Evidence for Non-perturbative String Symmetries

TL;DR

This paper reviews evidence that string theory possesses exact non-perturbative discrete symmetries called S dualities, which are analogous to perturbative T dualities, and discusses related theoretical speculations.

Contribution

It provides a review of the evidence for S duality in string theory and explores its implications as a non-perturbative symmetry.

Findings

Evidence supports S duality as a non-perturbative symmetry.

S duality is mathematically similar to T duality but applies non-perturbatively.

The paper discusses theoretical implications and speculations regarding S duality.

Abstract

String theory appears to admit a group of discrete field transformations -- called $S$ dualities -- as exact non-perturbative quantum symmetries. Mathematically, they are rather analogous to the better-known $T$ duality symmetries, which hold perturbatively. In this talk the evidence for $S$ duality is reviewed and some speculations are presented.