Speaker
Aya Ghaleb
(Swansea University)
Description
Primordial curvature perturbations enhanced at small scales can generate a stochastic background of gravitational waves at second order. The shape and amplitude of this signal depend not only on the primordial power spectrum but also on the Universe’s thermal history. While many studies assume radiation domination, an early matter-dominated era followed by reheating leaves characteristic imprints on the scalar-induced gravitational wave spectrum. The speed and nature of the transition between these eras can significantly modify the gravitational wave spectrum. In this talk, I introduce the topic, current literature, and show how we compute the kernel beyond sharp analytical approximations, and implications for LISA.