Stochastic gravitational wave background from early dark energy

Understand

We study the production of stochastic gravitational wave background from early dark energy (EDE) model.

• It is caused by resonant amplification of scalar field fluctuations, which easily takes place for typical EDE potential based on the string axion or $\alpha$-attractor model.
• The resultant spectrum of gravitational wave background is computed by performing 3D lattice simulations.
• We show that, specifically in some class of generalized $\alpha$-attractor EDE model, a significant amount of gravitational waves can be produced via tachyonic instability with a peak around femto-Hz frequency range.