2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/34318The expectation value of the energy-momentum tensor and the Hawking flux of a scalar field on a Schwarzschild spacetime is calculated using the zeta-function regularisation of the heat kernel. In particular, massless particles are considered in a spherically reduced dilaton model. The effective action is thereby obtained by the covariant perturbation theory and the boundary conditions are fixed by means of the energy-momentum conservation equation. In contrast to previous approaches the expectation values are calculated directly from the effective action which itself is derived in a straightforward manner.168 pages, 14 figures, PhD thesisGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext