Non-local gravitational effective action and particle production

TL;DR

This paper derives a non-local gravitational effective action from scalar fields using Riemann normal coordinates, and explores its application to particle production in cosmology, offering an alternative to Bogolyubov methods.

Contribution

It introduces a novel approach to compute non-local gravitational effective actions and applies it to cosmological particle production analysis.

Findings

Derived non-local effective action for gravity with scalar fields.

Compared the new method with traditional Bogolyubov transformations.

Discussed applicability to cosmological particle production rates.

Abstract

We study the effective action for gravity obtained after the integration of scalar matter fields, using the local momentum representation based on the Riemann normal coordinates expansion. By considering this expansion around different space-time points, we also compute the non-local terms together with the more usual divergent ones. We discuss the applicability of our results to the calculation of particle production rates in cosmological backgrounds and compare this method with the traditional Bogolyubov transformations.