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Path integral formalism of open quantum systems with non-diagonal system-bath coupling
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作者 Ruofan Chen 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第11期145-150,共6页
Most path integral expressions for quantum open systems are formulated with diagonal systembath coupling,where the influence functional is a functional of scalar-valued trajectories.This formalism is enough if only a ... Most path integral expressions for quantum open systems are formulated with diagonal systembath coupling,where the influence functional is a functional of scalar-valued trajectories.This formalism is enough if only a single bath is under consideration.However,when multiple baths are present,non-diagonal system-bath couplings need to be taken into consideration.In such a situation,using an abstract Liouvillian method,the influence functional can be obtained as a functional of operator-valued trajectories.The value of the influence functional itself also becomes a superoperator rather than an ordinary scalar,whose meaning is ambiguous at first glance and its connection to the conventional understanding of the influence functional needs extra careful consideration.In this article,we present another concrete derivation of the superoperator-valued influence functional based on the straightforward Trotter-Suzuki splitting,which can provide a clear picture to interpret the superoperator-valued influence functional. 展开更多
关键词 path integral non-additive enviroments Caldeira-Leggett model
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Path Integral Approach to the Interaction of Two-Electron Atoms with Elliptically Polarized Pulses
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作者 Emmanouil George Thrapsaniotis 《Journal of Applied Mathematics and Physics》 2024年第11期3655-3678,共24页
We study the dynamics of a two-electron atom interacting with a pulsed, elliptically polarized, ultrashort, excited coherent state. We use path integral methods and integrate on the photonic part. We angularly decompo... We study the dynamics of a two-electron atom interacting with a pulsed, elliptically polarized, ultrashort, excited coherent state. We use path integral methods and integrate on the photonic part. We angularly decompose the Coulomb interaction term of the two electrons and the interaction term of the two electrons with the photonic field and solve the sign problem. We give results on the survival probability of the ground state of Helium. 展开更多
关键词 HELIUM path integrals Angular Decomposition Sign Solved Propagator Elliptic Polarization
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Feynman Path Integral Using Operator Integration in Banach Space
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作者 Reza R. Ahangar Erbil Cetin Serife Muge Ege 《Journal of Applied Mathematics and Physics》 2024年第2期432-444,共13页
Feynman-Path Integral in Banach Space: In 1940, R.P. Feynman attempted to find a mathematical representation to express quantum dynamics of the general form for a double-slit experiment. His intuition on several slits... Feynman-Path Integral in Banach Space: In 1940, R.P. Feynman attempted to find a mathematical representation to express quantum dynamics of the general form for a double-slit experiment. His intuition on several slits with several walls in terms of Lagrangian instead of Hamiltonian resulted in a magnificent work. It was known as Feynman Path Integrals in quantum physics, and a large part of the scientific community still considers them a heuristic tool that lacks a sound mathematical definition. This paper aims to refute this prejudice, by providing an extensive and self-contained description of the mathematical theory of Feynman Path Integration, from the earlier attempts to the latest developments, as well as its applications to quantum mechanics. About a hundred years after the beginning of modern physics, it was realized that light could in fact show behavioral characteristics of both waves and particles. In 1927, Davisson and Germer demonstrated that electrons show the same dual behavior, which was later extended to atoms and molecules. We shall follow the method of integration with some modifications to construct a generalized Lebesgue-Bochner-Stieltjes (LBS) integral of the form , where u is a bilinear operator acting in the product of Banach spaces, f is a Bochner summable function, and μ is a vector-valued measure. We will demonstrate that the Feynman Path Integral is consistent and can be justified mathematically with LBS integration approach. 展开更多
关键词 Feynman path integral Lebesgue-Bochner-Stieltjes integral Operator integral Particle-Wave Function Operator Integration Position and Momentum Operators
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PATH INTEGRAL SOLUTION OF NONLINEAR DYNAMIC BEHAVIOR OF STRUCTURE UNDER WIND EXCITATION 被引量:1
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作者 王仲刚 程华 邓洪洲 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2005年第10期1303-1311,共9页
