9812340 Larkin This award is for the study of quantum fluctuations in superconductors. Of particular interest is the role of quantum fluctuations in two-dimensional superconducting films and Josephson junction arrays. The PI's plan to calculate the quantum corrections to the mean-field theory of the transition temperature suppression in a continuous disordered superconducting film. It is hoped that a connection will be made to the scaling theory description of the critical region around the quantum phase transition point. Localization effects that occur for strong superconducting fluctuations will be studied. Motivated by recent experiments in Josephson junction arrays, the PI's aim to study phase transitions in systems of interacting quantum vortices. Investigations of the Hall effect and vortex charge in two-dimensional Josephson arrays will also be carried out. %%% Two PI's, one an eminent senior expert in the theory of superconductivity and the other a rising star in the field of mesoscopics will team up to study the role of quantum mechanical fluctuation effects that are beyond the standard (BCS) theory of superconductivity. Phenomena assocated with these effects are observed in experiments on superconducting thin films and on arrays of superconducting grains or islands, where neighboring grains are weakly coupled to each other. Research on these systems may give rise to new electronic device technologies that exploit superconductivity. ***