D-brane Dynamics in the c=1 Matrix Model

TL;DR

This paper explores the detailed dynamics of D-branes in two-dimensional string theory using the c=1 matrix model, including higher order effects and the correspondence between open and closed string states.

Contribution

It systematically incorporates higher order string perturbation effects and clarifies the relationship between matrix model eigenvalues and D-brane states.

Findings

Higher order string effects can be extracted from the matrix model.

Sum of planar diagrams corresponds to classical bulk theory.

Static D-branes relate to deformed Fermi sea solutions.

Abstract

Recent work has shown that unstable D-branes in two dimensional string theory are represented by eigenvalues in a dual matrix model. We elaborate on this proposal by showing how to systematically include higher order effects in string perturbation theory. The full closed string state produced by a rolling open string tachyon corresponds to a sum of string amplitudes with any number of boundaries and closed string vertex operators. These contributions are easily extracted from the matrix model. As in the AdS/CFT correspondence, the sum of planar diagrams in the open string theory is directly related to the classical theory in the bulk, i.e. sphere diagrams. We also comment on the description of static D-branes in the matrix model, in terms of a solution representing a deformed Fermi sea.