Dissipation due to fermions in inflaton equations of motion

According to quantum field theory, the inflaton equation of motion does not have the local form that is generally assumed for cosmological purposes. In particular, earlier investigations of the nonequilibrium dynamics of an inflaton that decays into scalar particles suggest that the loss of inflaton energy is not well approximated by the local friction term derived from linear response theory. We extend this analysis to the case of an inflaton that decays into fermions, and reach broadly the same conclusion.