报告题目： Primordial Non-Gaussianity, Primordial Black Holes, and Anisotropies in Scalar-Induced Gravitational Waves
报 告 人： 王赛（副研究员），中科院高能物理研究所
邀 请 人： 周思益
时 间： 2023年8月9号（星期三）10:00
地 点： 腾讯会议389-376-503 和 0638太阳集团LE201
Abstract: Recent pulsar timing array (PTA) data releases have provided strong evidence for the existence of a gravitational wave background (GWB) at nano-Hertz frequency bands. While the astrophysical origin of this GWB, such as supermassive black hole (SMBH) binaries, has been considered, we propose that it could also have cosmological origins, specifically scalar-induced gravitational waves (SIGWs). Our recent papers (arXiv:2307.00572 & arXiv:2307.03095) have explored this possibility. In our first work, we consider both primordial Gaussianity and non-Gaussianity on equal footing and determine the allowed range of the local-type non-Gaussian parameter. Additionally, we conduct the first comprehensive analysis of the anisotropies in SIGWs (arXiv:2305.19950), suggesting that the angular power spectrum can serve as a powerful probe to differentiate between cosmological and astrophysical origins of the PTA signal. We anticipate that the Square Kilometre Array (SKA) project in the future will enable the measurement of this angular power spectrum. In our second work, we perform a joint analysis of the big-bang nucleosynthesis (BBN), cosmic microwave background (CMB), and PTA datasets to simultaneously explore second-order and third-order gravitational waves. This analysis yields the most stringent constraints on the related model parameters at the current stage. Furthermore, we investigate the implications of our findings for the scenario of primordial black holes (PBHs) and find support for PBHs in the Jupiter-mass range based on the current datasets. Our studies not only provide new insights into understanding the origin of our universe but also shed light on the nature of dark matter.
Brief CV: 个人简介：王赛，高能物理研究所理论物理室，副研究员。2009年本科毕业于华中科技大学，2014年博士毕业于中国科学院高能物理研究所，2014至2019年在中国科学院理论物理所、香港中文大学物理系、日本高能加速器研究机构（KEK）理论中心做博士后研究。研究方向为宇宙学，主要从事暗物质、宇宙起源及早期演化相关理论研究。目前在PRL等国际期刊上发表40余篇论文，获得中国科学院“百人计划”支持。
