Stochastic gravitational waves induced by scalar perturbation: theory and recent developments

Our universe is filled with stochastic gravitational waves (GWs) with a large range of frequencies, which may have various astrophysical/cosmological origins in the early universe. In this talk I will briefly review the properties of stochastic GWs induced by the scalar perturbation, as well as its connection to the phenomenology of primordial black holes (PBHs). Recently, NANOGrav reported the discovery of a common-spectrum process of the time residuals in their 12.5-yr data set of pulsar timing array, which might be the first detection of stochastic GWs. Based on the recent developments on the spectral shape of such waves, I will show that this signal could be connected to the planet-mass PBH candidates observed by OGLE recently.

Shi Pi
Xian Chen
Thursday, June 17, 2021 - 4:00PM to Thursday, June 17, 2021 - 5:00PM
Shi Pi studied in the Department of Astronomy, Peking University from 2001 to 2005. He got his Ph.D. in 2013 in the Physics Department, Peking University. Then he worked as a postdoc in Asian Pacific Center for Theoretical Physics (2013-2015), Institute of Theoretical Physics, CAS (2015-2017), Yukawa Institute for Theoretical Physics, Kyoto University (2017-2018), and the Kavli Institute of Physics and Mathematics of the Universe, the University of Tokyo (2018-2020). He became an associate professor in Institute of Theoretical Physics, CAS in 2020. His main interests include early cosmology inflation, and the stochastic gravitational waves.