. I will then turn to show that the newly proposed TMD definition with non-dipolar Wilson lines is equivalent to the one with dipolar gauge links and with a complicated soft function, to all orders of the perturbative expansion in the strong coupling, as far as the infrared behavior is concerned. (author)

Coulomb singularities in scattering wave functions of spin-orbit-coupled states

International Nuclear Information System (INIS)

Bogdanski, P.; Ouerdane, H.

2011-01-01

We report on our analysis of the Coulomb singularity problem in the frame of the coupled channel scattering theory including spin-orbit interaction. We assume that the coupling between the partial wave components involves orbital angular momenta such that Δl= 0, ±2. In these conditions, the two radial functions, components of a partial wave associated to two values of the angular momentum l, satisfy a system of two second-order ordinary differential equations. We examine the difficulties arising in the analysis of the behavior of the regular solutions near the origin because of this coupling. First, we demonstrate that for a singularity of the first kind in the potential, one of the solutions is not amenable to a power series expansion. The use of the Lippmann-Schwinger equations confirms this fact: a logarithmic divergence arises at the second iteration. To overcome this difficulty, we introduce two auxilliary functions which, together with the two radial functions, satisfy a system of four first-order differential equations. The reduction of the order of the differential system enables us to use a matrix-based approach, which generalizes the standard Frobenius method. We illustrate our analysis with numerical calculations of coupled scattering wave functions in a solid-state system.

Symmetrized partial-wave method for density-functional cluster calculations

International Nuclear Information System (INIS)

Averill, F.W.; Painter, G.S.

1994-01-01

The computational advantage and accuracy of the Harris method is linked to the simplicity and adequacy of the reference-density model. In an earlier paper, we investigated one way the Harris functional could be extended to systems outside the limits of weakly interacting atoms by making the charge density of the interacting atoms self-consistent within the constraints of overlapping spherical atomic densities. In the present study, a method is presented for augmenting the interacting atom charge densities with symmetrized partial-wave expansions on each atomic site. The added variational freedom of the partial waves leads to a scheme capable of giving exact results within a given exchange-correlation approximation while maintaining many of the desirable convergence and stability properties of the original Harris method. Incorporation of the symmetry of the cluster in the partial-wave construction further reduces the level of computational effort. This partial-wave cluster method is illustrated by its application to the dimer C 2 , the hypothetical atomic cluster Fe 6 Al 8 , and the benzene molecule

The linear potential propagator via wave function expansion

International Nuclear Information System (INIS)

Nassar, Antonio B.; Cattani, Mauro S.D.

2002-01-01

We evaluate the quantum propagator for the motion of a particle in a linear potential via a recently developed formalism [A.B. Nassar et al., Phys. Rev. E56, 1230, (1997)]. In this formalism, the propagator comes about as a type of expansion of the wave function over the space of the initial velocities. (author)

A method of acoustic wave registration and determination their generation region

International Nuclear Information System (INIS)

Kozin, I.D.; Marchenko, M.V.

1998-01-01

Here is presented a method of acoustic wave registration with using of a synchronous LF broadcasting system. This method of detection and determination of underground nuclear explosion location is based on a registration of ionospheric disturbances induced by acoustic waves at the region of LF sign al reflection. The measuring complex created in the institute of the Ionosphere /1/ allows to register amplitude-frequency characteristics of composite signal from synchronous broadcasting net

Gravity induced corrections to quantum mechanical wave functions

International Nuclear Information System (INIS)

Singh, T.P.

1990-03-01

We perform a semiclassical expansion in the Wheeler-DeWitt equation, in powers of the gravitational constant. We then show that quantum gravitational fluctuations can provide a correction to the wave-functions which are solutions of the Schroedinger equation for matter. This also implies a correction to the expectation values of quantum mechanical observables. (author). 6 refs

Influence of wetting-layer wave functions on phonon-mediated carrier capture into self-assembled quantum dots

DEFF Research Database (Denmark)

Markussen, Troels; Kristensen, Philip Trøst; Tromborg, Bjarne

2006-01-01

Models of carrier dynamics in quantum dots rely strongly on adequate descriptions of the carrier wave functions. In this work we numerically solve the one-band effective mass Schrodinger equation to calculate the capture times of phonon-mediated carrier capture into self-assembled quantum dots. C....... Comparing with results obtained using approximate carrier wave functions, we demonstrate that the capture times are strongly influenced by properties of the wetting layer wave functions not accounted for by earlier theoretical analyses....

Wave functions and two-electron probability distributions of the Hooke's-law atom and helium

International Nuclear Information System (INIS)

O'Neill, Darragh P.; Gill, Peter M. W.

2003-01-01

The Hooke's-law atom (hookium) provides an exactly soluble model for a two-electron atom in which the nuclear-electron Coulombic attraction has been replaced by a harmonic one. Starting from the known exact position-space wave function for the ground state of hookium, we present the momentum-space wave function. We also look at the intracules, two-electron probability distributions, for hookium in position, momentum, and phase space. These are compared with the Hartree-Fock results and the Coulomb holes (the difference between the exact and Hartree-Fock intracules) in position, momentum, and phase space are examined. We then compare these results with analogous results for the ground state of helium using a simple, explicitly correlated wave function

Inelastic electron scattering as an indicator of clustering in wave functions

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-09-01

While the shell model is the most fundamental of nuclear structure models, states in light nuclei also have been described successfully in terms of clusters. Indeed, Wildemuth and Tang have shown a correspondence between the cluster and shell models, the clusters arising naturally as correlations out of the shell model Hamiltonian. For light nuclei, the cluster model reduces the many-body problem to a few-body one, with interactions occurring between the clusters. These interactions involve particle exchanges, since the nucleons may still be considered somewhat freely moving, with their motion not strictly confined to the clusters themselves. Such is the relation of the cluster model to the shell model. For a realistic shell model then, one may expect some evidence of clustering in the wave functions for those systems in which the cluster model is valid. The results obtained using the multi-{Dirac_h}{omega}shell model wave functions are closer in agreement with experiment than the results obtained using the 0{Dirac_h}{omega}wave functions. Yet in all cases, that level of agreement is not good, with the calculations underpredicting the measured values by at least a factor of two. This indicates that the shell model wave functions do not exhibit clustering behavior, which is expected to manifest itself at small momentum transfer. The exception is the transition to the 7{sup -}/2 state in {sup 7}Li, for which the value obtained from the {gamma}-decay width is in agreement with the value obtained from the MK3W and (0 + 2 + 4){Dirac_h}{omega}shell model calculations 17 refs., 1 tab., 2 figs.

Amplitude modulation of atomic wave functions. Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-11-01

The major theoretical advance has been to show that one can modulate Rydberg wave functions using either of two methods: (1) the amplitude modulation technique which depends on autoionization to deplete part of the wave function, or (2) a phase modulation method, which uses a change in the core potential to create a localized phase shift in the wave function. Essentially, these two methods can both be seen as using the core potential to change the Rydberg wave function, using the imaginary part of the potential to do amplitude modulation, or using the real part of the potential to do phase modulation. This work will be published as the authors acquire experimental results which show the differences between the two methods. One of the results of this theoretical study is that the initial proposal to study Barium 6snd states had a significant flaw. Neither the autoionization time, nor the quantum defect shifts are very large in these cases. This means that the modulation is relatively small. This shows itself primarily in the difficulty of seeing significant population redistribution into different 6snd states. The authors intend to correct this in the next funding cycle either: (a) by using the more quickly decaying Ba 6pnf states to modulate 6snd states, or (b) by using Sr 5 snd states, as outlined in this report. Their first, low power experiments are complete. These experiments have used two pulses to do a temporal version of the Ramsey separated oscillatory fields excitation. The two pulses are generated by passing the single pulse through a Michelson-Morley interferometer, which is computer controlled to sweep one arm through 2.5 {micro}m in steps of 10 nm. The second pulse`s excitation interferes with that of the first pulse, and so the total excitation has a sinusoidal variation (with a time period equal to the optical period) on top of a constant background. The amplitude of the total variation should decay at half of the rate decay rate of the autoionizing

Hartle-Hawking wave function and large-scale power suppression of CMB*

Directory of Open Access Journals (Sweden)

Yeom Dong-han

2018-01-01

Full Text Available In this presentation, we first describe the Hartle-Hawking wave function in the Euclidean path integral approach. After we introduce perturbations to the background instanton solution, following the formalism developed by Halliwell-Hawking and Laflamme, one can obtain the scale-invariant power spectrum for small-scales. We further emphasize that the Hartle-Hawking wave function can explain the large-scale power suppression by choosing suitable potential parameters, where this will be a possible window to confirm or falsify models of quantum cosmology. Finally, we further comment on possible future applications, e.g., Euclidean wormholes, which can result in distinct signatures to the power spectrum.

Useful variational principle for the scattering length for the target ground-state wave function imprecisely known

International Nuclear Information System (INIS)

Blau, R.; Rosenberg, L.; Spruch, L.

1977-01-01

A minimum principle for the calculation of the scattering length, applicable when the ground-state wave function of the target system is known precisely, has been available for some time. When, as is almost always the case, the target wave function is imprecisely known, a minimum principle is available but the simple minimum principle noted above is not applicable. Further, as recent calculations show, numerical instabilities usually arise which severely limit the utility of even an ordinary variational approach. The difficulty, which can be traced to the appearance of singularities in the variational construction, is here removed through the introduction of a minimum principle, not for the true scattering length, but for one associated with a closely connected problem. This guarantees that no instability difficulties can arise as the trial scattering wave function and the trial target wave function are improved. The calculations are little different from those required when the target ground-state wave function is known, and, in fact, the original version of the minimum principle is recovered as the trial target wave function becomes exact. A careful discussion is given of the types of problems to which the method can be applied. In particular, the effects of the Pauli principle, and the existence of a finite number of composite bound states, can be accounted for

Variability In Long-Wave Runup as a Function of Nearshore Bathymetric Features

Energy Technology Data Exchange (ETDEWEB)

Dunkin, Lauren McNeill [Texas A & M Univ., College Station, TX (United States)

2010-05-01

Beaches and barrier islands are vulnerable to extreme storm events, such as hurricanes, that can cause severe erosion and overwash to the system. Having dunes and a wide beach in front of coastal infrastructure can provide protection during a storm, but the influence that nearshore bathymetric features have in protecting the beach and barrier island system is not completely understood. The spatial variation in nearshore features, such as sand bars and beach cusps, can alter nearshore hydrodynamics, including wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regions to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect infrastructure. In this thesis, long-wave runup variation due to changing bathymetric features as determined with the numerical model XBeach is quantified (eXtreme Beach behavior model). Wave heights are analyzed to determine the energy through the surfzone. XBeach assumes that coastal erosion at the land-sea interface is dominated by bound long-wave processes. Several hydrodynamic conditions are used to force the numerical model. The XBeach simulation results suggest that bathymetric irregularity induces significant changes in the extreme long-wave runup at the beach and the energy indicator through the surfzone.

Determining Ocean-Bottom Seismometer Orientations from the RHUM-RUM experiment from P-wave and Rayleigh wave polarizations

Science.gov (United States)

Scholz, John-Robert; Barruol, Guilhem; Fontaine, Fabrice R.; Sigloch, Karin

2016-04-01

To image the upper mantle structure beneath La Réunion hotspot, a large-scale seismic network has been deployed on land and at sea in the frame of the RHUM-RUM project (Réunion Hotspot and Upper Mantle - Réunions Unterer Mantel). This French-German passive seismic experiment was designed to investigate and image the deep structure beneath La Réunion, from crust to core, to precise the shape and depth origin of a mantle plume, if any, and to precise the horizontal and vertical mantle flow associated to a possible plume upwelling, to its interaction with the overlying plate and with the neighboring Indian ridges. For this purpose, 57 Ocean-Bottom Seismometers (OBS) were installed around La Réunion and along the Central and Southwest Indian ridges. Broad-band instruments were deployed with the French R/V Marion Dufresne in late 2012 (cruise MD192), and recovered 13 months later by the German R/V Meteor (cruise M101). The pool of OBS was complemented by ~60 terrestrial stations, installed on different islands in the western Indian Ocean, such as La Réunion, Madagascar, Mauritius, Seychelles, Mayotte and the Îles Éparses in the Mozambique channel. The OBS installation is a free-fall down to the seafloor, where they landed in an unknown orientation. Since seismologic investigations of crustal and upper mantle structure (e.g., receiver functions) and azimuthal anisotropy (e.g., SKS-splitting and Rayleigh waves) rely on the knowledge of the correct OBS orientation with respect to the geographic reference frame, it is of importance to determine the orientations of the OBS while recording on the seafloor. In an isotropic, horizontally homogeneous and non-dipping layered globe, the misorientation of each station refers to the offset between theoretical and recorded back-azimuth angle of a passive seismic event. Using large earthquakes (MW > 5.0), it is possible to establish multiple successful measurements per station and thus to determine with good confidence the

Determining the wavelength of Langmuir wave packets at the Earth's bow shock

Directory of Open Access Journals (Sweden)

V. V. Krasnoselskikh

2011-03-01

Full Text Available The propagation of Langmuir waves in plasmas is known to be sensitive to density fluctuations. Such fluctuations may lead to the coexistence of wave pairs that have almost opposite wave-numbers in the vicinity of their reflection points. Using high frequency electric field measurements from the WIND satellite, we determine for the first time the wavelength of intense Langmuir wave packets that are generated upstream of the Earth's electron foreshock by energetic electron beams. Surprisingly, the wavelength is found to be 2 to 3 times larger than the value expected from standard theory. These values are consistent with the presence of strong inhomogeneities in the solar wind plasma rather than with the effect of weak beam instabilities.

