Asymptotically Safe Quantum Gravity and Essential RG

Tuesday 27 Aug 2024, 17:30 → 19:00 Asia/Tokyo

Date: 27 August (Tue) 17:30 (JST)
Speaker: Nobuyoshi Ohta (Kindai U./APCTP)
Title: Asymptotically Safe Quantum Gravity and Essential RG

Abstract: We first explain one of the approaches to quantum gravity based on the Functional Renormalization Group, what is called asymptotic safety. The main issue is how to control the high energy behavior of the gravity theory, keeping predictability without ghosts (negative metric states). Asymptotic safety tries to achieve this goal by finding UV fixed points of the finite number of the gravitational couplings. We discuss how to deal with the wave function renormalization, which is one of the inessential couplings, which do not affect physical quantities. We find that higher derivative operators are necessary but with Gaussian fixed point. This leads to negative metric states. We suggest that a possible resolution of this conflict may be the essential RG which deals with only the essential couplings.