Dual Gravitational Wave Signatures of Instant Preheating

TL;DR

This paper predicts unique gravitational wave signals from instant preheating in the early Universe, arising from particle decay and nonlinear field dynamics, which could be detected to probe early cosmological processes.

Contribution

It demonstrates that instant preheating produces two distinct gravitational wave signatures, a novel prediction linking early Universe dynamics to observable signals.

Findings

Two types of GW signals predicted: bremsstrahlung from particle decay and nonlinear field dynamics.

GW spectrum peak shifts with coupling constants, as shown by numerical simulations.

Detection of these signals could provide insights into early Universe physics.

Abstract

In the instant preheating scenario efficient particle production occurs immediately following the period of inflationary expansion in the early Universe. We demonstrate that instant preheating predicts unique gravitational wave (GW) signals arising from two distinct origins. One source is the bremsstrahlung GWs produced through the decay of superheavy particles, an inevitable consequence of instant preheating. The other is GWs generated from the nonlinear dynamics of the inflaton and coupled scalar fields. Using numerical simulations, we show that the peak of the GW spectrum shifts depending on the coupling constants of the theory. The detection of these dual GW signatures, characteristic of instant preheating, provides novel opportunities for probing the dynamics of the early Universe.