Gravitational wave generation in loop quantum cosmology

TL;DR

This paper calculates the gravitational wave spectrum in loop quantum cosmology, revealing that quantum effects can produce distinctive low-frequency signatures that could be used to test the theory.

Contribution

It provides the first detailed prediction of the gravitational wave spectrum in loop quantum cosmology, highlighting observable quantum signatures.

Findings

Loop quantum effects cause over-production of low-frequency gravitational waves.

Pre-inflationary processes leave detectable imprints on the gravitational wave spectrum.

The spectrum can serve as a test for loop quantum cosmology models.

Abstract

We calculate the full spectrum, as observed today, of the cosmological gravitational waves generated within a model based on loop quantum cosmology. It is assumed that the universe, after the transition to the classical regime, undergoes a period of inflation driven by a scalar field with a chaotic-type potential. Our analysis shows that, for certain conditions, loop quantum effects leave a clear signature on the spectrum, namely, an over-production of low-frequency gravitational waves. One of the aims of our work is to show that loop quantum cosmology models can be tested and that, more generally, pre-inflationary physical processes, contrary to what is usually assumed, leave their imprint in those spectra and can also be tested.