Wave function of a microwave-driven Bose-Einstein magnon condensate

International Nuclear Information System (INIS)

Rezende, Sergio M.

2010-01-01

It has been observed experimentally that a magnon gas in a film of yttrium-iron garnet at room temperature driven by a microwave field exhibits Bose-Einstein condensation (BEC) when the driving power exceeds a critical value. In a previous paper we presented a model for the dynamics of the magnon system in wave-vector space that provides firm theoretical support for the formation of the BEC. Here we show that the wave function of the magnon condensate in configuration space satisfies a Gross-Pitaevskii equation similarly to other BEC systems. The theory is consistent with the previous model in wave-vector space, and its results are in qualitative agreement with recent measurements of the spatial distribution of the magnon condensate driven by a nonuniform microwave field.

Characterizing Bonding Patterns in Diradicals and Triradicals by Density-Based Wave Function Analysis: A Uniform Approach.

Science.gov (United States)

Orms, Natalie; Rehn, Dirk R; Dreuw, Andreas; Krylov, Anna I

2018-02-13

Density-based wave function analysis enables unambiguous comparisons of the electronic structure computed by different methods and removes ambiguity of orbital choices. We use this tool to investigate the performance of different spin-flip methods for several prototypical diradicals and triradicals. In contrast to previous calibration studies that focused on energy gaps between high- and low spin-states, we focus on the properties of the underlying wave functions, such as the number of effectively unpaired electrons. Comparison of different density functional and wave function theory results provides insight into the performance of the different methods when applied to strongly correlated systems such as polyradicals. We show that canonical molecular orbitals for species like large copper-containing diradicals fail to correctly represent the underlying electronic structure due to highly non-Koopmans character, while density-based analysis of the same wave function delivers a clear picture of the bonding pattern.

Periodic heat wave determination of thermal diffusivity of clays ...

African Journals Online (AJOL)

The responses of Ankaful, Tetegu (# 1 & 2) and Mamfe clays to periodic heat waves were analyzed to deter-mine the thermal diffusivity values. The temperature amplitude attenuated with depth of penetration, while the phase shift increased. The thermal diffusivity values ranged from 3.0 - 9.5 x 10P-7P mP2P/s by amplitude ...

On Green's function for 3-D wave-body interaction in a channel

DEFF Research Database (Denmark)

Xia, Jinzhu

1997-01-01

series of images is evaluated accurately based on an asmptotic analysis. It is demonstrated that the Green's function has a square-root singular behaviour due to the side walls when the wave frequency approaches one of the resonant frequencies. The numerical results for the Green's function has a square......An analytical and numerical study is presented for efficient evaluation of the Green's function that satisfies the linear free surface condition and the non-penetration condition on the channel bottomand the side walls. the formulation is based on the open-sea green's function and the complete......-root singular behaviour due to the side walls when the wave frequency approaches one of the resonant frequencies. The numerical results for the Green's funciton presented in the present paper are believed to have an absolute accuracy of 10-5....

Determination of gravity wave parameters in the airglow combining photometer and imager data

Science.gov (United States)

Nyassor, Prosper K.; Arlen Buriti, Ricardo; Paulino, Igo; Medeiros, Amauri F.; Takahashi, Hisao; Wrasse, Cristiano M.; Gobbi, Delano

2018-05-01

Mesospheric airglow measurements of two or three layers were used to characterize both vertical and horizontal parameters of gravity waves. The data set was acquired coincidentally from a multi-channel filter (Multi-3) photometer and an all-sky imager located at São João do Cariri (7.4° S, 36.5° W) in the equatorial region from 2001 to 2007. Using a least-square fitting and wavelet analysis technique, the phase and amplitude of each observed wave were determined, as well as the amplitude growth. Using the dispersion relation of gravity waves, the vertical and horizontal wavelengths were estimated and compared to the horizontal wavelength obtained from the keogram analysis of the images observed by an all-sky imager. The results show that both horizontal and vertical wavelengths, obtained from the dispersion relation and keogram analysis, agree very well for the waves observed on the nights of 14 October and 18 December 2006. The determined parameters showed that the observed wave on the night of 18 December 2006 had a period of ˜ 43.8 ± 2.19 min, with the horizontal wavelength of 235.66 ± 11.78 km having a downward phase propagation, whereas that of 14 October 2006 propagated with a period of ˜ 36.00 ± 1.80 min with a horizontal wavelength of ˜ 195 ± 9.80 km, and with an upward phase propagation. The observation of a wave taken by a photometer and an all-sky imager allowed us to conclude that the same wave could be observed by both instruments, permitting the investigation of the two-dimensional wave parameter.

Love-type waves in functionally graded piezoelectric material (FGPM) sandwiched between initially stressed layer and elastic substrate

Science.gov (United States)

Saroj, Pradeep K.; Sahu, S. A.; Chaudhary, S.; Chattopadhyay, A.

2015-10-01

This paper investigates the propagation behavior of Love-type surface waves in three-layered composite structure with initial stress. The composite structure has been taken in such a way that a functionally graded piezoelectric material (FGPM) layer is bonded between initially stressed piezoelectric upper layer and an elastic substrate. Using the method of separation of variables, frequency equation for the considered wave has been established in the form of determinant for electrical open and short cases on free surface. The bisection method iteration technique has been used to find the roots of the dispersion relations which give the modes for electrical open and short cases. The effects of gradient variation of material constant and initial stress on the phase velocity of surface waves are discussed. Dependence of thickness on each parameter of the study has been shown explicitly. Study has been also done to show the existence of cut-off frequency. Graphical representation has been done to exhibit the findings. The obtained results are significant for the investigation and characterization of Love-type waves in FGPM-layered media.

Geometrical Determinants of Neuronal Actin Waves

OpenAIRE

Tomba, Caterina; Bra?ni, C?line; Bugnicourt, Ghislain; Cohen, Floriane; Friedrich, Benjamin M.; Gov, Nir S.; Villard, Catherine

2017-01-01

Hippocampal neurons produce in their early stages of growth propagative, actin-rich dynamical structures called actin waves. The directional motion of actin waves from the soma to the tip of neuronal extensions has been associated with net forward growth, and ultimately with the specification of neurites into axon and dendrites. Here, geometrical cues are used to control actin wave dynamics by constraining neurons on adhesive stripes of various widths. A key observable, the average time betwe...

Eikonal Approximation in AdS/CFT From Shock Waves to Four-Point Functions

CERN Document Server

Cornalba, L; Costa, Miguel S; Penedones, Joao; Cornalba, Lorenzo; Costa, M S; Penedones, J; Schiappa, Ricardo

2007-01-01

We initiate a program to generalize the standard eikonal approximation to compute amplitudes in Anti-de Sitter spacetimes. Inspired by the shock wave derivation of the eikonal amplitude in flat space, we study the two-point function E ~ _{shock} in the presence of a shock wave in Anti-de Sitter, where O_1 is a scalar primary operator in the dual conformal field theory. At tree level in the gravitational coupling, we relate the shock two-point function E to the discontinuity across a kinematical branch cut of the conformal field theory four-point function A ~ , where O_2 creates the shock geometry in Anti-de Sitter. Finally, we extend the above results by computing E in the presence of shock waves along the horizon of Schwarzschild BTZ black holes. This work gives new tools for the study of Planckian physics in Anti-de Sitter spacetimes.

Probing spontaneous wave-function collapse with entangled levitating nanospheres

Science.gov (United States)

Zhang, Jing; Zhang, Tiancai; Li, Jie

2017-01-01

Wave-function collapse models are considered to be the modified theories of standard quantum mechanics at the macroscopic level. By introducing nonlinear stochastic terms in the Schrödinger equation, these models (different from standard quantum mechanics) predict that it is fundamentally impossible to prepare macroscopic systems in macroscopic superpositions. The validity of these models can only be examined by experiments, and hence efficient protocols for these kinds of experiments are greatly needed. Here we provide a protocol that is able to probe the postulated collapse effect by means of the entanglement of the center-of-mass motion of two nanospheres optically trapped in a Fabry-Pérot cavity. We show that the collapse noise results in a large reduction of the steady-state entanglement, and the entanglement, with and without the collapse effect, shows distinguishable scalings with certain system parameters, which can be used to determine unambiguously the effect of these models.

Method to map one-dimensional electronic wave function by using multiple Brillouin zone angle resolved photoemission

Directory of Open Access Journals (Sweden)

Dong-Wook Lee

2010-10-01

Full Text Available Angle resolved photoemission spectroscopy (ARPES is a powerful tool to investigate electronic structures in solids and has been widely used in studying various materials. The electronic structure information by ARPES is obtained in the momentum space. However, in the case of one-dimensional system, we here show that we extract the real space information from ARPES data taken over multiple Brillouin zones (BZs. Intensities in the multiple BZs are proportional to the photoemission matrix element which contains information on the coefficient of the Bloch wave function. It is shown that the Bloch wave function coefficients can be extracted from ARPES data, which allows us to construct the real space wave function. As a test, we use ARPES data from proto-typical one-dimensional system SrCuO2 and construct the real space wave function.

Probing α-particle wave functions by (d,α) tensor analyzing powers

International Nuclear Information System (INIS)

Crosson, E.R.; Das, R.K.; Lemieux, S.K.; Ludwig, E.J.; Thompson, W.J.; Bisenberger, M.; Hertenberger, R.; Hofer, D.; Kader, H.; Schiemenz, P.; Graw, G.; Eiro, A.M.; Santos, F.D.

1992-01-01

Components of α-particle wave functions corresponding to d-d configurations are used to predict analyzing powers in the (d,α) reaction. Tensor analyzing powers, especially A xx , are shown to clearly distinguish between wave functions generated by different realistic nucleon-nucleon interactions. Data for the 58 Ni(d,α) 56 Co reaction to the 7 + stretched-nucleon-orbital state at 2.283-MeV excitation in 56 Co, measured with 22-MeV deuterons, are compared to predictions from the Argonne and Urbana interactions. Similar comparisons are made to data for the lowest J π =7 + state in 48 Sc populated by the 50 Ti(d,α) 48 Sc reaction at 16 MeV

Frequency-domain Green's functions for radar waves in heterogeneous 2.5D media

Science.gov (United States)

Ellefsen, K.J.; Croize, D.; Mazzella, A.T.; McKenna, J.R.

2009-01-01

Green's functions for radar waves propagating in heterogeneous 2.5D media might be calculated in the frequency domain using a hybrid method. The model is defined in the Cartesian coordinate system, and its electromagnetic properties might vary in the x- and z-directions, but not in the y-direction. Wave propagation in the x- and z-directions is simulated with the finite-difference method, and wave propagation in the y-direction is simulated with an analytic function. The absorbing boundaries on the finite-difference grid are perfectly matched layers that have been modified to make them compatible with the hybrid method. The accuracy of these numerical Greens functions is assessed by comparing them with independently calculated Green's functions. For a homogeneous model, the magnitude errors range from -4.16% through 0.44%, and the phase errors range from -0.06% through 4.86%. For a layered model, the magnitude errors range from -2.60% through 2.06%, and the phase errors range from -0.49% through 2.73%. These numerical Green's functions might be used for forward modeling and full waveform inversion. ?? 2009 Society of Exploration Geophysicists. All rights reserved.

Traveling waves and conservation laws for highly nonlinear wave equations modeling Hertz chains

Science.gov (United States)

Przedborski, Michelle; Anco, Stephen C.

2017-09-01

A highly nonlinear, fourth-order wave equation that models the continuum theory of long wavelength pulses in weakly compressed, homogeneous, discrete chains with a general power-law contact interaction is studied. For this wave equation, all solitary wave solutions and all nonlinear periodic wave solutions, along with all conservation laws, are derived. The solutions are explicitly parameterized in terms of the asymptotic value of the wave amplitude in the case of solitary waves and the peak of the wave amplitude in the case of nonlinear periodic waves. All cases in which the solution expressions can be stated in an explicit analytic form using elementary functions are worked out. In these cases, explicit expressions for the total energy and total momentum for all solutions are obtained as well. The derivation of the solutions uses the conservation laws combined with an energy analysis argument to reduce the wave equation directly to a separable first-order differential equation that determines the wave amplitude in terms of the traveling wave variable. This method can be applied more generally to other highly nonlinear wave equations.

Phase function of a spherical particle when scattering an inhomogeneous electromagnetic plane wave.

