title: Reentrant behavior of the phase stiffness in Josephson junction arrays.
abstract: The phase diagram of a 2D Josephson junction array with large substrate resistance, described by a quantum XY model, is studied by means of Fourier path-integral Monte Carlo. A genuine Berezinskii-Kosterlitz-Thouless transition is found up to a threshold value g( small star, filled ) of the quantum coupling, beyond which no phase coherence is established. Slightly below g( small star, filled ) the phase stiffness shows a reentrant behavior with temperature, in connection with a low-temperature disappearance of the superconducting phase, driven by strong nonlinear quantum fluctuations.
authors.affiliation: Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: Luca
authors.initials: L
authors.lastname: Capriotti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cuccoli
authors.forename: Andrea
authors.initials: A
authors.lastname: Fubini
authors.forename: Valerio
authors.initials: V
authors.lastname: Tognetti
authors.forename: Ruggero
authors.initials: R
authors.lastname: Vaia