Quantum fluctuations in superconducting arrays

We study quantum-fluctuation effects on the critical behavior of superconducting arrays via the Feynman path-integral formalism. We compute the path-integral approximately and obtain an effective classical Hamiltonian. The renormalization-group technique is then applied, leading to the result that there exists a reentrant transition only for intermediate quantum fluctuations. Unlike previous semiclassical calculations, this is consistent with the known exact result at zero temperature. Effects of quantum fluctuations together with external magnetic fields are also discussed