共查询到20条相似文献,搜索用时 15 毫秒
1.
A. Kyrala 《Foundations of Physics》1974,4(1):31-51
The integrodifferential equations satisfied by the statistical frequency functions for physical systems undergoing stochastic transitions are derived by application of a causality principle and selection rules to the Markov chain equations. The result equations can be viewed as generalizations of the diffusion equation, but, unlike the latter, they have a direct bearing onactive transport problems in biophysics andcondensation aggregation problems of astrophysics and phase transition theory. Simple specific examples of the effects of severe selection rules, such as the relaxational Boltzmann transport equation and the diffusion equation, are also given. Finally, partial differential equations for the probability amplitudes of quantum mechanics are derived, usingunitarity instead of causality, and a selection rule is applied directly to obtain ageneralization of the Dirac equation in which infinite transitions between states arenot allowed. 相似文献
2.
Mayeul Arminjon 《Foundations of Physics》2008,38(11):1020-1045
An analysis of the classical-quantum correspondence shows that it needs to identify a preferred class of coordinate systems,
which defines a torsionless connection. One such class is that of the locally-geodesic systems, corresponding to the Levi-Civita
connection. Another class, thus another connection, emerges if a preferred reference frame is available. From the classical
Hamiltonian that rules geodesic motion, the correspondence yields two distinct Klein-Gordon equations and two distinct Dirac-type
equations in a general metric, depending on the connection used. Each of these two equations is generally-covariant, transforms
the wave function as a four-vector, and differs from the Fock-Weyl gravitational Dirac equation (DFW equation). One obeys
the equivalence principle in an often-accepted sense, whereas the DFW equation obeys that principle only in an extended sense.
Part of this work was done while the author was at Dipartimento di Fisica, Università di Bari and INFN Bari, Italy. 相似文献
3.
Gaussian sum rules in quantum chromodynamics and local duality 总被引:1,自引:0,他引:1
A new type of hadronic sum rules are studied in QCD. They correspond to the Gauss-Weierstrass transform of hadronic spectral functions. There is an interesting analogy between these sum rules and the theory of the heat equation which provides a useful framework for formulating quantitatively the notion of local duality. In particular, finite energy sum rules are shown to follow within this framework from the principle of conservation of total heat. Explicit calculations of these sum rules in QCD - from both perturbative and non-perturbative contributions à la Shifman, Vainshtein and Zakharov [1] - have been made in a rather general way which should cover all the practical cases involving light quark systems. A particular case of the -spectral function and its duality to QCD is discussed in detail as an illustration of this new approach. 相似文献
4.
A boson-fermion hybrid representation is presented. In this framework, a fermion system is described concurrently by the bosonic and the fermionic degrees of freedom. A fermion pair in this representation can be treated as a boson without violating the Pauli principle. Furthermore the “bosonic interactions” are shown to originate from the exchange processes of the fermions and can be calculated from the original fermion interactions. Both the formulation of the BFH representations for the even and odd nuclear systems are given. We find that the basic equation of the nuclear field theory (NFT) is just the usual Schrödinger equation in such a representation with the empirical NFT diagrammatic rules emerging naturally. This theory was numerically checked in the case of four nucleons moving in a single-j shell and the exactness of the theory was established. 相似文献
5.
M. Schulz 《The European physical journal. Special topics》2008,161(1):143-150
Lattice systems with one species diffusion-reaction
processes under local complete exclusion rules are studied
analytically. We discuss a rigorously derived Fokker-Planck
equation for a so-called pseudo-probability. This probability
distribution depends on continuous variables in contrast to the
original discrete master equation, and their stochastic dynamics
may be interpreted as a substitute process which is completely
equivalent to the original lattice dynamics. Especially, averages
and correlation functions of the continuous variables are
connected to corresponding lattice quantities by simple relations.
Although the substitute process for diffusion-reaction systems
with exclusion rules has some similarities to the well known
substitute process for the same system without exclusion rules,
their exist a set of remarkable differences.
The given approach is not only valid for the discussed single species
processes. We give sufficient arguments that arbitrary combinations of
uni-molecular and bimolecular lattice reactions under complete local exclusions
may be described in terms of our approach. 相似文献
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8.
Sami I. Muslih Om P. Agrawal Dumitru Baleanu 《International Journal of Theoretical Physics》2010,49(8):1746-1752
This paper presents a fractional Schrödinger equation and its solution. The fractional Schrödinger equation may be obtained using a fractional variational principle and a fractional Klein-Gordon equation; both methods are considered here. We extend the variational formulations for fractional discrete systems to fractional field systems defined in terms of Caputo derivatives to obtain the fractional Euler-Lagrange equations of motion. We present the Lagrangian for the fractional Schrödinger equation of order α. We also use a fractional Klein-Gordon equation to obtain the fractional Schrödinger equation which is the same as that obtained using the fractional variational principle. As an example, we consider the eigensolutions of a particle in an infinite potential well. The solutions are obtained in terms of the sines of the Mittag-Leffler function. 相似文献
9.
提出一种基于变分原理的估计混沌系统未知参数的方法,对以x= F(x,θ) 为控制方程的所有混沌系统具有普适性.首先将混沌系统方程引入到目标泛函中;接着利用变分原理导出了混沌系统的伴随方程和待辨识参数泛函梯度的通用公式;然后设计了估计混沌系统未知参数的算法;最后对典型的Lorenz混沌系统和超混沌Chen系统的未知参数进行了估计.数值仿真结果表明该方法是一种非常有效的估计混沌系统未知参数的方法.