Science.gov (United States)

Frisvad, Jeppe Revall

2018-04-01

In absorbing media, electromagnetic plane waves are most often inhomogeneous. Existing solutions for the scattering of an inhomogeneous plane wave by a spherical particle provide no explicit expressions for the scattering components. In addition, current analytical solutions require evaluation of the complex hypergeometric function F 1 2 for every term of a series expansion. In this work, I develop a simpler solution based on associated Legendre functions with argument zero. It is similar to the solution for homogeneous plane waves but with new explicit expressions for the angular dependency of the far-field scattering components, that is, the phase function. I include recurrence formulas for practical evaluation and provide numerical examples to evaluate how well the new expressions match previous work in some limiting cases. The predicted difference in the scattering phase function due to inhomogeneity is not negligible for light entering an absorbing medium at an oblique angle. The presented theory could thus be useful for predicting scattering behavior in dye-based random lasing and in solar cell absorption enhancement.

Impact of Wave Dragon on Wave Climate

DEFF Research Database (Denmark)

Andersen, Thomas Lykke; Tedd, James; Kramer, Morten

This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator.......This report is an advisory paper for use in determining the wave dragon effects on hydrography, by considering the effect on the wave climate in the region of a wave dragon. This is to be used in the impact assessment for the Wave Dragon pre-commercial demonstrator....

Effect of logarithmic terms on the energy level and wave function of a dtμ system

International Nuclear Information System (INIS)

Zhen, Z.

1990-01-01

The effect of the logarithmic terms on the ground-state energy level and wave function of a dtμ system is investigated. No significant contribution of the logarithmic terms on either the energy level or wave function is found. At the same time, we find the lowest upper bound of the ground-state energy ever obtained by the variational method using the Hylleraas-type trial function and that the corresponding wave function satisfies the cusp condition as r dt →0 automatically to a reasonable accuracy for r<3 (muonic a.u.), where r is the distance between the fused dt nuclear compound and the muon

Fine structure and analytical quantum-defect wave functions

International Nuclear Information System (INIS)

Kostelecky, V.A.; Nieto, M.M.; Truax, D.R.

1988-01-01

We investigate the domain of validity of previously proposed analytical wave functions for atomic quantum-defect theory. This is done by considering the fine-structure splitting of alkali-metal and singly ionized alkaline-earth atoms. The Lande formula is found to be naturally incorporated. A supersymmetric-type integer is necessary for finite results. Calculated splittings correctly reproduce the principal features of experimental values for alkali-like atoms

Quantum wave packet dynamics with trajectories: Implementation with distributed approximating functionals

International Nuclear Information System (INIS)

Wyatt, Robert E.; Kouri, Donald J.; Hoffman, David K.

2000-01-01

The quantum trajectory method (QTM) was recently developed to solve the hydrodynamic equations of motion in the Lagrangian, moving-with-the-fluid, picture. In this approach, trajectories are integrated for N fluid elements (particles) moving under the influence of both the force from the potential surface and from the quantum potential. In this study, distributed approximating functionals (DAFs) are used on a uniform grid to compute the necessary derivatives in the equations of motion. Transformations between the physical grid where the particle coordinates are defined and the uniform grid are handled through a Jacobian, which is also computed using DAFs. A difficult problem associated with computing derivatives on finite grids is the edge problem. This is handled effectively by using DAFs within a least squares approach to extrapolate from the known function region into the neighboring regions. The QTM-DAF is then applied to wave packet transmission through a one-dimensional Eckart potential. Emphasis is placed upon computation of the transmitted density and wave function. A problem that develops when part of the wave packet reflects back into the reactant region is avoided in this study by introducing a potential ramp to sweep the reflected particles away from the barrier region. (c) 2000 American Institute of Physics

Optimal determination of the elastic constants of composite materials from ultrasonic wave-speed measurements

Science.gov (United States)

Castagnède, Bernard; Jenkins, James T.; Sachse, Wolfgang; Baste, Stéphane

1990-03-01

A method is described to optimally determine the elastic constants of anisotropic solids from wave-speeds measurements in arbitrary nonprincipal planes. For such a problem, the characteristic equation is a degree-three polynomial which generally does not factorize. By developing and rearranging this polynomial, a nonlinear system of equations is obtained. The elastic constants are then recovered by minimizing a functional derived from this overdetermined system of equations. Calculations of the functional are given for two specific cases, i.e., the orthorhombic and the hexagonal symmetries. Some numerical results showing the efficiency of the algorithm are presented. A numerical method is also described for the recovery of the orientation of the principal acoustical axes. This problem is solved through a double-iterative numerical scheme. Numerical as well as experimental results are presented for a unidirectional composite material.

Green function iterative solution of ground state wave function for Yukawa potential

International Nuclear Information System (INIS)

Zhang Zhao

2003-01-01

The newly developed single trajectory quadrature method is applied to solve central potentials. First, based on the series expansion method an exact analytic solution of the ground state for Hulthen potential and an approximate solution for Yukawa potential are obtained respectively. Second, the newly developed iterative method based on Green function defined by quadratures along the single trajectory is applied to solve Yukawa potential using the Coulomb solution and Hulthen solution as the trial functions respectively. The results show that a more proper choice of the trial function will give a better convergence. To further improve the convergence the iterative method is combined with the variational method to solve the ground state wave function for Yukawa potential, using variational solutions of the Coulomb and Hulthen potentials as the trial functions. The results give much better convergence. Finally, the obtained critical screen coefficient is applied to discuss the dissociate temperature of J/ψ in high temperature QGP

Connection of relativistic and nonrelativistic wave functions in the calculation of leptonic widths

International Nuclear Information System (INIS)

Durand, B.; Durand, L.

1984-01-01

We generalize our previous JWKB relations between the relativistic qq-bar wave function at the origin and (a) the inverse density of states of the qq-bar system and (b) the nonrelativistic qq-bar wave function at the origin, to the case of potentials with a Coulomb singularity. We show that the square of the Bethe-Salpeter wave function at the the origin is given approximately for 1 - states by for M/sub n/>2m/sub q/, where F(v) = (4πα/sub s//3v)[1-exp(-4πα /sub s//3v)] -1 is the usual Coulomb factor and g(v)approx. =1 is associated with the lowest-order gluonic radiative corrections. We present numerical evidence for the remarkable accuracy of these relations, which have important implications for the use of nonrelativistic potential models to describe quarkonium systems. We also discuss some subtleties in the v and α/sub s/ dependence of corrections to leptonic widths

Second-Order Moller-Plesset Perturbation Theory for Molecular Dirac-Hartree-Fock Wave Functions

Science.gov (United States)

Dyall, Kenneth G.; Arnold, James O. (Technical Monitor)

1994-01-01

Moller-Plesset perturbation theory is developed to second order for a selection of Kramers restricted Dirac-Hartree-Fock closed and open-shell reference wave functions. The open-shell wave functions considered are limited to those with no more than two electrons in open shells, but include the case of a two-configuration SCF reference. Denominator shifts are included in the style of Davidson's OPT2 method. An implementation which uses unordered integrals with labels is presented, and results are given for a few test cases.

Approximated calculation of the vacuum wave function and vacuum energy of the LGT with RPA method

International Nuclear Information System (INIS)

Hui Ping

2004-01-01

The coupled cluster method is improved with the random phase approximation (RPA) to calculate vacuum wave function and vacuum energy of 2 + 1 - D SU(2) lattice gauge theory. In this calculating, the trial wave function composes of single-hollow graphs. The calculated results of vacuum wave functions show very good scaling behaviors at weak coupling region l/g 2 >1.2 from the third order to the sixth order, and the vacuum energy obtained with RPA method is lower than the vacuum energy obtained without RPA method, which means that this method is a more efficient one

Generating gravity waves with matter and electromagnetic waves

International Nuclear Information System (INIS)

Barrabes, C.; Hogan, P A.

2008-01-01

If a homogeneous plane lightlike shell collides head on with a homogeneous plane electromagnetic shock wave having a step-function profile then no backscattered gravitational waves are produced. We demonstrate, by explicit calculation, that if the matter is accompanied by a homogeneous plane electromagnetic shock wave with a step-function profile then backscattered gravitational waves appear after the collision

Stability analysis and reconstruction of wave distribution functions in warm plasmas

International Nuclear Information System (INIS)

Oscarsson, T.E.

1989-05-01

The purpose of this thesis is first to describe stability analysis and reconstruction of the wave distribution function (WDF) separately, and then to show how the two approaches can be combined in an investigation of satellite data. To demonstrate the type of stability investigation that is often used in space physics we study instabilities below the local proton gyrofrequency which are caused by anisotropic proton distributions. Arbitrary angles between the wavevector and the background magnetic field are considered, and effects of warm plasma on the wave propagation properties are included. We also comment briefly given on an often-used scheme for classifying instabilities. In our discussion on WDF analysis we develop a completely new and general method for reconstructing the WDF. Our scheme can be used to reconstruct the distribution function of waves in warm as well as cold plasma. Doppler effects introduced by satellite motion are included, and the reconstructions can be performed over a broad frequency range simultaneously. The applicability of our new WDF reconstruction method is studied in model problems and in an application to observations made by the Swedish satellite Viking. In the application to Viking data we combine stability and WDF analyses in a unique way that promises to become an important tool in future studies of wave-particle interactions in space plasmas. (author)

Wave packet autocorrelation functions for quantum hard-disk and hard-sphere billiards in the high-energy, diffraction regime.

Science.gov (United States)

Goussev, Arseni; Dorfman, J R

2006-07-01

We consider the time evolution of a wave packet representing a quantum particle moving in a geometrically open billiard that consists of a number of fixed hard-disk or hard-sphere scatterers. Using the technique of multiple collision expansions we provide a first-principle analytical calculation of the time-dependent autocorrelation function for the wave packet in the high-energy diffraction regime, in which the particle's de Broglie wavelength, while being small compared to the size of the scatterers, is large enough to prevent the formation of geometric shadow over distances of the order of the particle's free flight path. The hard-disk or hard-sphere scattering system must be sufficiently dilute in order for this high-energy diffraction regime to be achievable. Apart from the overall exponential decay, the autocorrelation function exhibits a generally complicated sequence of relatively strong peaks corresponding to partial revivals of the wave packet. Both the exponential decay (or escape) rate and the revival peak structure are predominantly determined by the underlying classical dynamics. A relation between the escape rate, and the Lyapunov exponents and Kolmogorov-Sinai entropy of the counterpart classical system, previously known for hard-disk billiards, is strengthened by generalization to three spatial dimensions. The results of the quantum mechanical calculation of the time-dependent autocorrelation function agree with predictions of the semiclassical periodic orbit theory.

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

Science.gov (United States)

Branson, David

1979-01-01

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

Square Wave Voltammetry: An Alternative Technique to Determinate Piroxicam Release Profiles from Nanostructured Lipid Carriers.

Science.gov (United States)

Otarola, Jessica; Garrido, Mariano; Correa, N Mariano; Molina, Patricia G

2016-08-04

A new, simple, and fast electrochemical (EC) method has been developed to determine the release profile of piroxicam, a nonsteroidal anti-inflammatory drug, loaded in a drug delivery system based on nanostructured lipid carriers (NLCs). For the first time, the samples were analyzed by using square wave voltammetry, a sensitive EC technique. The piroxicam EC responses allow us to propose a model that explains the experimental results and to subsequently determine the amount of drug loaded into the NLCs formulation as a function of time. In vitro drug release studies showed prolonged drug release (up to 5 days), releasing 60 % of the incorporated drug. The proposed method is a promising and stable alternative for the study of different drug delivery systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of Real Ship Rolling Dynamics under Wave Excitement Force Composed of Sums of Cosine Functions

International Nuclear Information System (INIS)

Zhang, Y. S.; Cai, F.; Xu, W. M.

2011-01-01

The ship motion equation with a cosine wave excitement force describes the slip moments in regular waves. A new kind of wave excitement force model, with the form as sums of cosine functions was proposed to describe ship rolling in irregular waves. Ship rolling time series were obtained by solving the ship motion equation with the fourth-order-Runger-Kutta method. These rolling time series were synthetically analyzed with methods of phase-space track, power spectrum, primary component analysis, and the largest Lyapunove exponent. Simulation results show that ship rolling presents some chaotic characteristic when the wave excitement force was applied by sums of cosine functions. The result well explains the course of ship rolling's chaotic mechanism and is useful for ship hydrodynamic study.

Wave-particle dualism of spiral waves dynamics.

Science.gov (United States)

Biktasheva, I V; Biktashev, V N

2003-02-01

We demonstrate and explain a wave-particle dualism of such classical macroscopic phenomena as spiral waves in active media. That means although spiral waves appear as nonlocal processes involving the whole medium, they respond to small perturbations as effectively localized entities. The dualism appears as an emergent property of a nonlinear field and is mathematically expressed in terms of the spiral waves response functions, which are essentially nonzero only in the vicinity of the spiral wave core. Knowledge of the response functions allows quantitatively accurate prediction of the spiral wave drift due to small perturbations of any nature, which makes them as fundamental characteristics for spiral waves as mass is for the condensed matter.

