Review of W Strings

TL;DR

This paper reviews recent progress in W-string theories, which extend ordinary string models by gauging higher-spin algebras, allowing explicit spectrum calculations despite algebraic complexity.

Contribution

It provides a comprehensive review of W-string constructions and demonstrates explicit spectrum computation for these complex models.

Findings

Spectrum can be explicitly computed for most W-string models

W-string spectra are equivalent to Virasoro strings with unusual parameters

Despite non-linearity, W-algebras allow complete spectrum determination

Abstract

We review some of the recent developments in the construction of $W$-string theories. These are generalisations of ordinary strings in which the two-dimensional ``worldsheet'' theory, instead of being a gauging of the Virasoro algebra, is a gauging of a higher-spin extension of the Virasoro algebra---a $W$ algebra. Despite the complexity of the (non-linear) $W$ algebras, it turns out that the spectrum can be computed completely and explicitly for more or less any $W$ string. The result is equivalent to a set of spectra for Virasoro strings with unusual central charge and intercepts.