``Alternative $N=(4,0)$ Superstring and $\s$-Models''

TL;DR

This paper introduces an alternative $N=(4,0)$ superstring theory modeled as a non-linear sigma-model on a specific coset space, challenging previous assumptions about the target space geometry for such theories.

Contribution

It presents a new $N=(4,0)$ superstring formulation with a different target space, expanding the landscape of superstring models beyond hyper-Kähler or quaternionic Kähler manifolds.

Findings

The target space for $N=4$ superstring need not be hyper-Kähler.

The theory is formulated as a non-linear sigma-model with torsion.

It couples to $N=(4,0)$ superconformal gravity.

Abstract

We present an alternative $N=(4,0)$ superstring theory, with field content different from that of previously-known $N=(4,0)$ superstring theories. This theory is presented as a non-linear $\s$-model on the coset $SU(n,1) / SU(n) \otimes U(1)$ as the target space-time with torsion, which is coupled to $N=(4,0)$ world-sheet superconformal gravity. Our result indicates that the target space-time for $N=4$ superstring theory does not necessarily have to be a hyper-K\"ahler or quaternionic K\"ahler manifold.