Dynamic structure factor of the three-dimensional Ising model with purely relaxational dynamics

Abstract

We compute the dynamic structure factor for the three-dimensional Ising model with a purely relaxational dynamics (model A). We perform a perturbative calculation in the e expansion, at two loops in the high temperature phase and at one loop in the temperature magnetic-field plane, and a Monte Carlo simulation in the high-temperature phase. We find that the dynamic structure factor is very well approximated by its mean-field Gaussian form up to moderately large values of frequency ω and momentum k. In the region we can investigate, kξ≤5, ωϮ≤10, where ξ is the correlation length and Ϯ is the zero-momentum autocorrelation time, deviations are at most of a few percent.