Breakdown of large-N reduction in the quenched Eguchi-Kawai model

We study the validity of the large-N equivalence between four-dimensional SU(N) lattice gauge theory and its momentum quenched versionothe Quenched Eguchi-Kawai (QEK) model. We have found strong evidence that this equivalence does not hold in the weak-coupling regime (and thus in the continuum limit). This is based on weak-coupling analytic arguments and MontoCarlo simulations at intermediate couplings with 20 N 200. Since detailed expositions of our arguments, methods and results have already appeared in Phys. Rev. D78:034507 (2008) and arXiv:0807.1275, we attempt here to give a more intuitive explanation of our results. The breakdown of reduction that we nd is due to a dynamically generated correlation between different Euclidean components of the gauge elds.