Memory effect in uniformly heated granular gases

TL;DR

This paper demonstrates a Kovacs-like memory effect in a uniformly driven granular gas, showing non-monotonic temperature evolution after specific driving protocols, with theoretical and simulation agreement.

Contribution

It reveals a novel memory effect in granular gases and provides a theoretical framework explaining its dependence on dissipation and protocol.

Findings

Memory effect observed in granular gases.

Analytical and simulation results agree.

Memory response becomes anomalous above a dissipation threshold.

Abstract

We evidence a Kovacs-like memory effect in a uniformly driven granular gas. A system of inelastic hard particles, in the low density limit, can reach a non-equilibrium steady state when properly forced. By following a certain protocol for the drive time dependence, we prepare the gas in a state where the granular temperature coincides with its long time value. The temperature subsequently does not remain constant, but exhibits a non-monotonic evolution with either a maximum or a minimum, depending on the dissipation, and on the protocol. We present a theoretical analysis of this memory effect, at Boltzmann-Fokker-Planck equation level, and show that when dissipation exceeds a threshold, the response can be coined anomalous. We find an excellent agreement between the analytical predictions and direct Monte Carlo simulations.