Conservation of with radiative corrections from heavy field
Oct 16, 2015
27 pages
Published in:
- JCAP 06 (2016) 020
- Published: Jun 8, 2016
e-Print:
- 1510.05059 [hep-th]
Report number:
- KUNS-2581,
- YITP-15-87
View in:
Citations per year
Abstract: (IOP)
In this paper, we address a possible impact of radiative corrections from a heavy scalar field χ on the curvature perturbation ζ. Integrating out χ, we derive the effective action for ζ, which includes the loop corrections of the heavy field χ. When the mass of χ is much larger than the Hubble scale H, the loop corrections of χ only yield a local contribution to the effective action and hence the effective action simply gives an action for ζ in a single field model, where, as is widely known, ζ is conserved in time after the Hubble crossing time. Meanwhile, when the mass of χ is comparable to H, the loop corrections of χ can give a non-local contribution to the effective action. Because of the non-local contribution from χ, in general, ζ may not be conserved, even if the classical background trajectory is determined only by the evolution of the inflaton. In this paper, we derive the condition that ζ is conserved in time in the presence of the radiative corrections from χ. Namely, we show that when the dilatation invariance, which is a part of the diffeomorphism invariance, is preserved at the quantum level, the loop corrections of the massive field χ do not disturb the constant evolution of ζ at super Hubble scales. In this discussion, we show the Ward-Takahashi identity for the dilatation invariance, which yields a consistency relation for the correlation functions of the massive field χ.Note:
- 27 pages, 1 figure; v2: updated references and minor revisions
- radiative correction
- curvature: perturbation
- effective action
- inflation
- field theory: scalar
- inflaton
- symmetry: scaling
- diffeomorphism: invariance
- Ward-Takahashi identity
- correlation function
References(82)
Figures(1)
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