Boundary Deformation Theory and Moduli Spaces of D-Branes

TL;DR

This paper develops boundary deformation theory within conformal field theory to analyze how D-brane boundary conditions change via marginal boundary fields, revealing the global structure of D-brane moduli spaces including stringy phenomena.

Contribution

It introduces a comprehensive boundary deformation framework with all-order formulas, enabling global analysis of D-brane moduli spaces in arbitrary CFT backgrounds.

Findings

Identification of truly marginal boundary fields.

Derivation of all-order deformation formulas.

Analysis of the moduli space of c=1 theories with stringy phenomena.

Abstract

Boundary conformal field theory is the suitable framework for a microscopic treatment of D-branes in arbitrary CFT backgrounds. In this work, we develop boundary deformation theory in order to study the changes of boundary conditions generated by marginal boundary fields. The deformation parameters may be regarded as continuous moduli of D-branes. We identify a large class of boundary fields which are shown to be truly marginal, and we derive closed formulas describing the associated deformations to all orders in perturbation theory. This allows us to study the global topology properties of the moduli space rather than local aspects only. As an example, we analyse in detail the moduli space of c=1 theories, which displays various stringy phenomena.