String Spectrum of 1+1-Dimensional Large N QCD with Adjoint Matter

TL;DR

This paper investigates the spectrum of large N 1+1-dimensional QCD with adjoint matter, proposing a gauged matrix model approach to eliminate non-singlet states and exploring the resulting string-like excitations.

Contribution

It introduces a discretised light-cone quantisation method for large N gauge theory with adjoint matter, analyzing the spectrum and convergence properties, and discusses extensions towards new string theories.

Findings

Spectrum consists of bosonic and fermionic closed-string excitations.

Good convergence observed for adjoint fermions case.

Potential for discovering new non-critical string theories.

Abstract

We propose gauging matrix models of string theory to eliminate unwanted non-singlet states. To this end we perform a discretised light-cone quantisation of large N gauge theory in 1+1 dimensions, with scalar or fermionic matter fields transforming in the adjoint representation of SU(N). The entire spectrum consists of bosonic and fermionic closed-string excitations, which are free as N tends to infinity. We analyze the general features of such bound states as a function of the cut-off and the gauge coupling, obtaining good convergence for the case of adjoint fermions. We discuss possible extensions of the model and the search for new non-critical string theories.