Exploring Curved Superspace

TL;DR

This paper classifies four-dimensional manifolds that admit rigid supersymmetry, revealing geometric conditions for different numbers of supercharges and their implications for supersymmetric theories.

Contribution

It provides a systematic analysis of the geometric structures underlying supersymmetric manifolds in four dimensions, including classifications based on the number of supercharges.

Findings

Single supercharge implies Hermitian manifold.

Two supercharges of opposite R-charge exist on certain fibrations.

Four supercharges imply the manifold is locally M_3 x R.

Abstract

We systematically analyze Riemannian manifolds M that admit rigid supersymmetry, focusing on four-dimensional N=1 theories with a U(1)_R symmetry. We find that M admits a single supercharge, if and only if it is a Hermitian manifold. The supercharge transforms as a scalar on M. We then consider the restrictions imposed by the presence of additional supercharges. Two supercharges of opposite R-charge exist on certain fibrations of a two-torus over a Riemann surface. Upon dimensional reduction, these give rise to an interesting class of supersymmetric geometries in three dimensions. We further show that compact manifolds admitting two supercharges of equal R-charge must be hyperhermitian. Finally, four supercharges imply that M is locally isometric to M_3 x R, where M_3 is a maximally symmetric space.