Universal Characterization of Classical Qubit Noise

• URL: http://arxiv.org/abs/2604.25705v1
• Date: Tue, 28 Apr 2026 14:33:10 GMT
• Title: Universal Characterization of Classical Qubit Noise
• Abstract summary: We propose a general method to fully characterize a classical noise process causing qubit dephasing on the qubit.<n>Compared to filter-function-based spectroscopy, our method does not require complicated dynamical decoupling pulses.<n>We numerically demonstrate this method for characterizing two typical examples of classical noises, including the Ornstein-Uhlenbeck processes producing Gaussian noises and an ensemble of TLFs producing non-Gaussian noises.
• Score: 0.10923877073891443
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We propose a general method to fully characterize a classical stochastic noise process causing qubit dephasing through repetitive Ramsey interferometry measurements (RIMs) on the qubit. Compared to filter-function-based spectroscopy, our method does not require complicated dynamical decoupling pulses and can directly detect arbitrary-order correlation functions of such noise processes. We show that each RIM with a short evolution time and suitably chosen control pulses can perform a direct sampling of the noise field and the $n$-point correlations of the RIM outcomes are proportional to the $n$-point correlation functions of the noise processes. Then we numerically demonstrate this method for characterizing two typical examples of classical noises, including the Ornstein-Uhlenbeck processes producing Gaussian noises and an ensemble of TLFs producing non-Gaussian noises. Our method is independent of qubit lifetime and robust against qubit decoherence and measurement errors, thus offering a universal and efficient protocol for qubit noise spectroscopy across diverse platforms.

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