|DATE||December 14 (Tue), 2021|
|INSTITUTE||University of Tokyo|
|TITLE||Axion Quality Problem Alleviated by Non-Minimal Coupling to Gravity|
|ABSTRACT||It is known that gravitational instantons, or Euclidean wormholes, induce the Peccei-Quinn symmetry breaking effects, spoiling the Peccei-Quinn solution to the strong CP problem. In this talk, I will first review this argument based on some old studies. I will then discuss that this U(1)-breaking effect can sufficiently be suppressed if the Peccei-Quinn field has a non-minimal coupling to gravity. The required size of the non-minimal coupling can be compatible with that needed for successful inflation, where the Peccei-Quinn scalar field plays the role of inflaton.