Colloquium on Nov. 18, 2022

Cosmological hints for new physics: theories and tests

Speaker: Weikang Lin (Shanghai Jiaotong University)

Venue: SWIFAR Building 1115

Time: 16:00 PM, Friday, Nov. 17, 2022

Abstract:

Physics thrives on crisis. A few cosmological anomalies are reported which might be hints for new physics such as the nature of dark energy and dark matter. I will focus on the recently reported cosmic birefringence detection and the hotly debated Hubble tension. The former can be explained by a variation of the quintessence axion. If true, it predicts a dark energy equation of state different from a cosmological constant with , which is testable with near future observations. The latter is often attributed to some new component(s) in the early universe. However, pure geometrical information can be extracted from the cosmic microwave background, which incorporates other late-time observations and provide early-physics insensitive determinations of the Hubble constant and tests of early-universe physics.

Report PPT:  SWIFAR_Weikang Lin.pdf