Linear response domain in glassy systems

Molecular dynamics simulations are performed on a realistic glass forming model system. The linear and nonlinear response domains are explored numerically for the case where one of the particles interacts with a constant external force. As the temperature is lowered towards the glass transition, we find that the range of fields over which the response is linear shrinks towards zero. We show that the time required for convergence of the steady state fluctuation theorem and the valid application of the central limit theorem becomes very large as the glass transition is approached. This in turn implies that the domain over which a linear response can be observed becomes progressively smaller.