Stochastic wave-function unravelling of the generalized Lindblad equation using correlated states

International Nuclear Information System (INIS)

Moodley, Mervlyn; Nsio Nzundu, T; Paul, S

2012-01-01

We perform a stochastic wave-function unravelling of the generalized Lindblad master equation using correlated states, a combination of the system state vectors and the environment population. The time-convolutionless projection operator method using correlated projection superoperators is applied to a two-state system, a qubit, that is coupled to an environment consisting of two energy bands which are both populated. These results are compared to the data obtained from Monte Carlo wave-function simulations based on the unravelling of the master equation. We also show a typical quantum trajectory and the average time evolution of the state vector on the Bloch sphere. (paper)

Distortions of the distribution function of collisionless particles by high-frequency gravitational waves

International Nuclear Information System (INIS)

Vainer, B.V.; Nasel'skii, P.D.

1983-01-01

Equations for the correlation functions of fluctuations in the spectra of relativistic collisionless particles are obtained from the combined system of Einstein's equations and the Vlasov equation. It is shown that the interaction of high-frequency gravitational waves with collisionless particles leads to diffusion of their spectrum in the momentum space. The distortions in the spectrum of the microwave background radiation in a cosmological model with high-frequency gravitational waves are discussed. Bounds are obtained on the spectral characteristics of background gravitational waves

Using wave intensity analysis to determine local reflection coefficient in flexible tubes.

Science.gov (United States)

Li, Ye; Parker, Kim H; Khir, Ashraf W

2016-09-06

It has been shown that reflected waves affect the shape and magnitude of the arterial pressure waveform, and that reflected waves have physiological and clinical prognostic values. In general the reflection coefficient is defined as the ratio of the energy of the reflected to the incident wave. Since pressure has the units of energy per unit volume, arterial reflection coefficient are traditionally defined as the ratio of reflected to the incident pressure. We demonstrate that this approach maybe prone to inaccuracies when applied locally. One of the main objectives of this work is to examine the possibility of using wave intensity, which has units of energy flux per unit area, to determine the reflection coefficient. We used an in vitro experimental setting with a single inlet tube joined to a second tube with different properties to form a single reflection site. The second tube was long enough to ensure that reflections from its outlet did not obscure the interactions of the initial wave. We generated an approximately half sinusoidal wave at the inlet of the tube and took measurements of pressure and flow along the tube. We calculated the reflection coefficient using wave intensity (R dI and R dI 0.5 ) and wave energy (R I and R I 0.5 ) as well as the measured pressure (R dP ) and compared these results with the reflection coefficient calculated theoretically based on the mechanical properties of the tubes. The experimental results show that the reflection coefficients determined by all the techniques we studied increased or decreased with distance from the reflection site, depending on the type of reflection. In our experiments, R dP , R dI 0.5 and R I 0.5 are the most reliable parameters to measure the mean reflection coefficient, whilst R dI and R I provide the best measure of the local reflection coefficient, closest to the reflection site. Additional work with bifurcations, tapered tubes and in vivo experiments are needed to further understand, validate the

Arterial stiffness and wave reflection: sex differences and relationship with left ventricular diastolic function.

Science.gov (United States)

Russo, Cesare; Jin, Zhezhen; Palmieri, Vittorio; Homma, Shunichi; Rundek, Tatjana; Elkind, Mitchell S V; Sacco, Ralph L; Di Tullio, Marco R

2012-08-01

Increased arterial stiffness and wave reflection have been reported in heart failure with normal ejection fraction (HFNEF) and in asymptomatic left ventricular (LV) diastolic dysfunction, a precursor of HFNEF. It is unclear whether women, who have higher frequency of HFNEF, are more vulnerable than men to the deleterious effects of arterial stiffness on LV diastolic function. We investigated, in a large community-based cohort, whether sex differences exist in the relationship among arterial stiffness, wave reflection, and LV diastolic function. Arterial stiffness and wave reflection were assessed in 983 participants from the Cardiovascular Abnormalities and Brain Lesions study using applanation tonometry. The central pulse pressure/stroke volume index, total arterial compliance, pulse pressure amplification, and augmentation index were used as parameters of arterial stiffness and wave reflection. LV diastolic function was evaluated by 2-dimensional echocardiography and tissue-Doppler imaging. Arterial stiffness and wave reflection were greater in women compared with men, independent of body size and heart rate (all Pfunction in both sexes. Further adjustment for cardiovascular risk factors attenuated these relationships; however, a higher central pulse pressure/stroke volume index predicted LV diastolic dysfunction in women (odds ratio, 1.54; 95% confidence intervals, 1.03 to 2.30) and men (odds ratio, 2.09; 95% confidence interval, 1.30 to 3.39), independent of other risk factors. In conclusion, in our community-based cohort study, higher arterial stiffness was associated with worse LV diastolic function in men and women. Women's higher arterial stiffness, independent of body size, may contribute to their greater susceptibility to develop HFNEF.

Fast waves near the lower hybrid frequency. Final contract report

International Nuclear Information System (INIS)

McWilliams, R.

1984-01-01

The main function of this contract has been to advance the theory of fast waves near the lower hybrid frequency. Special emphasis was to be given to aspects which would assist experimentalists in planning and performing experiments to test the feasibility of using the fast wave for plasma heating and current drive. Evanescent and propagating conditions for the wave were to be determined. Possible antennas for launching the waves were to be determined. Coupling coefficients of the waves into the plasma were to be found. The results were to be applied to present day and reactor grade plasma parameters

Analysis shear wave velocity structure obtained from surface wave methods in Bornova, Izmir

Energy Technology Data Exchange (ETDEWEB)

Pamuk, Eren, E-mail: eren.pamuk@deu.edu.tr; Akgün, Mustafa, E-mail: mustafa.akgun@deu.edu.tr [Department of Geophysical Engineering, Dokuz Eylul University, Izmir (Turkey); Özdağ, Özkan Cevdet, E-mail: cevdet.ozdag@deu.edu.tr [Dokuz Eylul University Rectorate, Izmir (Turkey)

2016-04-18

Properties of the soil from the bedrock is necessary to describe accurately and reliably for the reduction of earthquake damage. Because seismic waves change their amplitude and frequency content owing to acoustic impedance difference between soil and bedrock. Firstly, shear wave velocity and depth information of layers on bedrock is needed to detect this changing. Shear wave velocity can be obtained using inversion of Rayleigh wave dispersion curves obtained from surface wave methods (MASW- the Multichannel Analysis of Surface Waves, ReMi-Refraction Microtremor, SPAC-Spatial Autocorrelation). While research depth is limeted in active source study, a passive source methods are utilized for deep depth which is not reached using active source methods. ReMi method is used to determine layer thickness and velocity up to 100 m using seismic refraction measurement systems.The research carried out up to desired depth depending on radius using SPAC which is utilized easily in conditions that district using of seismic studies in the city. Vs profiles which are required to calculate deformations in under static and dynamic loads can be obtained with high resolution using combining rayleigh wave dispersion curve obtained from active and passive source methods. In the this study, Surface waves data were collected using the measurements of MASW, ReMi and SPAC at the İzmir Bornova region. Dispersion curves obtained from surface wave methods were combined in wide frequency band and Vs-depth profiles were obtained using inversion. Reliability of the resulting soil profiles were provided by comparison with theoretical transfer function obtained from soil paremeters and observed soil transfer function from Nakamura technique and by examination of fitting between these functions. Vs values are changed between 200-830 m/s and engineering bedrock (Vs>760 m/s) depth is approximately 150 m.

Tight-binding analysis of Si and GaAs ultrathin bodies with subatomic wave-function resolution

Science.gov (United States)

Tan, Yaohua P.; Povolotskyi, Michael; Kubis, Tillmann; Boykin, Timothy B.; Klimeck, Gerhard

2015-08-01

Empirical tight-binding (ETB) methods are widely used in atomistic device simulations. Traditional ways of generating the ETB parameters rely on direct fitting to bulk experiments or theoretical electronic bands. However, ETB calculations based on existing parameters lead to unphysical results in ultrasmall structures like the As-terminated GaAs ultrathin bodies (UTBs). In this work, it is shown that more transferable ETB parameters with a short interaction range can be obtained by a process of mapping ab initio bands and wave functions to ETB models. This process enables the calibration of not only the ETB energy bands but also the ETB wave functions with corresponding ab initio calculations. Based on the mapping process, ETB models of Si and GaAs are parameterized with respect to hybrid functional calculations. Highly localized ETB basis functions are obtained. Both the ETB energy bands and wave functions with subatomic resolution of UTBs show good agreement with the corresponding hybrid functional calculations. The ETB methods can then be used to explain realistically extended devices in nonequilibrium that cannot be tackled with ab initio methods.

STM contrast of a CO dimer on a Cu(1 1 1) surface: a wave-function analysis

Science.gov (United States)

Gustafsson, Alexander; Paulsson, Magnus

2017-12-01

We present a method used to intuitively interpret the scanning tunneling microscopy (STM) contrast by investigating individual wave functions originating from the substrate and tip side. We use localized basis orbital density functional theory, and propagate the wave functions into the vacuum region at a real-space grid, including averaging over the lateral reciprocal space. Optimization by means of the method of Lagrange multipliers is implemented to perform a unitary transformation of the wave functions in the middle of the vacuum region. The method enables (i) reduction of the number of contributing tip-substrate wave function combinations used in the corresponding transmission matrix, and (ii) to bundle up wave functions with similar symmetry in the lateral plane, so that (iii) an intuitive understanding of the STM contrast can be achieved. The theory is applied to a CO dimer adsorbed on a Cu(1 1 1) surface scanned by a single-atom Cu tip, whose STM image is discussed in detail by the outlined method.

STM contrast of a CO dimer on a Cu(1 1 1) surface: a wave-function analysis.

Science.gov (United States)

Gustafsson, Alexander; Paulsson, Magnus

2017-12-20

We present a method used to intuitively interpret the scanning tunneling microscopy (STM) contrast by investigating individual wave functions originating from the substrate and tip side. We use localized basis orbital density functional theory, and propagate the wave functions into the vacuum region at a real-space grid, including averaging over the lateral reciprocal space. Optimization by means of the method of Lagrange multipliers is implemented to perform a unitary transformation of the wave functions in the middle of the vacuum region. The method enables (i) reduction of the number of contributing tip-substrate wave function combinations used in the corresponding transmission matrix, and (ii) to bundle up wave functions with similar symmetry in the lateral plane, so that (iii) an intuitive understanding of the STM contrast can be achieved. The theory is applied to a CO dimer adsorbed on a Cu(1 1 1) surface scanned by a single-atom Cu tip, whose STM image is discussed in detail by the outlined method.

Wave friction factor rediscovered

Science.gov (United States)

Le Roux, J. P.

2012-02-01

The wave friction factor is commonly expressed as a function of the horizontal water particle semi-excursion ( A wb) at the top of the boundary layer. A wb, in turn, is normally derived from linear wave theory by {{U_{{wb}}/T_{{w}}}}{{2π }} , where U wb is the maximum water particle velocity measured at the top of the boundary layer and T w is the wave period. However, it is shown here that A wb determined in this way deviates drastically from its real value under both linear and non-linear waves. Three equations for smooth, transitional and rough boundary conditions, respectively, are proposed to solve this problem, all three being a function of U wb, T w, and δ, the thickness of the boundary layer. Because these variables can be determined theoretically for any bottom slope and water depth using the deepwater wave conditions, there is no need to physically measure them. Although differing substantially from many modern attempts to define the wave friction factor, the results coincide with equations proposed in the 1960s for either smooth or rough boundary conditions. The findings also confirm that the long-held notion of circular water particle motion down to the bottom in deepwater conditions is erroneous, the motion in fact being circular at the surface and elliptical at depth in both deep and shallow water conditions, with only horizontal motion at the top of the boundary layer. The new equations are incorporated in an updated version (WAVECALC II) of the Excel program published earlier in this journal by Le Roux et al. Geo-Mar Lett 30(5): 549-560, (2010).

Quantum Ising model in transverse and longitudinal fields: chaotic wave functions

International Nuclear Information System (INIS)

Atas, Y Y; Bogomolny, E

2017-01-01

The construction of a statistical model for eigenfunctions of the Ising model in transverse and longitudinal fields is discussed in detail for the chaotic case. When the number of spins is large, each wave function coefficient has the Gaussian distribution with zero mean and variance calculated from the first two moments of the Hamiltonian. The main part of the paper is devoted to the discussion of various corrections to the asymptotic result. One type of correction is related to higher order moments of the Hamiltonian, and can be taken into account by Gibbs-like formulae. Other corrections are due to symmetry contributions, which manifest as different numbers of non-zero real and complex coefficients. The statistical model with these corrections included agrees well with numerical calculations of wave function moments. (paper)

Scaling observations of surface waves in the Beaufort Sea

Directory of Open Access Journals (Sweden)

Madison Smith

2016-04-01

Full Text Available Abstract The rapidly changing Arctic sea ice cover affects surface wave growth across all scales. Here, in situ measurements of waves, observed from freely-drifting buoys during the 2014 open water season, are interpreted using open water distances determined from satellite ice products and wind forcing time series measured in situ with the buoys. A significant portion of the wave observations were found to be limited by open water distance (fetch when the wind duration was sufficient for the conditions to be considered stationary. The scaling of wave energy and frequency with open water distance demonstrated the indirect effects of ice cover on regional wave evolution. Waves in partial ice cover could be similarly categorized as distance-limited by applying the same open water scaling to determine an ‘effective fetch’. The process of local wave generation in ice appeared to be a strong function of the ice concentration, wherein the ice cover severely reduces the effective fetch. The wave field in the Beaufort Sea is thus a function of the sea ice both locally, where wave growth primarily occurs in the open water between floes, and regionally, where the ice edge may provide a more classic fetch limitation. Observations of waves in recent years may be indicative of an emerging trend in the Arctic Ocean, where we will observe increasing wave energy with decreasing sea ice extent.

