Tuesday 14^th June, 2011 - 3,00 P.M.

Sala Direzione INFN (Physics Dept., Old Building - 2nd Floor)

Title: Thermalization of degenerate electron-positron plasma

Abstract: The process of thermalization of mildly relativistic pair plasma has been studied by Aksenov et al. (2007,2009,2010) where arbitrary nonequilibrium initial states were considered and the corresponding relaxation timescales towards respectively kinetic and thermal equilibrium were determined. We extend that work to higher energy densities, where degeneracy of relativistic plasma becomes important. The corresponding Pauli blocking and Bose enhancement factors need to be included in the collision integrals for all possible two-particle and three-particle reactions considered before, so the numerical scheme has to be improved. In particular, three particle interactions have to be computed from first principles, using the corresponding QED matrix elements, similarly to two-particle interactions. It is found that characteristic time scale of thermalization is progressively increasing with particle density, i.e. average degeneracy of initial state. We also find that in degenerate plasma relaxation to kinetic equilibrium has oscillatory character.