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In this paper hyperbolic partial differential equations with random coefficients are discussed. We consider the challenging problem of flux functions with coefficients modeled by spatiotemporal random fields. Those fields are given by…

Analysis of PDEs · Mathematics 2024-11-22 Andrea Barth , Franz Georg Fuchs

The relativistic kinetic theory of the phonon gas in superfluids is developed. The technique of the derivation of macroscopic balance equations from microscopic equations of motion for individual particles is applied to an ensemble of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Vladimir Popov

The Liouville theorem is a fundamental concept in understanding the properties of systems that adhere to Hamilton's equations. However, the traditional notion of the theorem may not always apply. Specifically, when the entropy gradient in…

General Physics · Physics 2023-03-29 Mario J. Pinheiro

A detailed derivation of the Lattice Boltzmann (LB) scheme for relativistic fluids recently proposed in Ref. [1], is presented. The method is numerically validated and applied to the case of two quite different relativistic fluid dynamic…

Solar and Stellar Astrophysics · Physics 2010-12-28 M. Mendoza , B. M. Boghosian , H. J. Herrmann , S. Succi

Starting from Doi-Onsager equation for the liquid crystal, we first derive the Q-tensor equation by the Bingham closure. Then we derive the Ericksen-Leslie equation from the Q-tensor equation by taking the small Deborah number limit.

Analysis of PDEs · Mathematics 2016-11-26 Wei Wang , Pingwen Zhang , Zhifei Zhang

A fully coupled system of two second-order parabolic degenerate equations arising as a thin film approximation to the Muskat problem is interpreted as a gradient flow for the 2-Wasserstein distance in the space of probability measures with…

Analysis of PDEs · Mathematics 2013-08-29 Philippe Laurencot , Bogdan-Vasile Matioc

In this work we present the fundamental ideas of inference over paths, and show how this formalism implies the continuity equation, which is central for the derivation of the main partial differential equations that constitute…

Statistical Mechanics · Physics 2016-11-03 Diego González , Daniela Díaz , Sergio Davis

We derive the fluctuating hydrodynamic equation for the number and momentum densities exactly from the underdamped Langevin equation. This derivation is an extension of the Kawasaki-Dean formula in underdamped case. The steady state…

Statistical Mechanics · Physics 2009-03-02 Takenobu Nakamura , Akira Yoshimori

We explain why the conventional argument for deriving the time-dependent Born-Oppenheimer approximation is incomplete and review recent mathematical results, which clarify the situation and at the same time provide a systematic scheme for…

Mathematical Physics · Physics 2007-12-31 Gianluca Panati , Herbert Spohn , Stefan Teufel

It is shown that in the complex trajectory representation of quantum mechanics, the Born's Psi^{\star}\Psi probability density can be obtained from the imaginary part of the velocity field of particles on the real axis. Extending this…

Quantum Physics · Physics 2010-08-17 Moncy V. John

The covariant Klein-Gordon equation requires twice the boundary conditions of the Schrodinger equation and does not have an accepted single-particle interpretation. Instead of interpreting its solution as a probability wave determined by an…

Quantum Physics · Physics 2014-11-18 K. B. Wharton

Considering the example of interacting Brownian particles we present a linear response derivation of the boundary condition for the corresponding hydrodynamic description (the diffusion equation). This requires us to identify a non-analytic…

Statistical Mechanics · Physics 2009-11-07 M. Fuchs , K. Kroy

We derive a fluid theory for spin-1/2 particles starting from an extended kinetic model based on a spin-projected density matrix formalism. The evolution equation for the spin density is found to contain a pressure-like term. We give an…

Plasma Physics · Physics 2010-11-02 Jens Zamanian , Martin Stefan , Mattias Marklund , Gert Brodin

Using the linearized version of the time dependent Gross-Pitaevskii equation we calculate the dynamic response of a Bose-Einstein condensed gas to periodic density and particle perturbations. The zero temperature limit of the…

Quantum Gases · Physics 2019-02-20 Sandro Stringari

We present here a conjecture about the equivalence between the noise density of states of a system governed by a generalized Langevin equation and the fluctuation in the energy density of states in a Hamiltonian system. We present evidence…

Disordered Systems and Neural Networks · Physics 2007-05-23 Mendeli H. Vainstein , Rafael Morgado , Fernando A. Oliveira

A formalism of classical mechanics is given for time-dependent many-body states of quantum mechanics, describing both fluid flow and point mass trajectories. The familiar equations of energy, motion, and those of Lagrangian mechanics are…

Quantum Physics · Physics 2025-01-31 James P. Finley

Probability waves in the configuration space are associated with coherent solutions of the classical Liouville or Fokker-Planck equations. Distributions localized in the momentum space provide action waves, specified by the probability…

Quantum Physics · Physics 2009-11-13 M. Grigorescu

We show that the usual Born-Oppenheimer type of approximation used in quantum gravity, in which a semiclassical time parameter emerges from a weak-coupling expansion of the Wheeler-DeWitt constraint, leads to a unitary theory at least up to…

General Relativity and Quantum Cosmology · Physics 2022-05-20 Leonardo Chataignier

This paper is focused on the generalized Forchheimer flows of slightly compressible fluids in porous media. They are reformulated as a degenerate parabolic equation for the pressure. The initial boundary value problem is studied with…

Analysis of PDEs · Mathematics 2015-10-02 Luan Hoang , Thinh Kieu

The probability distribution of a time measurement $T_x$ at position $x$ can be inferred from the probability distribution of a position measurement $X_t$ at time $t$ as given by the Born rule [Time-of-arrival distributions for continuous…

Quantum Physics · Physics 2025-07-30 Mathieu Beau , Timothey Szczepanski , Rafael Martellini , Lionel Martellini