Mpemba effect in the relaxation of an active Brownian particle in a trap without metastable states

TL;DR

This paper investigates how activity influences the Mpemba effect in active colloids within a potential landscape, revealing that activity can both induce and suppress the effect through phase space shifts.

Contribution

It demonstrates that activity modifies the Mpemba effect in active colloids, showing how activity can induce or suppress the effect by shifting phase space.

Findings

Activity can induce the Mpemba effect in active colloids.

Activity can suppress the Mpemba effect depending on system parameters.

Phase space shifts explain the activity's impact on the Mpemba effect.

Abstract

We explore the role of activity in the occurrence of the Mpemba effect within a system of an active colloid diffusing in a potential landscape devoid of metastable minimum. The Mpemba effect is characterized by a phenomenon where a hotter system reaches equilibrium quicker than a colder one when both are rapidly cooled to the same low temperature. While a minimal asymmetry in the potential landscape is crucial for observing this effect in passive colloidal systems, the introduction of activity can either amplify or reduce the threshold of this minimal asymmetry, resulting in the activity-induced and suppressed Mpemba effect. We attribute these variations in the Mpemba effect to the effective translational shift in the phase space, which occurs as activity is changed.