RG boundaries and interfaces in Ising field theory

Understand

Perturbing a CFT by a relevant operator on a half space and letting the perturbation flow to the far infrared we obtain an RG interface between the UV and IR CFTs.

• If the IR CFT is trivial we obtain an RG boundary condition.
• The space of massive perturbations thus breaks up into regions labelled by conformal boundary conditions of the UV fixed point.
• For the 2D critical Ising model perturbed by a generic relevant operator we find the assignment of RG boundary conditions to all flows.