It is known that gravitational waves (GWs) can be generated during the decay of the inflaton through the process of graviton bremsstrahlung. The resulting signal contributes to a stochastic GW background, with a characteristic peak frequency typically around the GHz range. In this presentation, I will discuss my recent work (arXiv:2410.11175), where we computed the GW spectrum from graviton bremsstrahlung under the assumption of a polynomial inflaton potential near its minimum. We find that when the potential exponent is four or larger, the spectrum develops multiple peaks, though their prominence decreases for higher powers. Our results indicate that future GW detectors operating in the GHz band, such as resonant cavity experiments, may have the sensitivity required to probe these signals. Such observations could provide valuable insights into the reheating stage of the early universe.

Biography

Dr. Teruaki Suyama is a Professor at Institute of Science Tokyo. He received his PhD in Physics from Kyoto University in 2007. After spending at a few places such as the University of Tokyo and Louvain Catholic University as a postdoc, he became an assistant professor at Research Center for the Early Universe in 2012. He moved to the current place as an associate professor in 2018 and was promoted to a professor in 2023. He is a theoretical cosmologist and has published more than 90 articles in scientific journals. He has worked on various topics on cosmology to elucidate the earliest moments of and the evolution of our universe. His current interest is to understand what kind of new information about our universe can be gained by using gravitational waves.

Inviter: Shi Pi