Onset of Fokker-Planck dynamics within a closed finite spin system
Hendrik Niemeyer, Daniel Schmidtke, Jochen Gemmer B
Relaxation according to Fokker-Planck equations is a standard scenario in classical statistical mechanics. It is, however, not obvious how such a Fokker-Planck dynamics may emerge within a closed, finite quantum system. We present an analysis of a system comprising sixteen spins in which spatial inhomogeneities of the magnetization relax approximately in accord with a standard Fokker-Planck equation for a Brownian particle in a parabolic potential. While a single, specfic example is addressed in detail, arguments which indicate that the above findings may hold for a wider range of systems are given.
arXiv:1211.3265•Europhysics Letters (EPL)•Jan 1, 2013•13 citations