Jordan–Brans–Dicke quantum wormholes and Coleman’s mechanism

We consider the quantum gravity and cosmology of a Jordan-Brans-Dicke theory, predicted by string effective actions. We study its canonical formalism and find that the constraint algebra is that of general relativity, as a consequence of the general covariance of scalar-tensor theories. We also anal...

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Detalhes bibliográficos
Autores: Garay Elizondo, Luis Javier, García Bellido, Juan
Formato: artículo
Fecha de publicación:1993
País:España
Recursos:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/59560
Acesso em linha:https://hdl.handle.net/20.500.14352/59560
Access Level:acceso abierto
Palavra-chave:51-73
Extended inflation
Baby universes
Spacetime diffeomorphisms
Cosmological constant
String theory
Gravity
Field
Representations
Flatness
Horizon
Física-Modelos matemáticos
Física matemática
Descrição
Resumo:We consider the quantum gravity and cosmology of a Jordan-Brans-Dicke theory, predicted by string effective actions. We study its canonical formalism and find that the constraint algebra is that of general relativity, as a consequence of the general covariance of scalar-tensor theories. We also analyze the problem of boundary conditions and propose that they must be imposed in the Jordan frame, in which particles satisfy the strong equivalence principle. Specifically, we discuss both Hartle-Hawking and wormhole boundary conditions in the context of quantum cosmology. We find quantum wormhole solutions for Jordan-Brans-Dicke gravity even in the absence of matter. Wormholes may affect the constants of nature and, in particular, the Brans-Dicke parameter. Following Coleman's mechanism, we find a probability distribution which is strongly peaked at zero cosmological constant and infinite Brans-Dicke parameter. That is, we recover general relativity as the effective low energy theory of gravity.