Low-temperature nucleation in a kinetic Ising model with soft stochastic dynamics

TL;DR

This paper investigates low-temperature nucleation in kinetic Ising models, revealing that the nucleation parameters depend on the stochastic dynamic used, especially contrasting soft dynamics with standard Glauber dynamics.

Contribution

It demonstrates that both the prefactor and the nucleation barrier depend on the stochastic dynamic, challenging previous assumptions that they are solely determined by energy barriers.

Findings

Gamma depends on the stochastic dynamic used

Soft dynamic leads to Gamma not equal to the energy barrier

Results confirmed through analytical and simulation methods

Abstract

We study low-temperature nucleation in kinetic Ising models by analytical and simulational methods, confirming the general result for the average metastable lifetime, <tau> = A*exp(beta*Gamma) (beta = 1/kT) [E. Jordao Neves and R.H. Schonmann, Commun. Math. Phys. 137, 209 (1991)]. Contrary to common belief, we find that both A and Gamma depend significantly on the stochastic dynamic. In particular, for a ``soft'' dynamic, in which the effects of the interactions and the applied field factorize in the transition rates, Gamma does NOT simply equal the energy barrier against nucleation, as it does for the standard Glauber dynamic, which does not have this factorization property.