Covariant Effective Action for Loop Quantum Cosmology from Order Reduction

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dc.creatorSotiriou, Thomas P.
dc.date2008-11-11
dc.date2009-02-26
dc.date.accessioned2026-07-07T12:46:33Z
dc.date.available2026-07-07T12:46:33Z
dc.descriptionLoop quantum cosmology (LQC) seems to be predicting modified effective Friedmann equations without extra degrees of freedom. A puzzle arises if one decides to seek for a covariant effective action which would lead to the given Friedmann equation: The Einstein--Hilbert action is the only action that leads to second order field equations and, hence, there exists no covariant action which, under metric variation, leads to modified Friedmann equation without extra degrees of freedom. It is shown that, at least for isotropic models in LQC, this issue is naturally resolved and a covariant effective action can be found if one considers higher order theories of gravity but faithfully follows effective field theory techniques. However, our analysis also raises doubts on whether a covariant description without background structures can be found for anisotropic models.
dc.descriptionminor changes to match published version
dc.identifierhttps://arxiv.org/abs/0811.1799
dc.identifierhttp://arxiv.org/abs/0811.1799
dc.identifierPhys.Rev.D79:044035,2009
dc.identifierdoi:10.1103/PhysRevD.79.044035
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/221421
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectAstrophysics
dc.subjectHigh Energy Physics - Theory
dc.titleCovariant Effective Action for Loop Quantum Cosmology from Order Reduction
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