Juan S. Rojas-Arias, Akito Noiri, J. Yoneda, Peter Stano, Takashi Nakajima, Kenta Takeda, T. Kobayashi, Giordano Scappucci, Seigo Tarucha, Daniel Loss
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.