Demonstration of High-Fidelity Gates in a Strongly Anharmonic with Long-Coherence C-Shunt Flux Qubit

• URL: http://arxiv.org/abs/2603.11692v1
• Date: Thu, 12 Mar 2026 09:00:08 GMT
• Title: Demonstration of High-Fidelity Gates in a Strongly Anharmonic with Long-Coherence C-Shunt Flux Qubit
• Abstract summary: We demonstrate high-fidelity single-qubit gates on a C-shunt flux qubit that simultaneously combines a large anharmonicity and long relaxation time.<n>The large anharmonicity significantly suppresses leakage to higher energy levels, enabling fast and precise microwave control.<n>Using DRAG pulses and randomized benchmarking, the qubit achieves gate fidelities exceeding 99.9%, highlighting the capability of C-shunt flux qubits for robust and high-performance quantum operations.
• Score: 11.97040088334061
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We demonstrate high-fidelity single-qubit gates on a C-shunt flux qubit that simultaneously combines a large anharmonicity ($\mathcal{A}/2π=848~\mathrm{MHz}$) with long relaxation time ($T_1 = 23~μ\text{s}$). The large anharmonicity significantly suppresses leakage to higher energy levels, enabling fast and precise microwave control. Using DRAG pulses and randomized benchmarking, the qubit achieves gate fidelities exceeding 99.9\%, highlighting the capability of C-shunt flux qubits for robust and high-performance quantum operations. These results establish them as a promising platform for scalable quantum information processing.

Related papers

• Mitigating crosstalk errors for simultaneous single-qubit gates on a superconducting quantum processor [59.06950309601253]
  Single-qubit gates on superconducting quantum processors are typically implemented using microwave pulses applied through dedicated control lines.<n>These microwave pulses may also drive other qubits due to crosstalk arising from capacitive coupling and wavefunction overlap.<n>Crosstalk and frequency crowding increase errors during simultaneous single-qubit operations relative to isolated gates.
  arXiv  Detail & Related papers  (2026-03-11T17:47:32Z)
• Above 99.9% Fidelity Single-Qubit Gates, Two-Qubit Gates, and Readout in a Single Superconducting Quantum Device [58.154405222706146]
  tuning of qubit-coupler coupling strengths in a superconducting circuit with two transmon qubits coupled via a tunable coupler enables high-fidelity single- and two-qubit gates.<n>We achieve a 40h-averaged CZ gate fidelity of 99.93%, simultaneous single-qubit gate fidelities of 99.98%, and readout fidelities over 99.94% in a single device.
  arXiv  Detail & Related papers  (2025-08-22T14:49:47Z)
• High-fidelity transmon coupler activated CCZ gate on fluxonium qubits [0.0]
  We propose a novel way to perform a high-fidelity CCZ gate on fluxoniums capacitively connected via a transmon qubit, activated by a microwave pulse on the coupler. We provide numerical simulation of 95-ns long gate of higher than 99.99% fidelity with realistic circuit parameters in the noiseless model and estimate an error of about 0.25% under the conventional decoherence rates.
  arXiv  Detail & Related papers  (2023-08-29T11:36:19Z)
• Enhancing Dispersive Readout of Superconducting Qubits Through Dynamic Control of the Dispersive Shift: Experiment and Theory [47.00474212574662]
  A superconducting qubit is coupled to a large-bandwidth readout resonator. We show a beyond-state-of-the-art two-state-readout error of only 0.25,%$ in 100 ns integration time. The presented results are expected to further boost the performance of new and existing algorithms and protocols.
  arXiv  Detail & Related papers  (2023-07-15T10:30:10Z)
• Overcoming I/O bottleneck in superconducting quantum computing: multiplexed qubit control with ultra-low-power, base-temperature cryo-CMOS multiplexer [40.37334699475035]
  Large-scale superconducting quantum computing systems entail high-fidelity control and readout of qubits at millikelvin temperatures. Cryo-electronics may offer a scalable and versatile solution to overcome this bottleneck. Here we present an ultra-low power radio-frequency (RF) multiplexing cryo-electronics solution operating below 15 mK.
  arXiv  Detail & Related papers  (2022-09-26T22:38:09Z)
• Demonstration of the Two-Fluxonium Cross-Resonance Gate [1.8568045743509223]
  Current implementations of two-qubit gates compromise fluxonium's coherence properties. We realize a fast all-microwave cross-resonance gate between two capacitively-coupled fluxoniums. Our results project a possible pathway towards reducing the two-qubit error rate below $10-4$ with present-day technologies.
  arXiv  Detail & Related papers  (2022-04-25T17:59:17Z)
• High fidelity two-qubit gates on fluxoniums using a tunable coupler [47.187609203210705]
  Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale quantum computing. A major challenge for multi-qubit fluxonium devices is the experimental demonstration of a scalable crosstalk-free multi-qubit architecture. Here, we present a two-qubit fluxonium-based quantum processor with a tunable coupler element.
  arXiv  Detail & Related papers  (2022-03-30T13:44:52Z)
• Scalable High-Performance Fluxonium Quantum Processor [0.0]
  We propose a superconducting quantum information processor based on compact high-coherence fluxoniums with suppressed crosstalk. We numerically investigate the cross resonance controlled-NOT and the differential AC-Stark controlled-Z operations, revealing low gate error for qubit-qubit detuning bandwidth of up to 1 GHz.
  arXiv  Detail & Related papers  (2022-01-23T21:49:04Z)
• Coherent effects contribution to a fast gate fidelity in ion quantum computer [47.187609203210705]
  We develop a numerical model for full simulation of coherence effects using a linear ion microtrap array and a 2D microtrap array. We have also studied the dependency of the gate fidelity on the laser power fluctuations.
  arXiv  Detail & Related papers  (2021-12-12T12:53:00Z)
• Scalable quantum computation with fast gates in two-dimensional microtrap arrays of trapped ions [68.8204255655161]
  We investigate the use of fast pulsed two-qubit gates for trapped ion quantum computing in a two-dimensional microtrap architecture. We demonstrate that fast pulsed gates are capable of implementing high-fidelity entangling operations between ions in neighbouring traps faster than the trapping period.
  arXiv  Detail & Related papers  (2020-05-01T13:18:22Z)
• Universal non-adiabatic control of small-gap superconducting qubits [47.187609203210705]
  We introduce a superconducting composite qubit formed from two capacitively coupled transmon qubits. We control this low-frequency CQB using solely baseband pulses, non-adiabatic transitions, and coherent Landau-Zener interference. This work demonstrates that universal non-adiabatic control of low-frequency qubits is feasible using solely baseband pulses.
  arXiv  Detail & Related papers  (2020-03-29T22:48:34Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.