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We present measurements of temperature and magnetic field dependence of the critical current and excess current in a carbon nanotube Josephson quantum dot junction. The junction is fabricated in a controlled environment which allows for…

Superconductivity · Physics 2009-04-30 H. Ingerslev Jørgensen , K. Grove-Rasmussen , K. Flensberg , P. E. Lindelof

We investigate the Josephson effect through a two-level quantum dot with an exchange coupling between two dot electrons. We compute the superconducting phase relationship and construct the phase diagram in the superconducting gap--exchange…

Mesoscale and Nanoscale Physics · Physics 2011-08-25 Minchul Lee , Thibaut Jonckheere , Thierry Martin

We develop a microscopic model to describe the Josephson dynamics between two superfluid reservoirs of ultracold fermionic atoms which accounts for the dependence of the critical current on both the barrier height and the interaction…

Quantum Gases · Physics 2019-12-04 Matteo Zaccanti , Wilhelm Zwerger

We investigate Josephson junctions among conventional superconducting wires, in the presence of externally applied Zeeman fields and supercurrents. We demonstrate that the critical Josephson current and the current-phase relation of the…

Superconductivity · Physics 2022-08-02 Giorgos Livanas

We show that two capacitively-coupled Josephson junctions, in the quantum limit, form a simple coupled qubit system with effective coupling controlled by the junction bias currents. We compute numerically the energy levels and wave…

The problem of Josephson current through Coulomb-blocked nanoscale superconductor-normal-superconductor structure with tunnel contacts is reconsidered. Two different contributions to the phase-biased supercurrent are identified, which are…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 P. M. Ostrovsky , M. V. Feigel'man

We calculate the equilibrium Josephson current through a disordered interacting quantum dot described by a Sachdev-Ye-Kitaev model fully contacted by two BCS superconductors, such that all modes of the dot contribute to the coupling, which…

Strongly Correlated Electrons · Physics 2024-10-25 Luca Dell'Anna

On the basis of the Usadel equation we study a multi-terminal Josephson junction. This junction is composed by "magnetic" superconductors S$_{\text{m}}$ which have singlet pairing and are separated from the normal n~wire by spin filters so…

Superconductivity · Physics 2016-04-07 Andreas Moor , Anatoly F. Volkov , Konstantin B. Efetov

The critical current modulation and the spontaneous flux of the vortex states in corner Josephson junctions between Sr$_2$RuO$_4$ and a conventional s-wave superconductor are calculated as a function of the crystal orientation, and the…

Superconductivity · Physics 2009-11-07 N. Stefanakis

Numerical modeling of dependences ``critical current -- external magnetic field'' for geometrically symmetric $0-\pi$ Josephson junctions is performed. The calculation of critical current is reduced to non-linear eigenvalue problem. The…

Superconductivity · Physics 2007-05-23 J. A. Angelova , T. L. Boyadjiev

We study a junction between two time-reversal-invariant topological superconductors and show this system goes through a series of multiple transitions between a $0$-junction phase, where the free energy has its minimum for a superconducting…

Mesoscale and Nanoscale Physics · Physics 2019-11-01 Arbel Haim

We investigate the supercurrent through a quantum dot for the whole range of couplings using the numerical renormalization group method. We find that the Josephson current switches abruptly from a $\pi$- to a 0-phase as the coupling…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Mahn-Soo Choi , Minchul Lee , Kicheon Kang , W. Belzig

Josephson junctions containing ferromagnetic layers are of considerable interest for the development of practical cryogenic memory and superconducting qubits. Such junctions exhibit a phase shift of $\pi$ for certain ranges of ferromagnetic…

The multiterminal Josephson effect aroused considerable interest recently, in connection with theoretical and experimental evidence for correlations among Cooper pairs, that is, the so-called Cooper quartets. It was further predicted that…

Superconductivity · Physics 2023-08-25 Régis Mélin , Romain Danneau , Clemens B. Winkelmann

We consider theoretically a Josephson junction with a superconducting critical current density which has a random sign along the junction's surface. We show that the ground state of the junction corresponds to the phase difference equal to…

Disordered Systems and Neural Networks · Physics 2009-10-31 A. Zyuzin , B. Spivak

The equilibrium Josephson current through a nanoscale multi-level quantum dot with Rashba or Dresselhaus spin-orbit coupling $\alpha$ has been computed. The critical current can be drastically modified already by moderate $\alpha$. In the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 L. Dell'Anna , A. Zazunov , R. Egger , T. Martin

Josephson effect in a planar graphene junction is studied by assuming that the coupling of a graphene sheet and two superconductors deposited on its top is described by a tunneling Hamiltonian. This model properly takes account of the…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Yositake Takane , Ken-Ichiro Imura

We report measurements of the temperature dependence of the critical current in Josephson junctions consisting of conventional superconducting banks of Nb and a weakly ferromagnetic interlayer of a Cu$_x$Ni$_{1-x}$ alloy, with $x$ around…

Superconductivity · Physics 2009-10-31 V. V. Ryazanov , V. A. Oboznov , A. Yu. Rusanov , A. V. Veretennikov , A. A. Golubov , J. Aarts

Josephson superconducting qubits and parametric amplifiers are prominent examples of superconducting quantum circuits that have shown rapid progress in recent years. With the growing complexity of such devices, the requirements for…

We report the first experimental observation of the two-node thickness dependence of the critical current in Josephson junctions with a ferromagnetic interlayer. Vanishings of the critical current correspond to transitions into pi-state and…

Superconductivity · Physics 2007-05-23 V. A. Oboznov , V. V. Bol'ginov , A. K. Feofanov , V. V. Ryazanov , A. I. Buzdin