相关论文: Quantum Phase in Nanoscopic Superconductors
It has long been thought that macroscopic phase coherence breaks down in effectively lower-dimensional superconducting systems even at zero temperature due to enhanced topological quantum phase fluctuations. In quasi-1D wires, these…
Superconductivity is reformulated as a phenomenon in which a stable velocity field is created by a $U(1)$ phase neglected by Dirac in the Schroedinger representation of quantum mechanics. The neglected phase gives rise to a $U(1)$ gauge…
Extended defects are known to strongly affect nanoscale superconductors. Here we report the properties of superconducting nanoribbons with a constriction formed between two adjacent step-edges, by solving the Bogoliubov-de Gennes equations…
In a recent Letter [Phys. Rev. Lett. 129, 087001, (2022)], Masuki, Sudo, Oshikawa, and Ashida studied a Josephson junction, with Josephson energy $E_{\rm J}$ and charging energy $E_{\rm C}$, shunted by an ohmic transmission line with…
We argue that quantum fluctuations of the phase of the order parameter may strongly affect the electron density of states (DOS) in ultrathin superconducting wires. We demonstrate that the effect of such fluctuations is equivalent to that of…
Superconducting order parameters that are odd under exchange of time-coordinates of the electrons constituting a Cooper-pair, are potentially of great importance both conceptually and technologically. Recent experiments report that such an…
The superconducting diode effect, reminiscent of the unidirectional charge transport in semiconductor diodes, is characterized by a nonreciprocal, dissipationless flow of Cooper pairs. This remarkable phenomenon arises from the interplay…
A chain of Josephson junctions implements one of the simplest many-body models undergoing a superconductor-insulator (SI) quantum phase transition between states with zero and infinite resistance. Apart from zero resistance, the…
Coherence of superconducting qubits can be improved by implementing designs that protect the parity of Cooper pairs on superconducting islands. Here, we introduce a parity-protected qubit based on voltage-controlled semiconductor nanowire…
The dc Josephson effect provides a powerful phase-sensitive tool for investigating superfluid order parameters. We report on the observation of dc Josephson supercurrents in strongly interacting fermionic superfluids across a tunnelling…
We characterize a fluxonium qubit consisting of a Josephson junction inductively shunted with a NbTiN nanowire superinductance. We explain the measured energy spectrum by means of a multimode theory accounting for the distributed nature of…
We consider a Rashba spin-orbit coupled nanowire with anisotropic spin-singlet superconducting pairing and time-reversal-invariant symmetry. We explore the evolution of the topological superconducting phases of this system due to geometric…
Superconducting circuits can exhibit quantized energy levels and long coherence times. Harnessing the anharmonicity offered by Josephson junctions, such circuits have been successfully employed as qubits, quantum limited amplifiers and…
We observe a series of discontinuities in the above gap current/voltage characteristics of highly transmissive Nb/Si superconductor/semiconductor interfaces. The bias at which each switch occurs decreases in quantized steps as a function of…
Superconducting circuits based on Josephson junctions exhibit macroscopic quantum coherence and can behave like artificial atoms. Recent technological advances have made it possible to implement atomic-physics and quantum-optics experiments…
We apply a Gutzwiller-like variational technique to study Josephson conduction across a quantum dot with an odd number of electrons connected to two superconducting leads. Our method projects out all states on the dot but the Kondo singlet…
Superconducting circuits offer tremendous design flexibility in the quantum regime culminating most recently in the demonstration of few qubit systems supposedly approaching the threshold for fault-tolerant quantum information processing.…
We study a superconducting quantum point contact made of a narrow In$_{0.75}% $Ga$_{0.25}$As channel with Nb proximity electrodes. The narrow channel is formed in a gate-fitted constriction of InGaAs/InAlAs/InP heterostructure hosting a…
Topological superconductors are appealing building blocks for robust and reliable quantum information processing. Most platforms for engineering topological superconductivity rely on a combination of superconductors, materials with…
We propose an active mechanism for coupling the quantized mode of a nanomechanical resonator to the persistent current in the loop of a superconducting Josephson junction (or phase slip) flux qubit. This coupling is independently controlled…