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Josephson junctions constructed from superconductor-semiconductor-superconductor heterostructures have been used to realize a variety of voltage-tunable superconducting quantum devices, including qubits and parametric amplifiers. To date…

Mesoscale and Nanoscale Physics · Physics 2025-06-03 Utkan Güngördü , Rusko Ruskov , Silas Hoffman , Kyle Serniak , Andrew J. Kerman , Charles Tahan

Superconducting qubits are a promising route to achieving large-scale quantum computers. A key challenge in realising large-scale superconducting quantum processors involves mitigating frequency collisions. In this paper, we present an…

We introduce a novel superconducting qubit architecture utilizing parallel arrays of Josephson junctions. This design offers a substantialy improved relative anharmonicity, typically within the range of $|\alpha_r| \approx 0.1 - 0.3$, while…

Quantum Physics · Physics 2024-04-09 Oguzhan Can , Marcel Franz

We report a superconducting artificial atom with an observed quantum coherence time of T2*=95us and energy relaxation time T1=70us. The system consists of a single Josephson junction transmon qubit embedded in an otherwise empty copper…

Significant progress has been made in building large-scale superconducting quantum processors based on flip-chip technology. In this work, we use the flip-chip technology to realize a modified transmon qubit, donated as the "flipmon", whose…

Improvements in circuit design and more recently in materials and surface cleaning have contributed to a rapid development of coherent superconducting qubits. However, organic resists commonly used for shadow evaporation of Josephson…

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…

Superconductivity · Physics 2024-11-12 Samuel Feldman , Andrey Rogachev

Superinductances are superconducting circuit elements that combine a large inductance with a low parasitic capacitance to ground, resulting in a characteristic impedance exceeding the resistance quantum $R_Q = h/(2e)^2 \simeq 6.45…

Superconducting quantum circuits are sensitive to their electrostatic environment: uncontrolled charges accumulating on the electrodes of a Josephson junction shift the energy levels of a qubit, perturbing its operation and restricting…

Electrostatically tunable Josephson field-effect transistors (JoFETs) are one of the most desired building blocks of quantum electronics. JoFET applications range from parametric amplifiers and superconducting qubits to a variety of…

We present a method for fabricating Josephson junctions and superconducting quantum interference devices (SQUIDs) which is based on the local anodization of niobium strip lines 3 to 6.5 nm-thick under the voltage-biased tip of an Atomic…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 V. Bouchiat , M. Faucher , C. Thirion , W. Wernsdorfer , T. Fournier , B. Pannetier

The non-dissipative non-linearity of a Josephson junction converts macroscopic superconducting circuits into artificial atoms, enabling some of the best controlled quantum bits (qubits) today. Three fundamental types of superconducting…

A superconducting transmon qubit resilient to strong magnetic fields is an important component for proposed topological and hybrid quantum computing (QC) schemes. Transmon qubits consist of a Josephson junction (JJ) shunted by a large…

Mesoscale and Nanoscale Physics · Physics 2018-11-20 J. G. Kroll , W. Uilhoorn , K. L. van der Enden , D. de Jong , K. Watanabe , T. Taniguchi , S. Goswami , M. C. Cassidy , L. P. Kouwenhoven

The performance of various superconducting devices operating at ultra-low temperatures is impaired by the presence of non-equilibrium quasiparticles. Inelastic quasiparticle (QP) tunneling across Josephson junctions in superconducting…

Quantum Physics · Physics 2024-05-14 Plamen Kamenov , Thomas DiNapoli , Michael Gershenson , Srivatsan Chakram

Establishment of phase-coherence and a non-dissipative (super)current between two weakly coupled superconductors, known as the Josephson effect, plays a foundational role in basic physics and applications to metrology, precision sensing,…

A model system consisting of a mesoscopic superconducting grain coupled by Josephson junctions to two macroscopic superconducting electrodes is studied. We focus on the effects of ohmic dissipation caused by resistive shunts and…

Superconductivity · Physics 2009-11-10 Gil Refael , Eugene Demler , Yuval Oreg , Daniel S. Fisher

Designing the spatial profile of the superconducting gap -- gap engineering -- has long been recognized as an effective way of controlling quasiparticles in superconducting devices. In aluminum films, their thickness modulates the gap;…

Mesoscale and Nanoscale Physics · Physics 2023-01-02 Giampiero Marchegiani , Luigi Amico , Gianluigi Catelani

We present a novel shadow evaporation technique for the realization of junctions and capacitors. The design by E-beam lithography of strongly asymmetric undercuts on a bilayer resist enables in-situ fabrication of junctions and capacitors…

In this paper we discuss solid-state nanoelectronic realizations of Josephson flux qubits with large tunneling amplitude between the two macroscopic states. The latter can be controlled via the height and wells form of the potential…

Superconductivity · Physics 2013-04-02 V. I. Shnyrkov , A. A. Soroka , S. I. Melnik

Josephson junctions (JJs) are the key element of many devices operating at cryogenic temperatures. Development of time-efficient wafer-scale JJ characterization for process optimization and control of JJ fabrication is essential. Such…