Dispersion relation for Bernstein waves using a new transformation for the modified Bessel function

International Nuclear Information System (INIS)

Sato, Masumi

1985-01-01

Aitken's or Shanks' transformation of the exponent-modified Bessel function produces better approximations. Dispersion relations for the hybrid and Bernstein waves using these provide better thermal and parallel wavenumber corrections. They also predict more closely the evolution and mode-conversion of these waves. (author)

Crustal structure of northern Egypt from joint inversion of receiver functions and surface wave dispersion velocities

Science.gov (United States)

Badawy, Ahmed; Hegazi, Mona; Gaber, Hanan; Korrat, Ibrahim

2018-01-01

In this study, we used a combined inversion of body wave receiver functions and surface wave dispersion measurements to provide constraints on the crustal structure of northern Egypt. The two techniques are complementary to each other: receiver functions (RFs) are sensitive to shear-wave velocity contrasts, while surface wave dispersion (SWD) measurements are sensitive to finite variations of shear-wave velocity with depth. A database of 122 teleseismic events digitally recorded by the Egyptian National Seismological Network (ENSN) stations has been used as well. To enhance the resulting RFs at each ENSN station, the H-k stacking method was applied. A joint inversion process between the resulting receiver functions and the surface wave dispersion curves was applied as well. We have produced three averaged velocity structure models for distinct geographic and tectonic provinces namely Sinai, eastern desert, and western desert from east to the west respectively. These models will deeply help in estimation the epicenter distance of earthquake, focal mechanism solutions, and earthquake hazard analysis in northern Egypt. An obvious image of the subsurface structure has been determined which shows that generally the crustal structure of northern Egypt consists of three layers covered with a sequence of sediments that differs in thickness from across the region except in the Sharm area where the sedimentary cover is absent. The obtained results indicate that crustal thickness differs from east to west and reaches its maximum value of about 36 km at Siwa station (SWA) in the western desert and its minimum value of about 28 km at Sharm station (SHR) of the southern tip of the Sinai Peninsula. The Vp/Vs ratio varies between 1.71 and 2.07 in northern Egypt. Generally, the high values (1.93) of (Vp/Vs) at SWA station may reflect the well-known rich aquifer with fully saturated sediments of the Swia Oasis in the Western Desert. Moreover, the highest value (2.07) of (Vp/Vs) at

Crustal structure of northern Egypt from joint inversion of receiver functions and surface wave dispersion velocities

Science.gov (United States)

Badawy, Ahmed; Hegazi, Mona; Gaber, Hanan; Korrat, Ibrahim

2018-05-01

In this study, we used a combined inversion of body wave receiver functions and surface wave dispersion measurements to provide constraints on the crustal structure of northern Egypt. The two techniques are complementary to each other: receiver functions (RFs) are sensitive to shear-wave velocity contrasts, while surface wave dispersion (SWD) measurements are sensitive to finite variations of shear-wave velocity with depth. A database of 122 teleseismic events digitally recorded by the Egyptian National Seismological Network (ENSN) stations has been used as well. To enhance the resulting RFs at each ENSN station, the H-k stacking method was applied. A joint inversion process between the resulting receiver functions and the surface wave dispersion curves was applied as well. We have produced three averaged velocity structure models for distinct geographic and tectonic provinces namely Sinai, eastern desert, and western desert from east to the west respectively. These models will deeply help in estimation the epicenter distance of earthquake, focal mechanism solutions, and earthquake hazard analysis in northern Egypt. An obvious image of the subsurface structure has been determined which shows that generally the crustal structure of northern Egypt consists of three layers covered with a sequence of sediments that differs in thickness from across the region except in the Sharm area where the sedimentary cover is absent. The obtained results indicate that crustal thickness differs from east to west and reaches its maximum value of about 36 km at Siwa station (SWA) in the western desert and its minimum value of about 28 km at Sharm station (SHR) of the southern tip of the Sinai Peninsula. The Vp/Vs ratio varies between 1.71 and 2.07 in northern Egypt. Generally, the high values (1.93) of (Vp/Vs) at SWA station may reflect the well-known rich aquifer with fully saturated sediments of the Swia Oasis in the Western Desert. Moreover, the highest value (2.07) of (Vp/Vs) at

Suppression of electron waves in relation to the deformation of the electron beam distribution function

International Nuclear Information System (INIS)

Fukumasa, O.; Itatani, R.

1978-01-01

The change of the electron beam distribution function due to the wave excited by the beam density modulation is observed, in relation to the suppression of electron waves in a beam-plasma system. (Auth.)

Analytic structure of the wave function for a hydrogen atom in an analytic potential

International Nuclear Information System (INIS)

Hill, R.N.

1984-01-01

The rate of convergence of an approximate method for solving Schroedinger's equation depends on the ability of the approximating sequence to mimic the analytic structure of the unknown exact wave function. Thus a knowledge of the analytic structure of the wave function can be of great value when approximation schemes are designed. Consider the Schroedinger equation [- 1/2 del 2 -r -1 +V(r)]Psi(r) = EPsi(r) for a hydrogen atom in a potential V(r). The general theory of elliptic partial differential equations implies that Psi is analytic at regular points, but no general theory is available at singular points. The present paper investigates the Coulomb singular point at r = 0 and shows that, if V(r) = V 1 (x, y, z)+rV 2 (x, y, z) where V 1 and V 2 are analytic functions of x, y, z at x = y = z = 0, then the wave function has the form Psi(r) = Psi 1 (x, y, z)+rPsi 2 (x, y, z) where Psi 1 and Psi 2 are analytic functions of x, y, z at x = y = z = 0

Measurement as absorption of Feynman trajectories: Collapse of the wave function can be avoided

International Nuclear Information System (INIS)

Marchewka, A.; Schuss, Z.

2002-01-01

We define a measuring device (detector) of the coordinate of quantum particle as an absorbing wall that cuts off the particle's wave function. The wave function in the presence of such a detector vanishes on the detector. The trace the absorbed particles leave on the detector is identified as the absorption current density on the detector. This density is calculated from the solution of Schroedinger's equation with a reflecting boundary at the detector. This current density is not the usual Schroedinger current density. We define the probability distribution of the time of arrival to a detector in terms of the absorption current density. We define coordinate measurement by an absorbing wall in terms of four postulates. In the resulting theory the quantum-mechanical collapse of the wave function is replaced with the usual collapse of the probability distribution after observation. Two measurement experiments are proposed to measure time of arrival and the probability density function of a freely propagating two-dimensional Gaussian packet from the measurement of the absorption current on two planes

Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

Energy Technology Data Exchange (ETDEWEB)

Nakra Mohajer, Soukaina; El Harouny, El Hassan [Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121 M’Hannech II, 93030 Tétouan (Morocco); Ibral, Asmaa [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B. P. 20 El Jadida Principale, El Jadida (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B. P. 20 El Jadida Principale, El Jadida (Morocco); El Khamkhami, Jamal [Laboratoire de Physique de la Matière Condensée, Département de Physique, Faculté des Sciences, Université Abdelmalek Essaadi, B.P. 2121 M’Hannech II, 93030 Tétouan (Morocco); and others

2016-09-15

Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

International Nuclear Information System (INIS)

Nakra Mohajer, Soukaina; El Harouny, El Hassan; Ibral, Asmaa; El Khamkhami, Jamal

2016-01-01

Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

On the Quantum Mechanical Wave Function as a Link Between Cognition and the Physical World A Role for Psychology

CERN Document Server

Snyder, D

2002-01-01

A straightforward explanation of fundamental tenets of quantum mechanics concerning the wave function results in the thesis that the quantum mechanical wave function is a link between human cognition and the physical world. The reticence on the part of physicists to adopt this thesis is discussed. A comparison is made to the behaviorists' consideration of mind, and the historical roots of how the problem concerning the quantum mechanical wave function arose are discussed. The basis for an empirical demonstration that the wave function is a link between human cognition and the physical world is provided through developing an experiment using methodology from psychology and physics. Based on research in psychology and physics that relied on this methodology, it is likely that Einstein, Podolsky, and Rosen's theoretical result that mutually exclusive wave functions can simultaneously apply to the same concrete physical circumstances can be implemented on an empirical level.

Capillary waves at the interface of two Bose–Einstein condensates. Long wavelengths asymptotic by trial function approach

International Nuclear Information System (INIS)

Mishonov, T.M.

2015-01-01

The dispersion relation for capillary waves at the boundary of two different Bose condensates is investigated using a trial wave-function approach applied to the Gross-Pitaevskii (GP) equations. The surface tension is expressed by the parameters of the GP equations. In the long wave-length limit the usual dispersion relation is re-derived while for wavelengths comparable to the healing length we predict significant deviations from the ω ∝ k 3/2 law which can be experimentally observed. We approximate the wave variables by a frozen order parameter, i.e. the wave function is frozen in the superfluid analogous to the magnetic field in highly conductive space plasmas. PACS codes: 67.85.Jk

Energy spectra and wave function of trigonometric Rosen-Morse potential as an effective quantum chromodynamics potential in D-dimensions

Energy Technology Data Exchange (ETDEWEB)

Deta, U. A., E-mail: utamaalan@yahoo.co.id [Theoretical Physics Group, Physics Department of Post Graduate Program, Sebelas Maret University, Jl. Ir. Sutami 36A, Surakarta 57126, Indonesia and Physics Department, State University of Surabaya, Jl. Ketintang, Surabaya 60231 (Indonesia); Suparmi,; Cari,; Husein, A. S.; Yuliani, H.; Khaled, I. K. A.; Luqman, H.; Supriyanto [Theoretical Physics Group, Physics Department of Post Graduate Program, Sebelas Maret University, Jl. Ir. Sutami 36A, Surakarta 57126 (Indonesia)

2014-09-30

The Energy Spectra and Wave Function of Schrodinger equation in D-Dimensions for trigonometric Rosen-Morse potential were investigated analytically using Nikiforov-Uvarov method. This potential captures the essential traits of the quark-gluon dynamics of Quantum Chromodynamics. The approximate energy spectra are given in the close form and the corresponding approximate wave function for arbitrary l-state (l ≠ 0) in D-dimensions are formulated in the form of differential polynomials. The wave function of this potential unnormalizable for general case. The wave function of this potential unnormalizable for general case. The existence of extra dimensions (centrifugal factor) and this potential increase the energy spectra of system.

Towards Finding the Global Minimum of the D-Wave Objective Function for Improved Neural Network Regressions

Science.gov (United States)

Dorband, J. E.

2017-12-01

The D-Wave 2X has successfully been used for regression analysis to derive carbon flux data from OCO-2 CO2 concentration using neural networks. The samples returned from the D-Wave should represent the minimum of an objective function presented to it. An accurate as possible minimum function value is needed for this analysis. Samples from the D-Wave are near minimum, but seldom are the global minimum of the function due to quantum noise. Two methods for improving the accuracy of minimized values represented by the samples returned from the D-Wave are presented. The first method finds a new sample with a minimum value near each returned D-Wave sample. The second method uses all the returned samples to find a more global minimum sample. We present three use-cases performed using the former method. In the first use case, it is demonstrated that an objective function with random qubits and coupler coefficients had an improved minimum. In the second use case, the samples corrected by the first method can improve the training of a Boltzmann machine neural network. The third use case demonstrated that using the first method can improve virtual qubit accuracy.The later method was also performed on the first use case.

Is wave-particle objectivity compatible with determinism and locality?

Science.gov (United States)

Ionicioiu, Radu; Jennewein, Thomas; Mann, Robert B; Terno, Daniel R

2014-09-26

Wave-particle duality, superposition and entanglement are among the most counterintuitive features of quantum theory. Their clash with our classical expectations motivated hidden-variable (HV) theories. With the emergence of quantum technologies, we can test experimentally the predictions of quantum theory versus HV theories and put strong restrictions on their key assumptions. Here, we study an entanglement-assisted version of the quantum delayed-choice experiment and show that the extension of HV to the controlling devices only exacerbates the contradiction. We compare HV theories that satisfy the conditions of objectivity (a property of photons being either particles or waves, but not both), determinism and local independence of hidden variables with quantum mechanics. Any two of the above conditions are compatible with it. The conflict becomes manifest when all three conditions are imposed and persists for any non-zero value of entanglement. We propose an experiment to test our conclusions.

Imaging electron wave functions inside open quantum rings.

Science.gov (United States)

Martins, F; Hackens, B; Pala, M G; Ouisse, T; Sellier, H; Wallart, X; Bollaert, S; Cappy, A; Chevrier, J; Bayot, V; Huant, S

2007-09-28

Combining scanning gate microscopy (SGM) experiments and simulations, we demonstrate low temperature imaging of the electron probability density |Psi|(2)(x,y) in embedded mesoscopic quantum rings. The tip-induced conductance modulations share the same temperature dependence as the Aharonov-Bohm effect, indicating that they originate from electron wave function interferences. Simulations of both |Psi|(2)(x,y) and SGM conductance maps reproduce the main experimental observations and link fringes in SGM images to |Psi|(2)(x,y).

