Brane-Antibrane Action from Boundary String Field Theory

TL;DR

This work develops a boundary string field theory description of brane–antibrane systems, delivering an exact off-shell framework for tachyon dynamics and condensation. It shows that RR couplings in these systems are naturally captured by superconnections, tying D-brane charges to K-theory classes $K^0(M)$ and $K^1(M)$, and generalizes these couplings to include transverse scalars that generate Myers terms. The authors demonstrate exact tachyon condensation producing lower-dimensional branes with correct tensions and connect these results to the Atiyah–Bott–Shapiro construction. They also derive the brane–antibrane world-volume action, including higher-derivative corrections and a noncommutative extension, as well as discuss implications for non-BPS branes and future directions in curved backgrounds and instanton effects.

Abstract

In this paper we give the boundary string field theory description of brane-antibrane systems. From the world-sheet action of brane-antibrane systems we obtain the tachyon potential and discuss the tachyon condensation exactly. We also find the world-volume action including the gauge fields. Moreover we determine RR-couplings exactly for non-BPS branes and brane-antibranes. These couplings are written by superconnections and correspond to K^1(M) and K^0(M) for the non-BPS branes and brane-antibranes, respectively. We also show that Myers terms appear if we include the transverse scalars in the boundary sigma model action.