Algorithms for mori chain dynamics : a unified treatment

Abstract

Within the realm of stochastic dynamics we point out a natural distinction between ‘Mori chain’ and ‘non-Mori chain’ techniques, depending on the mathematical form of the memory functions used. A universal algorithm for Mori chain dynamics is developed which contains former, seemingly disparate algorithms as special cases. In the absence of systematic forces the algorithm is exact for time steps of any length Δt, otherwise it is of third order in Δt. Some suggestions are made regarding ‘non-Mori chain’ techniques.