The quantum dual string wave functional in Yang-Mills theories

International Nuclear Information System (INIS)

Gervais, J.-L.; Neveu, A.

1979-01-01

From any solution of the classical Yang-Mills equations, a string wave functional based on the Wilson loop integral is defined. Its precise definition is given by replacing the string by a finite set of N points, and taking the limit N → infinity. It is shown that this functional satisfies the Schroedinger equation of the relativistic dual string to leading order in N. The relevance of this object to the quantum problem is speculated. (Auth.)

The Yang-Mills vacuum wave functional in Coulomb gauge

International Nuclear Information System (INIS)

Campagnari, Davide R.

2011-01-01

Yang-Mills theories are the building blocks of today's Standard Model of elementary particle physics. Besides methods based on a discretization of space-time (lattice gauge theory), also analytic methods are feasible, either in the Lagrangian or in the Hamiltonian formulation of the theory. This thesis focuses on the Hamiltonian approach to Yang-Mills theories in Coulomb gauge. The thesis is presented in cumulative form. After an introduction into the general formulation of Yang-Mills theories, the Hamilton operator in Coulomb gauge is derived. Chap. 1 deals with the heat-kernel expansion of the Faddeev-Popov determinant. In Chapters 2 and 3, the high-energy behaviour of the theory is investigated. To this purpose, perturbative methods are applied, and the results are compared with the ones stemming from functional methods in Coulomb and Landau gauge. Chap. 4 is devoted to the variational approach. Variational ansatzes going beyond the Gaussian form for the vacuum wave functional are considered and treated using Dyson-Schwinger techniques. Equations for the higher-order variational kernels are derived and their effects are estimated. Chap. 5 presents an application of the previously obtained propagators, namely the evaluation of the topological susceptibility, which is related to the mass of the η meson. Finally, a short overview of the perturbative treatment of dynamical fermion fields is presented.

Bound-state wave functions at rest in describing deep inelastic scattering

International Nuclear Information System (INIS)

Khvedelidze, A.M.; Kvinikhidze, A.N.

1991-01-01

The deep inelastic process of the lepton-hadron scattering is studied in the bound-state rest frame. A new version of expanding structure functions in interaction constant powers is proposed, each term in it having spectral properties. This expansion makes it possible to consider contributions of composites in the final state to the cross section. It is shown that, as compared with the system P z →∞, the impulse approximation is insufficient for describing correctly the elastic limit in the composite particle rest frame. The leading asymptotics of structure functions as χ Bj →1 can be obtained by taking into account the interaction of contituents in the final state. It is shown that in contrast to the 'light-cone' formalism the ratio F 2 en (χ)/F 2 ep (χ) as χ Bj →1 depends on the explicit form of the spatial part of the nucleon wave function and, in particular, assuming the relativistic character of internal motion, it may be lower than the well-known prediction (i.e. 3/7). This is due to the correct consideration of spin degrees of freedom of the wave function of the nucleon at rest. (orig.)

Lithospheric Structure of the Arabian Shield from the Joint Inversion of Receiver Function and Surface-Wave Dispersion Observations

National Research Council Canada - National Science Library

Julia, Jordi; Ammon, Charles J; Herrimann, Robert B

2006-01-01

.... Receiver functions are primarily sensitive to shear-wave velocity contrasts and vertical travel times and surface-wave dispersion measurements are sensitive to vertical shear-wave velocity averages...

Lithospheric Structure of the Arabian Shield From the Joint Inversion of Receiver Function and Surface-Wave Dispersion Observations

National Research Council Canada - National Science Library

Herrmann, Robert B; Julia, Jordi; Ammon, Charles J

2007-01-01

.... Receiver functions are primarily sensitive to shear-wave velocity contrast and vertical travel times and surface-wave dispersion measurements are sensitive to vertical shear-wave velocity averages...

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.

2010-02-01

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.

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.

Configuration mixing of mean-field wave functions projected on angular momentum and particle number: Application to 24Mg

International Nuclear Information System (INIS)

Valor, A.; Heenen, P.-H.; Bonche, P.

2000-01-01

We present in this paper the general framework of a method which permits to restore the rotational and particle number symmetries of wave functions obtained in Skyrme HF + BCS calculations. This restoration is nothing but a projection of mean-field intrinsic wave functions onto good particle number and good angular momentum. The method allows us also to mix projected wave functions. Such a configuration mixing is discussed for sets of HF + BCS intrinsic states generated in constrained calculations with suitable collective variables. This procedure gives collective states which are eigenstates of the particle number and the angular momentum operators and between which transition probabilities are calculated. An application to 24 Mg is presented, with mean-field wave functions generated by axial quadrupole constraints. Theoretical spectra and transition probabilities are compared to the experiment

Covariant two-particle wave functions for model quasipotential allowing exact solutions

International Nuclear Information System (INIS)

Kapshaj, V.N.; Skachkov, N.B.

1982-01-01

Two formulations of quasipotential equations in the relativistic configurational representation are considered for the wave function of relative motion of a bound state of two relativistic particles. Exact solutions of these equations are found for some model quasipotentials

Compact two-electron wave function for bond dissociation and Van der Waals interactions: a natural amplitude assessment.

Science.gov (United States)

Giesbertz, Klaas J H; van Leeuwen, Robert

2014-05-14

Electron correlations in molecules can be divided in short range dynamical correlations, long range Van der Waals type interactions, and near degeneracy static correlations. In this work, we analyze for a one-dimensional model of a two-electron system how these three types of correlations can be incorporated in a simple wave function of restricted functional form consisting of an orbital product multiplied by a single correlation function f (r12) depending on the interelectronic distance r12. Since the three types of correlations mentioned lead to different signatures in terms of the natural orbital (NO) amplitudes in two-electron systems, we make an analysis of the wave function in terms of the NO amplitudes for a model system of a diatomic molecule. In our numerical implementation, we fully optimize the orbitals and the correlation function on a spatial grid without restrictions on their functional form. Due to this particular form of the wave function, we can prove that none of the amplitudes vanishes and moreover that it displays a distinct sign pattern and a series of avoided crossings as a function of the bond distance in agreement with the exact solution. This shows that the wave function ansatz correctly incorporates the long range Van der Waals interactions. We further show that the approximate wave function gives an excellent binding curve and is able to describe static correlations. We show that in order to do this the correlation function f (r12) needs to diverge for large r12 at large internuclear distances while for shorter bond distances it increases as a function of r12 to a maximum value after which it decays exponentially. We further give a physical interpretation of this behavior.

Interface waves propagating along tensile fractures in dolomite

International Nuclear Information System (INIS)

Roy, S.; Pyrak-Nolte, L.J.

1995-01-01

Elastic interface waves have been observed in induced tensile fractures in dolomite rock cores. Multiscaling wavelet analysis distinguishes the interface wave from bulk shear waves, quantifies the interface wave spectral content, and determines the arrival time of peak energy. The dominant seismic energy is concentrated in the slow interface wave, with little or no detectable energy in the fast wave. As stress across the fracture increases, the slow interface wave velocity increases, and the frequency of the spectral peak shifts to higher frequencies. The shear dynamic specific stiffness of the fracture was calculated from the peak energy arrival time as a function of stress. 13 refs., 5 figs., 1 tab

Determining integral density distribution in the mach reflection of shock waves

Science.gov (United States)

Shevchenko, A. M.; Golubev, M. P.; Pavlov, A. A.; Pavlov, Al. A.; Khotyanovsky, D. V.; Shmakov, A. S.

2017-05-01

We present a method for and results of determination of the field of integral density in the structure of flow corresponding to the Mach interaction of shock waves at Mach number M = 3. The optical diagnostics of flow was performed using an interference technique based on self-adjusting Zernike filters (SA-AVT method). Numerical simulations were carried out using the CFS3D program package for solving the Euler and Navier-Stokes equations. Quantitative data on the distribution of integral density on the path of probing radiation in one direction of 3D flow transillumination in the region of Mach interaction of shock waves were obtained for the first time.

Wave functions, evolution equations and evolution kernels form light-ray operators of QCD

International Nuclear Information System (INIS)

Mueller, D.; Robaschik, D.; Geyer, B.; Dittes, F.M.; Horejsi, J.

1994-01-01

The widely used nonperturbative wave functions and distribution functions of QCD are determined as matrix elements of light-ray operators. These operators appear as large momentum limit of non-local hardron operators or as summed up local operators in light-cone expansions. Nonforward one-particle matrix elements of such operators lead to new distribution amplitudes describing both hadrons simultaneously. These distribution functions depend besides other variables on two scaling variables. They are applied for the description of exclusive virtual Compton scattering in the Bjorken region near forward direction and the two meson production process. The evolution equations for these distribution amplitudes are derived on the basis of the renormalization group equation of the considered operators. This includes that also the evolution kernels follow from the anomalous dimensions of these operators. Relations between different evolution kernels (especially the Altarelli-Parisi and the Brodsky-Lepage kernels) are derived and explicitly checked for the existing two-loop calculations of QCD. Technical basis of these resluts are support and analytically properties of the anomalous dimensions of light-ray operators obtained with the help of the α-representation of Green's functions. (orig.)

Traveling waves in a diffusive predator-prey model with holling type-III functional response

International Nuclear Information System (INIS)

Li Wantong; Wu Shiliang

2008-01-01

We establish the existence of traveling wave solutions and small amplitude traveling wave train solutions for a reaction-diffusion system based on a predator-prey model with Holling type-III functional response. The analysis is in the three-dimensional phase space of the nonlinear ordinary differential equation system given by the diffusive predator-prey system in the traveling wave variable. The methods used to prove the results are the shooting argument, invariant manifold theory and the Hopf bifurcation theorem

SCATTERING OF SPIN WAVES BY MAGNETIC DEFECTS

Energy Technology Data Exchange (ETDEWEB)

Callaway, Joseph

1962-12-15

The scattering of spin waves by magnetic point defects is considered using a Green's function method. A partial wave expansion for the scattering amplitude is derived. An expression for the cross section is determined that includes the effect of resonant states. Application is made to the calculation of the thermal conductivity of an insulating ferromagnet. (auth)

Covariant two-particle wave functions for model quasipotentials admitting exact solutions

International Nuclear Information System (INIS)

Kapshaj, V.N.; Skachkov, N.B.

1983-01-01

Two formulations of quasipotential equations in the relativistic configurational representation are considered for the wave function of the internal motion of the bound system of two relativistic particles. Exact solutions of these equations are found for some model quasipotentials

Joint Inversion of Surface Waves Dispersion and Receiver Function at Cuba Seismic Stations

International Nuclear Information System (INIS)

Gonzalez, O'Leary; Moreno, Bladimir; Romanelli, Fabio; Panza, Giuliano F.

2010-06-01

Joint inversion of Rayleigh wave group velocity dispersion and receiver functions have been used to estimate the crust and upper mantle structure at eight seismic stations in Cuba. Receiver functions have been computed from teleseismic recordings of earthquakes at epicentral (angular) distances between 30 o and 90 o and Rayleigh wave group velocity dispersion have been taken from a surface-wave tomography study of the Caribbean area. The thickest crust (around 27 km) is found at Cascorro (CCC), Soroa (SOR), Moa (MOA) and Maisi (MAS) stations while the thinnest crust (around 18 km) is found at stations Rio Carpintero (RCC) and Guantanamo Bay (GTBY), in the southeastern of Cuba; this result is in agreement with the southward gradual thinning of the crust revealed by previous studies. The inversion shows a crystalline crust with S-wave velocity between 2.9 km/s and 3.9 km/s and at the crust-mantle transition zone the shear wave velocity varies from 3.9 km/s and 4.3 km/s. The lithospheric thickness varies from 74 km, in the youngest lithosphere, to 200 km in the middle of the Cuban island. Evidences of a subducted slab possibly belonging to the Caribbean plate are present below the stations Las Mercedes (LMG), RCC and GTBY and a thicker slab is present below the SOR station. (author)

Investigation of Wave Transmission from a Floating Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

2012-01-01

This paper focuses on the calibration of the MIKE21BW model against the measured wave height reduction behind a 24 kW/m Wave Dragon (WD) wave energy converter. A numerical model is used to determine the wave transmission through the floating WD in varying wave conditions. The transmission obtained...

Publisher Correction: Imaging the square of the correlated two-electron wave function of a hydrogen molecule.

Science.gov (United States)

Waitz, M; Bello, R Y; Metz, D; Lower, J; Trinter, F; Schober, C; Keiling, M; Lenz, U; Pitzer, M; Mertens, K; Martins, M; Viefhaus, J; Klumpp, S; Weber, T; Schmidt, L Ph H; Williams, J B; Schöffler, M S; Serov, V V; Kheifets, A S; Argenti, L; Palacios, A; Martín, F; Jahnke, T; Dörner, R

2018-06-05

The original version of this Article contained an error in the fifth sentence of the first paragraph of the 'Application on H 2 ' section of the Results, which incorrectly read 'The role of electron correlation is quite apparent in this presentation: Fig. 1a is empty for the uncorrelated Hartree-Fock wave function, since projection of the latter wave function onto the 2pσ u orbital is exactly zero, while this is not the case for the fully correlated wave function (Fig. 1d); also, Fig. 1b, c for the uncorrelated description are identical, while Fig. 1e, f for the correlated case are significantly different.' The correct version replaces 'Fig. 1e, f' with 'Fig. 2e and f'.

