IR divergence and anomalous temperature dependence of the condensate in the quenched Schwinger model -: art. no. 034506

The Schwinger model is used to study the artifacts of quenching in a controlled way. The model is solved on a finite-temperature cylinder of circumference beta = 1/T with bag-inspired local boundary conditions at the two ends x(1) = 0 and x(1) = L which break the gamma(5) invariance and thus play the role of a small quark mass. The quenched chiral condensate is found to diverge exponentially as L-->infinity, and to diverge (rather than melt as for N(f)greater than or equal to 1) if the high-temperature limit beta-->0 is taken at finite box length L. We comment on the generalization of our results to the massive quenched theory, arguing that the condensate is finite as L-->infinity and proportional to 1/m up to logarithms.