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Pound-Drever-Hall Method for Superconducting-Qubit Readout
Ibukunoluwa Adisa1,2, Won Chan Lee1,2, Kevin C Cox1,3
1University of Maryland, Department of Physics, College Park, Maryland 20742, USA.
Physical Review Letters
|June 26, 2026
Summary
We developed a stable superconducting qubit readout method using the Pound-Drever-Hall (PDH) technique. This method achieves high phase stability and enables accurate single-shot qubit readout, crucial for scaling quantum computers.
Area of Science:
- Quantum Computing
- Superconducting Circuits
- Quantum Measurement
Background:
- Scaling quantum computers necessitates efficient parallel qubit readout.
- Existing readout methods face challenges with stability and phase drift.
Purpose of the Study:
- To present an ultrastable superconducting-qubit readout method.
- To benchmark the Pound-Drever-Hall (PDH) technique for transmon qubit readout.
Main Methods:
- Utilized the multitone self-phase-referenced Pound-Drever-Hall (PDH) technique.
- Employed room-temperature heterodyne detection for signal reconstruction.
- Benchmarked PDH readout on a single transmon qubit.
Main Results:
- Demonstrated high phase stability (0.73° over 2 hours), showing insensitivity to microwave phase drift.
- Achieved single-shot readout even with phase errors exceeding qubit-induced shifts.
- Confirmed no unwanted measurement-induced state transitions, with potential signal enhancement of at least 14 dB.
Conclusions:
- The PDH technique offers an ultrastable and robust method for superconducting qubit readout.
- This method is suitable for large-scale quantum computing architectures requiring precise parallel readouts.
- The demonstrated stability and accuracy pave the way for improved quantum information processing.
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