On infrared and ultraviolet divergences of cosmological perturbations
- College de France, 11 Place M. Berthelot, 75005 Paris (France)
We study a consistent infrared and ultraviolet regularization scheme for the cosmological perturbations. The infrared divergences are cured by assuming that the Universe undergoes a transition between a nonsingular preinflationary, radiation-dominated phase and a slow-roll inflationary evolution. The ultraviolet divergences are eliminated via adiabatic subtraction. A consistent regularization of the field fluctuations through this transition is obtained by performing a mode matching for both the gauge invariant Mukhanov variable and its adiabatic expansion. We show that these quantities do not generate ultraviolet divergences other than the standard ones, when evolving through the matching time. We also show how the DeWitt-Schwinger expansion, which can be used to construct the counter-terms regularizing the ultraviolet divergences, ceases to be valid well before horizon exit of the scales of interest. Thus, such counter-terms should not be used beyond the time of the horizon exit and it is unlikely that the observed power spectrum is modified by adiabatic subtraction, as claimed in some literature. On the contrary, the infrared regularization might have an impact on the observed spectrum, and we briefly discuss this possibility.
- OSTI ID:
- 21502640
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 83, Issue 10; Other Information: DOI: 10.1103/PhysRevD.83.105017; (c) 2011 American Institute of Physics; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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COSMOLOGY AND ASTRONOMY
COSMOLOGICAL MODELS
DISTURBANCES
EVOLUTION
EXPANSION
FLUCTUATIONS
GAUGE INVARIANCE
INFRARED DIVERGENCES
PERTURBATION THEORY
SPECTRA
ULTRAVIOLET DIVERGENCES
ULTRAVIOLET RADIATION
UNIVERSE
ELECTROMAGNETIC RADIATION
INVARIANCE PRINCIPLES
MATHEMATICAL MODELS
RADIATIONS
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