We investigate low-frequency noise in a spin-qubit device made in isotopically purified Si/Si-Ge. Observing sizable cross-correlations among energy fluctuations of different qubits, we conclude that these fluctuations are dominated by charge noise. At low frequencies, the noise spectra are not well described by a power law; instead, they reveal the presence of a few individual two-level fluctuators (TLFs). We demonstrate that the noise cross-correlations allow one to get information on the spatial location of such individual TLFs.
@article{arxiv.2505.05875,
title = {Inferring charge-noise source locations from correlations in spin qubits},
author = {Juan S. Rojas-Arias and Akito Noiri and Jun Yoneda and Peter Stano and Takashi Nakajima and Kenta Takeda and Takashi Kobayashi and Giordano Scappucci and Seigo Tarucha and Daniel Loss},
journal= {arXiv preprint arXiv:2505.05875},
year = {2026}
}