Temperature overshooting in the Mpemba effect of frictional active matter

TL;DR

This paper predicts a frictional Mpemba effect where a hotter active body cools faster than a warm one due to temperature overshoot, with potential applications in robotics and granular materials.

Contribution

It introduces a novel frictional Mpemba effect in macroscopic active matter systems governed by Coulomb friction, expanding the understanding of anomalous relaxation phenomena.

Findings

High initial temperature leads to faster relaxation than intermediate temperature.

Temperature overshooting causes the counterintuitive cooling behavior.

Potential applications in controlling robot and granular motion.

Abstract

The traditional Mpemba effect refers to an anomalous cooling phenomenon when an initial hotter system cools down faster than an initial warm system. Such counterintuitive behavior has been confirmed and explored across phase transitions in condensed matter systems and also for colloidal particles exposed to a double-well potential. Here we predict a frictional Mpemba effect for a macroscopic body moving actively on a surface governed by Coulomb (dry) friction. For an initial high temperature, relaxation towards a cold state occurs much faster than that for an intermediate initial temperature, due to a large temperature overshooting in the latter case. This frictional Mpemba effect can be exploited to steer the motion of robots and granules.