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A spatially flat Friedmann-Robertson-Walker background with a general scale factor is considered. In this space-time, the energy-momentum tensor of the scalar field with a general curvature coupling parameter is obtained. Using the Thermo…

High Energy Physics - Theory · Physics 2020-07-15 A. F. Santos , S. C. Ulhoa , Faqir C. Khanna

First order phase transitions in the early universe may have left a variety of experimentally accessible imprints. The dynamics of such transitions is governed by the density perturbations caused by the propagation of the bubble wall in the…

High Energy Physics - Phenomenology · Physics 2024-10-02 Carlo Branchina , Angela Conaci , Stefania De Curtis , Luigi Delle Rose , Andrea Guiggiani , Angel Gil Muyor , Giuliano Panico

We consider a system made up of exictations of a neutral scalar field, \phi, having a \lambda\phi^4 interaction term. Starting from an ensemble where the occupation number f is large, but \lambda f is small, we develop a classical field…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. H. Mueller , D. T. Son

A jump-diffusion process along with a particle scheme is devised as an accurate and efficient particle solution to the Boltzmann equation. The proposed process (hereafter Gamma-Boltzmann model) is devised to match the evolution of all…

Computational Physics · Physics 2023-08-09 Fabian Mies , Mohsen Sadr , Manuel Torrilhon

By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic…

High Energy Astrophysical Phenomena · Physics 2014-11-20 A. G. Aksenov , R. Ruffini , G. V. Vereshchagin

The Boltzmann equation is the traditional framework in which one extends the time-dependent mean field classical description of a many-body system to include the effect of particle-particle collisions in an approximate manner. A…

Nuclear Theory · Physics 2022-02-10 A. Bulgac

The quantum Boltzmann equation, or Fokker-Planck equation, has been used to successfully explain a number of experiments in semiconductor optics in the past two decades. This paper reviews some of the developments of this work, including…

Statistical Mechanics · Physics 2010-11-18 D. W. Snoke

The particles model, the collision model, the polynomial development used for the equilibrium distribution, the time discretization and the velocity discretization are factors that let the lattice Boltzmann framework (LBM) far away from its…

Nonequilibrium quantum field theory is often used to derive an approximation for the evolution of number densities and asymmetries in astroparticle models when a more precise treatment of quantum thermal effects is required. This work…

High Energy Physics - Phenomenology · Physics 2022-03-14 Tomáš Blažek , Peter Maták

Recent experiments access the time-resolved photoelectron signal originating from plasmon satellites in correlated materials and address their build-up and decay in real time. Motivated by these developments, we present the Kadanoff-Baym…

Strongly Correlated Electrons · Physics 2016-02-24 Michael Schüler , Jamal Berakdar , Yaroslav Pavlyukh

A quantum linear Boltzmann equation is proposed, constructed in terms of the operator-valued dynamic structure factor of the macroscopic system the test particle is interacting with. Due to this operator structure it is a non-Abelian linear…

Quantum Physics · Physics 2009-11-07 Bassano Vacchini

We derive quantum Boltzmann equations for preheating by means of the density matrix formalism, which account for both the non-adiabatic particle production and the leading collisional processes between the produced particles. In so doing,…

High Energy Physics - Theory · Physics 2018-10-01 William T. Emond , Peter Millington , Paul M. Saffin

A univariate polynomial equation is presented. It provides models of the thermal lattice Boltzmann equation. The models can be accurate up to any required level and can be applied to regular lattices, which allow efficient and accurate…

Mathematical Physics · Physics 2020-11-10 Jae Wan Shim

A linear Boltzmann equation with nonautonomous collision operator is rigorously derived in the Boltzmann-Grad limit for the deterministic dynamics of a Rayleigh gas where a tagged particle is undergoing hard-sphere collisions with…

Analysis of PDEs · Mathematics 2019-04-24 Karsten Matthies , George Stone

Real-time perturbation theory is formulated for complex scalar fields away from thermal equilibrium in such a way that dissipative effects arising from the absorptive parts of loop diagrams are approximately resummed into the unperturbed…

High Energy Physics - Theory · Physics 2009-10-30 I. D. Lawrie , D. B. McKernan

We consider the spatially inhomogeneous Boltzmann equation for inelastic hard-spheres, with constant restitution coefficient $\alpha\in(0,1)$, under the thermalization induced by a host medium with a fixed Maxwellian distribution and any…

Analysis of PDEs · Mathematics 2020-08-17 Rafael Sanabria

The equivalence between thermal field theory and the Boltzmann transport equation is investigated at higher orders in the context of quantum electrodynamics. We compare the contributions obtained from the collisionless transport equation…

High Energy Physics - Theory · Physics 2015-03-04 F. T. Brandt , R. B. Ferreira , J. F. Thuorst

The collisionless Boltzmann equation, also called free-streaming, is a convenient approximation. It is rather simple to implement numerically, and and it is effective at reducing the irregularities of rough initial conditions. It can be…

High Energy Physics - Phenomenology · Physics 2023-04-04 Leonardo Tinti

The notion of distance between a global Maxwellian function and an arbitrary solution $f$ (with the same total density $\rho$ at the fixed moment $t$) of Boltzmann equation is introduced. In this way we essentially generalize the important…

Mathematical Physics · Physics 2015-06-03 Lev Sakhnovich

The Boltzmann equation is a powerful theoretical tool for modeling the collective dynamics of quantum many-body systems subject to external perturbations. Analysis of the equation gives access to linear response properties including…