Chern-Simons from Dirichlet 2-brane instantons

TL;DR

This paper demonstrates that membrane instantons in type IIA string theory near degenerating three-cycles can be described by Chern-Simons theory on the brane world-volume, linking geometric degenerations to topological field theories.

Contribution

It establishes a direct connection between membrane instantons in string theory and Chern-Simons theory, providing a new perspective on non-perturbative effects in Calabi-Yau compactifications.

Findings

Membrane instantons are described by Chern-Simons theory.

Degenerating three-cycles influence the effective action significantly.

The world-volume theory captures instanton effects in string compactifications.

Abstract

In the vicinity of points in Calabi-Yau moduli space where there are degenerating three-cycles the low energy effective action of type IIA string theory will contain significant contributions arising from membrane instantons that wrap around these three-cycles. We show that the world-volume description of these instantons is Chern-Simons theory.