CHIRAL TRANSITION AND MONOPOLE PERCOLATION IN LATTICE SCALER QED WITHQUENCHED FERMIONS

We study the interplay between topological observables and chiral and Higgs transitions in lattice scalar QED with quenched fermions. Emphas is is put on the chiral transition line and magnetic monopole percolat ion at strong gauge coupling. We confirm that at infinite gauge coupli ng the chiral transition is described by mean field exponents. We find a rich and complicated behavior at the end point of the Higgs transit ion line which hampers a satisfactory analysis of the chiral transitio n. We study in detail an intermediate coupling, where the data are con sistent both with a trivial chiral transition clearly separated from m onopole percolation and with a chiral transition coincident with monop ole percolation, and characterized by the same critical exponent v sim ilar or equal to 0.65. We discuss the relevance (or lack thereof) of t hese quenched results to our understanding of the U-chi phi(4)del. We comment on the interplay of magnetic monopoles and fermion dynamics in more general contexts.