Herbert Neuberger

The Quenched Eguchi-Kawai Model

Abstract It is argued that spontaneous symmetry breaking occurs in the recently proposed Eguchi-Kawai model. The argument is based on an analytic investigation and on Monte Carlo simulations. A quenched version of the model is proposed which gives good behavior at weak couplings.

Large-N reduction in the continuum three-dimensional Yang-Mills theory.

Numerical and theoretical evidence leads us to propose the following: Three-dimensional Euclidean Yang-Mills theory in the planar limit undergoes a phase transition on a torus of side l=l(c). For l>l(c) the planar limit is l independent, as expected of a noninteracting string theory. We expect the situation in four dimensions to be similar.

Nonperturbative BRS invariance and the Gribov problem

Abstract The requirement of lattice BRS invariance is argued to successfully replace local gauge invariance to any order in a perturbative expansion. In a nonperturbative setting, however, one encounters an obstacle which, on a formal level, exists also in the continuum formulation. The origin of the problem and possible ways to avoid it are discussed.

A phase transition in the quenched Eguchi-Kawai model☆

Abstract Numerical evidence is given that the QEK model has the same phase structure as the large- N limit of the infinite volume lattice gauge theory with a Wilson action.

A quenched reduction for the topological limit of QCD

Abstract We extend the reduction of large N QCD to include an infinite number of fermion flavors. The applicability to numerical experiments is discussed.

The finite-temperature phase transition at infinite N

Abstract The finite-temperature breakdown of the global Z( N ) symmetry of 3 + 1 dimensional lattice gauge theories is studied within the framework of a reduced, quenched, large- N model using both analytical and numerical methods.

Analytical results for mixed action SU(2) lattice gauge theory

Abstract Strong and weak coupling expansions for the SU(2), mixed action lattice gauge theories are given. Nonperturbative configurations are identified and their contribution is also estimated. A comparison with Monte Carlo data is presented.

The role of gauge theories in constructing reduced models at infinite N

Abstract Reduced large- N matrix and chiral models are derived as limiting cases of interacting gauge theories. It is shown that the quenched Eguchi-Kawai prescription is a general as Parisis rule. The equivalence with the infinite volume theories is extended to the strong coupling regime.

The decay of a false vacuum and the density of states in a random, repulsive potential

Abstract The replica method is applied to a disordered system built out of ramdomly distributed, purely repulsive scattering centers. The emerging field theoretical model has a classical solution, a bounce, which gives both the leading form of the level density and the typical ground-state wave function.