CFT in AdS and boundary RG flows

Understand

Using the fact that flat space with a boundary is related by a Weyl transformation to anti-de Sitter (AdS) space, one may study observables in boundary conformal field theory (BCFT) by placing a CFT in AdS.

• In addition to correlation functions of local operators, a quantity of interest is the free energy of the CFT computed on the AdS space with hyperbolic ball metric, i.e.
• with a spherical boundary.
• It is natural to expect that the AdS free energy can be used to define a quantity that decreases under boundary renormalization group (RG) flows.