String Theory Origin of Constrained Multiplets

TL;DR

This paper explores how the worldvolume fields of (anti-)D3-branes in type IIB string theory can be described using constrained non-linear supermultiplets, linking string theory to supersymmetric multiplet structures and cosmological models.

Contribution

It introduces a novel packaging of D3-brane worldvolume fields into constrained non-linear N=1 supermultiplets, connecting string theory brane actions with supersymmetry multiplet constraints.

Findings

Worldvolume fields form constrained N=1 multiplets.

Certain multiplet constraints encode brane fields.

Implications for inflationary cosmology with anti-D3-branes.

Abstract

We study the non-linearly realized spontaneously broken supersymmetry of the (anti-)D3-brane action in type IIB string theory. The worldvolume fields are one vector $A_\mu$, three complex scalars $\phi^i$ and four 4d fermions $\lambda^0$, $\lambda^i$. These transform, in addition to the more familiar N=4 linear supersymmetry, also under 16 spontaneously broken, non-linearly realized supersymmetries. We argue that the worldvolume fields can be packaged into the following constrained 4d non-linear N=1 multiplets: four chiral multiplets $S$, $Y^i$ that satisfy $S^2=SY^i=0$ and contain the worldvolume fermions $\lambda^0$ and $\lambda^i$; and four chiral multiplets $W_\alpha$, $H^i$ that satisfy $S W_\alpha=0$ and $S \bar D_{\dot \alpha} \bar H^{\bar \imath}=0$ and contain the vector $A_\mu$ and the scalars $\phi^i$. We also discuss how placing an anti-D3-brane on top of intersecting O7-planes can lead to an orthogonal multiplet $\Phi$ that satisfies $S(\Phi-\bar \Phi)=0$, which is particularly interesting for inflationary cosmology.