17-20 December 2018
Kenkyu-Honkan bldg. 1F
Japan timezone

Towards a C-theorem in defect CFT

18 Dec 2018, 16:50
15m
Kobayashi Hall (Kenkyu-Honkan bldg. 1F)

Kobayashi Hall

Kenkyu-Honkan bldg. 1F

Speaker

Dr Kento Watanabe (University of Tokyo)

Description

We explore a C-theorem in defect conformal field theories (DCFT) that unify all the known conjectures and theorems until now. We examine as a candidate C-function the additional contributions from conformal defects to the sphere free energy and the entanglement entropy across a sphere in a number of examples including holographic models. We find the two quantities are equivalent, when suitably regularized, for codimension-one defects (or boundaries), but differ by a universal constant term otherwise. Moreover, we find in a few field theoretic examples that the sphere free energy decreases but the entanglement entropy increases along a certain renormalization group (RG) flow triggered by a defect localized perturbation which is assumed to have a trivial IR fixed point without defects. We hence propose a C-theorem in DCFTs stating that the increment of the regularized sphere free energy due to the defect does not increase under any defect RG flow. We also provide a proof of our proposal in several holographic models of defect RG flows. (Ref: 1810.06995[hep-th])

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