Native CCZ Gate with Fluxonium Qubits and a Microwave-Driven Coupler

• URL: http://arxiv.org/abs/2607.27094v1
• Date: Wed, 29 Jul 2026 16:23:50 GMT
• Title: Native CCZ Gate with Fluxonium Qubits and a Microwave-Driven Coupler
• Abstract summary: We experimentally realize a 65-ns native controlled-controlled-phase operation, with a fidelity of 99.39(5)% in a three-qubit processor unit.<n>Results establish native multi-qubit gates as a viable hardware-efficient primitive for scalable superconducting quantum processors.
• Score: 27.308408027453012
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Native multi-qubit gates could reduce the overhead associated with decompositions into single- and two-qubit operations, but whether they can simultaneously provide high fidelity, simple control and robustness against parasitic interactions in scalable architectures remains unclear. Here we experimentally realize a 65-ns native controlled-controlled-phase operation, locally equivalent to the Toffoli gate, with a fidelity of 99.39(5)% in a three-qubit processor unit based on fluxonium qubits coupled via a microwave-driven transmon coupler. The implemented operation would require CZ fidelities of approximately 99.94% if realized through a conventional decomposition. The gate is implemented with a single control pulse, that relies on a simple calibration procedure yielding coherence-limited performance. This processor unit naturally extends to scalable two-dimensional layouts with low parasitic interactions. Altogether, these results establish native multi-qubit gates as a viable hardware-efficient primitive for scalable superconducting quantum processors.

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