Qubit Noise Spectroscopy of Superconducting Dynamics in a Magnetic Field

Fuente: arXiv
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Autori principali: Cheng, Jiajie, Kim, Jaewon, Diessel, Oriana K., Zu, Chong, Chatterjee, Shubhayu
Natura: Preprint
Pubblicazione: 2026
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author Cheng, Jiajie
Kim, Jaewon
Diessel, Oriana K.
Zu, Chong
Chatterjee, Shubhayu
author_facet Cheng, Jiajie
Kim, Jaewon
Diessel, Oriana K.
Zu, Chong
Chatterjee, Shubhayu
contents An applied magnetic field affects a superconductor in two ways -- by promoting pairing fluctuations, and by inducing topological defects called vortices that carry quantized magnetic flux. A quantitative characterization of the resultant field-induced superconducting dynamics with spatio-temporal resolution remains challenging, particularly in two-dimensional materials. In this work, we analyze magnetic noise measured by the depolarization rate of a proximate single spin qubit as a non-invasive probe of such dynamical fluctuations. We demonstrate that the temperature dependence of the magnetic noise spectrum near $T_c$ deviates from predictions based on quasiparticle excitations due to critical superconducting fluctuations, which in turn are enhanced by a weak applied field. By analyzing the magnetic noise due to vortex dynamics, we further show that noise spectroscopy is not only able to distinguish between different vortex phases, but also extract key physical quantities of interest, such as oscillation frequencies of pinned vortices, phonon dispersion of vortex lattices and vortex diffusivity in a vortex liquid. Complementing recent work on noise magnetometry of quasiparticle excitations and Berezinskii-Kosterlitz-Thouless transitions in two-dimensional superconductors without an applied field, our work highlights the ability of noise spectroscopy to reveal a wealth of superconducting dynamical phenomena in an applied field.
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id arxiv_https___arxiv_org_abs_2602_20265
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Qubit Noise Spectroscopy of Superconducting Dynamics in a Magnetic Field
Cheng, Jiajie
Kim, Jaewon
Diessel, Oriana K.
Zu, Chong
Chatterjee, Shubhayu
Superconductivity
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
An applied magnetic field affects a superconductor in two ways -- by promoting pairing fluctuations, and by inducing topological defects called vortices that carry quantized magnetic flux. A quantitative characterization of the resultant field-induced superconducting dynamics with spatio-temporal resolution remains challenging, particularly in two-dimensional materials. In this work, we analyze magnetic noise measured by the depolarization rate of a proximate single spin qubit as a non-invasive probe of such dynamical fluctuations. We demonstrate that the temperature dependence of the magnetic noise spectrum near $T_c$ deviates from predictions based on quasiparticle excitations due to critical superconducting fluctuations, which in turn are enhanced by a weak applied field. By analyzing the magnetic noise due to vortex dynamics, we further show that noise spectroscopy is not only able to distinguish between different vortex phases, but also extract key physical quantities of interest, such as oscillation frequencies of pinned vortices, phonon dispersion of vortex lattices and vortex diffusivity in a vortex liquid. Complementing recent work on noise magnetometry of quasiparticle excitations and Berezinskii-Kosterlitz-Thouless transitions in two-dimensional superconductors without an applied field, our work highlights the ability of noise spectroscopy to reveal a wealth of superconducting dynamical phenomena in an applied field.
title Qubit Noise Spectroscopy of Superconducting Dynamics in a Magnetic Field
topic Superconductivity
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2602.20265