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The anharmonicity of a transmon qubit, defined as the difference in energy level spacing, is a key design parameter. In transmons built from hybrid superconductor-semiconductor Josephson elements, the anharmonicity is tunable with gate…

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…

Superconductivity · Physics 2018-04-23 L. Flammia , L. -F. Zhang , L. Covaci , A. Perali , M. V. Milošević

The field of superconducting quantum computing, based on Josephson junctions, has recently seen remarkable strides in scaling the number of logical qubits. In particular, the fidelities of one- and two-qubit gates have reached the breakeven…

Superconducting circuits with Josephson junctions are promising candidates for developing future quantum technologies. Of particular interest is to use these circuits to study effects that typically occur in complex condensed-matter…

We consider a planar SIS-type Josephson junction between diffusive superconductors (S) through an insulating tunnel interface (I). We construct fully self-consistent perturbation theory with respect to the interface conductance. As a…

Superconductivity · Physics 2021-09-15 A. S. Osin , Ya. V. Fominov

Conventional superconductor/insulator/superconductor (SIS) Josephson junctions, devices where two superconductors are separated by a tunnel barrier are technologically important as elements in quantum circuits, particularly with their key…

Superconductivity · Physics 2025-09-19 Venkat Chandrasekhar

We investigate the current-voltage characteristics of high-transparency superconductor-insulator-normal metal (SIN) junctions with the specific tunnel resistance below 30 kOhm per square micron. The junctions were fabricated from different…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 S. V. Lotkhov , D. V. Balashov , M. I. Khabipov , F. -I. Buchholz , A. B. Zorin

Planar Josephson junctions (JJs) based on InSb nanoflags have recently emerged as an intriguing platform in superconducting electronics. This letter presents the fabrication and investigation of superconducting quantum interference devices…

Josephson junctions form the essential non-linearity for almost all superconducting qubits. The junction is formed when two superconducting electrodes come within $\sim$1 nm of each other. Although the capacitance of these electrodes is a…

Superconducting qubits are solid state electrical circuits fabricated using techniques borrowed from conventional integrated circuits. They are based on the Josephson tunnel junction, the only non-dissipative, strongly non-linear circuit…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. H. Devoret , A. Wallraff , J. M. Martinis

Quantum bits, or qubits, are an example of coherent circuits envisioned for next-generation computers and detectors. A robust superconducting qubit with a coherent lifetime of $O$(100 $\mu$s) is the transmon: a Josephson junction…

Quantum Physics · Physics 2020-05-11 J. M. Kreikebaum , K. P. O'Brien , A. Morvan , I. Siddiqi

Coherent operation of gate-voltage-controlled hybrid transmon qubits (gatemons) based on semiconductor nanowires was recently demonstrated. Here we experimentally investigate the anharmonicity in epitaxial InAs-Al Josephson junctions, a key…

Mesoscale and Nanoscale Physics · Physics 2018-02-28 A. Kringhøj , L. Casparis , M. Hell , T. W. Larsen , F. Kuemmeth , M. Leijnse , K. Flensberg , P. Krogstrup , J. Nygård , K. D. Petersson , C. M. Marcus

Flux tuning of qubit frequencies in superconducting quantum processors is fundamental for implementing single and multi-qubit gates in quantum algorithms. Typical architectures involve the use of DC or fast RF lines. However, these lines…

Tunable Josephson harmonics open new avenues for qubit design. We demonstrate a superconducting circuit element consisting of a tunnel junction in series with a SQUID loop, yielding a Josephson potential whose harmonic content is strongly…

Recent improvements in materials growth and fabrication techniques may finally allow for superconducting semiconductors to realize their potential. Here we build on a recent proposal to construct superconducting devices such as wires,…

Mesoscale and Nanoscale Physics · Physics 2015-04-13 Yun-Pil Shim , Charles Tahan

We introduce a hybrid qubit based on a semiconductor nanowire with an epitaxially grown superconductor layer. Josephson energy of the transmon-like device ("gatemon") is controlled by an electrostatic gate that depletes carriers in a…

Mesoscale and Nanoscale Physics · Physics 2015-09-22 T. W. Larsen , K. D. Petersson , F. Kuemmeth , T. S. Jespersen , P. Krogstrup , J. Nygard , C. M. Marcus

We report the realization of multilayer three-dimensional nanobridge Josephson junctions based on Nb/NbN and Nb/TiN superconducting stacks fabricated using electron-beam lithography and chlorine-based dry etching. In this architecture, a…

The development of quantum circuits based on hybrid superconductor-semiconductor Josephson junctions holds promise for exploring their mesoscopic physics and for building novel superconducting devices. The gate-tunable superconducting…

A superconductor-normal metal-superconductor (SNS) transistor based on superconducting microcoolers is presented. The proposed 4-terminal device consists of a long SNS Josephson junction whose N region is in addition symmetrically connected…

Superconductivity · Physics 2008-07-12 F. Giazotto , F. Taddei , T. T. Heikkila , R. Fazio , F. Beltram

Superconducting quantum interference devices (SQUIDs) that incorporate two superconductor/insulator/superconductor (SIS) Josephson junctions in a closed loop form the core of some of the most sensitive detectors of magnetic and electric…

Mesoscale and Nanoscale Physics · Physics 2021-08-11 Taewan Noh , Andrew Kindseth , Venkat Chandrasekhar