Dynamical transition in the D = 3 Edwards-Anderson spin glass in an external magnetic field

TL;DR

This study investigates the off-equilibrium dynamics of a 3D Ising spin glass under an external magnetic field, identifying a dynamical transition point that varies with the field, using advanced simulations on a specialized computer.

Contribution

It provides new insights into the dynamical transition in 3D spin glasses under magnetic fields through large-scale simulations, exploring different physical interpretations.

Findings

Identification of a positive dynamical transition temperature depending on the magnetic field

Evidence supporting various physical scenarios including thermodynamic transition and mode-coupling crossover

Use of the Janus computer enabled simulation times comparable to experimental timescales

Abstract

We study the off-equilibrium dynamics of the three-dimensional Ising spin glass in the presence of an external magnetic field. We have performed simulations both at fixed temperature and with an annealing protocol. Thanks to the Janus special-purpose computer, based on FPGAs, we have been able to reach times equivalent to 0.01 seconds in experiments. We have studied the system relaxation both for high and for low temperatures, clearly identifying a dynamical transition point. This dynamical temperature is strictly positive and depends on the external applied magnetic field. We discuss different possibilities for the underlying physics, which include a thermodynamical spin-glass transition, a mode-coupling crossover or an interpretation reminiscent of the random first-order picture of structural glasses.