关键词:
混沌系统
参数估计
变分方法
伴随方程 相似文献
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11.
A generalization of the multi-symplectic form for Hamiltonian systems to self-adjoint systems with dissipation terms is studied. These systems can be expressed as multi-symplectic Birkhoffian equations, which leads to a natural definition of Birkhoffian multi-symplectic structure. The concept of Birkhoffian multi-symplectic integrators for Birkhoffian PDEs is investigated. The Birkhoffian multi-symplectic structure is constructed by the continuous variational principle, and the Birkhoffian multi-symplectic integrator by the discrete variational principle. As an example, two Birkhoffian multi-symplectic integrators for the equation describing a linear damped string are given. 相似文献
12.
Xiao-feng Pang 《Physica B: Condensed Matter》2009,404(16):2353-2358
There are a lot of difficulties and troubles in quantum mechanics, when the linear Schrödinger equation is used to describe microscopic particles. Thus, we here replace it by a nonlinear Schrödinger equation to investigate the properties and rule of microscopic particles. In such a case we find that the motion of microscopic particle satisfies classical rule and obeys the Hamiltonian principle, Lagrangian and Hamilton equations. We verify further the correctness of these conclusions by the results of nonlinear Schrödinger equation under actions of different externally applied potential. From these studies, we see clearly that rules and features of motion of microscopic particle described by nonlinear Schrödinger equation are greatly different from those in the linear Schrödinger equation, they have many classical properties, which are consistent with concept of corpuscles. Thus, we should use the nonlinear Schrödinger equation to describe microscopic particles. 相似文献
13.
R. F. Pannatoni 《Acoustical Physics》2011,57(1):36-50
The coupled mode theory of Shevchenko for irregular acoustic waveguides is extended to account for loss. An energy dissipation
principle for truncated systems of the coupled mode equations is established. Two-point boundary value problems for these
equations are solved by means of a differential Riccati equation. Solutions of a related algebraic Riccati equation are used
to approximate solutions of the differential Riccati equation and to formulate radiation boundary conditions. 相似文献
14.
The Bogolyubov variational principle for classical systems is used to obtain the variation equation for a self-consistent field. With the help of this equation, various approximations of the self-consistent field method in the theory of a crystal with a multiparticle interaction are studied. The free energy of the crystal is calculated. 相似文献
15.
Miguel Navarro 《Foundations of Physics Letters》1998,11(6):585-593
Rules of quantization and equations of motion for a finite-dimensional formulation of quantum field theory are proposed which fulfill the following properties: (a) Both the rules of quantization and the equations of motion are covariant; (b) the equations of evolution are second order in derivatives and first order in derivatives of the spacetime coordinates; and (c) these rules of quantization and equations of motion lead to the usual (canonical) rules of quantization and the (Schrödinger) equation of motion of quantum mechanics in the particular case of mechanical systems. We also comment briefly on further steps to fully develop a satisfactory quantum field theory and the difficuties which may be encountered when doing so. 相似文献
16.
Two integrable cases of two-dimensional Schrödinger equation with a magnetic field are proposed. Using the polar coordinates and the symmetrical gauge, we will obtain solutions of these equations through biconfluent and confluent Heun functions. The quantization rules will be derived for both systems under consideration. 相似文献
17.
J. SUKY. KIM 《Journal of sound and vibration》2002,254(3):503-521
In this paper, several dynamic systems are modelled using the time-domain finite element method. Galerkin's weak principle is used to model the general second order mechanical system, and is applied to the dynamics of the simple pendulum. Problems that arise during the approximation of the final momentum are also investigated. Furthermore, additional dynamic analysis methods are suggested for hybrid co-ordinate systems that have both slew and flexible modes. The proposed methods are based on both extended Hamilton's principle and Galerkin's weak principle. The matrix wave equation is propagated in a space domain, satisfying the geometric/natural boundary conditions. As a result, the flexible motion can be obtained, and this was compatible with the applied control input. A numerical example is used to demonstrate the effectiveness of the proposed modelling methods for the hybrid co-ordinate systems. 相似文献
18.
T.?S.?Biró G.?Purcsel K.?ürm?ssy 《The European Physical Journal A - Hadrons and Nuclei》2009,40(3):325-340
We review the idea of generating non-extensive stationary distributions based on aaabstract composition rules of the subsystem
energies, in particular the parton cascade method, using a Boltzmann equation with relativistic kinematics and modified two-body
energy composition rules. The thermodynamical behavior of such model systems is investigated. As an application hadronic spectra
with power law tails are analyzed in the framework of a quark coalescence model.
This paper is part of the Topical Issue Statistical Power Law Tails in High-Energy Phenomena. 相似文献
19.
The density matrix describing the state of a sybsystem of a physical system whose time dependence is assumed to follow a Schrödinger equation does not itself obey a von Neumann equation. The behavior of the eigenvalues and eigenfunctions of this density matrix is studied. An expression for the rate at which initially separating systems are de-separated is derived in perturbation theory. Indications are given that coherent photon states are more stable in the presence of charged particles than photon number eigenstates. The possible dynamical origin of super selection rules is discussed. A simple model is solved analytically. 相似文献