Würzburg Seminar on Quantum Field Theory and Gravity

Unlike conformal boundary conditions, conformal defects of Virasoro minimal models lack classification. Alternatively to the defect perturbation theory and the truncated conformal space approach, we can employ open string field theory (OSFT) to explore the space of conformal defects. I will illustrate the method by an analysis of OSFT around the background associated with the (1,2) topological defect in diagonal unitary minimal models. Numerical analysis of OSFT equations of motion leads to an identification of a nice family of solutions, recovering the picture of infrared fixed points due to Kormos, Runkel and Watts. OSFT provides us with numerical estimates of the g-function and other coefficients of the boundary state.