Vacuum energy-momentum tensors in Schwarzschild-De Sitter space-time

The authors deal with a quantum, massless, scalar field, minimally coupled to the Schwarzschild-De Sitter metric. In this system, the thermal radiation by a collapsing shell is studied. In both two and four dimensions, Hawking radiation is found. In this system but without the shell, and, therefore, with the past event horizon, the quantized energy-momentum tensor is constructed with respect to the inequivalent vacuum states. The fluxes and energy distributions are studied and they are given the physical meaning. The results are consistent with other models for this problem. (author)