相关论文: BCS models of Josephson qubits I. Energy spectra
Flux qubits, small superconducting loops interrupted by Josephson junctions, are successful realizations of quantum coherence for macroscopic variables. Superconductivity in these loops is carried by $\sim 10^6$ -- $10^{10}$ electrons,…
We propose an effective scheme for manipulating quantum information stored in a superconducting nanocircuit. The Josephson qubits are coupled via their separate interactions with an information bus, a large current-biased Josephson junction…
With microwave irradiation, the switching current of a Josephson junction coupled to a microscopic two-level system jumps randomly between two discrete states. We modeled the switching process of the coupled system with quantum jump…
We realized a time-domain simulator based on the electrodynamics of Cooper pairs and quasiparticles in Josephson junctions. The tool, based on the charge carriers' densities of states described by the Werthamer and Harris formalisms of…
The Josephson junction is the fundamental nonlinear building block of superconducting quantum technologies. Its macroscopic quantum tunneling physics underpins superconducting quantum computing, sensing, and communication, but scaling these…
Josephson junctions and the quantum phase-slip (QPS) junctions are two quantum circuit elements introduced by superconducting electronics to create various hybrid circuits. Josephson junctions bring the developments of superconducting…
Quasiparticle tunneling across a Josephson junction sets a limit for the lifetime of a superconducting qubit state. We develop a general theory of the corresponding decay rate in a qubit controlled by a magnetic flux. The flux affects…
Josephson junction spectroscopy is a powerful local microwave spectroscopy technique that has promising potential as a diagnostic tool to probe the microscopic origins of noise in superconducting qubits. We present advancements toward…
Superconductivity is commonly described as a macroscopic quantum phenomenon. However, it arises from microscopic mechanisms occurring at the nanometer scale as illustrated, for example, by the non-trivial pairing in unconventional…
In the tunnel limit, the current-phase relation of Josephson junctions can be expanded as $I(\phi)=I_1\sin\phi+I_2\sin 2\phi$. Standard BCS theory predicts that $I_1R_N\sim\Delta/e$ and $I_2/I_1\sim D$, where $R_N$ is the resistance of the…
We study large arrays of mesoscopic junctions between gapless superconductors where the tunneling processes of both, particle-hole and Cooper, pairs give rise to a strongly retarded effective action which, contrary to the standard case, can…
For decades following its introduction in 1968, the resistively and capacitively shunted junction (RCSJ) model, sometimes referred to as the Stewart-McCumber model, was successfully applied to study the dynamics of Josephson junctions…
The superconductor-insulator-superconductor Josephson junction is the fundamental nonlinear element of superconducting circuits. Connecting two junctions in series gives rise to higher-harmonic content in the total energy-phase relation,…
Theoretically, Josephson junction (JJ) arrays can exhibit either a superconducting or insulating state, separated by a quantum phase transition (QPT). In this work, we analyzed published data on QPTs in three one-dimensional arrays and two…
We theoretically analyze two setups of low energy single-photon counters based on Josephson junctions (JJ). For this, we propose two simple and general models, based on the macroscopic quantum tunneling formalism (MQT). The first setup is…
Circuit quantum electrodynamics (QED) has emerged as a promising platform for implementing quantum computation and simulation. Typically, junctions in these systems are of a sufficiently small size, such that only the lowest plasma…
Superconducting flux qubits are a promising candidate for solid-state quantum computation. One of the reasons is that implementing a controlled coupling between the qubits appears to be relatively easy, if one uses tunable Josephson…
Several physical realizations of quantum bits have been proposed. Of those, nano-electronic devices appear most suitable for large-scale integration and potential applications. We suggest to use low-capacitance Josephson junctions,…
Josephson tunnel junctions are essential elements of superconducting quantum circuits. The operability of these circuits presumes a $2\pi$-periodic sinusoidal potential of a tunnel junction, but higher-order corrections to this Josephson…
There is a wide recognition that Josephson-junction-like structures intrinsic to the layered cuprate high temperature superconductors offer an attractive stage for exploiting possible applications to new quantum technologies. On the other…