Relaxation dynamics of disordered Ising model. Two-site cluster approximation

TL;DR

This paper investigates the spin relaxation dynamics in a disordered Ising model using a two-site cluster approximation, revealing effects beyond mean field theory and comparing results with experimental dielectric data.

Contribution

It introduces a two-site cluster approximation to study spin relaxation in disordered Ising models, capturing effects missed by mean field approaches.

Findings

Calculated $oldsymbol{q},oldsymbol{ au}$-dependent susceptibility.

Identified effects beyond mean field approximation.

Compared theoretical results with dielectric measurements.

Abstract

Spin relaxation in a site-disordered Ising model within master equation approach is studied. The $\vec{q},\omega$-dependent susceptibility of the model is calculated and investigated. Effects described by the two-site cluster approximation and lost by the mean field approximation are discussed. Comparison of obtained results with dielectric measurements in $Cs(H_{1-x}D_x)_2PO_4$ is presented.