Quantum backreaction in evolving FLRW spacetimes

Journal Article · Tue Feb 15 00:00:00 EST 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.044015· OSTI ID:21504983

Koivisto, Tomi S; Prokopec, Tomislav ^[1]

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1. Institute for Theoretical Physics and Spinoza Institute, Leuvenlaan 4, 3584 CE Utrecht (Netherlands)

Quantum fluctuations of a nonminimally coupled scalar field in D-dimensional homogeneous and isotropic background are calculated within the operator formalism in curved models with time evolutions of the scale factor that allow smooth transitions between contracting and expanding and between decelerating and accelerating regimes. The coincident propagator is derived and used to compute the one-loop backreaction from the scalar field. The inflationary infrared divergences are absent in Bunch-Davies vacuum when taking into account a preceding cosmological era or spatial curvature which can be either positive or negative. It is found that asymptotically, the backreaction energy density in the minimally coupled case grows logarithmically with the scale factor in quasi-de Sitter space and in a class of models decays in slow-roll inflation and grows as a power law during superinflation. The backreaction increases generically in a contracting phase or in the presence of a negative nonminimal coupling. The effects of the coupling and renormalization scale upon the quantum fluctuations together with the novel features due to nontrivial time evolution and spatial curvature are clarified with exact solutions and numerical examples.

• OSTI ID: 21504983
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 4; Other Information: DOI: 10.1103/PhysRevD.83.044015; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COMPUTERIZED SIMULATION
COUPLING
DE SITTER SPACE
ENERGY DENSITY
EVOLUTION
EXACT SOLUTIONS
FLUCTUATIONS
INFRARED DIVERGENCES
PARTICLE DECAY
PROPAGATOR
QUANTUM MECHANICS
RENORMALIZATION
SCALAR FIELDS
SPACE-TIME
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MATHEMATICAL SPACE
MECHANICS
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SPACE
VARIATIONS