Gravitational Wave from Graviton Bremsstrahlung during Reheating

In this talk, we explore the stochastic Gravitational Waves (GW) resulting from graviton Bremsstrahlung during inflationary reheating. I start by discussing the motivation behind the study and introduce the computational formalism, with a specific emphasis on the graviton production rate. Then, I present the GW spectrum for inflaton oscillations around a quadratic potential ~ φ². By generalizing the potential to ~ φⁿ with $n>2$, I show that distinct features in the GW spectrum emerge depending on both the value of n and type of inflaton-matter couplings. Finally, I demonstrate that Bremsstrahlung-induced GW can serve as a novel pathway for probing the dynamics of inflationary reheating.