Charged open strings in a background field and Euler-Heisenberg effective action

TL;DR

This paper derives a multiloop partition function for open bosonic strings in a constant gauge field, connecting string theory with the Euler-Heisenberg effective action in a field theory limit.

Contribution

It provides an explicit multiloop partition function expression in the presence of a background field, bridging string theory and effective field theories.

Findings

Reproduces Euler-Heisenberg action at two loops

Uses Schottky parametrization for field theory limit

Extends understanding of open string interactions in background fields

Abstract

This talk is based on work made with L. Magnea and R. Russo. We give an explicit expression of the multiloop partition function of open bosonic string theory in the presence of a constant gauge field strength. The Schottky parametrization allows to perform the field theory limit, which at two-loop level reproduces the Euler-Heisenberg effective action for adjoint scalars minimally coupled to the background gauge field.