主 讲 人 :蔡一夫 教授
活动时间:10月09日09时00分
地 点 :理科2号楼B409
讲座内容:
Astonishingly, human beings discovered thatdistant Type Ia supernovae (SN Ia) were accelerating away at an increasingpace. This led to the great discovery of late-time cosmic acceleration andbrought us the concept of dark energy, responsible for such a phenomenon, butthe underlying nature remains mysterious. Theoretically, modified gravity canbe a framework to provide an alternative explanation for the the existence ofdark energy. In this talk, we will go further into the effective field theoryof f(T) gravity and beyond. Then using the latest Dark Energy SpectroscopicInstrument (DESI) data combined with other observations, we reconstructed thecosmological background evolution and find that the reconstructed dark-energyequation-of-state (EoS) parameter w(z) exhibits the so-called quintom-Bbehavior, crossing −1 from phantom to quintessence regime as the universeexpands. In particular, we reconstruct the corresponding actions for f(R),f(T), and f(Q) gravity, respectively. We conclude that, certain modifiedgravity such as metric-affine gravity can exhibit the quintom dynamics and fitthe recent DESI data efficiently, and for all cases the quadratic deviationfrom the ΛCDM scenario is mildly favored.
主讲人介绍:
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,获得过国家创新人才青年项目、基金委优秀青年基金、重点项目等资助,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学术论文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。