Realization of high-fidelity CZ gates in extensible superconducting qubits design with a tunable coupler

Abstract

High-fidelity two-qubits gates are essential for the realization of large-scale quantum computation and simulation. Tunable coupler design is used to reduce the problem of parasitic coupling and frequency crowding in many-qubit systems and thus thought to be advantageous. Here we design a extensible 5-qubit system in which center transmon qubit can couple to every four near-neighbor qubit via a capacitive tunable coupler and experimentally demonstrate high-fidelity controlled-phase (CZ) gate by manipulating center qubit and one near-neighbor qubit. Speckle purity benchmarking (SPB) and cross entrophy benchmarking (XEB) are used to assess the purity fidelity and the fidelity of the CZ gate. The average purity fidelity of the CZ gate is 99.69$\pm$0.04\% and the average fidelity of the CZ gate is 99.65$\pm$0.04\% which means the control error is about 0.04\%. Our work will help resovle many chanllenges in the implementation of large scale quantum systems.

arXiv comment6 pages, 6 figures

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Cited by in corpus (10)

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• Building Blocks of a Flip-Chip Integrated Superconducting Quantum Processor
• Long-distance transmon coupler with CZ gate fidelity above $99.8\%$
• Realization of fast all-microwave CZ gates with a tunable coupler
• High-precision pulse calibration of tunable couplers for high-fidelity two-qubit gates in superconducting quantum processors
• Direct calculation of the ZZ-interaction rates in the multi-mode circuit-QED
• Direct Implementation of High-Fidelity Three-Qubit Gates for Superconducting Processor with Tunable Couplers
• Fast microwave-driven two-qubit gates between fluxonium qubits with a transmon coupler
• Above 99.9% Fidelity Single-Qubit Gates, Two-Qubit Gates, and Readout in a Single Superconducting Quantum Device
• Optimizing the frequency positioning of tunable couplers in a circuit QED processor to mitigate spectator effects on quantum operations