Field-Shift Aging Protocol on the 3D Ising Spin-Glass Model: Dynamical Crossover between the Spin-Glass and Paramagnetic States

TL;DR

This study uses Monte Carlo simulations to analyze the dynamical crossover in 3D Ising spin glasses under a magnetic field, revealing a scaling relation that suggests the instability of the spin-glass phase in the presence of even tiny fields.

Contribution

It introduces a field-shift aging protocol to identify the dynamical crossover time and demonstrates a scaling relation linking characteristic length scales, supporting the instability of the spin-glass phase.

Findings

Scaling relation between characteristic length scales and crossover time.

Evidence for spin-glass phase instability under infinitesimal magnetic fields.

Comparison with experimental observations on real spin glasses.

Abstract

Spin-glass (SG) states of the 3-dimensional Ising Edwards-Anderson model under a static magnetic field $h$ are examined by means of the standard Monte Carlo simulation on the field-shift aging protocol at temperature $T$. For each process with $(T; \tw, h)$, $\tw$ being the waiting time before the field is switched on, we extract the dynamical crossover time, $\tcr(T; \tw, h)$. We have found a nice scaling relation between the two characteristic length scales which are properly determined from $\tcr$ and $\tw$ and then are normalized by the static field crossover length introduced in the SG droplet theory. This scaling behavior implies the instability of the SG phase in the equilibrium limit even under an infinitesimal $h$. In comparison with this numerical result the field effect on real spin glasses is also discussed.