Scale-Invariant Curvature Fluctuations from an Extended Semiclassical Gravity

Nicola Pinamonti, Daniel Siemssen
February 20, 2015
We present an extension of the semiclassical Einstein equations which couples n-point correlation functions of a stochastic Einstein tensor to the n-point functions of the quantum stress-energy tensor. We apply this extension to calculate the quantum fluctuations during an inflationary period, where we take as a model a massive conformally coupled scalar field on a perturbed de Sitter space and describe how a renormalization independent, almost-scale-invariant power spectrum of the scalar metric perturbation is produced. Furthermore, we discuss how this model yields a natural basis for the calculation of non-Gaussianities of the considered metric fluctuations.
open access link Journal of Mathematical Physics 56, 022303
@article{Pinamonti:2013zba, author = "Pinamonti, Nicola and Siemssen, Daniel", title = "{Scale-invariant curvature fluctuations from an extended semiclassical gravity}", journal = "J. Math. Phys.", volume = "56", year = "2015", number = "2", pages = "022303", doi = "10.1063/1.4908127", eprint = "1303.3241", archivePrefix = "arXiv", primaryClass = "gr-qc", SLACcitation = "%%CITATION = ARXIV:1303.3241;%%" }

Keywords: 
QFT on curved spacetimes, semiclassical Einstein equation, inflation, cosmology