Deviations from Perfect Memory in Spin Glass Temperature Cycling Experiments

TL;DR

This paper investigates how spin glasses deviate from perfect memory during temperature cycling, revealing non-monotonous behavior in memory anomalies and modeling it with Random Energy trap models and droplet/temperature chaos theories.

Contribution

It demonstrates that the complex memory deviations in spin glasses can be explained by simple trap models and discusses alternative droplet and temperature chaos interpretations.

Findings

Memory anomaly is negative for small temperature jumps.

Memory anomaly becomes positive for intermediate jumps.

Anomalies vanish for large temperature jumps.

Abstract

We study the deviations from perfect memory in negative temperature cycle spin glass experiments. It is known that the a.c. susceptibility after the temperature is raised back to its initial value is superimposed to the reference isothermal curve for large enough temperature jumps DT (perfect memory). For smaller DT, the deviation from this perfect memory has a striking non monotonous behavior: the memory anomaly is negative for small DT's, becomes positive for intermediate DT's, before vanishing for still larger DT's. We show that this interesting behavior can be reproduced by simple Random Energy trap models. We discuss an alternative interpretation in terms of droplets and temperature chaos.