c=1 Matrix Model from String Field Theory

TL;DR

This paper demonstrates the equivalence between boundary string field theory on unstable D0-branes in 2D string theory and the double scaled c=1 matrix model, simplifying the understanding of open-closed string duality.

Contribution

It shows that BSFT on unstable D0-branes reduces to a quadratic matrix model, clarifying the open string dynamics and holographic interpretation in 2D string theory.

Findings

S-matrices are trivial in open string theory on D0-branes

BSFT is equivalent to a quadratic c=1 matrix model

Insights into higher-dimensional BSFT from 2D results

Abstract

We show that the boundary string field theory (BSFT) on unstable D0-branes in 2d string theory is equivalent to the double scaled c=1 matrix model (i.e. quadratic action), even though we naively expect many interaction terms in BSFT. It is checked that S-matrices are trivial in the open string theory on the D0-branes. We discuss how to take the closed string decoupling limit in our model in order to make its holographic interpretation clear. We also find some useful lessons from our results in 2d string toward the further understanding of the higher dimensional BSFT action.