D-branes and extended characters in image Original Research Article

We present a detailed study of D-branes in the axially gauged image coset conformal field theory for integer level k. Our analysis is based on the modular bootstrap approach and utilizes the extended image characters and the embedding of the parafermionic coset algebra in the image superconformal algebra. We propose three basic classes of boundary states corresponding to D0-, D1- and D2-branes. We verify that these boundary states satisfy the Cardy consistency conditions and discuss their physical properties. The D0- and D1-branes agree with those found in earlier work by Ribault and Schomerus using different methods (descent from the Euclidean image model). The D2-branes are new. They are not, in general, space-filling but extend from the asymptotic circle at infinity up to a minimum distance image from the tip of the cigar.