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Related papers: A gate tunable transmon qubit in planar Ge

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We report voltage-tuned phase transitions in arrays of hybrid semiconductor-superconductor islands arranged in a square lattice. A double-layer electrostatic gate geometry enables independent tuning of inter-island coupling and…

Mesoscale and Nanoscale Physics · Physics 2025-10-09 S. Sasmal , M. Efthymiou-Tsironi , G. Nagda , E. Fugl , L. L. Olsen , F. Krizek , C. M. Marcus , S. Vaitiekėnas

The integration of semiconductor Josephson junctions (JJs) in superconducting quantum circuits provides a versatile platform for hybrid qubits and offers a powerful way to probe exotic quasiparticle excitations. Recent proposals for using…

Superconducting protected qubits aim to achieve sufficiently low error rates so as to allow realization of error-corrected, utility-scale quantum computers. A recent proposal encodes a protected qubit in the quasicharge degree of freedom of…

Quantum Physics · Physics 2026-01-09 Nicholas M. Christopher , Deniz E. Stiegemann , Abhijeet Alase , Thomas M. Stace

Incorporating van der Waals (vdW) superconductors into Josephson elements extends circuit-QED beyond conventional Al/AlO$_x$/Al tunnel junctions and enables microwave probes of unconventional condensates and subgap excitations. In this…

Quantum Physics · Physics 2026-01-28 Eliya Blumenthal , Ilay Mangel , Amit Kanigel , Shay Hacohen-Gourgy

Superconducting diodes are a recently-discovered quantum analogueue of classical diodes. The superconducting diode effect relies on the breaking of both time-reversal and inversion symmetry. As a result, the critical current of a…

High-purity germanium (Ge) has re-emerged as a versatile semiconductor platform for spin-based quantum information processing because it combines mature materials processing, access to spin-free isotopes, high mobilities, small effective…

Quantum Physics · Physics 2026-05-14 D. -M. Mei , K. -M. Dong , S. A. Panamaldeniya , A. Prem , S. Chhetri , N. Budhathoki , S. Bhattarai

Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale superconductor-based quantum computing due to their better coherence and larger anharmonicity. A major challenge for multi-qubit…

We report the observation of Josephson diode effect (JDE) in hybrid devices made from semiconductor InAs nanosheets and superconductor Al contacts. By applying an in-plane magnetic field ($B_{\mathrm{xy}}$), we detect non-reciprocal…

Mesoscale and Nanoscale Physics · Physics 2025-04-17 Shili Yan , Yi Luo , Haitian Su , Han Gao , Xingjun Wu , Dong Pan , Jianhua Zhao , Ji-Yin Wang , Hongqi Xu

We propose to combine the advantages of graphene, such as easy tunability and long coherence times, with Josephson physics to manufacture qubits. If these qubits are built around a 0 and $\pi$ junction they can be controlled by an external…

Mesoscale and Nanoscale Physics · Physics 2009-10-06 Colin Benjamin , Jiannis K. Pachos

We report a gate-tunable Josephson diode effect in hybrid nanowire junctions consisting of a spin-orbit-coupled semiconductor core coated with epitaxial ferromagnetic insulator and superconductor shells. The wires display a hysteretic…

Mesoscale and Nanoscale Physics · Physics 2025-08-19 Sjoerd Telkamp , Junting Zhao , Saulius Vaitiekėnas

Josephson junctions supply the nonlinear inductance element in superconducting qubits. In the widely used transmon configuration, where the junction is shunted by a large capacitor, the low charging energy minimizes the sensitivity of the…

Mesoscale and Nanoscale Physics · Physics 2024-12-17 Maxwell Wisne , Yanpei Deng , Hilal Cansizoglu , Cameron Kopas , Josh Mutus , Venkat Chandrasekhar

The phenomenon of non-reciprocal critical current in a Josephson device, termed the Josephson diode effect, has garnered much recent interest. Realization of the diode effect requires inversion symmetry breaking, typically obtained by…

Mesoscale and Nanoscale Physics · Physics 2023-06-06 Mohit Gupta , Gino V. Graziano , Mihir Pendharkar , Jason T. Dong , Connor P. Dempsey , Chris Palmstrøm , Vlad S. Pribiag

We consider a Josephson bijunction consisting of a thin $SIS$ $\pi$-Josephson junction sandwiched between two-dimensional semiconducting layers with strong Rashba spin-orbit interaction. Each of these layers forms an $SNS$ junction due to…

Mesoscale and Nanoscale Physics · Physics 2020-07-08 Yanick Volpez , Daniel Loss , Jelena Klinovaja

The reproducibility of qubit parameters is a challenge for scaling up superconducting quantum processors. Signal crosstalk imposes constraints on the frequency separation between neighboring qubits. The frequency uncertainty of transmon…

Hybrid semiconductor-superconductor qubits have recently emerged as a promising alternative to traditional platforms, combining material advantages with device-level tunability. A defining feature is their gate-tunable Josephson coupling,…

We report low-temperature measurements of two adjacent, gate-defined Josephson junctions (JJs) in magic-angle twisted bilayer graphene (MATBG) at a moir\'e filling factor near $\nu = -2$. We show that both junctions exhibit a prominent,…

Mesoscale and Nanoscale Physics · Physics 2026-05-26 A. Rothstein , R. J. Dolleman , L. Klebl , A. Achtermann , F. Volmer , K. Watanabe , T. Taniguchi , F. Hassler , L. Banszerus , B. Beschoten , C. Stampfer

Atomtronics has the potential for engineering new types of functional devices, such as Josephson junctions (JJs). Previous studies have mainly focused on JJs whose ground states have 0 or $\pi $ superconducting phase difference across the…

Quantum Gases · Physics 2016-10-19 Lei Jiang , Yong Xu , Chuanwei Zhang

In conventional transmon qubits, decoherence is dominated by a large number of parasitic two-level systems (TLS) residing at the edges of its large area coplanar shunt capacitor and junction leads. Avoiding these defects by improvements in…

Superconductivity · Physics 2025-09-29 Etienne Daum , Benedikt Berlitz , Steffen Deck , Alexey V. Ustinov , Jürgen Lisenfeld

The transmon, which has a short gate time and remarkable scalability, is the most commonly utilized superconducting qubit, based on the Cooper pair box as a qubit or coupler in superconducting quantum computers. Lattice and heavy-hexagon…

Quantum Physics · Physics 2024-12-23 Jeongsoo Kang , Chanpyo Kim , Younghun Kim , Younghun Kwon

Multimode circuits provide an avenue for flexible control of single and multi-qubit gates. In this work we implement a multimode circuit known as a trimon integrated in a planar geometry. The trimon features three transmon-like modes with…