Branes, fermions, and superspace dualities

TL;DR

This paper develops a superspace-based method to compute fermionic couplings on M2-branes and D$p$-branes, utilizing geometric techniques and dualities to extend results across different brane types and backgrounds.

Contribution

It introduces a systematic approach to derive fermionic couplings on various branes using superspace and duality transformations, advancing the understanding of brane interactions in supergravity.

Findings

Derived fermionic couplings for M2-brane using normal coordinate expansion.

Established a translation method for fermionic couplings from M2-brane to D$p$-branes.

Demonstrated the applicability of techniques to arbitrary background fields.

Abstract

We use the superspace formulation of supergravity in eleven and ten dimensions to compute fermion couplings on the M2-brane and on D$p$-branes. In this formulation fermionic couplings arise naturally from the $\theta$-expansion of the superfields from which the brane actions are constructed. The techniques we use and develop can in principle be applied to determine the fermionic couplings to general background fields up to arbitrary order. Starting with the superspace formulation of 11-dimensional supergravity, we use a geometric technique known as the `normal coordinate' method to obtain the $\theta$-expansion of the M2-brane action. We then present a method which allows us to translate the knowledge of fermionic couplings on the M2-brane to knowledge of such couplings on the D2-brane, and then to any D$p$-brane. This method is based on superspace generalizations of both the compactification taking 11-dimensional supergravity to type IIA supergravity and the T-duality rules connecting the type IIA and type IIB supergravities.