The Mpemba effect in spin glasses is a persistent memory effect

TL;DR

This paper demonstrates that the Mpemba effect in spin glasses is a non-equilibrium phenomenon linked to the coherence length, offering insights into glassy dynamics and potential experimental applications.

Contribution

It reveals that the Mpemba effect in spin glasses is governed by the coherence length and occurs without crossing the critical temperature, providing a new perspective on glassy systems.

Findings

The Mpemba effect occurs in the glassy phase when the bath temperature is in this regime.

The effect is related to a strong correlation between internal energy and coherence length.

The phenomenon does not require crossing the critical temperature during thermal protocols.

Abstract

The Mpemba effect occurs when a hot system cools faster than an initially colder one, when both are refrigerated in the same thermal reservoir. Using the custom built supercomputer Janus II, we study the Mpemba effect in spin glasses and show that it is a non-equilibrium process, governed by the coherence length \xi of the system. The effect occurs when the bath temperature lies in the glassy phase, but it is not necessary for the thermal protocol to cross the critical temperature. In fact, the Mpemba effect follows from a strong relationship between the internal energy and \xi that turns out to be a sure-tell sign of being in the glassy phase. Thus, the Mpemba effect presents itself as an intriguing new avenue for the experimental study of the coherence length in supercooled liquids and other glass formers.