Semi-classical kinetic theory for massive spin-half fermions with leading-order spin effects

Abstract

We consider the quantum kinetic-theory description for interacting massive spin-half fermions using the Wigner function formalism. We derive general collision kernel involving local as well as nonlocal collisions between particles assuming that the spin effects can have both classical and quantum origins. To track the effect of such different contributions we use the semi-classical expansion method to obtain the generalized kinetic equations with spin. Employing the ansatz for the equilibrium distribution function we derive global equilibrium conditions, assuming the total angular momentum is conserved in the microscopic collisions.