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We consider the mass heterogeneity in a gas of polydisperse hard particles as a key to optimizing a dynamical property: the kinetic relaxation rate. Using the framework of the Boltzmann equation, we study the long time approach of a…

Soft Condensed Matter · Physics 2015-06-17 Matthieu Barbier , Emmanuel Trizac

We exactly solve the one-dimensional boost-invariant Boltzmann equation in the relaxation time approximation for arbitrary shear viscosity. The results are compared with the predictions of viscous and anisotropic hydrodynamics. Studying…

Nuclear Theory · Physics 2013-08-08 Wojciech Florkowski , Radoslaw Ryblewski , Michael Strickland

We study the Cauchy problem for a system of equations corresponding to a singular limit of radiative hydrodynamics, namely the 3D radiative compressible Euler system coupled to an electromagnetic field through the MHD approximation.…

Analysis of PDEs · Mathematics 2017-08-15 X. Blanc , B. Ducomet , S. Necasova

The problem of collisionless plasma slab expansion into vacuum is solved within a two-temperature hydrodynamic approximation in the dispersionless limit of zero Debye radius. In the framework of such an approach, the solution by the Riemann…

Pattern Formation and Solitons · Physics 2021-11-08 S. K. Ivanov , A. M. Kamchatnov

Riemannian accelerated gradient methods have been well studied for smooth optimization, typically treating geodesically convex and geodesically strongly convex cases separately. However, their extension to nonsmooth problems on manifolds…

Optimization and Control · Mathematics 2025-09-29 Shuailing Feng , Yuhang Jiang , Wen Huang , Shihui Ying

We study the one-dimensional boost-invariant Boltzmann equation in the relaxation-time approximation using special moments of the distribution function for a system with a finite particle mass. The infinite hierarchy of moments can be…

Nuclear Theory · Physics 2022-11-08 Sunil Jaiswal , Jean-Paul Blaizot , Rajeev S. Bhalerao , Zenan Chen , Amaresh Jaiswal , Li Yan

This work is concerned with our recently developed formalism of non-equilibrium thermodynamics. This formalism extends the classical irreversible thermodynamics which leads to classical thermodynamics and can not describe physical phenomena…

Analysis of PDEs · Mathematics 2018-09-06 Zaibao Yang , Wen-An Yong , Yi Zhu

Gradient Langevin dynamics and a variety of its variants have attracted increasing attention owing to their convergence towards the global optimal solution, initially in the unconstrained convex framework while recently even in convex…

Optimization and Control · Mathematics 2024-08-15 Kanji Sato , Akiko Takeda , Reiichiro Kawai , Taiji Suzuki

A general analysis of the hydrodynamic limit of multi-relaxation time lattice Boltzmann models is presented. We examine multi-relaxation time BGK collision operators that are constructed similarly to those for the MRT case, however, without…

Soft Condensed Matter · Physics 2010-11-10 Goetz Kaehler , Alexander Wagner

A class of linear kinetic Fokker-Planck equations with a non-trivial diffusion matrix and with periodic boundary conditions in the spatial variable is considered. After formulating the problem in a geometric setting, the question of the…

Mathematical Physics · Physics 2012-10-03 Simone Calogero

By means of a scaling ansatz, we investigate an approximated solution of the Boltzmann-Vlasov equation for a classical gas. Within this framework, we derive the frequencies and the damping of the collective oscillations of a harmonically…

Condensed Matter · Physics 2009-11-10 P. Pedri , D. Guéry-Odelin , S. Stringari

We consider the spatially homogeneous Boltzmann equation for regularized soft potentials and Grad's angular cutoff. We prove that uniform (in time) bounds in $L^1 ((1 + |v|^s)dv)$ and $H^k$ norms, $s, k \ge 0$ hold for its solution. The…

Analysis of PDEs · Mathematics 2016-08-16 Laurent Desvillettes , Clément Mouhot

In this paper, we consider a BGK-type kinetic model relaxing to the isentropic gas dynamics in the hydrodynamic limit. We introduce a linearization of the equation around the global equilibrium. Then we prove the global existence of…

Analysis of PDEs · Mathematics 2024-02-16 Byung-Hoon Hwang

This article derives lower bounds on the convergence rate of continuous-time gradient-based optimization algorithms. The algorithms are subjected to a time-normalization constraint that avoids a reparametrization of time in order to make…

Optimization and Control · Mathematics 2020-08-04 Michael Muehlebach , Michael I. Jordan

We derive the equations of motion for a system undergoing boost-invariant longitudinal and azimuthally-symmetric transverse "Gubser flow" using leading-order anisotropic hydrodynamics. This is accomplished by assuming that the one-particle…

Nuclear Theory · Physics 2015-02-05 Mohammad Nopoush , Radoslaw Ryblewski , Michael Strickland

New exact solutions of relativistic perfect fluid hydrodynamics are described, including the first family of exact rotating solutions. The method used to search for them is an investigation of the relativistic hydrodynamical equations and…

Nuclear Theory · Physics 2011-05-13 M. I. Nagy

We introduce an accurate non-Hermitian Schr\"odinger-type approximation of Bloch optical equations for two-level systems. This approximation provides a complete description of the excitation, relaxation and decoherence dynamics in both weak…

Quantum Physics · Physics 2016-07-11 Raiju Puthumpally-Joseph , Maxim Sukharev , Eric Charron

Second-order relativistic hydrodynamics is surprisingly predictive, even in the presence of large gradients. The hydrodynamic expansion from the method of moments does not require a gradient expansion, but it is intrinsically bound to the…

Nuclear Theory · Physics 2020-03-23 Leonardo Tinti

A truncated Hilbert expansion with multiple scales is used to construct asymptotic solution of the linearized one-dimensional Boltzmann equation with small Knudsen number. The freedom ganed by introducing new independent time variables is…

Mathematical Physics · Physics 2025-09-04 O. M. Chekmareva , I. B. Chekmarev

A spatially-periodic longitudinal wave is considered in relativistic dissipative hydrodynamics. At sufficiently small wave amplitudes, an analytic solution is obtained in the linearised limit of the macroscopic conservation equations within…

Fluid Dynamics · Physics 2018-03-07 Victor E. Ambrus