A numerical scheme for the nonlinear behavior of structure under wind excitation is investigated. With the white noise filter of turbulent-wind fluctuations, the nonlinear motion equation of structures subjected to wi... A numerical scheme for the nonlinear behavior of structure under wind excitation is investigated. With the white noise filter of turbulent-wind fluctuations, the nonlinear motion equation of structures subjected to wind load was modeled as the Ito' s stochastic differential equation. The state vector associated with such a model is a diffusion process. A continuous linearization strategy in the time-domain was adopted. Based on the solution series of its stochastic linearization equations, the formal probabilistic density of the structure response was developed by the path integral technique. It is shown by the numerical example of a guyed mast that compared with the frequency-domain method and the time-domain nonlinear analysis, the proposed approach is highlighted by high accuracy and effectiveness. The influence of the structure non-linearity on the dynamic reliability assessment is also analyzed in the example. 展开更多
关键词 NONLINEAR dynamic response wind load path integral solution white noise joint statistical distribution
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Path integral solutions for n-dimensional stochastic differential equations underα-stable Lévy excitation 被引量:1
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作者 Wanrong Zan Yong Xu Jürgen Kurths 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2023年第2期98-112,共15页
In this paper,the path integral solutions for a general n-dimensional stochastic differential equa-tions(SDEs)withα-stable Lévy noise are derived and verified.Firstly,the governing equations for the solutions of... In this paper,the path integral solutions for a general n-dimensional stochastic differential equa-tions(SDEs)withα-stable Lévy noise are derived and verified.Firstly,the governing equations for the solutions of n-dimensional SDEs under the excitation ofα-stable Lévy noise are obtained through the characteristic function of stochastic processes.Then,the short-time transition probability density func-tion of the path integral solution is derived based on the Chapman-Kolmogorov-Smoluchowski(CKS)equation and the characteristic function,and its correctness is demonstrated by proving that it satis-fies the governing equation of the solution of the SDE,which is also called the Fokker-Planck-Kolmogorov equation.Besides,illustrative examples are numerically considered for highlighting the feasibility of the proposed path integral method,and the pertinent Monte Carlo solution is also calculated to show its correctness and effectiveness. 展开更多
关键词 path integral method α-stable Lévy noise Monte carlo method Fokker-Planck-Kolmogorov equation
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Hooke's Atom in an Arbitrary External Electric Field: Analytical Solutions of Two-Electron Problem by Path Integral Approach
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作者 蔡亮 张萍 +1 位作者 杨涛 潘孝胤 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第4期565-568,共4页
By using the path integral approach, we investigate the problem of Hooke's atom (two electrons interacting with Coulomb potential in an external harmonic-oscillator potential) in an arbitrary time-dependent electri... By using the path integral approach, we investigate the problem of Hooke's atom (two electrons interacting with Coulomb potential in an external harmonic-oscillator potential) in an arbitrary time-dependent electric field. For a certain infinite set of discrete oscillator frequencies, we obtain the analytical solutions. The ground state polarization of the atom is then calculated. The same result is also obtained through linear response theory. 展开更多
关键词 Hooke's atom path integral PROPAGATOR POLARIZATION
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Unified treatment of the bound states of the Schioberg and the Eckart potentials using Feynman path integral approach
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作者 A.Diaf 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第2期39-45,共7页
We obtain analytical expressions for the energy eigenvalues of both the Schioberg and Eckart potentials using an approximation of the centrifugal term. In order to determine the l-states solutions, we use the Feynman ... We obtain analytical expressions for the energy eigenvalues of both the Schioberg and Eckart potentials using an approximation of the centrifugal term. In order to determine the l-states solutions, we use the Feynman path integral approach to quantum mechanics. We show that by performing nonlinear space-time transformations in the radial path integral, we can derive a transformation formula that relates the original path integral to the Green function of a new quantum solvable system. The explicit expression of bound state energy is obtained and the associated eigenfunctions are given in terms of hypergeometric functions. We show that the Eckart potential can be derived from the Schioberg potential. The obtained results are compared to those produced by other methods and are found to be consistent. 展开更多
关键词 path integrals l-states Schioberg potential Eckart potential
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Quantum Measurement and Extended Feynman Path Integral
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作者 文伟 白彦魁 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第6期967-982,共16页
