Title:Detecting the early universe and new physics through stochastic gravitational wave backgrounds

Speaker:Jing Liu 刘京 (Hangzhou Institute of Advanced Study, UCAS)

Time:1:30pm, Nov. 25, 2021 (Thursday)

Location:New Science Building 理科楼 C302

Abstract:The improvement of gravitational-wave (GW) detection opens a new window of GW astronomy and cosmology. Besides the well-known GW events from astrophysical compact objects, the observation of GWs from the early Universe can give constraints on particle physics models at a very high energy scale. In this talk, I will briefly review the history of the early Universe and the main GW sources, including inflation, preheating, generation of topological defects and first-order phase transitions. Through the observation of the characteristic energy spectrum of GWs, we can distinguish the sources and give constraints to the underlying model parameters. The anisotropies in those stochastic GW backgrounds yield unique information of the inflationary model. The mutual predictions and constraints between GWs, primordial black holes and primordial magnetic fields are also mentioned in the talk.

Bio:Jing Liu is a postdoctoral fellow at Hangzhou Institute of Advanced Study, UCAS. He earned his PHD at the Institute of Theoretical physics, CAS in 2020. His research interests mainly focus on the physical processes in the early Universe, underlying new physics models and corresponding observational methods. The relevant papers are published in journals such as Phys.Rev.Lett, Phys.Rev.D and JCAP.