Truncated Lévy Flights and Weak Ergodicity Breaking in the Hamiltonian Mean Field Model

Abstract: The dynamics of the Hamiltonian mean field model is studied in the context of continuous time random walks. We show that the sojourn times in cells in the momentum space are well described by a L\'evy truncated distribution. Consequently the system in weakly non-ergodic for long times that diverge with the number of particles. For a finite number of particles ergodicity is only attained for very long times both at thermodynamical equilibrium and at quasi-stationary out of equilibrium states.