D-branes in Gepner models

TL;DR

This paper analyzes D-branes in Gepner models using conformal field theory, deriving explicit boundary states, and computing their spectra, tensions, and charges without classical assumptions.

Contribution

It provides explicit formulas for boundary states in Gepner models and links boundary states to physical brane properties.

Findings

Explicit boundary state formulas for Gepner models

Computed excitation spectra of D-branes

Derived brane tensions and RR charges from boundary states

Abstract

We discuss D-branes from a conformal field theory point of view. In this approach, branes are described by boundary states providing sources for closed string modes, independently of classical notions. The boundary states must satisfy constraints which fall into two classes: The first consists of gluing conditions between left- and right-moving Virasoro or further symmetry generators, whereas the second encompasses non-linear consistency conditions from world sheet duality, which severely restrict the allowed boundary states. We exploit these conditions to give explicit formulas for boundary states in Gepner models, thereby computing excitation spectra of brane configurations. From the boundary states, brane tensions and RR charges can also be read off directly.