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Based on a cocycle structure, we identify a new derivation of the Boltzmann distribution for finite energy-level systems from the maximal entropy principle (MEP). Our approach does not rely on the method of the Lagrange multiplier, and it…

Statistical Mechanics · Physics 2025-12-30 Chuan-Tsung Chan , Chan-Yi Chang , Zhong-Tang Wu

Within the framework of the post-Newtonian $2\frac12$ approximation theory, a kinetic theory for relativistic gases in the presence of gravitational fields is developed. The Boltzmann equation and the equilibrium Maxwell-J\"uttner…

General Relativity and Quantum Cosmology · Physics 2026-05-01 Gilberto M. Kremer

A well-known result across information theory, machine learning, and statistical physics shows that the maximum entropy distribution under a mean constraint has an exponential form called the Gibbs-Boltzmann distribution. This is used for…

Machine Learning · Computer Science 2020-06-26 Amir R. Asadi , Emmanuel Abbe

The influence and validity of wall boundary conditions for non-equilibrium fluid flows described by the Boltzmann equation remains an open problem. The substantial computational cost of directly solving the Boltzmann equation has limited…

Fluid Dynamics · Physics 2024-01-02 Tarik Dzanic , Freddie D. Witherden , Luigi Martinelli

We study a two phase flow with interactions of liquid and rarefied gas inside the gas phase. The gas phase is modeled by the BGK model of the Boltzmann equation. The liquid phase is modeled by the incompressible Navier-Stokes equations. In…

Fluid Dynamics · Physics 2022-04-06 S. Tiwari , A. Klar , G. Russo

In this work we study the evolution of Boltzmann's entropy in the context of free expansion of a one dimensional interacting gas inside a box. Boltzmann's entropy is defined for single microstates and is given by the phase-space volume…

Statistical Mechanics · Physics 2023-03-29 Subhadip Chakraborti , Abhishek Dhar , Anupam Kundu

In this paper we derive accurate numerical methods for the quantum Boltzmann equation for a gas of interacting bosons. The schemes preserve the main physical features of the continuous problem, namely conservation of mass and energy, the…

Numerical Analysis · Mathematics 2010-09-15 P. A. Markowitch , L. Pareschi

Numerical simulations of turbulent flows are well known to pose extreme computational challenges due to the huge number of dynamical degrees of freedom required to correctly describe the complex multi-scale statistical correlations of the…

Fluid Dynamics · Physics 2025-02-27 Giulio Ortali , Alessandro Gabbana , Nicola Demo , Gianluigi Rozza , Federico Toschi

For increasingly rarefied flowfields, the Navier-Stokes (NS) equations lose accuracy partially due to the single temperature approximation. To overcome this barrier, a continuum multi-temperature model based on the Bhatnagar-Gross-Krook…

Fluid Dynamics · Physics 2018-10-12 Guiyu Cao , Hualin Liu , Kun Xu

Many entropy-conservative and entropy-stable (summarized as entropy-preserving) methods for hyperbolic conservation laws rely on Tadmor's theory for two-point entropy-preserving numerical fluxes and its higher-order extension via flux…

Numerical Analysis · Mathematics 2026-03-26 Marco Artiano , Hendrik Ranocha

We systematically derived hydrodynamic equations and transport coefficients for a class of multi-speed lattice Boltzmann models in D dimensions, using the multi-scale technique. The constitutive relation of physical fluid is recovered by a…

comp-gas · Physics 2008-02-03 Yu Chen , Hirotada Ohashi , Mamoru Akiyama

Modeling transition-continuum hypersonic flows poses significant challenges due to thermodynamic nonequilibrium and the associated breakdown of the continuum assumption. Standard continuum models such as the Navier-Stokes equations are…

Fluid Dynamics · Physics 2025-06-18 Mikolaj Kryger , Jonathan F. MacArt

In this paper, we present an energy method for the system of Boltzmann equations in the multicomponent mixture case, based on a micro-macro decomposition. More precisely, the perturbation of a solution to the Boltzmann equation around a…

Analysis of PDEs · Mathematics 2023-05-24 Laurent Boudin , Bérénice Grec , Milana Pavić-Čolić , Srboljub Simić

To obtain further insight on possible power law generalizations of Boltzmann equilibrium concepts, a stochastic collision model is investigated. We consider the dynamics of a tracer particle of mass $M$, undergoing elastic collisions with…

Statistical Mechanics · Physics 2009-11-10 Eli Barkai

The foundations of the Boltzmann-Gibbs (BG) distributions for describing equilibrium statistical mechanics of systems are examined. Broadly, they fall into: (i) probabilistic paaroaches based on the principle of equal a priori probability…

Statistical Mechanics · Physics 2009-11-10 A. K. Rajagopal , Sumiyoshi Abe

We establish Extended Thermodynamics (ET) of rarefied polyatomic gases with six independent fields, i.e., the mass density, the velocity, the temperature and the dynamic pressure, without adopting the near-equilibrium approximation. The…

Mathematical Physics · Physics 2015-04-23 Tommaso Ruggeri

Using methods of kinetic theory and liquid state theory we propose a description of the non-equilibrium behavior of molecular fluids which takes into account their microscopic structure and thermodynamic properties. The present work…

Statistical Mechanics · Physics 2009-02-24 Umberto Marini Bettolo Marconi , Simone Melchionna

This work is devoted to the consistent modeling of a three-phase mixture of a gas, a liquid and its vapor. Since the gas and the vapor are mis-cible, the mixture is subjected to a non-symmetric constraint on the volume. Adopting the Gibbs…

Analysis of PDEs · Mathematics 2017-10-13 Hélène Mathis

The lattice Boltzmann (LB) method intrinsically links to the Boltzmann equation with the Bhatnagar-Gross-Krook collision operator; however, it has been questioned to be able to simulate noncontinuum bounded gas flows at the micro and…

Computational Physics · Physics 2022-08-24 Yong Shi

Gaseous flows show a diverse set of behaviors on different characteristic scales. Given the coarse-grained modeling in theories of fluids, considerable uncertainties may exist between the flow-field solutions and the real physics. To study…

Computational Physics · Physics 2021-05-05 Tianbai Xiao , Martin Frank