2025/04/01 by Cai, Yucong, Robbins, Daniel, Saleem, Hassaan
#FOS: Physical sciences #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2504.00367
We revisit the question of conformal boundary conditions in the compact free boson CFT in two dimensions. Besides the well-known Neumann and Dirichlet cases, there is an additional proposed one-parameter family of boundary states when the radius is an irrational multiple of the self-dual radius. These additional states have a continuous open string spectrum and we give an explicit formula for the density of states. We also discuss several pathologies of these states, including a violation of the cluster condition and that they have a divergent g-function.