Conformal defects from string field theory

Abstract

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 employ open string field theory (OSFT) techniques to explore the space of conformal defects. We illustrate the method by an analysis of OSFT around the background associated to 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. In particular, we find a continuum of solutions in the Ising model case and 6 solutions for other minimal models. OSFT provides us with numerical estimates of the g-function and other coefficients of the boundary state.

Deriving on-shell open string field amplitudes without using Feynman rules

“…The equation ( 53) is considered as the physical state condition around the classical solution Ψ naturally (see [34,35,36] for general discussion). Throughout this paper, the term an external state refers to a state O i which satisfies (53) and (54).…”

“…When a certain classical solution to ( 8) is given, it might be possible to obtain such information by sending 'the coupling constant' to small. 'what quantities can be read naturally from classical solutions [2,49,50,23,51,52,53]' are important questions related to one another. In addition, there are physical quantities which are not defined yet even though they are expected to exist.…”

Defects and perturbation

“…A further recent motivation to search for tractable instances of pure defect flows was [21]. We also want to mention the interesting approach in [22] where the authors explore the space of conformal defects by using open string field theory techniques.…”