The Floquet Fluxonium Molecule: Driving Down Dephasing in Coupled Superconducting Qubits

• URL: http://arxiv.org/abs/2401.08762v3
• Date: Thu, 07 Nov 2024 16:26:12 GMT
• Title: The Floquet Fluxonium Molecule: Driving Down Dephasing in Coupled Superconducting Qubits
• Authors: Matthew Thibodeau, Angela Kou, Bryan K. Clark,
• Abstract summary: We propose a driven erasure qubit, the Floquet fluxonium molecule, which minimizes bit-flip rates through disjoint support of its qubit states and suppresses phase flips by a novel second-order insensitivity to flux-noise dephasing. We estimate the bit-flip, phase-flip, and erasure rates through numerical simulations, with predicted coherence times of approximately 50 ms in the computational subspace and erasure lifetimes of about 500 $mu$s.
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• Abstract: High-coherence qubits, which can store and manipulate quantum states for long times with low error rates, are necessary building blocks for quantum computers. Here we propose a driven superconducting erasure qubit, the Floquet fluxonium molecule, which minimizes bit-flip rates through disjoint support of its qubit states and suppresses phase flips by a novel second-order insensitivity to flux-noise dephasing. We estimate the bit-flip, phase-flip, and erasure rates through numerical simulations, with predicted coherence times of approximately 50 ms in the computational subspace and erasure lifetimes of about 500 $\mu$s. We also present a protocol for performing high-fidelity single-qubit rotation gates via additional flux modulation, on timescales of roughly 500 ns, and propose a scheme for erasure detection and logical readout. Our results demonstrate the utility of drives for building new qubits that can outperform their static counterparts.

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