Dissipation coefficients for supersymmetric inflatonary models

Dissipative effects can lead to a friction term in the equation of motion for an inflaton field during the inflationary era. The friction term may be linear and localised, in which case it is described by a dissipation coefficient. The dissipation coefficient is calculated here in a supersymmetric model with a two stage decay process in which the inflaton decays into a thermal gas of light particles through a heavy intermediate. At low temperatures, the dissipation coefficient $\propto T^3$ in a thermal approximation. Results are also given for a non-equilibrium anzatz. The dissipation coefficient is consistent with a warm inflationary regime for moderate ($\sim 0.1$) values of the coupling constants.