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This article describes a method for constructing approximations to periodic solutions of dynamic Lorenz system with classical values of the system parameters. The author obtained a system of nonlinear algebraic equations in general form…

Numerical Analysis · Mathematics 2021-02-10 Alexander N. Pchelintsev

While quantum computing provides an exponential advantage in solving system of linear equations, there is little work to solve system of nonlinear equations with quantum computing. We propose quantum Newton's method (QNM) for solving…

Quantum Physics · Physics 2025-12-29 Cheng Xue , Yu-Chun Wu , Guo-Ping Guo

An exact invariant operator of time-dependent coupled oscillators is derived using the Liouville-von Neumann equation. The unitary relation between this invariant and the invariant of two uncoupled simple harmonic oscillators is…

Quantum Physics · Physics 2022-10-17 Jeong Ryeol Choi

The quantum mechanical equivalent of parametric resonance is studied. A simple model of a periodically kicked harmonic oscillator is introduced which can be solved exactly. Classically stable and unstable regions in parameter space are…

Quantum Physics · Physics 2009-11-07 Stefan Weigert

We propose an alternative to the usual time--independent Born--Oppenheimer approximation that is specifically designed to describe molecules with non--symmetrical hydrogen bonds. In our approach, the masses of the hydrogen nuclei are scaled…

Mathematical Physics · Physics 2009-11-13 George A. Hagedorn , Alain Joye

The dynamics of a quantum nonlinear oscillator is studied in terms of its quasi-flow, a dynamical mapping of the classical phase plane that represents the time-evolution of the quantum observables. Explicit expressions are derived for the…

Quantum Physics · Physics 2009-11-13 Omri Gat

The Koopman-von Neumann (KvN) formalism recasts classical mechanics in a Hilbert space framework using complex wavefunctions and linear operators, akin to quantum mechanics. Instead of evolving probability densities in phase space (as in…

Quantum Physics · Physics 2025-12-17 Xinfeng Gao , Olivier Pfister , Stefan Bekiranov

Severe methodological and numerical problems of the traditional quantum mechanical approach to the description of molecular systems are outlined. To overcome these, a simple alternative to the Born-Oppenheimer approximation is presented on…

Chemical Physics · Physics 2014-02-06 Irmgard Frank

A causal, non-Hermitian, renormalizable, local, unitary and Lorentz convariant formulation of Quantum Theory (QT) (= Quantum Mechanics (QM) and Quantum Field Theory (QFT)) is developed which is free of formalistic problems we face in the…

High Energy Physics - Phenomenology · Physics 2011-07-19 F. Kleefeld

Starting from the von Neumann-Maxwell equations for the Wigner quasi-probability distribution and for the self-consistent electric field, the quantum analog of the classical single-wave model has been derived. The linear stability of the…

Plasma Physics · Physics 2011-10-24 Stephan I. Tzenov , Kiril B. Marinov

We investigate the time-periodic solutions to the nonlinear wave and beam equations and uncover their intricate, fractal-like structure. In particular, we identify a new class of large-energy solutions with complex mode compositions and…

Mathematical Physics · Physics 2025-08-27 Filip Ficek , Maciej Maliborski

We derive the basic equations of the cosmological first-order post-Newtonian approximation from the recently formulated fully nonlinear and exact cosmological perturbation theory in Einstein's gravity. Apparently the latter, being exact,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Hyerim Noh , Jai-chan Hwang

Exact solutions of several nonstationary problems of quantum mechanics are obtained. It is shown that if the initial conditions of the problem correspond to the localized-in-space particle, then it moves exactly along the classical…

Quantum Physics · Physics 2007-05-23 Vladimir E. Mitroshin

A quantum mechanics analogy is used to determine the forces acting on and the energies of solitons governed by the nonlinear Schr\"odinger equation in finite intervals with periodic and with homogeneous Dirichlet, Neumann and Robin boundary…

Pattern Formation and Solitons · Physics 2013-01-18 Juan I. Ramos , Francisco R. Villatoro

Classes of the nonlinear Schrodinger-type equations compatible with the Galilei relativity principle are described. Solutions of these equations satisfy the continuity equation.

Mathematical Physics · Physics 2007-05-23 Wilhelm I. Fushchych , Vyacheslav M. Boyko

We study a class of nonlinear kinetic Fokker-Planck type equations modeling quantum particles which obey the Bose-Einstein and Fermi-Dirac statistics, respectively. We establish the existence of classical solutions in the perturbative…

Analysis of PDEs · Mathematics 2007-08-01 Lukas Neumann , Christof Sparber

The quantum version of a non-linear oscillator, previouly analyzed at the classical level, is studied. This is a problem of quantization of a system with position-dependent mass of the form $m={(1+\lambda x^2)}^{-1}$ and with a…

Mathematical Physics · Physics 2014-11-18 José F. Cariñena , Manuel F. Rañada , Mariano Santander

The article provides an overview of some advances in the mathematical understanding of the nature of the kinetic equations of quantum systems of many particles. The fundamental equations of modern mathematical physics are studied, in…

Mathematical Physics · Physics 2022-05-17 V. I. Gerasimenko

In this article, we follow an idea that is opposite to the idea of Hopf and Cole: we use transformations in order to transform simpler linear or nonlinear differential equations (with known solutions) to more complicated nonlinear…

Exactly Solvable and Integrable Systems · Physics 2023-12-07 Nikolay K. Vitanov

Based on the analysis of biquaternion quadratic forms of field, it is shown that Maxwell equations arise as a consequence of the principle of conservation of the energy-momentum flow of field in space-time. It turns out that this principle…

Classical Physics · Physics 2024-03-05 Sergey Y. Kotkovskiy