$\theta$ Vacuum in a Random Matrix Model

Abstract

Inspired by recent lattice calculations, we model certain aspects of the $\theta$-vacuum using a matrix model with gaussian weights. The vacuum energy exhibits a cusp at $\theta <\pi$ that is sensitive to both the accuracy of the numerical analysis and the maximum density of winding modes present in a finite volume.

Comments: 3 pages with 2 EPS figures and World Scientific style file. Talk given by G. Papp at the Workshop "Understanding Deconfinement in QCD", ECT*, Trento, 1-13/March, 1999