Aging, rejuvenation and memory phenomena in spin glasses

TL;DR

This paper reviews the out-of-equilibrium dynamics of spin glasses, focusing on aging, rejuvenation, and memory effects, and introduces new findings on sub-aging behavior and the influence of anisotropy.

Contribution

It provides a comprehensive review of aging phenomena in spin glasses and presents new results on sub-aging and the impact of anisotropy on hierarchical processes.

Findings

Identification of sub-aging behavior in spin glasses

Rejuvenation and memory effects depend on temperature variations

Hierarchy in aging processes varies with spin anisotropy

Abstract

In this paper, we review several important features of the out-of-equilibrium dynamics of spin glasses. Starting with the simplest experiments, we discuss the scaling laws used to describe the isothermal aging observed in spin glasses after a quench down to the low temperature phase. We report in particular new results on the sub-aging behaviour of spin glasses. We then discuss the rejuvenation and memory effects observed when a spin glass is submitted to temperature variations during aging, from the point of view of both energy landscape pictures and of real space pictures. We highlight the fact that both approaches point out the necessity of hierarchical processes involved in aging. Finally, we report an investigation of the effect of small temperature variations on aging in spin glass samples with various anisotropies which indicates that this hierarchy depends on the spin anisotropy.