Heat conduction in one-dimensional lattice dynamical systems far from equilibrium

TL;DR

This paper investigates heat conduction in one-dimensional lattice systems far from equilibrium, comparing momentum-conserving and nonconserving models to understand their differing behaviors in heat flux response.

Contribution

It provides a numerical comparison between the Fermi-Pasta-Ulam and $^4$ models, highlighting differences in heat flux behavior related to momentum conservation.

Findings

Heat flux in the $^4$ model does not increase monotonically with temperature difference.

In the FPU chain, heat flux increases monotonically with temperature difference.

Distinct behaviors are linked to momentum conservation properties.

Abstract

We study heat conduction in one dimensional lattice dynamical systems far from equilibrium. The Fermi-Pasta-Ulam model and the $\phi^4$ model are numerically compared to elucidate differences between momentum-conserving and nonconserving systems. As a results, it is found that the heat flux in the $\phi^4$ model does not increase monotonically as the temperature differences at the ends of the lattice is increased, while it does in the FPU chain.