Love waves in functionally graded piezoelectric materials by stiffness matrix method.

Science.gov (United States)

Ben Salah, Issam; Wali, Yassine; Ben Ghozlen, Mohamed Hédi

2011-04-01

A numerical matrix method relative to the propagation of ultrasonic guided waves in functionally graded piezoelectric heterostructure is given in order to make a comparative study with the respective performances of analytical methods proposed in literature. The preliminary obtained results show a good agreement, however numerical approach has the advantage of conceptual simplicity and flexibility brought about by the stiffness matrix method. The propagation behaviour of Love waves in a functionally graded piezoelectric material (FGPM) is investigated in this article. It involves a thin FGPM layer bonded perfectly to an elastic substrate. The inhomogeneous FGPM heterostructure has been stratified along the depth direction, hence each state can be considered as homogeneous and the ordinary differential equation method is applied. The obtained solutions are used to study the effect of an exponential gradient applied to physical properties. Such numerical approach allows applying different gradient variation for mechanical and electrical properties. For this case, the obtained results reveal opposite effects. The dispersive curves and phase velocities of the Love wave propagation in the layered piezoelectric film are obtained for electrical open and short cases on the free surface, respectively. The effect of gradient coefficients on coupled electromechanical factor, on the stress fields, the electrical potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the well known heterostructure PZT-5H/SiO(2), the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Love wave propagation behaviour. Copyright © 2010 Elsevier B.V. All rights reserved.

Dynamic selection of ship responses for estimation of on-site directional wave spectra

DEFF Research Database (Denmark)

Andersen, Ingrid Marie Vincent; Storhaug, Gaute

2012-01-01

-estimate of the wave spectrum is suggested. The selection method needs to be robust for what reason a parameterised uni-directional, two-parameter wave spectrum is treated. The parameters included are the zero up-crossing period, the significant wave height and the main wave direction relative to the ship’s heading...... with the best overall agreement are selected for the actual estimation of the directional wave spectrum. The transfer functions for the ship responses can be determined using different computational methods such as striptheory, 3D panel codes, closed form expressions or model tests. The uncertainty associated......Knowledge of the wave environment in which a ship is operating is crucial for most on-board decision support systems. Previous research has shown that the directional wave spectrum can be estimated by the use of measured global ship responses and a set of transfer functions determined...

[Factorial division of the visual N1 wave and functional significance].

Science.gov (United States)

Munoz-Ruata, J; Caro-Martinez, E

2011-05-16

It has been argued if the frontal, N1a, is the early part of the occipito-temporal, N1b, or there are two different waves. It is also not clear whether the N1 of distractor is equivalent to the target N1, neither to distinguish these four waves has some functional value. We performed a principal component analysis of latencies and amplitudes of N1 derived from an oddball visual paradigm in a sample of 82 persons with intellectual disability, and factor scores were correlated with measures of intellectual performance on the Wechsler Intelligence Scale for Children-Fourth Edition. There is not significant dependency between N1a and N1b waves. The N1 from the target stimulus is functionally different to the N1 from the distractor. The N1a 'target' is related to the perceptual reasoning while the N1a 'distractor' is related to the working memory. The correlation between latencies and amplitudes of the target stimuli in posterior locations suggests that, similar to as observed in auditory areas, there is a visual synchronization with the prefrontal cortex; its dysfunction may explain some of the perceptual problems of people with intellectual disabilities.

Ground state energy and wave function of an off-centre donor in spherical core/shell nanostructures: Dielectric mismatch and impurity position effects

Energy Technology Data Exchange (ETDEWEB)

Ibral, Asmaa [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida 24000 (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida (Morocco); Zouitine, Asmae [Département de Physique, Ecole Nationale Supérieure d’Enseignement Technique, Université Mohammed V Souissi, B.P. 6207 Rabat-Instituts, Rabat (Morocco); Assaid, El Mahdi, E-mail: eassaid@yahoo.fr [Equipe d’Optique et Electronique du Solide, Département de Physique, Faculté des Sciences, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida 24000 (Morocco); Laboratoire d’Instrumentation, Mesure et Contrôle, Département de Physique, Université Chouaïb Doukkali, B.P. 20 El Jadida Principale, El Jadida (Morocco); Feddi, El Mustapha [Département de Physique, Ecole Nationale Supérieure d’Enseignement Technique, Université Mohammed V Souissi, B.P. 6207 Rabat-Instituts, Rabat (Morocco); and others

2014-09-15

Ground state energy and wave function of a hydrogen-like off-centre donor impurity, confined anywhere in a ZnS/CdSe spherical core/shell nanostructure are determined in the framework of the envelope function approximation. Conduction band-edge alignment between core and shell of nanostructure is described by a finite height barrier. Dielectric constant mismatch at the surface where core and shell materials meet is taken into account. Electron effective mass mismatch at the inner surface between core and shell is considered. A trial wave function where coulomb attraction between electron and off-centre ionized donor is used to calculate ground state energy via the Ritz variational principle. The numerical approach developed enables access to the dependence of binding energy, coulomb correlation parameter, spatial extension and radial probability density with respect to core radius, shell radius and impurity position inside ZnS/CdSe core/shell nanostructure.

Ground state energy and wave function of an off-centre donor in spherical core/shell nanostructures: Dielectric mismatch and impurity position effects

International Nuclear Information System (INIS)

Ibral, Asmaa; Zouitine, Asmae; Assaid, El Mahdi; Feddi, El Mustapha

2014-01-01

Ground state energy and wave function of a hydrogen-like off-centre donor impurity, confined anywhere in a ZnS/CdSe spherical core/shell nanostructure are determined in the framework of the envelope function approximation. Conduction band-edge alignment between core and shell of nanostructure is described by a finite height barrier. Dielectric constant mismatch at the surface where core and shell materials meet is taken into account. Electron effective mass mismatch at the inner surface between core and shell is considered. A trial wave function where coulomb attraction between electron and off-centre ionized donor is used to calculate ground state energy via the Ritz variational principle. The numerical approach developed enables access to the dependence of binding energy, coulomb correlation parameter, spatial extension and radial probability density with respect to core radius, shell radius and impurity position inside ZnS/CdSe core/shell nanostructure

On a functional equation related to the intermediate long wave equation

International Nuclear Information System (INIS)

Hone, A N W; Novikov, V S

2004-01-01

We resolve an open problem stated by Ablowitz et al (1982 J. Phys. A: Math. Gen. 15 781) concerning the integral operator appearing in the intermediate long wave equation. We explain how this is resolved using the perturbative symmetry approach introduced by one of us with Mikhailov. By solving a certain functional equation, we prove that the intermediate long wave equation and the Benjamin-Ono equation are the unique integrable cases within a particular class of integro-differential equations. Furthermore, we explain how the perturbative symmetry approach is naturally extended to treat equations on a periodic domain. (letter to the editor)

Simultaneous projection of particle-number and angular momentum BCS wave-functions in the rare-earth nuclei

International Nuclear Information System (INIS)

Oudih, M.R.; Fellah, M.; Allal, N.H.; Benhamouda, N.

1999-01-01

It is well established that the BCS wave-functions are neither eigen-functions of the particle-number operator nor of the angular momentum operator. In a previous paper, we have developed a particle-number projection before variation method (of FBCS type). This discrete projection method is based on the SBCS wave-function. The aim of the present contribution is to perform a subsequent angular momentum projection by means of the Peierls-Yoccoz method. The general expression of the system energy, after the double projection, is established in the case of axial symmetry. For practical calculations, an approximation method is introduced. It leads to a semi-classical form of the rotational energy. The rotational spectra have been evaluated numerically for some even-even rare-earth nuclei. The single-particle energies and eigen-states are those of a deformed Woods-Saxon mean field. The obtained results are compared on one hand, to the experimental data, and on the other hand, to the theoretical spectra evaluated by a particle-number projection after variation method (of PBCS type). For all studied nuclei, the spectra determined by the FBCS method reproduce the experimental data better than those of the PBCS method. However, even if the present method is satisfying for low angular momenta, the agreement with the experimental data is lesser for I ≥ 8, particularly for the lighter studied nuclei. (authors)

Natural generalization of Slater determinants to more than one dimension

Science.gov (United States)

Sunko, Denis

The calculation of realistic N-body wave functions for identical fermions is still an open problem in physics, chemistry, and materials science, even for N as small as two. Here a fundamental algebraic structure of many-body Hilbert space is described, enabling theoretically well-founded systematic investigation of wave-function space. The structure allows an arbitrary many-fermion wave function to be written in terms of a finite number of antisymmetric functions called shapes, which cannot be constructed by combining one-dimensional wave functions. Shapes naturally generalize the single-Slater-determinant form for the ground state to more than one dimension. Their number is exactly N! d - 1 in d dimensions. A general algorithm is given to list them all in terms of standard Slater determinants. Conversely, excitations which can be induced from the one-dimensional case are bosonised into a system of distinguishable bosons, called Euler bosons, much like the electromagnetic field is quantized in terms of photons distinguishable by their wave numbers. Their wave functions are given explicitly in terms of elementary symmetric functions, reflecting the fact that the fermion sign problem is trivial in one dimension. The shapes are all possible vacua for the Euler bosons.

Computer network defense through radial wave functions

Science.gov (United States)

Malloy, Ian J.

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

Photo double ionization of He: C3-like wave function for the two electron continuum

Energy Technology Data Exchange (ETDEWEB)

Otranto, S.; Garibotti, C.R. [Conicet and Centro Atomico Bariloche (Argentina); Otranto, S. [Universidad Nacional del Sur, Dept. de Fisica, Bahia Blanca (Argentina)

2002-12-01

We evaluate the triply differential cross-section (TDCS) for photo double ionization (PDI) of helium. A first approximation to the final state can be obtained by neglecting the e-e interaction and the non-orthogonal kinetic energy. This leads to the C2 model which proposes as solution a product of 2 independent Coulomb wave plane waves. A better approximation is the C3 model where the C3 wave describes the e-e motion as independent of the presence of the nucleus and represents it by a Coulomb continuum wave. The C3 wave function mainly consists in the product of 3 Coulomb waves, each one representing the interaction between a pair of particles. We use a C3 final continuum wave function with an inter-electronic effective coordinate to express the nuclear screening. Comparison with the standard C3 model shows that the TDCS is enhanced in the threshold region by effect of the reduced inter-electronic repulsion introduced by the present model. A more accurate description of the intermediate energy region is also obtained. Comparison with recent experimental data shows a good overall agreement of the angular distributions. The theoretical PDI total cross-section shows a relevant improvement in the intermediate energy region relative to the C3 model, which converges to data for photon energies larger than 1 keV.

Photo double ionization of He: C3-like wave function for the two electron continuum

International Nuclear Information System (INIS)

Otranto, S.; Garibotti, C.R.; Otranto, S.

2002-01-01

We evaluate the triply differential cross-section (TDCS) for photo double ionization (PDI) of helium. A first approximation to the final state can be obtained by neglecting the e-e interaction and the non-orthogonal kinetic energy. This leads to the C2 model which proposes as solution a product of 2 independent Coulomb wave plane waves. A better approximation is the C3 model where the C3 wave describes the e-e motion as independent of the presence of the nucleus and represents it by a Coulomb continuum wave. The C3 wave function mainly consists in the product of 3 Coulomb waves, each one representing the interaction between a pair of particles. We use a C3 final continuum wave function with an inter-electronic effective coordinate to express the nuclear screening. Comparison with the standard C3 model shows that the TDCS is enhanced in the threshold region by effect of the reduced inter-electronic repulsion introduced by the present model. A more accurate description of the intermediate energy region is also obtained. Comparison with recent experimental data shows a good overall agreement of the angular distributions. The theoretical PDI total cross-section shows a relevant improvement in the intermediate energy region relative to the C3 model, which converges to data for photon energies larger than 1 keV

An analysis of the accuracy of an initial value representation surface hopping wave function in the interaction and asymptotic regions

International Nuclear Information System (INIS)

Sergeev, Alexey; Herman, Michael F.

2006-01-01

The behavior of an initial value representation surface hopping wave function is examined. Since this method is an initial value representation for the semiclassical solution of the time independent Schroedinger equation for nonadiabatic problems, it has computational advantages over the primitive surface hopping wave function. The primitive wave function has been shown to provide transition probabilities that accurately compare with quantum results for model problems. The analysis presented in this work shows that the multistate initial value representation surface hopping wave function should approach the primitive result in asymptotic regions and provide transition probabilities with the same level of accuracy for scattering problems as the primitive method

Relativistic form factors for hadrons with quark-model wave functions

International Nuclear Information System (INIS)

Stanley, D.P.; Robson, D.

