Phase transition between synchronous and asynchronous updating algorithms

TL;DR

This paper investigates a phase transition in a one-dimensional Ising spin system driven by a parameterized updating algorithm, revealing a transition between ferromagnetic and antiferromagnetic stationary states with critical behavior in the parity conservation class.

Contribution

It introduces a unified updating scheme interpolating between Metropolis and synchronous updates, identifying a phase transition with critical exponents in the parity conservation universality class.

Findings

Identifies a phase transition at a critical probability p_c.

Stationary states switch from ferromagnetic to antiferromagnetic across p_c.

Critical exponents match the parity conservation universality class.

Abstract

We update a one-dimensional chain of Ising spins of length $L$ with algorithms which are parameterized by the probability $p$ for a certain site to get updated in one time step. The result of the update event itself is determined by the energy change due to the local change in the configuration. In this way we interpolate between the Metropolis algorithm at zero temperature for $p$ of the order of 1/L and for large $L$, and a synchronous deterministic updating procedure for $p=1$. As function of $p$ we observe a phase transition between the stationary states to which the algorithm drives the system. These are non-absorbing stationary states with antiferromagnetic domains for $p>p_c$, and absorbing states with ferromagnetic domains for $p\leq p_c$. This means that above this transition the stationary states have lost any remnants to the ferromagnetic Ising interaction. A measurement of the critical exponents shows that this transition belongs to the universality class of parity conservation.