Classical Open String Amplitudes and Boundary String Field Theory

TL;DR

This paper demonstrates that boundary string field theory encodes the minimal model of open string field theory, reproducing perturbative string S-matrices through its cohomological structure.

Contribution

It shows that boundary string field theory naturally realizes the minimal model of open string field theory, connecting mathematical structures with physical S-matrix computations.

Findings

Boundary string field theory reproduces open string S-matrices.

The cohomological vector field expansion matches perturbative results.

Boundary string field theory realizes the minimal model map.

Abstract

Abstract: We show that boundary string field theory realizes the minimal model of open string field theory. More precisely, we observe that the expansion of the (co)homological vector field, $Q$ of boundary string field theory in the cohomology of its linear part reproduces the S-matrices of perturbative string theory. In mathematical terms, boundary string field theory realizes the minimal model map of the cohomological perturbation lemma.