Rejuvenation and Memory in Migdal-Kadanoff Spin Glasses

TL;DR

This paper investigates aging, rejuvenation, and memory effects in Migdal-Kadanoff spin glasses, revealing how temperature chaos influences these phenomena through extensive simulations across wide time and length scales.

Contribution

It demonstrates the distinct roles of temperature chaos and equilibration speed in causing rejuvenation and memory effects in spin glasses.

Findings

Temperature chaos causes rejuvenation with positive temperature changes.

Slower equilibration at lower temperatures leads to memory effects.

Simulations match experimental observations of spin glass behavior.

Abstract

We study aging phenomena of Migdal-Kadanoff spin glasses in order to clarify relevancy of temperature chaos to rejuvenation and memory. By exploiting renormalization, we do efficient dynamical simulations in very wide time/length scales including the chaos length. As a consequence, we find that temperature chaos and temperature dependence of speed of equilibration cause two significantly different effects against temperature variations, i.e., rejuvenation for positive temperature variation and memory for negative temperature variation, as are observed experimentally in spin glasses.