Title: Spectator mechanism and CMB power asymmetry

Speaker: Dr. Lingfei Wang (Lancaster University)

Time: 10:00AM, Feb. 26th (Wednesday)

Place: Theoretical Physics Division，319

Abstract:

The speaker will explain the spectator scenario and show its advantages compared to the curvaton scenario, under the latest Planck constraints. The spectator scenario generates a smaller non-Gaussianity, negligible isocurvature perturbations, and less tuning. It agrees well with the current Planck data in the visible sector inflation setup, as an example.

The recent CMB power asymmetry is particularly difficult to explain with small non-Gaussianities, but the spectator scenario succeeds with a brief tachyonic fast roll phase. Despite that the significance of the CMB power asymmetry is, and will remain, controversial, some of its properties still suggest it be an anomaly.