Stochastic gravitational wave background from early dark energy

Abstract

AbstractWe study the production of stochastic gravitational wave background in early dark energy (EDE) models. It is generated by resonant amplification of scalar field fluctuations, which can easily take place for typical EDE potential based on the string axion or α-attractor model. The resultant spectrum of gravitational wave background is computed by performing 3D lattice simulations. We show that, specifically in some class of a generalized α-attractor EDE model, a significant amount of gravitational waves can be produced via tachyonic instability with a peak around femto-Hz frequency range. Models predicting such gravitational waves can be constrained by cosmic microwave background observations.