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In this paper we revisit the derivation of boundary conditions for the Boltzmann Equation. The interaction between the wall atoms and the gas molecules within a thin surface layer is described by a kinetic equation introduced in [9] and…

Analysis of PDEs · Mathematics 2013-06-20 Stéphane Brull , Pierre Charrier , Luc Mieussens

We study the bosonic Boltzmann-Nordheim kinetic equation, which describes the kinetic regime of weakly interacting bosons with s-wave scattering only. We consider a spatially homogeneous fluid with an isotropic momentum distribution. The…

Mesoscale and Nanoscale Physics · Physics 2008-09-29 Herbert Spohn

In this paper we develop a gapless theory of BEC which can be applied to both trapped and homogeneous gases at zero and finite temperature. The many-body Hamiltonian for the system is written in a form which is approximately quadratic with…

Statistical Mechanics · Physics 2009-10-31 S. A. Morgan

We study the single-particle distributions of three-dimensional hard sphere gas described by the Boltzmann equation. We focus on the steady homogeneous isotropic solutions in thermodynamically open conditions, i.e. in the presence of…

Chaotic Dynamics · Physics 2011-10-10 Davide Proment , Sergey Nazarenko , Pietro Asinari , Miguel Onorato

We use guiding principles from nonequilibrium thermodynamics to develop an admissible set of 13 moment equations for rarefied gas flows. The main benefits of our thermodynamic approach are an explicit entropy expression fulfilling an $H$…

Statistical Mechanics · Physics 2010-11-10 Hans Christian Öttinger

The isothermal Tolman condition and the constancy of the Klein potentials originally expressed for the sole gravitational interaction in a single fluid are here generalized to the case of a three quantum fermion fluid duly taking into…

General Relativity and Quantum Cosmology · Physics 2012-06-01 Jorge A. Rueda , R. Ruffini , S. -S. Xue

Using the information current, we develop a Lorentz-covariant framework for modeling equilibrium fluctuations in relativistic kinetic theory in the grand-canonical ensemble. The resulting stochastic theory is proven to be causal and…

Nuclear Theory · Physics 2024-07-24 Gabriel Soares Rocha , Lorenzo Gavassino , Nicki Mullins

Advanced kinetic theory with the Boltzmann-Curtiss equation provides a promising tool for polyatomic gas flows, especially for fluid flows containing inner structures, such as turbulence, polyatomic gas flows and others. Although a…

Fluid Dynamics · Physics 2018-02-14 James Chen

Starting with the relativistic Boltzmann equation where the collision term was generalized to include gradients of the phase-space distribution function, we recently presented a new derivation of the equations for the relativistic…

Nuclear Theory · Physics 2013-05-23 Amaresh Jaiswal , Rajeev S. Bhalerao , Subrata Pal

In dilute gas kinetic theory, model collision dynamics such as Bhatnagar-Gross-Krook (BGK) model is often used to get a better insight and numerical modelling. BGK model and its variants assume that highly nonlinear collision term can be…

Statistical Mechanics · Physics 2020-08-26 Samarth Agrawal , S. K. Singh , Santosh Ansumali

The existence of stationary distributions in a multicomponent Boltzmann equation using a non-additive kinetic energy composition rule for binary collisions is discussed. It is found that detailed balance is not achieved when -- in contrast…

Statistical Mechanics · Physics 2014-08-19 M. Horváth , T. S. Biró

The derivation of the Nordheim-Boltzmann transport equation for weakly interacting quantum fluids is a longstanding problem in mathematical physics. Inspired by the method developed to handle classical dilute gases, a conventional approach…

Mathematical Physics · Physics 2009-05-25 Jani Lukkarinen , Herbert Spohn

Direct Monte Carlo simulations of the Enskog-Boltzmann equation for a spatially uniform system of smooth inelastic spheres are performed. In order to reach a steady state, the particles are assumed to be under the action of an external…

Statistical Mechanics · Physics 2016-08-31 J. M. Montanero , A. Santos

In the present contribution, we derive from kinetic theory a unified fluid model for multicomponent plasmas by accounting for the electromagnetic field influence. We deal with a possible thermal nonequilibrium of the translational energy of…

Plasma Physics · Physics 2011-03-07 Benjamin Graille , Thierry E. Magin , Marc Massot

We study a hard sphere gas at equilibrium, and prove that in the low density limit, the fluctuations converge to a Gaussian process governed by the fluctuating Boltzmann equation. This result holds for arbitrarily long times. The method of…

Analysis of PDEs · Mathematics 2022-01-13 Thierry Bodineau , Isabelle Gallagher , Laure Saint-Raymond , Sergio Simonella

Small perturbations of the homogeneous cooling state (HCS) for a low density granular gas are described by means of the linearized Boltzmann equation. The spectrum of the generator for this dynamics is shown to contain points corresponding…

Statistical Mechanics · Physics 2009-11-11 J. Javier Brey , J. W. Dufty

While accurate simulations of dense gas flows far from the equilibrium can be achieved by Direct Simulation adapted to the Enskog equation, the significant computational demand required for collisions appears as a major constraint. In order…

Computational Physics · Physics 2023-08-11 Mohsen Sadr , M. Hossein Gorji

The non-equilibrium contributions to the post-Newtonian hydrodynamic equations are determined from a relaxation-time model of the post-Newtonian Boltzmann equation. The Chapman-Enskog method is used to calculate the non-equilibrium…

General Relativity and Quantum Cosmology · Physics 2023-04-05 Gilberto M. Kremer

In this paper, we present a formalism to generate a family of interior solutions to the Einstein-Maxwell system of equations for a spherically symmetric relativistic charged fluid sphere matched to the exterior Reissner-Nordstr\"om…

General Physics · Physics 2018-05-09 K. Komathiraj , Ranjan Sharma

We present the derivation of a novel third-order hydrodynamic evolution equation for shear stress tensor from kinetic theory. Boltzmann equation with relaxation time approximation for the collision term is solved iteratively using…

Nuclear Theory · Physics 2013-09-02 Amaresh Jaiswal