Stabilizing an individual charge fluctuator in a Si/SiGe quantum dot

TL;DR

This paper introduces feedback control techniques to stabilize a charge fluctuator in a Si/SiGe quantum dot, significantly reducing charge noise and potentially enhancing qubit coherence times.

Contribution

The work presents a novel feedback-based method to control and stabilize individual charge fluctuators in semiconductor quantum dots, a new approach to mitigate charge noise.

Findings

Reduced low-frequency noise by an order of magnitude.

Successfully stabilized the fluctuator in either of its states.

Potential to improve qubit coherence times.

Abstract

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 by exploiting sensitive gate-voltage dependence of the switching times. 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.