Pérez-Nadal, GuillemRoura Crumols, AlbertVerdaguer Oms, Enric, 1950-2010-05-062010-05-0620080556-2821https://hdl.handle.net/2445/12385A spatially flat Robertson-Walker spacetime driven by a cosmological constant is nonconformally coupled to a massless scalar field. The equations of semiclassical gravity are explicitly solved for this case, and a self-consistent de Sitter solution associated with the Bunch-Davies vacuum state is found (the effect of the quantum field is to shift slightly the effective cosmological constant). Furthermore, it is shown that the corrected de Sitter spacetime is stable under spatially isotropic perturbations of the metric and the quantum state. These results are independent of the free renormalization parameters.19 p.application/pdfeng(c) The American Physical Society, 2008Relativitat general (Física)Gravetat quànticaCosmologiaPertorbació (Dinàmica quàntica)Teoria quàntica de campsGeneral relativity (Physics)Quantum gravityCosmologyPerturbation (Quantum dynamics)Quantum field theoryinfo:eu-repo/semantics/article558479info:eu-repo/semantics/openAccess