Conserved densities of hard rods: microscopic to hydrodynamic solutions

Fuente: arXiv
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Main Authors: Powdel, Mrinal Jyoti, Kundu, Anupam
Format: Preprint
Published: 2024
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author Powdel, Mrinal Jyoti
Kundu, Anupam
author_facet Powdel, Mrinal Jyoti
Kundu, Anupam
contents We consider a system of many hard rods moving in one dimension. As it is an integrable system, it possesses an extensive number of conserved quantities and its evolution on macroscopic scale can be described by generalised hydrodynamics. Using a microscopic approach, we compute the evolution of the conserved densities starting from non-equilibrium initial conditions of both quenched and annealed type. In addition to getting reduced to the Euler solutions of the hydrodynamics in the thermodynamic limit, the microscopic solutions can also capture effects of the Navier-Stokes terms and thus go beyond the Euler solutions. We demonstrate this feature from microscopic analysis and numerical solution of the Navier-Stokes equation in two problems -- first, tracer diffusion in a background of hard rods and second, the evolution from a domain wall initial condition in which the velocity distribution of the rods are different on the two sides of the interface. We supplement our analytical results using extensive numerical simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2407_17067
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Conserved densities of hard rods: microscopic to hydrodynamic solutions
Powdel, Mrinal Jyoti
Kundu, Anupam
Statistical Mechanics
We consider a system of many hard rods moving in one dimension. As it is an integrable system, it possesses an extensive number of conserved quantities and its evolution on macroscopic scale can be described by generalised hydrodynamics. Using a microscopic approach, we compute the evolution of the conserved densities starting from non-equilibrium initial conditions of both quenched and annealed type. In addition to getting reduced to the Euler solutions of the hydrodynamics in the thermodynamic limit, the microscopic solutions can also capture effects of the Navier-Stokes terms and thus go beyond the Euler solutions. We demonstrate this feature from microscopic analysis and numerical solution of the Navier-Stokes equation in two problems -- first, tracer diffusion in a background of hard rods and second, the evolution from a domain wall initial condition in which the velocity distribution of the rods are different on the two sides of the interface. We supplement our analytical results using extensive numerical simulations.
title Conserved densities of hard rods: microscopic to hydrodynamic solutions
topic Statistical Mechanics
url https://arxiv.org/abs/2407.17067