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Related papers: Millisecond coherence in a superconducting qubit

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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…

Quantum Physics · Physics 2019-01-30 T. M. Hazard , András Gyenis , A. Di Paolo , A. T. Asfaw , S. A. Lyon , A. Blais , A. A. Houck

State transitions during qubit measurements are extremely detrimental to quantum tasks that rely on repeated measurements, such as quantum error correction. These state transitions can occur when excessive measurement power leads to qubit…

Quantum Physics · Physics 2026-05-26 Yulong Li , Wuerkaixi Nuerbolati , Chunqing Deng , Xizheng Ma , Haonan Xiong , Haifeng Yu

Semiconductor double quantum dot hybrid qubits are promising candidates for high-fidelity quantum computing. However, their performance is limited by charge noise, which is ubiquitous in solid-state devices, and phonon-induced dephasing.…

Mesoscale and Nanoscale Physics · Physics 2019-09-04 Yuan-Chi Yang , S. N. Coppersmith , Mark Friesen

Fault-tolerant quantum computers which can solve hard problems rely on quantum error correction. One of the most promising error correction codes is the surface code, which requires universal gate fidelities exceeding the error correction…

Ten years ago, coherent oscillations between two quantum states of a superconducting circuit differing by the presence or absence of a single Cooper pair on a metallic island were observed for the first time. This result immediately…

Mesoscale and Nanoscale Physics · Physics 2009-10-19 Vladimir E. Manucharyan , Jens Koch , Markus Brink , Leonid I. Glazman , Michel H. Devoret

We present a hybrid semiconductor-based superconducting qubit device which remains coherent at magnetic fields up to 1 T. The qubit transition frequency exhibits periodic oscillations with magnetic field, consistent with interference…

High-quality two-qubit gate operations are crucial for scalable quantum information processing. Often, the gate fidelity is compromised when the system becomes more integrated. Therefore, a low-error-rate, easy-to-scale two-qubit gate…

Quantum Physics · Physics 2020-12-24 Yuan Xu , Ji Chu , Jiahao Yuan , Jiawei Qiu , Yuxuan Zhou , Libo Zhang , Xinsheng Tan , Yang Yu , Song Liu , Jian Li , Fei Yan , Dapeng Yu

We propose an erasure conversion scheme on the $|e\rangle-|f\rangle$ and $|g\rangle-|f\rangle$ qubits in integer fluxonium qubits (IFQs), which are both first-order insensitive to $1/f$ flux noise. The $|e\rangle-|f\rangle$ transition is…

Quantum Physics · Physics 2026-03-24 Jiakai Wang , Raymond A. Mencia , Vladimir E. Manucharyan , Maxim G. Vavilov

For successful realization of a quantum computer, its building blocks (qubits) should be simultaneously scalable and sufficiently protected from environmental noise. Recently, a novel approach to the protection of superconducting qubits has…

Mesoscale and Nanoscale Physics · Physics 2013-03-06 Sergey Gladchenko , David Olaya , Eva Dupont-Ferrier , Benoit Doucot , Lev B. Ioffe , Michael E. Gershenson

The superconducting transmon qubit is a leading platform for quantum computing and quantum science. Building large, useful quantum systems based on transmon qubits will require significant improvements in qubit relaxation and coherence…

We present a systematic study of the phase-coherent dynamics of a superconducting three-Josephson-junction flux qubit. The qubit state is detected with the integrated-pulse method, which is a variant of the pulsed switching DC SQUID method.…

Superconductivity · Physics 2008-09-19 F. Deppe , M. Mariantoni , E. P. Menzel , S. Saito , K. Kakuyanagi , H. Tanaka , T. Meno , K. Semba , H. Takayanagi , R. Gross

We propose a family of microwave-activated entangling gates on two capacitively coupled fluxonium qubits. A microwave pulse applied to either qubit at a frequency near the half-frequency of the $|00\rangle - |11\rangle$ transition induces…

Tunable couplers have recently become one of the most powerful tools for implementing two-qubit gates between superconducting qubits. A tunable coupler typically includes a nonlinear element, such as a SQUID, which is used to tune the…

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…

Mesoscale and Nanoscale Physics · Physics 2025-06-24 Priya Sharma , Jens Koch , Eran Ginossar

Superconducting qubits with in-situ tunable properties are important for constructing a quantum computer. Qubit tunability, however, often comes at the expense of increased noise sensitivity. Here, we propose a flux-tunable superconducting…

Quantum Physics · Physics 2017-08-09 Eyob A. Sete , Matthew Reagor , Nicolas Didier , Chad T. Rigetti

High-fidelity quantum state transfer and remote entanglement between superconducting fixed-frequency qubits have not yet been realized. In this study, we propose an alternative remote cross-resonance gate. Considering multiple modes of a…

Quantum Physics · Physics 2024-04-18 Mari Ohfuchi , Shintaro Sato

Native multiqubit gates could be essential for bridging the gap from current noisy devices to future utility-scale quantum computers, as they can substantially reduce circuit depth for near-term applications on noisy devices and may also…

Quantum Physics · Physics 2026-01-26 Peng Zhao , Peng Xu , Zheng-Yuan Xue

Fluxons in a superconducting loop can be coherently coupled by quantum phase slips occurring at a weak link such as a Josephson junction. If Cooper pair tunneling at the junction occurs through a resonant level, $2\pi$ quantum phase slips…

Mesoscale and Nanoscale Physics · Physics 2024-08-14 T. Vakhtel , P. D. Kurilovich , M. Pita-Vidal , A. Bargerbos , V. Fatemi , B. van Heck

The "quantronium" is a superconducting qubit consisting of a split Cooper pair box in which a large tunnel junction is inserted. This circuit has a special bias point where the Larmor frequency is, to first order, insensitive to…

Superconductivity · Physics 2009-11-11 I. Siddiqi , R. Vijay , M. Metcalfe , E. Boaknin , L. Frunzio , R. J. Schoelkopf , M. H. Devoret

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…