1982-01-01

The relationship between relativistic form factors and quark-potential-model wave functions is examined using an improved version of an approach by Licht and Pagnamenta. Lorentz-contraction effects are expressed in terms of an effective hadron mass which varies as the square root of the number of quark constituents. The effective mass is calculated using the rest-frame wave functions from the mean-square momentum along the direction of the momentum transfer. Applications with the parameter-free approach are made to the elastic form factors of the pion, proton, and neutron using a Hamiltonian which simultaneously describes mesons and baryons. A comparison of the calculated radii for pions and kaons suggests that the measured kaon radius should be slightly smaller than the corresponding pion radius. The large negative squared charge radius for the neutron is partially explained via the quark model but a full description requires the inclusion of a small component of a pion ''cloud'' configuration. The problematic connection between the sizes of hadrons deduced from form factors and the ''measured'' values of average transverse momenta is reconciled in the present model

Application of the Exp-function method to the equal-width wave equation

International Nuclear Information System (INIS)

Biazar, J; Ayati, Z

2008-01-01

In this paper, the Exp-function method is used to find an exact solution of the equal-width wave (EW) equation. The method is straightforward and concise, and its applications are promising. It is shown that the Exp-function method, with the help of symbolic computation, provides a very effective and powerful mathematical tool for solving the EW equation.

Estimating the Wet-Rock P-Wave Velocity from the Dry-Rock P-Wave Velocity for Pyroclastic Rocks

Science.gov (United States)

Kahraman, Sair; Fener, Mustafa; Kilic, Cumhur Ozcan

2017-07-01

Seismic methods are widely used for the geotechnical investigations in volcanic areas or for the determination of the engineering properties of pyroclastic rocks in laboratory. Therefore, developing a relation between the wet- and dry-rock P-wave velocities will be helpful for engineers when evaluating the formation characteristics of pyroclastic rocks. To investigate the predictability of the wet-rock P-wave velocity from the dry-rock P-wave velocity for pyroclastic rocks P-wave velocity measurements were conducted on 27 different pyroclastic rocks. In addition, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theories and it was seen that estimates for saturated P-wave velocity from the theories fit well measured data. For samples having values of less and greater than 20%, practical equations were derived for reliably estimating wet-rock P-wave velocity as function of dry-rock P-wave velocity.

Determination of Rayleigh wave ellipticity using single-station and array-based processing of ambient seismic noise

Science.gov (United States)

Workman, Eli Joseph

We present a single-station method for the determination of Rayleigh wave ellipticity, or Rayleigh wave horizontal to vertical amplitude ratio (H/V) using Frequency Dependent Polarization Analysis (FDPA). This procedure uses singular value decomposition of 3-by-3 spectral covariance matrices over 1-hr time windows to determine properties of the ambient seismic noise field such as particle motion and dominant wave-type. In FPDA, if the noise is mostly dominated by a primary singular value and the phase difference is roughly 90° between the major horizontal axis and the vertical axis of the corresponding singular vector, we infer that Rayleigh waves are dominant and measure an H/V ratio for that hour and frequency bin. We perform this analysis for all available data from the Earthscope Transportable Array between 2004 and 2014. We compare the observed Rayleigh wave H/V ratios with those previously measured by multicomponent, multistation noise cross-correlation (NCC), as well as classical noise spectrum H/V ratio analysis (NSHV). At 8 sec the results from all three methods agree, suggesting that the ambient seismic noise field is Rayleigh wave dominated. Between 10 and 30 sec, while the general pattern agrees well, the results from FDPA and NSHV are persistently slightly higher ( 2%) and significantly higher (>20%), respectively, than results from the array-based NCC. This is likely caused by contamination from other wave types (i.e., Love waves, body waves, and tilt noise) in the single station methods, but it could also reflect a small, persistent error in NCC. Additionally, we find that the single station method has difficulty retrieving robust Rayleigh wave H/V ratios within major sedimentary basins, such as the Williston Basin and Mississippi Embayment, where the noise field is likely dominated by reverberating Love waves.

Sun glitter imaging of submarine sand waves on the Taiwan Banks: Determination of the relaxation rate of short waves

Science.gov (United States)

Shao, Hao; Li, Yan; Li, Li

2011-06-01

Above sand waves on the seafloor, surface short waves, which are responsible for the radiance distribution in remote sensing imagery, are modulated gradually by the submarine topography. The relaxation rate μr characterizes the rate at which the short waves reach their saturation range after being disturbed. It is a key parameter in the weak hydrodynamic interaction theory and is also a most important parameter in the imaging mechanism used for mapping submarine bottom topography. In this study, a robust expression containing intensity and phase (advection effect) modulations of the perturbed action spectrum of short waves was deduced, by using the first-order weak hydrodynamic interaction theory. On the basis of the phase modulation, a method was developed to determine the relaxation rate in the Sun glitter imaging mechanism. The relaxation rates were estimated using in situ data measured on a cruise over the sand waves of the Taiwan Banks, a sea area between the East China Sea and the South China Sea, on 28-29 August 2006. Results showed that, under a wind speed of 5.0 m s-1, the relaxation rate of short waves was about 0.055 s-1 in response to current variations and about 0.025 s-1 equivalently in response to sea bottom topographic variations. The former value could be applied to interpret the amplitude of submarine topography by using satellite imagery, while the latter one (equivalent relaxation rate μ'r) could help to more accurately calibrate the spatial position of the retrieved sea bottom topography.

A simplified method of evaluating the stress wave environment of internal equipment

Science.gov (United States)

Colton, J. D.; Desmond, T. P.

1979-01-01

A simplified method called the transfer function technique (TFT) was devised for evaluating the stress wave environment in a structure containing internal equipment. The TFT consists of following the initial in-plane stress wave that propagates through a structure subjected to a dynamic load and characterizing how the wave is altered as it is transmitted through intersections of structural members. As a basis for evaluating the TFT, impact experiments and detailed stress wave analyses were performed for structures with two or three, or more members. Transfer functions that relate the wave transmitted through an intersection to the incident wave were deduced from the predicted wave response. By sequentially applying these transfer functions to a structure with several intersections, it was found that the environment produced by the initial stress wave propagating through the structure can be approximated well. The TFT can be used as a design tool or as an analytical tool to determine whether a more detailed wave analysis is warranted.

An unambiguous determination of the propagation of a compressional Pc 5 wave

International Nuclear Information System (INIS)

Lin, N.; McPherron, R.L.; Kivelson, M.G.; Williams, D.J.

1988-01-01

During a 3-hour interval on August 21 and 22, 1978, a compressional Pc 5 event was observed by the ISEE-1 magnetometer and medium energetic particle experiment instrument. The finite Larmor radii of the energetic protons allow the authors to determine unambiguously both the azimuthal and radial components of the phase velocity, and consequently the wave length and the azimuthal wave number. A 2nπ ambiguity in evaluating the phase velocity is removed by finding a consistent and physically reasonable solution for different energy channels. As the spacecraft approached the plasmapause, a quasi-sinusoidal wave form having a 165-s period was observed; it was found to be propagating azimuthally westward with a phase velocity of about 33 km/s and an azimuthal wave number of 60. In the outer magnetosphere, more irregular wave forms were observed. These waves also porpagated azimuthally westward and may possibly have had a small earthward (radial) component of phase velocity. To examine the effect of heavy ions on the estimated wavelength, the authors have derived the perturbation of differential flux by calculating the first-order perturbed phase space distribution of plasma consisting of two ion species. They found that, for the detector they used, the effect is very small even there is a significant fraction of heavy ions present. In all cases the modulation amplitude of ion fluxes decreases with an increasing ratio of the ion Larmor radius to the wavelength

Time-dependent density-functional theory in the projector augmented-wave method

DEFF Research Database (Denmark)

Walter, Michael; Häkkinen, Hannu; Lehtovaara, Lauri

2008-01-01

We present the implementation of the time-dependent density-functional theory both in linear-response and in time-propagation formalisms using the projector augmented-wave method in real-space grids. The two technically very different methods are compared in the linear-response regime where we...

A search for the Δ- wave-function component in light nuclei

International Nuclear Information System (INIS)

Morris, C.L.; Zumbro, J.D.; Boudrie, R.L.

1996-01-01

We have studied the (π + , π ± p) reactions on 3 He, 4 He, 6 Li, and 7 Li at incident energy 500 MeV in quasi-free kinematics. A signature attributable to pre-existing Δ components of the ground state wave function is observed

Hadron wave functions as a probe of a two-color baryonic medium

Energy Technology Data Exchange (ETDEWEB)

Amato, Alessandro [Swansea University, Department of Physics, College of Science, Swansea (United Kingdom); University of Helsinki, Department of Physics and Helsinki Institute of Physics, P.O. Box 64, Helsinki (Finland); Giudice, Pietro [Universitaet Muenster, Institut fuer Theoretische Physik, Muenster (Germany); Hands, Simon [Swansea University, Department of Physics, College of Science, Swansea (United Kingdom)

2015-04-01

The properties of the ground state of two-color QCD at non-zero baryon chemical potential μ present an interesting problem in strongly interacting gauge theory; in particular the nature of the physically relevant degrees of freedom in the superfluid phase in the post-onset regime μ > m{sub π} /2 still needs clarification. In this study we present evidence for in-medium effects at high μ by studying the wave functions of mesonic and diquark states using orthodox lattice simulation techniques, made possible by the absence of a sign problem for the model with N{sub f} = 2. Our results show that beyond onset the spatial extent of hadrons decreases as μ grows, and that the wave function profiles are consistent with the existence of a dynamically gapped Fermi surface in this regime. (orig.)

Angular momentum projection on a mesh of cranked Hartree-Fock wave functions

International Nuclear Information System (INIS)

Baye, D.; Heenen, P.

1984-01-01

A method for projecting on angular momentum wave functions discretized on a three-dimensional Cartesian mesh is presented. The method is based on a matrix representation of the rotation operator. It is applied to cranked Hartree-Fock wave functions calculated for 24 Mg with a simple interaction. In this case, the accuracy of the projected matrix elements is estimated to be of the order of 0.1%. An extensive comparison of the projected and cranking energies is made. The validity of the cranking method as an approximation to a variation-after-projection calculation seems to be wider than usually expected. The study of the fission barrier of 24 Mg for the channel 4 He- 16 O- 4 He shows that the cranking predictions for these very deformed states are quite reliable

Kinetic Alfven wave in the presence of kappa distribution function in plasma sheet boundary layer

Energy Technology Data Exchange (ETDEWEB)

Shrivastava, G., E-mail: geetphy9@gmail.com; Ahirwar, G. [School of Studies in Physics, Vikram University, Ujjain India (India); Shrivastava, J., E-mail: jayashrivastava2007@gmail.com [Dronacharya Group of Institutions, Greater Noida-India (India)

2015-07-31

The particle aspect approach is adopted to investigate the trajectories of charged particles in the electromagnetic field of kinetic Alfven wave. Expressions are found for the dispersion relation, damping/growth rate and associated currents in the presence of kappa distribution function. Kinetic effect of electrons and ions are included to study kinetic Alfven wave because both are important in the transition region. It is found that the ratio β of electron thermal energy density to magnetic field energy density and the ratio of ion to electron thermal temperature (T{sub i}/T{sub e}), and kappa distribution function affect the dispersion relation, damping/growth rate and associated currents in both cases(warm and cold electron limit).The treatment of kinetic Alfven wave instability is based on assumption that the plasma consist of resonant and non resonant particles. The resonant particles participate in an energy exchange process, whereas the non resonant particles support the oscillatory motion of the wave.

Relativistic wave functions of two spin 1/2 quarks in a model with QCD interaction

International Nuclear Information System (INIS)

Skachkov, N.B.; Solovtsov, I.L.

1981-01-01

Within the hamiltonian formulation of quantum field theory an equation is obtained for the vertex and wave functions of a composite system of two spin 1/2 quarks. Exact solutions are found for the relativistic potential having in the momentum representation the ''asymptotically-free'' behaviour at large values of momentum transfer Q 2 . It is shown that within the given model the π-meson wave function has zero at a finite distance corresponding to the point of discontinuity of the effective potential [ru

Determination of group velocity of propagation of Lamb waves in aluminium plate using piezoelectric transducers

Directory of Open Access Journals (Sweden)

Lašová Z.

2017-06-01

Full Text Available A prior knowledge of group velocities of Lamb wave modes is a key for analysis of time signals in guidedwave based structural health monitoring. The identification of multiple wave modes may be complicated due to dependency of group velocity on frequency (dispersion. These dependencies for infinite plate of constant thickness can be calculated by a numerical solution of analytic equation. Two alternative approaches to determine group velocities of zero-order Lamb wave modes in aluminum plate were used in this work: Two-dimensional Fast Fourier Transform (2D-FFT and methods of time-frequency processing. 2D-FFT requires a high number of time signals in equidistant points, therefore it was applied on data from finite element analysis of wave propagation in the plate. Group velocities for chosen frequencies were also determined using wavelet transform (WT of signals as differencies of times of arrival measured by a pair of piezoelectric transducers. The results from 2D-FFT and wavelet transform were compared to the analytic solution.

Wave anisotropy of shear viscosity and elasticity