Vacuum Polarization Effects During the Reheating Epoch

Quantum effects during the epoch of the unviverse reheating after inflation are considered. A semiclassical approach to the theory of gravity is applied in connection with the Starobinsky inflation model. Some subtleties associated with taking into account quantum effects in the one-loop approximation are clarified. An estimate of the contribution of vacuum polarization in the energy-momentum tensor of matter fields to the scalaron decay width is presented.