Numerical study of ageing in coupled two-level systems

Abstract

We study a lattice model of coupled two-level systems by Monte Carlo simulation. We find that it has glassy behaviour (non-exponential relaxation, Vogel-Fulcher relaxation times and ageing) at low temperatures. We study, in particular, ageing of the susceptibility in the frequency domain and find that it differs from spin-glass behaviour in that it does not obey ωt _w scaling. Its qualitative features indicate that it may be a good model of ageing in structural glasses.