Duality Symmetries of 4D Heterotic Strings

TL;DR

This paper explores the duality symmetries in 4D heterotic string theory, specifically target space duality and axion-dilaton duality, revealing a rich spectrum of solitons and multiple string descriptions.

Contribution

It demonstrates the realization of T duality as a world-sheet symmetry and discusses the conjectured S duality for five-branes, highlighting the theory's complex duality structure.

Findings

Target space duality is a symmetry of the world-sheet action.

The theory has a spectrum with both duality symmetries.

There are infinitely many dual string descriptions.

Abstract

Target space duality (T duality), which interchanges Kaluza--Klein and winding-mode excitations of the compactified heterotic string, is realized as a symmetry of a world-sheet action. Axion-dilaton duality (S duality), a conjectured nonperturbative SL(2,Z) symmetry of the same theory, plays an analogous role for five-branes. We describe a soliton spectrum possessing both duality symmetries and argue that the theory has an infinite number of dual string descriptions.