Why Are There So Many N = 4 Superstrings?

TL;DR

This paper reveals the existence of three distinct off-shell N=4 superstring formulations at the level of manifest locally supersymmetric world sheet Lagrangians.

Contribution

It identifies and characterizes three different off-shell N=4 superstring theories, expanding understanding of superstring formulations.

Findings

Existence of three off-shell N=4 superstring theories

Characterization of their differences at the Lagrangian level

Implications for superstring theory classifications

Abstract

We demonstrate the existence of three off-shell distinct N = 4 superstrings at the level of manifest locally supersymmetric Lagrangian field theories on the world sheet.