Mpemba effect in an anisotropically driven granular gas

TL;DR

This paper investigates the Mpemba effect in anisotropically driven granular gases, demonstrating its existence and conditions through theoretical analysis and molecular dynamics simulations, with initial stationary states enabling experimental study.

Contribution

It is the first to analyze the Mpemba effect in stationary, anisotropically driven granular gases, combining theory and simulations to identify conditions for various Mpemba effects.

Findings

Existence of regular, inverse, and strong Mpemba effects in granular gases.

Theoretical predictions align with molecular dynamics simulation results.

Initial stationary states facilitate experimental observation of the effect.

Abstract

We demonstrate the existence, as well as determine the conditions, of a Mpemba effect - a counterintuitive phenomenon where a hotter system equilibrates faster than a cooler system when quenched to a cold temperature - in anisotropically driven granular gases. In contrast to earlier studies of Mpemba effect in granular systems, the initial states are stationary, making it a suitable system to experimentally study the effect. Our theoretical predictions for the regular, inverse and strong Mpemba effects agree well with results of event-driven molecular dynamics simulations of hard discs.