Gravitational waves from oscillons after inflation

TL;DR

This paper studies how oscillons formed after inflation in asymmetric potentials can significantly boost gravitational wave signals, potentially improving detection prospects for low-scale inflation models.

Contribution

It demonstrates that oscillons in asymmetric potentials produce a pronounced peak in gravitational wave spectra, unlike symmetric cases, with implications for gravitational wave detection.

Findings

Oscillons generate a peak in gravitational wave spectrum exceeding linear preheating.

Asymmetric potentials associated with phase transitions enhance gravitational wave signals.

Enhanced gravitational wave amplitude improves detection prospects for low-scale inflation.

Abstract

We investigate the production of gravitational waves during preheating after inflation in the common case of field potentials that are asymmetric around the minimum. In particular, we study the impact of oscillons, comparatively long lived and spatially localized regions where a scalar field (e.g. the inflaton) oscillates with large amplitude. Contrary to a previous study, which considered a symmetric potential, we find that oscillons in asymmetric potentials associated with a phase transition can generate a pronounced peak in the spectrum of gravitational waves, that largely exceeds the linear preheating spectrum. We discuss the possible implications of this enhanced amplitude of gravitational waves. For instance, for low scale inflation models, the contribution from the oscillons can strongly enhance the observation prospects at current and future gravitational wave detectors.