Dean-Kawasaki fluctuating hydrodynamics for backscattering hard rods

Fuente: arXiv
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Main Author: Powdel, Mrinal Jyoti
Format: Preprint
Published: 2026
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author Powdel, Mrinal Jyoti
author_facet Powdel, Mrinal Jyoti
contents We study a system of backscattering hard rods in one dimension. Contrary to the usual ballistic hard rods, these hard rods flip the sign of their velocities with a rate $γ$. This leads to the decay of the odd moments of velocity while preserving the even moments: the number of conserved quantities in the system becomes half. The introduction of the flipping rate $γ$ is an integrability-breaking perturbation, and this leads to a change in the transport properties in the system. We show using a Dean-Kawasaki fluctuating hydrodynamic formulation that the unequal space-time correlation of the normal mode phase space densities attains a diffusive form at late times. Also, we show that for $t \gg 1/γ$, the two-time density-density correlation of mass densities spreads in a diffusive manner, and for $t \ll 1/γ$, the correlation spreads ballistically, for a background state given by the Boltzmann distribution. Our results present an elegant framework to study systems where integrability is broken by a stochastic noise.
format Preprint
id arxiv_https___arxiv_org_abs_2604_21553
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dean-Kawasaki fluctuating hydrodynamics for backscattering hard rods
Powdel, Mrinal Jyoti
Statistical Mechanics
We study a system of backscattering hard rods in one dimension. Contrary to the usual ballistic hard rods, these hard rods flip the sign of their velocities with a rate $γ$. This leads to the decay of the odd moments of velocity while preserving the even moments: the number of conserved quantities in the system becomes half. The introduction of the flipping rate $γ$ is an integrability-breaking perturbation, and this leads to a change in the transport properties in the system. We show using a Dean-Kawasaki fluctuating hydrodynamic formulation that the unequal space-time correlation of the normal mode phase space densities attains a diffusive form at late times. Also, we show that for $t \gg 1/γ$, the two-time density-density correlation of mass densities spreads in a diffusive manner, and for $t \ll 1/γ$, the correlation spreads ballistically, for a background state given by the Boltzmann distribution. Our results present an elegant framework to study systems where integrability is broken by a stochastic noise.
title Dean-Kawasaki fluctuating hydrodynamics for backscattering hard rods
topic Statistical Mechanics
url https://arxiv.org/abs/2604.21553