Quantum measurement problem has existed many years and inspired a large of literature in both physics and philosophy,but there is still no conclusion and consensus on it.We show it can be subsumed into the quantum the... Quantum measurement problem has existed many years and inspired a large of literature in both physics and philosophy,but there is still no conclusion and consensus on it.We show it can be subsumed into the quantum theory if we extend the Feynman path integral by considering the relativistic effect of Feynman paths.According to this extended theory,we deduce not only the Klein-Gordon equation,but also the wave-function-collapse equation.It is shown that the stochastic and instantaneous collapse of the quantum measurement is due to the "potential noise" of the apparatus or environment and "inner correlation" of wave function respectively.Therefore,the definite-status of the macroscopic matter is due to itself and this does not disobey the quantum mechanics.This work will give a new recognition for the measurement problem. 展开更多
关键词 quantum measurement Feynman path integral nonlocal correlation Klein-Gordon equation wave- function- collapse equation
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Generalized Fourth-Order Decompositions of Imaginary Time Path Integral:Implications of the Harmonic Oscillator
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作者 Cong Wang Lihan Zhang +1 位作者 Jian Liu Jiushu Shao 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第3期516-536,I0003,共22页
The imaginary time path integral formalism offers a powerful numerical tool for simulating thermodynamic properties of realistic systems.We show that,when second-order and fourth-order decompositions are employed,they... The imaginary time path integral formalism offers a powerful numerical tool for simulating thermodynamic properties of realistic systems.We show that,when second-order and fourth-order decompositions are employed,they share a remarkable unified analytic form for the partition function of the harmonic oscillator.We are then able to obtain the expression of the thermodynamic property and the leading error terms as well.In order to obtain reasonably optimal values of the free parameters in the generalized symmetric fourth-order decomposition scheme,we eliminate the leading error terms to achieve the accuracy of desired order for the thermodynamic property of the harmonic system.Such a strategy leads to an efficient fourth-order decomposition that produces thirdorder accurate thermodynamic properties for general systems. 展开更多
关键词 path integral DECOMPOSITION Partition function Harmonic oscillator
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Path Integrals and Alternative Effective Dynamics in Loop Quantum Cosmology
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作者 秦立 邓果 马永革 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第2期326-332,共7页
The alternative dynamics of loop quantum cosmology is examined by the path integral formulation.We consider the spatially flat FRW models with a massless scalar field,where the alternative quantizations inherit more f... The alternative dynamics of loop quantum cosmology is examined by the path integral formulation.We consider the spatially flat FRW models with a massless scalar field,where the alternative quantizations inherit more features from full loop quantum gravity.The path integrals can be formulated in both timeless and deparameterized frameworks.It turns out that the effective Hamiltonians derived from the two different viewpoints are equivalent to each other.Moreover,the first-order modified Friedmann equations are derived and predict quantum bounces for contracting universe,which coincide with those obtained in canonical theory. 展开更多
关键词 loop quantum cosmology path integral effective Hamiltonian modified Friedmann equation
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Finite Size Effect in Path Integral Monte Carlo Simulations of ~4He Systems
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作者 ZHAO Xing-Wen CHENG Xin-Lu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第10期987-989,共3页
Path integral Monte Carlo (PIMC) simulations are a powerful computational method to study interacting quantum systems at finite temperatures. In this work, PIMC has been applied to study the finite size effect of th... Path integral Monte Carlo (PIMC) simulations are a powerful computational method to study interacting quantum systems at finite temperatures. In this work, PIMC has been applied to study the finite size effect of the simulated systems of ^4He. We determine the energy as a function of temperature at saturated-vapor-pressure (SVP) conditions in the temperature range of T ∈ [1.0 K,4.0 K], and the equation of state (EOS) in the grmmd state For systems consisted of 32, 64 and 128 ^4He atoms, respectively, We find that the energy at SVP is influenced significantly by the size of the simulated system in the temperature range of T ∈ [2.1 K, 3.0 K] and the larger the system is, the better results are obtained in comparison with the experimental values; while the EOS appeared to be unrelated to it. 展开更多
关键词 path integral Monte Carlo simulation finite size effect HELIUM equation of state
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Path integral Monte Carlo study of(H_2)_n@C_(70)(n = 1, 2, 3)
