Non-equilibrium properties of small Lennard-Jones clusters

In this work, we analyze the dependency on the sample’s history of relaxation processes of small clusters of interacting particles. These particles interact with each other through the usual Lennard-Jones potential and are confined in a square box of volume V with perfect rigid walls. We use molecular dynamics to simulate a sudden quenching from a very high temperature into the glassy phase and measure the time evolution of the two-time auto-correlation function C(tw,tw+t) after the system has spent a certain time tw in the low temperature phase. We find a strong dependence of C(tw,tw+t) both on t and tw signaling the presence of aging. The scaling law that governs the behavior of C(tw,tw+t) differs from that found by previous works for larger similar systems and in particular displays a dependence on the number of particles N and on the density, ρ=N/V.