Efficient Measurement of Linear Susceptibilities in Molecular Simulations: Application to Aging Supercooled Liquids

Ludovic Berthier
2007 Physical Review Letters  
We propose a new method to measure time-dependent linear susceptibilities in molecular simulations, which does not require the use of nonequilibrium simulations, subtraction techniques, or fluctuation-dissipation theorems. The main idea is an exact reformulation of linearly perturbed quantities in terms of observables accessible in unperturbed trajectories. We have applied these ideas to two supercooled liquids in their nonequilibrium aging regime. We show that previous work had underestimated
more » ... had underestimated deviations from fluctuation-dissipation relations in the case of a Lennard-Jones system, while our results for silica are in qualitative disagreement with earlier results.
doi:10.1103/physrevlett.98.220601 pmid:17677827 fatcat:cqjc4gr2kfanth77dxfz4xjade