Tunable Coupling Architecture for Fixed-Frequency Transmon Superconducting Qubits

J. Stehlik, D. M. Zajac, Devin Underwood, Timothy Phung, J. M. Blair, Santino D. Carnevale, D. Klaus, George Keefe, April Carniol, Muir Kumph

Abstract

Implementation of high-fidelity two-qubit operations is a key ingredient for scalable quantum error correction. In superconducting qubit architectures tunable buses have been explored as a means to higher fidelity gates. However, these buses introduce new pathways for leakage. Here we present a modified tunable bus architecture appropriate for fixed-frequency qubits in which the adiabaticity restrictions on gate speed are reduced. We characterize this coupler on a range of two-qubit devices achieving a maximum gate fidelity of $99.85\%$. We further show the calibration is stable over one day.

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• Physical Review Letters - View - PDF
• arXiv (Cornell University) - View - PDF
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