CHARGE SCREENING IN THE FINITE-TEMPERATURE SCHWINGER MODEL

We compute the effective action and correlators of the Polyakov loop o perator in the Schwinger model at finite temperature and discuss the r ealization of the discrete symmetries that occur there. We show that, due to nonlocal effects of massless fermions in two space-time dimensi ons, the discrete symmetry which governs the screening of charges is s pontaneously broken even in an effective one-dimensional model, when t he volume is infinite. In this limit, the thermal state of the Schwing er model screens an arbitrary external charge; consequently the model is in the deconfined phase, with the charge of the deconfined fermions completely screened. In a finite volume we show that the Schwinger mo del is always confining.