Decoherence and back reaction: The origin of the semiclassical Einstein equations

Journal Article · Thu Aug 15 04:00:00 EDT 1991 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.44.1038· OSTI ID:5184797

Paz, J P ^[1]; Sinha, S ^[2]

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1. Department of Physics and Astronomy, University of Maryland, College Park, Maryland (USA) GRRG, Service de Physique et Chimie, Universite Libre de Bruxelles, CP 231, 1050 Brussels (Belgium)
2. Department of Physics and Astronomy, University of Maryland, College Park, Maryland (USA)

Two basic properties defining classical behavior are decoherence'' and correlations between coordinates and momenta.'' We study how the correlations that define the semiclassical decohering histories of the relevant cosmological variables are affected by the interaction with an environment formed by unobserved ( irrelevant'') degrees of freedom. For some quantum cosmological models we analyze under what conditions the semiclassical coarse-grained histories obey the so-called semiclassical Einstein's equations (i.e., {ital G}{sub {mu}{nu}}={kappa}{l angle}{ital T}{sub {mu}{nu}}{r angle}). These equations are shown to be valid only as a description of adiabatic regions of histories for which the interference effects have been suppressed. We also discuss the problem related to the existence of divergences in the decoherence factor of various quantum cosmological models.

• OSTI ID: 5184797
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 44:4; ISSN PRVDA; ISSN 0556-2821
• Country of Publication: United States
• Language: English

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