Fluctuations of the heat flux of a one-dimensional hard particle gas

TL;DR

This paper investigates the fluctuations of heat flux in a one-dimensional hard particle gas, revealing that cumulants of the heat flux follow size-dependent power laws and differ between equilibrium and non-equilibrium conditions, contributing to understanding anomalous heat conduction.

Contribution

The study provides numerical evidence that heat flux cumulants in a 1D hard particle gas follow distinct power laws, highlighting differences between equilibrium and non-equilibrium states.

Findings

Cumulants of heat flux scale as power laws with system size.

Higher-order cumulants follow different power laws in different geometries.

Results support the anomalous Fourier law in 1D systems.

Abstract

Momentum-conserving one-dimensional models are known to exhibit anomalous Fourier's law, with a thermal conductivity varying as a power law of the system size. Here we measure, by numerical simulations, several cumulants of the heat flux of a one-dimensional hard particle gas. We find that the cumulants, like the conductivity, vary as power laws of the system size. Our results also indicate that cumulants higher than the second follow different power laws when one compares the ring geometry at equilibrium and the linear case in contact with two heat baths (at equal or unequal temperatures). keywords: current fluctuations, anomalous Fourier law, hard particle gas