Analytic approximation and an improved method for computing the stress-energy of quantized scalar fields in Robertson-Walker spacetimes - art. no. 024003

An improved method is given for the computation of the stress-energy tensor of a quantized scalar field using adiabatic regularization. The method wor ks for fields with arbitrary mass and curvature coupling in Robertson-Walke r spacetimes and is particularly useful for spacetimes with compact spatial sections. For massless fields it yields an analytic approximation for the stress-energy tensor that is similar in nature to those obtained previously for massless fields in static spacetimes.