Towards a Statistical Theory of Finite Systems and Compound States:   Random Two-Body Interaction Approach
  The model of Fermi particles with random two-body interaction is investigated. This model allows to study the origin and accuracy of statistical laws in few-body systems, the role of interaction and chaos in thermalization, Fermi-Dirac distribution for quasi-particles with spreading widths, matrix elements of external field and enhancement of weak perturbation in chaotic compound states. 
V.V.Flambaum, F.M.Izrailev and G.Casati