UNIVERSAL STRING AND SMALL $N=4$ SUPERSTRING

TL;DR

This paper demonstrates that all known superstring theories, including small N=4 and N=2 strings, can be derived from a universal string framework through spontaneous supersymmetry breaking.

Contribution

It shows that the small N=4 superstring can be obtained from the large N=4 strings and that the N=2 string is a special vacuum of the small N=4 string, unifying superstring theories.

Findings

Small N=4 superstring derived from large N=4 strings

N=2 string identified as a vacuum of small N=4 string

Universal string framework encompasses all superstring theories

Abstract

It was previously shown that most of the superstrings can be obtained from those with higher world-sheet supersymmetry as spontaneously broken phases. In this paper, we show that the small $N=4$ superstring, which was left out of this hierarchy of the universal string, can be obtained from the large $N=4$ strings. We also show that the $N=2$ string is a special vacuum of small $N=4$ string. Thus all the known superstring theories can be derived from a universal string by spontaneous breakdown of supersymmetry.