D-branes in String theory Melvin backgrounds

TL;DR

This paper investigates the configurations of D-branes in non-supersymmetric Melvin backgrounds in string theory, using multiple approaches to confirm their consistency and explore supersymmetric cases and generalizations.

Contribution

It provides a comprehensive analysis of D-branes in Melvin backgrounds, including supersymmetric and non-supersymmetric configurations, using effective action, partition functions, and boundary states.

Findings

Existence of supersymmetric D-branes in Melvin backgrounds.

Agreement among different analytical approaches.

Generalization to backgrounds with multiple magnetic fields and rational flux.

Abstract

We determine the consistent D-brane configurations in type II nonsupersymmetric Melvin Background. The D-branes are analysed from three complementary points of view: the effective Born-Infeld action, the open string partition function and the boundary state approach. We show the agreement of the results obtained by the three different approaches. Among the surprising features is the existence of supersymmetric branes, some of them having a quasi-periodic direction. We also discuss the generalisation to backgrounds with several magnetic fields, some of them preserving in the closed and the open spectra some amount of supersymmetry. The case of rational magnetic flux, equivalent to freely-acting noncompact orbifolds, is also studied. It allows more possibilities of consistent D-brane configurations.