Speaker
Description
There are many aspects of 2D conformal field theories where we have a good understanding and powerful tools in the rational (RCFT) case, but these don't always apply to non-rational CFTs. As a laboratory to study these distinctions, we revisit conformal boundary states in the compact free boson CFT. At radii which are irrational multiples of the self-dual radius, an exceptional set of boundary states appear (we call them Friedan-Janik states) in the literature, but they have some undesirable properties, including a continuous spectrum of boundary operators and a divergent g-function. We discuss some arguments about how to interpret these boundary states, how they fit with sewing conditions such as the cluster condition, and derive an explicit closed-form expression for the density of states $\rho(h)$ for the boundary operators. This also lets us explore how the spectrum goes from continuous to discrete in certain limits where we expect to recover such behavior.
