Path integral evaluation of Dbrane amplitudes

TL;DR

This paper extends the path integral approach to evaluate D-brane amplitudes, clarifying the emergence of nonabelian limits and deriving the cylinder amplitude with detailed modulus dependence.

Contribution

It provides a detailed path integral derivation of D-brane amplitudes, including boundary effects and nonabelian limits, advancing the understanding of string interactions.

Findings

Derived the measure for open string amplitudes with boundaries and crosscaps.

Clarified the nonabelian limit of near-coincident D-branes.

Included modulus dependence of the conformal Killing group volume.

Abstract

We extend Polchinski's evaluation of the measure for the one-loop closed string path integral to open string tree amplitudes with boundaries and crosscaps embedded in Dbranes. We explain how the nonabelian limit of near-coincident Dbranes emerges in the path integral formalism. We give a careful path integral derivation of the cylinder amplitude including the modulus dependence of the volume of the conformal Killing group.