Minimal Fokker-Planck theory for the thermalization of mesoscopic   subsystems
  We explore a minimal paradigm for thermalization, consisting of two weakly-coupled, low dimensional, non-integrable subsystems. As demonstrated for Bose-Hubbard trimers, chaotic ergodicity results in a diffusive response of each subsystem, insensitive to the details of the drive exerted on it by the other. This supports the hypothesis that thermalization can be described by a Fokker Plank equation. We also observe, however, that Levy-flight type anomalies may arise in mesoscopic systems, due to the wide range of time scales that characterize `sticky' dynamics. 
Igor Tikhonenkov, Amichay Vardi, James R. Anglin, Doron Cohen
cond-mat.stat-mech cond-mat.mes-hall quant-ph