Gravitational Waves from the Non-Perturbative Decay of Condensates along Supersymmetric Flat Directions

TL;DR

This paper demonstrates that non-perturbative decay of supersymmetric flat direction condensates can produce a gravitational wave background detectable by future experiments, linking early universe physics with observational prospects.

Contribution

It provides the first explicit lattice simulation confirmation of rapid condensate decay and analyzes the resulting gravitational wave spectrum's dependence on key cosmological parameters.

Findings

Condensate decay efficiently converts energy into inhomogeneous fluctuations.

Generated gravitational waves fall within the Hz-kHz range and are potentially observable.

The gravitational wave spectrum depends on initial VEV, SUSY-breaking mass, and reheat temperature.

Abstract

It has recently been shown that specific non-perturbative effects may lead to an explosive decay of flat direction condensates in supersymmetric theories. We confirm explicitly the efficiency of this process with lattice simulations: after few rotations of the condensates in their complex plane, most of their energy is quickly converted into inhomogeneous fluctuations. We then point out that this generates a gravitational wave background which depends on the inflaton sector and falls in the Hz-kHz frequency range today. We compute the resulting spectrum and study how it depends on the parameters. We show that these gravity waves can be observable by upcoming experiments like Advanced LIGO and depend crucially on (i) the initial VEV of flat directions when they start to oscillate, (ii) their soft SUSY-breaking mass and (iii) the reheat temperature of the universe. This signal could open a new observational window on inflation and low-energy supersymmetry.