Superconductor-insulator transition in Josephson junction chains by Quantum Monte-Carlo
We study the zero-temperature phase diagram of a clean dissipationless chain of Josephson junctions between superconducting islands. Its realistic model must include two capacitances: the self-capacitance of each island and the capacitance of the junction between neighboring islands.
Using a novel imaginary-time path integral Quantum Monte-Carlo algorithm in the charge representation, which enables us to efficiently handle the electrostatic part of the chain Hamiltonian, we determine the critical Josephson energy below which the chain becomes insulating, as a function of the ratio of two capacitances. We find that the large part of the phase diagram is determined by corrections which are subleading to the standard Kosterlitz-Thouless scaling.
Department of Physics