Strings, Matrix Models, and Meanders

I briefly review the present status of bosonic strings and discretized random surfaces in D>1 which seem to be in a polymer rather than stringy phase. As an explicit example of what happens, I consider the Kazakov-Migdal model with a logarithmic potential which is exactly solvable for any D (at large D for an arbitrary potential). I discuss also the meander problem and report some new results on its representation via matrix models and the relation to the Kazakov-Migdal model. A supersymmetric matrix model is especially useful for describing the principal meanders.Comment: 12 pages, 4 Latex figures, uses espcrc2.sty Talk at the 29th Ahrenshoop Symp., Buckow, Germany, Aug.29 - Sep.2, 199

Large-N Reduction, Master Field and Loop Equations in Kazakov-Migdal Model

I study the large-N reduction a la Eguchi--Kawai in the Kazakov--Migdal lattice gauge model. I show that both quenching and twisting prescriptions lead to the coordinate-independent master field. I discuss properties of loop averages in reduced as well as unreduced models and demonstrate those coincide in the large mass expansion. I derive loop equations for the Kazakov--Migdal model at large N and show they are reduced for the quadratic potential to a closed set of two equations. I find an exact strong coupling solution of these equations for any D and extend the result to a more general interacting potential.Comment: 17 pages (1 Latex figure), ITEP-YM-6-92 The figure is replaced by printable on

The First Thirty Years of Large-N Gauge Theory

I review some developments in the large-N gauge theory since 1974. The main attention is payed to: multicolor QCD, matrix models, loop equations, reduced models, 2D quantum gravity, free random variables, noncommutative theories, AdS/CFT correspondence.Comment: 13.1pp., Latex, 2 figs; v2: 2 refs added. Talk at Large Nc QCD 200