KTH/Nordita/SU seminar in Theoretical Physics

Boundary conformal field theory and applications to geometrical critical phenomena.

by Jesper Jacobsen (LPT, ENS)

Europe/Stockholm
FA31

FA31

Description
We discuss how techniques from conformal field theory can produce exact information about two-dimensional geometrical models, such as percolation and lattice polymers, at the critical point. We then address more specifically the issue of conformally invariant boundary conditions (CIBC). While such CIBC have been extensively classified for unitary models, the geometrical theories of interest here are in general non-unitary. We provide several examples of new, infinite families of non-unitary CIBC, formulated in purely geometrical terms. The corresponding critical exponents are obtained exactly. Building on this, we compute exactly various crossing probabilities, boundary entropies, and partition functions in the continuum limit. As a specific application, we deduce the phase diagram of the O(N) model with boundary anisotropy.