Anomalous heating in a colloidal system

TL;DR

This paper reports the first observation of the inverse Mpemba effect in a colloidal system, where a colder system heats up faster than a warmer one under specific conditions, revealing anomalous heating behavior.

Contribution

It demonstrates the occurrence of anomalous heating and the inverse Mpemba effect in a colloidal system, supported by theoretical modeling and experimental tuning.

Findings

Observation of the inverse Mpemba effect in colloids

Non-monotonic dependence of heating times on initial temperature

Identification of a strong anomalous heating regime

Abstract

We report anomalous heating in a colloidal system, the first observation of the inverse Mpemba effect, where an initially cold system heats up faster than an identical warm system coupled to the same thermal bath. For an overdamped, Brownian colloidal particle moving in a tilted double-well potential, we find a non-monotonic dependence of the heating times on the initial temperature of the system, as predicted by an eigenfunction expansion of the associated Fokker-Planck equation. By carefully tuning parameters, we also observe a "strong" version of anomalous heating, where a cold system heats up exponentially faster than systems prepared under slightly different conditions