Nonequilibrium Statistical Mechanics of the Spin-1/2 van der Waals Model. 1. TimeEvolution of a Single Spin

摘要

In the late 1960's, molecular-dynamics studies gave evidence of slow decay in thevelocity autocorrelation function (VAF) of a particle in a simple fluid. The evidence of long-time tails observed in computer experiments has stimulated considerable activity both experimentally and theoretically. Measurements in aqueous solutions of polyestyrene spheres appear to indicate a slow-decay component in the VAF. A qualitative understanding of the origin of long-time tails was initially provided by mode-coupling theory. It is a hydrodynamic picture in which slow decay is attributed to shear modes generated by a moving particle, acting on itself at a later time. Presumably, coupling between a particle and its surroundings is an essential source of this anomalous behavior.