题 目： Exploring the dynamics of dark energy in light of DESI 2024
报 告 人：蔡一夫 教授 中国科学技术大学
时 间：2024年12月6日（星期五）14:00
地 点：虎溪校区理科楼LE201
邀 请 人：应蜀翾
报告摘要：Astonishingly, human beings discovered that distant Type Ia supernovae (SN Ia) were accelerating away at an increasing pace. This led to the great discovery of late-time cosmic acceleration and brought us the concept of dark energy, responsible for such a phenomenon, but the underlying nature remains mysterious. Theoretically, modified gravity can be a framework to provide an alternative explanation for the existence of dark energy. In this talk, we will go further into the effective field theory of f(T) gravity and beyond. Then using the latest Dark Energy Spectroscopic Instrument (DESI) data combined with other observations, we reconstructed the cosmological background evolution and find that the reconstructed dark-energy equation-of-state (EoS) parameter w(z) exhibits the so-called quintom-B behavior, crossing−1 from phantom to quintessence regime as the universe expands. In particular, we reconstruct the corresponding actions for f(R), f(T), and f(Q) gravity, respectively. We conclude that, certain modified gravity such as metric-affine gravity can exhibit the quintom dynamics and fit the recent DESI data efficiently, and for all cases the quadratic deviation from the ΛCDM scenario is mildly favored.
报告人介绍：蔡一夫，中国科学技术大学教授，教育部国家重大人才工程特聘教授，国家重点研发计划引力波专项首席，担任中国天文学会理事、安徽省天文学会秘书长等职务，获得过基金委重点项目、优秀青年基金、国家创新人才青年项目、国合面上、中国科协青年托举工程等资助，以及中国天文学会黄授书奖等荣誉。研究领域是粒子宇宙学，兴趣集中在宇宙起源、大尺度结构的早期形成、暗物质、暗能量等方面。在国际重要学术期刊上已发表论文180余篇，总被引用1万余次，连续多年入选爱思唯尔中国高被引学者、全球2%顶尖科学家等榜单。
