Reentrance during nonequilibrium relaxation

TL;DR

This paper investigates the nonequilibrium critical dynamics of the 2D Ising model, revealing a reentrant magnetization behavior over time influenced by initial cluster percolation and domain growth.

Contribution

It introduces a detailed analysis of reentrance phenomena during relaxation in the 2D Ising model with random initial fields, highlighting the effects of initial cluster percolation.

Findings

Magnetization exhibits a non-monotonic reentrant behavior over time.

Early cluster dissolution causes initial magnetization decrease.

Nonequilibrium autocorrelation decay is unaffected by initial percolation.

Abstract

We consider nonequilibrium critical dynamics of the two-dimensional Ising model for which the initial state is prepared by switching on random fields with zero mean and variance $H$. In the initial state there is no magnetic order but the clusters of parallel spins have a percolation transition for small enough $H$. Using heath-bath dynamics we measure the relaxation of the magnetization which shows a reentrance in time. Due to cluster dissolution in the early time regime there is a decrease of the magnetization, followed by an increase due to nonequilibrium domain growth which itself turns to a decrease due to equilibrium relaxation. The power law decay of the nonequilibrium autocorrelation function is not influenced by the percolation in the initial state.