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We reconsider the issue of Berezinskii-Kosterlitz-Thouless (BKT) transition into an insulating state in the Coulomb-dominated Josephson junction arrays. We show that previously predicted picture of the Cooper-pair BKT transtion at T = T_2…
Quantum phase transitions typically result in a broadened critical or crossover region at nonzero temperature. Josephson arrays are a model of this phenomenon, exhibiting a superconductor-insulator transition at a critical wave impedance,…
The discovery that a gate electrode suppresses the supercurrent in purely metallic systems is missing a complete physical understanding of the mechanisms at play. We here study the origin of this reduction in a Superconductor-Normal…
Superconductors separated by a thin tunneling barrier exhibit the Josephson effect that allows charge transport at zero voltage, typically with no phase shift between the superconductors in the lowest energy state. Recently, Josephson…
Coherent tunneling processes of multiple Cooper pairs across a Josephson junction give rise to higher harmonics in the current phase relation. In this work, we propose and study Josephson junctions based on…
We show that the zero-temperature physics of planar Josephson junction arrays in the self-dual approximation is governed by an Abelian gauge theory with periodic mixed Chern-Simons term describing the charge-vortex coupling. The periodicity…
We study a quantum Hamiltonian that models an two--dimensional array of Josephson junctions with short range Josephson couplings, (given by the Josephson energy E_J and charging energiey E_C due to the small capacitance of the junctions. We…
The superconductor to insulator transition is studied in a self-charging model for a ladder of Josephson-junctions in presence of an external magnetic field. Path integral Monte Carlo simulations of the equivalent (1+1)-dimensional…
Path Integral Quantum Monte Carlo simulation is used to study thermodynamic properties and a phase diagram of 2D quantum Josephson array, described by 2+1 XY model. The helicity and vorticity moduli, correlation function of phases and other…
When a Josephson junction array is built with hybrid superconductor/metal/superconductor junctions, a quantum phase transition from a superconducting to a two-dimensional (2D) metallic ground state is predicted to happen upon increasing the…
We study the behavior of a topological Josephson junction in which two topological superconductors are coupled through a quantum dot. We focus on the case with the bulk superconducting gap being the largest energy scale. Two parameter…
We study the quantum phase transition of the one-dimensional phase model in the presence of dissipative frustration, provided by an interaction of the system with the environment through two non-commuting operators. Such a model can be…
We study a quantum dot Josephson junction inside an Aharonov-Bohm environment. The geometry is modeled by an Anderson impurity coupled to two directly-linked BCS leads. We illustrate that the well-established picture of the low-energy…
The phase diagram of two dimensional Josephson arrays is studied by means of the mapping to the quantum XY model. The quantum effects onto the thermodynamics of the system can be evaluated with quantitative accuracy by a semiclassical…
We investigate the Josephson current J(\phi) through a quantum dot embedded between two superconductors showing a phase difference \phi. The system is modeled as a single Anderson impurity coupled to BCS leads, and the functional and the…
We study localization phenomena in two dimensional systems of charged particles in the presence of a metallic ground plane with a particular focus on the superconductor-insulator transition. The ground plane introduces a screening of the…
We study the superconductor-insulator quantum phase transition in disordered Josephson junction chains. To this end, we derive the field theory from the lattice model that describes a chain of superconducting islands with a capacitive…
Josephson junction field-effect transistors (JJFETs) have recently re-emerged as promising candidates for superconducting computing. For JJFETs to perform Boolean logic operations, the so-called gain factor $\alpha_{R}$ must be larger than…
We present a theory for the Josephson effect in an unconventional superconductor / one-dimensional electron gas / unconventional superconductor (s/o/s) junction, where the Josephson current is carried by components injected perpendicular to…
At zero temperature, a Josephson junction coupled to an ohmic environment displays a quantum phase transition between superconducting and insulating phases, depending whether the resistance of the environment is below or above the…