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arXiv · 2512.03138

The Pound-Drever-Hall Method for Superconducting-Qubit Readout

Ibukunoluwa Adisa·Won Chan Lee·Kevin C. Cox·Alicia J. Kollár
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Abstract

Scaling quantum computers to large sizes requires the implementation of many parallel qubit readouts. Here we present an ultrastable superconducting-qubit readout method using the multi-tone self-phase-referenced Pound-Drever-Hall (PDH) technique, originally developed for use with optical cavities. In this work, we benchmark PDH readout of a single transmon qubit, using room-temperature heterodyne detection of all tones to reconstruct the PDH signal. We demonstrate that PDH qubit readout is insensitive to microwave phase drift, displaying $0.73^\circ$ phase stability over 2 hours, and capable of single-shot readout in the presence of phase errors exceeding the phase shift induced by the qubit state. We show that the PDH sideband tones do not cause unwanted measurement-induced state transitions for a transmon qubit, leading to a potential signal enhancement of at least $14$~dB.

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Ibukunoluwa Adisa, Won Chan Lee, Kevin C. Cox, Alicia J. Kollár. 2025-12-02. The Pound-Drever-Hall Method for Superconducting-Qubit Readout. https://doi.org/10.1103/ng1d-6gb8

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