##
**Video URL**
http://pirsa.org/19080063

## Abstract

The g-theorem is a prominent example of C-theorems in two-dimensional boundary CFT and the extensions are conjectured to hold in higher-dimensional BCFTs. On the other hand, much less is known for C-theorems in a CFT with conformal defects of higher codimensions. I will investigate the entanglement entropy across a sphere and sphere free energy as a candidate for a C-function in DCFT, and show they differ by a universal term proportional to the vev of the stress tensor. Based on this relation, I will propose to use the sphere free energy as a C-function in DCFT. This proposal unifies the previously known theorems and conjectures, and passes several checks, including a few examples in field theories and a holographic proof in simple gravity dual models of DCFTs.

## Details

**Talk Number**19080063

**Speaker Profile**Tatsuma Nishioka

- Quantum Matter
- Quantum Fields and Strings
- Quantum Information

**Scientific Area**

- Conference

**Talk Type**

**Source Repository**PIRSA