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作者 郝妍 张红 程新路 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期577-581,共5页
The path integral Monte Carlo(PIMC) method is employed to study the thermal properties of C70 with one, two,and three H2 molecules confined in the cage, respectively. The interaction energies and vibrationally average... The path integral Monte Carlo(PIMC) method is employed to study the thermal properties of C70 with one, two,and three H2 molecules confined in the cage, respectively. The interaction energies and vibrationally averaged spatial distributions under different temperatures are calculated to evaluate the stabilities of(H2)n@C70(n = 1, 2, 3). The results show that(H2)2@C70is more stable than H2@C70. The interaction energy slowly changes in a large temperature range,so temperature has little effect on the stability of the system. For H2@C70and(H2)2@C70, the interaction energies keep negative; however, when three H2 molecules are in the cage, the interaction energy rapidly increases to a positive value.This implies that at most two H2 molecules can be trapped by C70. With an increase of temperature, the peak of the spatial distribution gradually shifts away from the center of the cage, but the maximum distance from the center of H2 molecule to the cage center is much smaller than the average radius of C70. 展开更多
关键词 endohedral fullerene complexes path integral Monte Carlo method interaction energy vibrationally averaged spatial distribution
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Effect of a force-free end on the mechanical property of a biopolymer--A path integral approach
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作者 周子聪 Bla Joós 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第8期468-473,共6页
We study the effect of a force-free end on the mechanical property of a stretched biopolymer.The system can be divided into two parts.The first part consists of the segment counted from the fixed point(i.e.,the origi... We study the effect of a force-free end on the mechanical property of a stretched biopolymer.The system can be divided into two parts.The first part consists of the segment counted from the fixed point(i.e.,the origin) to the forced point in the biopolymer,with arclength L_f.The second part consists of the segment counted from the forced point to the force-free end with arclength △L.We apply the path integral technique to find the relationship between these two parts.At finite temperature and without any constraint at the end,we show exactly that if we focus on the quantities related to the first part,then we can ignore the second part completely.Monte Carlo simulation confirms this conclusion.In contrast,the effect for the quantities related to the second part is dependent on what we want to observe.A force-free end has little effect on the relative extension,but it affects seriously the value of the end-to-end distance if △L is comparable to L_f. 展开更多
关键词 statistical physics path integral biopolymers mechanical property
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Coherent States and a Path Integral for the Relativistic Linear Singular Oscillator
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作者 S.M.Nagiyev E.I.Jafarov M.Y.Efendiyev 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第2期315-318,共4页
The SU(1,1) coherent states for a relativistic model of the linear singular oscillator are considered. The corresponding partition function is evaluated. The path integral for the transition amplitude between SU(1,... The SU(1,1) coherent states for a relativistic model of the linear singular oscillator are considered. The corresponding partition function is evaluated. The path integral for the transition amplitude between SU(1,1) coherent states is given. Classical equations of the motion in the generalized curved phase space are obtained. It is shown that the use of quasiclassical Bohr Sommerfeld quantization rule yields the exact expression for the energy spectrum. 展开更多
关键词 relativistic linear singular oscillator SU(1 1) coherent states path integral
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Establishing path integral in the entangled state representation for Hamiltonians in quantum optics
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作者 王继锁 孟祥国 +1 位作者 冯健 高云峰 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第1期23-31,共9页
Based on two mutually conjugate entangled state representations, we establish the path integral formalism for some Hamiltonians of quantum optics in entangled state representations. The Wigner operator in the entangle... Based on two mutually conjugate entangled state representations, we establish the path integral formalism for some Hamiltonians of quantum optics in entangled state representations. The Wigner operator in the entangled state representation is presented. Its advantages are explained. 展开更多
关键词 path integral HAMILTONIAN entangled state representation
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A Note on Calculation of Phase Space Path Integral by Means of Invariants
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作者 QIAN Shang-Wu GU Zhi-Yu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5期813-814,共2页
In this note we use the method of invariant to calculate the phase space path integral appearing in our previous article.
