Efficient Qubit Calibration by Binary-Search Hamiltonian Tracking

• URL: http://arxiv.org/abs/2501.05386v1
• Date: Thu, 09 Jan 2025 17:18:38 GMT
• Title: Efficient Qubit Calibration by Binary-Search Hamiltonian Tracking
• Authors: Fabrizio Berritta, Jacob Benestad, Lukas Pahl, Melvin Mathews, Jan A. Krzywda, Réouven Assouly, Youngkyu Sung, David K. Kim, Bethany M. Niedzielski, Kyle Serniak, Mollie E. Schwartz, Jonilyn L. Yoder, Anasua Chatterjee, Jeffrey A. Grover, Jeroen Danon, William D. Oliver, Ferdinand Kuemmeth,
• Abstract summary: We present a real-time method for calibrating the frequency of a resonantly driven qubit. A controller dynamically computes adaptive probing sequences for qubit-frequency estimation. We show the algorithm's efficacy by stabilizing a flux-tunable transmon qubit.
• Score: 20.90972493374798
• License:
• Abstract: We present a real-time method for calibrating the frequency of a resonantly driven qubit. The real-time processing capabilities of a controller dynamically compute adaptive probing sequences for qubit-frequency estimation. Each probing time and drive frequency are calculated to divide the prior probability distribution into two branches, following a locally optimal strategy that mimics a conventional binary search. We show the algorithm's efficacy by stabilizing a flux-tunable transmon qubit, leading to improved coherence and gate fidelity. By feeding forward the updated qubit frequency, the FPGA-powered control electronics also mitigates non-Markovian noise in the system, which is detrimental to quantum error correction. Our protocol highlights the importance of feedback in improving the calibration and stability of qubits subject to drift and can be readily applied to other qubit platforms.

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