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The departure of a granular gas in the instable region of parameters from the initial homogeneous cooling state is studied. Results from Molecular Dynamics and from Direct Monte Carlo simulation of the Boltzmann equation are compared. It is…

Statistical Mechanics · Physics 2009-11-10 J. Javier Brey , M. J. Ruiz-Montero

The hypothesis of molecular chaos plays the central role in kinetic theory, which provides a closure leading to the Boltzmann equation for quantitative description of classic fluids. Yet how to properly extend it to active systems is still…

We develop a set of coupled Boltzmann equations to describe the dynamical evolution of heavy quarks and quarkonia inside the quark-gluon plasma. The quarkonium dissociation and recombination terms are calculated from pNRQCD. Their interplay…

Nuclear Theory · Physics 2019-01-23 Xiaojun Yao , Weiyao Ke , Yingru Xu , Steffen Bass , Berndt Müller

We consider a linear Boltzmann equation that arises in a model for quantum friction. It describes a particle that is slowed down by the emission of bosons. We study the stochastic process generated by this Boltzmann equation and we show…

Mathematical Physics · Physics 2024-04-25 Roland Bauerschmidt , Wojciech de Roeck , Jürg Fröhlich

The Feynman-Vernon path integral formalism is used to derive the density matrix of a quantum oscillator that is linearly coupled to an environmental reservoir. Although low-temperature reservoirs thermalize the oscillator to the usual…

General Physics · Physics 2014-12-15 George E. Cragg

A full quantum theory beyond the mean-field regime is developed for an exciton polariton condensate, to gain a complete understanding of quantum fluctuations. We find analytical solution for the polariton density matrix, showing the…

Mesoscale and Nanoscale Physics · Physics 2022-04-29 Zhedong Zhang , Shixuan Zhao , Dangyuan Lei

We introduce a generalised relaxation-time-approximation form of the collision term in the Boltzmann kinetic equation that allows for using different relaxation times for elastic and inelastic collisions. The efficacy of the proposed…

Nuclear Theory · Physics 2016-06-15 Wojciech Florkowski , Radoslaw Ryblewski

A framework for relativistic thermodynamics and statistical physics is built by first exploiting the symmetries between energy and momentum in the derivation of the Boltzmann distribution, then using Einstein's energy-momentum relationship…

Statistical Mechanics · Physics 2020-07-09 Alexander Taskov

Fokker-Planck equation with the velocity-dependent coefficients is considered for various isotropic systems on the basis of probability transition (PT) approach. This method provides the self-consistent and universal description of friction…

Plasma Physics · Physics 2009-11-07 S. A. Trigger

We develop a highly efficient method to numerically simulate thermal fluctuations and correlations in non-relativistic continuous bosonic one-dimensional systems. The method is suitable for arbitrary local interactions as long as the system…

Quantum Gases · Physics 2020-04-21 Stefan Beck , Igor E. Mazets , Thomas Schweigler

Calculating the abundance of thermally produced dark matter particles has become a standard procedure, with sophisticated methods guaranteeing a precision that matches the percent-level accuracy in the observational determination of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-12 Tobias Binder , Torsten Bringmann , Michael Gustafsson , Andrzej Hryczuk

We discuss decay of unstable particles and pair annihilation of stable heavy particles that occur in the cosmic medium, from the point of the fundamental microscopic theory. A fully quantum mechanical treatment shows that the effect of…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Yoshimura

A linear Boltzmann equation is derived in the Boltzmann-Grad scaling for the deterministic dynamics of many interacting particles with random initial data. We study a Rayleigh gas where a tagged particle is undergoing hard-sphere collisions…

Analysis of PDEs · Mathematics 2017-11-29 Karsten Matthies , George Stone , Florian Theil

We consider the problem of the development of steady states in one-dimensional Bose gas tubes that are weakly coupled to one another through a density-density interaction. We analyze this development through a Boltzmann collision integral…

Quantum Gases · Physics 2024-07-10 Maciej Łebek , Miłosz Panfil , Robert M. Konik

In this paper the Boltzmann transport equation for thermal processes induced by ultra-short laser pulses is formulated and solved. For thermal process where the duration of the laser pulse (femtoseconds - attoseconds) is shorter than the…

Materials Science · Physics 2007-05-23 J. Marciak-Kozlowska , M. Kozlowski

The paper deals with non-equilibrium thermodynamics based on adiabatic particle creation mechanism with the motivation of considering it as an alternative choice to explain the recent observed accelerating phase of the universe. Using…

General Relativity and Quantum Cosmology · Physics 2015-04-14 Supriya Pan , Subenoy Chakraborty

Many experimentally relevant systems are quasi-one-dimensional, consisting of nearly decoupled chains. In these systems, there is a natural separation of scales between the strong intra-chain interactions and the weak interchain coupling.…

Quantum Gases · Physics 2023-02-21 Miłosz Panfil , Sarang Gopalakrishnan , Robert M. Konik

We develop the Cauchy theory of the spatially homogeneous inelastic Boltzmann equation for hard spheres, for a general form of collision rate which includes in particular variable restitution coefficients depending on the kinetic energy and…

Analysis of PDEs · Mathematics 2016-08-16 Stéphane Mischler , Clément Mouhot , Mariano Rodriguez Ricard

This article describes methods for the deterministic simulation of the collisional Boltzmann equation. It presumes that the transport and collision parts of the equation are to be simulated separately in the time domain. Time stepping…

Numerical Analysis · Mathematics 2009-11-19 Akil Narayan , Andreas Klöckner

Motivated by the recent interest in non-equilibrium phenomena in quantum many-body systems, we study strongly interacting fermions on a lattice by deriving and numerically solving quantum Boltzmann equations that describe their relaxation…

Quantum Physics · Physics 2019-12-10 Friedemann Queisser , Sebastian Schreiber , Peter Kratzer , Ralf Schützhold