Quantum fluctuations of Cosmological Perturbations in Generalized Gravity

TL;DR

This paper derives the spectrum of quantum-generated cosmological perturbations within generalized gravity theories, unifying various inflationary models and extending previous classical analyses to include quantum effects during early universe acceleration.

Contribution

It provides a unified framework for deriving perturbation spectra from quantum fluctuations in generalized gravity, encompassing known inflationary models as special cases.

Findings

Perturbation spectra derived from quantum fluctuations in generalized gravity.

Unified treatment includes power-law and exponential inflation as special cases.

Results applicable to early universe accelerated expansion scenarios.

Abstract

Recently, we presented a unified way of analysing classical cosmological perturbation in generalized gravity theories. In this paper, we derive the perturbation spectrums generated from quantum fluctuations again in unified forms. We consider a situation where an accelerated expansion phase of the early universe is realized in a particular generic phase of the generalized gravity. We take the perturbative semiclassical approximation which treats the perturbed parts of the metric and matter fields as quantum mechanical operators. Our generic results include the conventional power-law and exponential inflations in Einstein's gravity as special cases.