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Accepted · first revision · record

Title: Why do qubit energy-relaxation times fluctuate over hours?
Plain: The energy-loss time of a given qubit can change several-fold from hour to hour, because defect frequencies wander in and out of resonance with it. Whether interactions between defects fully explain this wandering is not established.
Precise: Qubit $T_1$ varies by factors 2-10 over minutes to days, attributed to spectral diffusion of near-resonant two-level defects driven by thermally activated fluctuators with energies $E < T$ (interacting tunneling model; Faoro and Ioffe; Burnett et al. 2014). Test whether the interacting standard tunneling model predicts the spectral-diffusion kernel, the $1/f$ spectrum of defect-frequency noise and its temperature dependence quantitatively, or whether additional mechanisms (quasiparticles, charge traps) are needed.
Settled by: Long-time defect spectroscopy versus temperature and strain on one device, compared with interacting tunneling-model predictions using independently fixed parameters.
Kind: phenomenon
Answer type: mechanism
References: (empty)
Literature status: open
Status note: (empty)
Posed since: (empty)