Noise correlations in an atom-based quantum dot array
M. B. Donnelly, J. Rowlands, Ludwik Kranz +9 more
Correlated noise across multiqubit architectures is known to be highly detrimental to the operation of error-correcting codes and the long-term feasibility of quantum processors. The recent discovery of spatially dependent correlated noise in multiqubit architectures of superconducting qubits arising from the impact of cosmic radiation and high-energy particles giving rise to quasiparticle poisoning within the substrate has led to intense investigations of mitigation strategies to address this. Correlated noise in semiconductor spin qubits is also now receiving attention, as this platform begins to scale. Here we report the magnitude, frequency, and spatial dependence of noise correlations between four silicon quantum dot pairs as a function of interdot distance at frequencies from 0.3 to 1 mHz. We find the magnitude of charge-noise correlations, quantified by the magnitude square coherence C x y , are significantly suppressed from > 0.5 to < 0.1 as the interdot distance increases from 75 to 300 nm. Using an analytical model we confirm that, in contrast to superconducting qubits, the dominant source of correlated noise arises from low-frequency charge noise from the presence of two level fluctuators (TLFs) at the native silicon-silicon dioxide surface. Knowing this, we conclude with a timely discussion of charge-noise mitigation strategies.
arXiv:2405.03763•Physical Review Applied•May 12, 2025•7 citations