MICROCANONICAL FERMIONIC AVERAGE METHOD IN THE SCHWINGER MODEL - A REALISTIC COMPUTATION OF THE CHIRAL CONDENSATE

The microcanonical fermionic average method has been used so far in the context of lattice models with phase transitions at finite coupling. To test its applicability to asymptotically free theories, we have implemented it in two-dimensional QED, i.e., the Schwinger model. We exploit the possibility, intrinsic to this method, of studying the whole β,m plane without extra computer cost, to follow constant physics trajectories and measure the m→0 limit of the chiral condensate. We recover the continuum result within three decimal places. Moreover, the possibility, intrinsic to the method, of performing simulations directly in the chiral limit allows us to compute the average plaquette energy at m=0, the result being in perfect agreement with the expected value. © 1994 The American Physical Society.