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We introduce a novel method for fabricating all-aluminum Josephson junctions with highly transmitted conduction channels. Such properties are typically associated with structures requiring intricate fabrication processes, such as atomic…

Mesoscale and Nanoscale Physics · Physics 2026-01-16 J. Griesmar , H. Riechert , M. Hantute , A. Peugeot , S. Annabi , Ç. Ö. Girit , G. O. Steffensen , A. L. Yeyati , E. Arrighi , L. Bretheau , J. -D. Pillet

Creating a transmon qubit using semiconductor-superconductor hybrid materials not only provides electrostatic control of the qubit frequency, it also allows parts of the circuit to be electrically connected and disconnected in situ by…

Mesoscale and Nanoscale Physics · Physics 2020-02-12 A. Kringhøj , T. W. Larsen , B. van Heck , D. Sabonis , O. Erlandsson , I. Petkovic , D. I. Pikulin , P. Krogstrup , K. D. Petersson , C. M. Marcus

Josephson junctions made from aluminium and its oxide are the most commonly used functional elements for superconducting circuits and qubits. It is generally known that the disordered thin-film AlOx contains atomic tunneling systems.…

Superconductivity · Physics 2018-05-30 Saskia M. Meißner , Arnold Seiler , Jürgen Lisenfeld , Alexey V. Ustinov , Georg Weiss

We present a planar qubit design based on a superconducting circuit that we call concentric transmon. While employing a straightforward fabrication process using Al evaporation and lift-off lithography, we observe qubit lifetimes and…

Mesoscopic Josephson junctions (JJs), consisting of overlapping superconducting electrodes separated by a nanometer thin oxide layer, provide a precious source of nonlinearity for superconducting quantum circuits and are at the heart of…

We present the results of an industry-grade fabrication of superconducting qubits on 200 mm wafers utilizing CMOS-established processing methods. By automated waferprober resistance measurements at room temperature, we demonstrate a…

Transmon qubits fabricated with tantalum metal have been shown to possess energy relaxation times greater than 300 $\mu$s and, as such, present an attractive platform for high precision, correlated noise studies across multiple higher…

Recent experiments have demonstrated superconducting transmon qubits with semiconductor nanowire Josephson junctions. These hybrid gatemon qubits utilize field effect tunability characteristic for semiconductors to allow complete qubit…

Mesoscale and Nanoscale Physics · Physics 2016-04-20 L. Casparis , T. W. Larsen , M. S. Olsen , F. Kuemmeth , P. Krogstrup , J. Nygård , K. D. Petersson , C. M. Marcus

We demonstrate a planar, tunable superconducting qubit with energy relaxation times up to 44 microseconds. This is achieved by using a geometry designed to both minimize radiative loss and reduce coupling to materials-related defects. At…

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…

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

Mesoscopic multi-terminal Josephson junctions are novel devices that provide weak coupling between several bulk superconductors through a common normal layer. Because of the nonlocal coupling of the superconducting banks, a current flow…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 M. H. S. Amin , A. N. Omelyanchouk , A. Blais , A. Maassen van den Brink , G. Rose , T. Duty , A. M. Zagoskin

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

A framework named Trainmon is introduced to reverse-engineer a quantum potential well for superconducting qubits. Trainmon consists of parallel branches of identical Josephson junctions. The Hamiltonian for this circuit resembles a discrete…

Quantum Physics · Physics 2025-09-03 Saeed Hajihosseini , Seyed Iman Mirzaei , Hesam Zandi , Mohsen Akbari

We present a new style of fluxonium qubit, gatemonium, based on an all superconductorsemiconductor hybrid platform. The linear inductance is achieved using six hundred planar Al-InAs Josephson junctions (JJs) in series. By tuning the single…

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…

We have engineered the bandgap profile of transmon qubits by combining oxygen-doped Al for tunnel junction electrodes and clean Al as quasiparticle traps to investigate energy relaxation due to quasiparticle tunneling. The relaxation time…

Superconducting qubit fabrication innovations continue to be explored to achieve higher performance. Despite improvements to base layer fabrication and processing, resist-based Josephson junction (JJ) schemes have largely remained…

Quantum Physics · Physics 2026-05-18 Tathagata Banerjee , Stephen Daniel Funni , Saswata Roy , Judy J. Cha , Valla Fatemi

We present a new type of transmon split-junction qubit which can be tuned by Meissner screening currents in the adjacent superconducting film electrodes. The best detected relaxation time ($T_1$) was of the order of 50 $\mu$s and the…

Mesoscale and Nanoscale Physics · Physics 2021-06-16 Jaseung Ku , Zack Yoscovits , Alex Levchenko , James Eckstein , Alexey Bezryadin

This study presents the design, simulation, and experimental characterization of a superconducting transmon qubit circuit prototype for potential applications in dark matter detection experiments. We describe a planar circuit design…