PGI Fall Seminar Series|Zimo Sun|Princeton University| "Harish-Chandra characters, de Sitter Quasinormal Modes and Sphere Partition Functions"

Abstract: Harish-Chandra characters generalize the ordinary group characters  to infinite dimensional representations of noncompact Lie groups.

In this talk, I first review the Harish-Chandra characters of de Sitter isometry group. Then I will show that these Harish-Chandra characters count quasinormal modes in the static patch of de Sitter spacetime, and they capture the one-loop sphere partition function of arbitrary effective field theory including gravity. These partition functions can be used to test microscopic models of de Sitter quantum gravity.