Superconductor-insulator transitions and magnetoresistance oscillations in superconducting strips

The magnetoresistance of thin superconducting (SC) strips subject to a perpendicular magnetic field B and low temperatures T manifests a sequence of alternating SC-insulator transitions (SITs). We study this phenomenon within a quasi-one-dimensional (1D) model for the quantum dynamics of vortices in a line junction between coupled parallel SC wires, at parameters close to their SITs. Mapping the vortex system to 1D Fermions at a chemical potential dictated by B, we find that a quantum phase transition of the Ising type occurs at critical values of the vortex filling, from a SC phase near integer filling to an insulator near 1/2 filling. For T→0, the resulting magnetoresistance R(B) exhibits oscillations similar to the experimental observation.