BPS states in Matrix Strings

TL;DR

This paper explores BPS states in matrix string theory, showing how supersymmetric Yang-Mills states with fractional momentum or instanton number match M(atrix) theory predictions, supporting a conjecture linking these quantities.

Contribution

It demonstrates the correspondence between BPS states in Yang-Mills theory and stringy degeneracies, highlighting the role of instanton number and momentum.

Findings

Supersymmetric states carry fractional momentum and instanton number.

Energies of these states align with M(atrix) theory predictions.

Evidence supports a conjecture linking momentum and instanton number.

Abstract

Matrix string theory (or more generally U-Duality) requires Super Yang-Mills theory to reflect a stringy degeneracy of BPS short multiplets. These are found as supersymmetric states in the Yang-Mills carrying (fractionated) momentum, or in some cases, instanton number. Their energies also agree with those expected from M(atrix) theory. A nice parallel also emerges in the relevant cases, between momentum and instanton number, (both integral as well as fractional) providing evidence for a recent conjecture relating the two.