Characterizing a two-level fluctuator through the Allan Variance

Gate-defined silicon single-electron devices are of interest for quantum technologies, however these devices face barriers relating to noise. To address these barriers, one needs to better understand the sources of noise. Recently, a tool from frequency metrology called the Allan Variance has gained some use as a potential way to characterize noise in quantum electronics. For example, it can provide information on the type of noise that dominates at different timescales. In this work, we apply the Allan variance to measurements of a charge sensing dot coupled to a donor atom. Specifically, we tune the device near the donor ionization point so it acts as a two-level fluctuator (TLF) with tunable tunnel rates. We use this well controlled system as a way to validate how the Allan variance can reveal characteristics of TLFs, a common source of noise.