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arXiv · 2402.10438

Broadband spectroscopy of quantum noise

Yuanlong Wang·Gerardo A. Paz-Silva
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Abstract

Characterizing noise is key to the optimal control of the quantum system it affects. Using a single-qubit probe and appropriate sequences of $\pi$ and non-$\pi$ pulses, we show how one can characterize the noise a quantum bath generates across a wide range of frequencies -- including frequencies below the limit set by the probe's $\mathbb{T}_2$ time. To do so we leverage an exact expression for the dynamics of the probe in the presence of non-$\pi$ pulses, and a general inequality between the symmetric (classical) and anti-symmetric (quantum) components of the noise spectrum generated by a Gaussian bath. Simulation demonstrates the effectiveness of our method.

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Yuanlong Wang, Gerardo A. Paz-Silva. 2024-02-16. Broadband spectroscopy of quantum noise. https://arxiv.org/abs/2402.10438

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