Possible Enhancement of High Frequency Gravitational Waves

TL;DR

This paper investigates non-local gravitational models that naturally end inflation with oscillations, leading to an enhancement of high-frequency gravitational waves below 10^{10} Hz, and derives the tensor power spectrum.

Contribution

It introduces a class of non-local gravitational models with a natural end to inflation and analyzes their impact on gravitational wave spectra.

Findings

Oscillatory phase causes enhancement of gravitational waves

Enhancement occurs at frequencies below 10^{10} Hz

Tensor power spectrum has a generic form

Abstract

We study the tensor perturbations in a class of non-local, purely gravitational models which naturally end inflation in a distinctive phase of oscillations with slight and short violations of the weak energy condition. We find the usual generic form for the tensor power spectrum. The presence of the oscillatory phase leads to an enhancement of gravitational waves with frequencies somewhat less than 10^{10} Hz.