Long-time tail in an electric conduction system

TL;DR

This study uses molecular dynamics simulations to analyze the long-time decay of velocity autocorrelation in a 2D electric conduction system, revealing a crossover from positive to negative tails influenced by disorder and electric field.

Contribution

It demonstrates the crossover behavior of velocity autocorrelation tails in a 2D electric system under varying disorder and electric field conditions.

Findings

Crossover from positive to negative tail with increasing disorder

Positive tail enhancement under stronger electric fields

Negative tail appears earlier with increased electric field

Abstract

The long-time behavior of the velocity autocorrelation function in a classical two-dimensional electric conduction system is studied by the molecular dynamics simulation. In equilibrium, the effect of coexistence of many-body interactions and a random potential is investigated. A crossover from a positive tail proportional to $t^{-1}$, to a negative tail proportional to $-t^{-2}$ is observed as the strength of the random potential increases. In nonequilibrium, the positive tail is enhanced whereas the negative tail appears at earlier times as an electric field increases.