Thermodynamic glass transition in a spin glass without time-reversal symmetry

TL;DR

This paper provides conclusive evidence of a thermodynamic phase transition in a four-dimensional spin glass subjected to an external magnetic field, using advanced simulations and a novel finite-size scaling method.

Contribution

The study demonstrates the existence of a phase transition in a 4D spin glass with broken time-reversal symmetry, employing large-scale simulations and a new scaling approach.

Findings

Evidence of a phase transition in 4D spin glass in a field

Use of massive simulations on Janus computer

Development of a new finite-size scaling method

Abstract

Spin glasses are a longstanding model for the sluggish dynamics that appears at the glass transition. However, spin glasses differ from structural glasses for a crucial feature: they enjoy a time reversal symmetry. This symmetry can be broken by applying an external magnetic field, but embarrassingly little is known about the critical behaviour of a spin glass in a field. In this context, the space dimension is crucial. Simulations are easier to interpret in a large number of dimensions, but one must work below the upper critical dimension (i.e., in d<6) in order for results to have relevance for experiments. Here we show conclusive evidence for the presence of a phase transition in a four-dimensional spin glass in a field. Two ingredients were crucial for this achievement: massive numerical simulations were carried out on the Janus special-purpose computer, and a new and powerful finite-size scaling method.