The gravitational wave background from super-inflation in Loop Quantum Cosmology

TL;DR

This paper studies tensor fluctuations in Loop Quantum Cosmology, revealing a strong blue tilt in the gravitational wave spectrum that significantly suppresses large-scale tensor modes compared to standard inflation.

Contribution

It provides a detailed analysis of tensor perturbations in Loop Quantum Cosmology, highlighting a distinctive blue-tilted gravitational wave spectrum.

Findings

Spectral index of tensor modes is approximately 2.

Tensor mode amplitudes are heavily suppressed on large scales.

Results differ from standard inflationary predictions.

Abstract

We investigate the behaviour of tensor fluctuations in Loop Quantum Cosmology, focusing on a class of scaling solutions which admit a near scale-invariant scalar field power spectrum. We obtain the spectral index of the gravitational field perturbations, and find a strong blue tilt in the power spectrum with $n_t \approx 2$. The amplitude of tensor modes are, therefore, suppressed by many orders of magnitude on large scales compared to those predicted by the standard inflationary scenario where $n_t \approx 0$.