  Charge noise is a major obstacle to improved gate fidelities in silicon spin
qubits. Numerous methods exist to mitigate charge noise, including improving
device fabrication, dynamical decoupling, and real-time parameter estimation.
In this work, we demonstrate a new class of techniques to mitigate charge noise
in semiconductor quantum dots by controlling the noise sources themselves.
Using two different classical feedback methods, we stabilize an individual
charged two-level fluctuator in a Si/SiGe quantum dot. These control methods
reduce the low-frequency component of the noise power spectrum by an order of
magnitude. These techniques also enable stabilizing the fluctuator in either of
its states. In the future, such techniques may enable improved coherence times
in quantum-dot spin qubits.
