报告题目:Gravitational Waves from Inflation and Reheating

报告人：Anna Tokareva

报告时间：2024年11月14 日(周四)上午 10:00-12:00

报告地点：浙江工业大学理学楼 二楼师生活动中心

摘要(Abstract)：The concept of early Universe inflation resolves several problems of hot Big Bang theory and quantitatively explains the origin of the inhomogeneities in the present Universe. However, it is not possible to arrange inflation in a scalar field model with renormalizable potential, such that it would not contradict the recent Planck data. For this reason, inflaton must have also higher derivative couplings suppressed at least by the Planck scale. We show that these couplings may be relevant during reheating and lead to non-negligible production of gravitons. We consider the possibility that the unitarity breaking scale for the model of inflation is lower than the Planck scale and compute production of gravitons during reheating, due to the inflaton decay to two gravitons and graviton bremsstrahlung process. The spectrum of produced gravitons is crucially dependent on reheating temperature and inflaton mass. We find that for low reheating temperature decay to gravitons lead to significant amount of dark radiation. Confironting this result with CMB constraints, we find reheating dependent bounds on the unitarity breaking scale. We also compare the obtained gravitational wave signals with the projected limits of future high frequency gravitational wave experiments.

报告人简介(Bio)：Anna Tokareva is an Associate Researcher at Hangzhou Institute for Advanced Study since June 2023. She got her PhD in 2016 from the Institute for Nuclear Research RAS in Moscow, Russia after doctoral studies at the Moscow State University.After that she got postdoctoral experience at EPFL, Lausanne, Switzerland, Institute for Nuclear Research, Moscow, Russia, University of Jyvaskyla, Finland, and lmperial College London in the UK, Her main scientific results and interests are at the borderline between cosmology, quantum gravity and formal aspects of quantum field theory.

邀请人：朱涛