关键词 phase space path integral INVARIANT PROPAGATOR
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Phase Space Path Integral Method for Problem of Obtaining Propagator of a Particle with a Force Quadratic in Velocity
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作者 GU Zhi-Yu HUANG Bo-Wen QIAN Shang-Wu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2期259-261,共3页
This article uses the phase space path integral method to find the propagator for a particle with a force quadratic in velocity. Two specific canonical transformations has been used for this purpose.
关键词 phase space path integral PROPAGATOR canonical transformation
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Path Integral Formalism for Nondegenerate Parametric Amplifiers in Entangled State Representation
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作者 FANHong-Yi LIChao +1 位作者 LIUQiu-Yu AlfredWiinsche 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第6期998-1002,共5页
We establish the path integral formalism for nondegenerate parametric amplifiers in the entangled state representations. Its advantage in obtaining the energy level gap of this system is analyzed.
关键词 path integral entangled states nondegenerate parametric amplifier
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A path integral approach to electronic friction of a nanometer-sized tip scanning a metal surface
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作者 Yang Wang Yu Jia 《Communications in Theoretical Physics》 SCIE CAS CSCD 2021年第4期111-120,共10页
In this work,we study the dissipation mechanism and frictional force of a nanometer-sized tip scanning a metal surface via a path integral approach.The metal,with internal degrees of freedom(c,c^(†))and a tip with an ... In this work,we study the dissipation mechanism and frictional force of a nanometer-sized tip scanning a metal surface via a path integral approach.The metal,with internal degrees of freedom(c,c^(†))and a tip with an internal degree of freedom(d,d^(†))couple with one another by means of an exchanged potential,V.Having integrated out all internal degrees of freedom,we obtain the in-out amplitude.Moreover,we calculate the imaginary part of the in-out amplitude and the frictional force.We find the imaginary part of the in-out amplitude to be positive,and correlated to the sliding velocity in most cases.The frictional force is proportional to the sliding velocity for the case where v<0.01.However,for cases where v>0.01,the frictional force demonstrates nonlinear dependence on sliding velocity. 展开更多
关键词 path integral electronic friction quantum field
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Path integral approach to electron scattering in classical electromagnetic potential
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作者 许闯 冯锋 李英骏 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第5期43-48,共6页
As is known to all, the electron scattering in classical electromagnetic potential is one of the most widespread applications of quantum theory. Nevertheless, many discussions about electron scattering are based upon ... As is known to all, the electron scattering in classical electromagnetic potential is one of the most widespread applications of quantum theory. Nevertheless, many discussions about electron scattering are based upon single-particle Schrodinger equation or Dirac equation in quantum mechanics rather than the method of quantum field theory. In this paper, by using the path integral approach of quantum field theory, we perturbatively evaluate the scattering amplitude up to the second order for the electron scattering by the classical electromagnetic potential. The results we derive are convenient to apply to all sorts of potential forms. Furthermore, by means of the obtained results, we give explicit calculations for the one-dimensional electric potential. 展开更多
关键词 electron scattering path integral approach quantum field theory
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