The Path to the Silicon Qubit Microchip: Tools and progress to advance exchange-only Si/SiGe quantum dot arrays

Key proofs of principle have now decisively demonstrated that Si/SiGe qubits can be reliably fabricated into extensible two-dimensional arrays and operated with the same fidelity as few-dot devices. However, many obstacles stand in the path to reliable scaling. How can scaled arrays be reliably and rapidly probed, at their target temperature, to check viability? How can they be calibrated in a reasonable amount of time? How can they be controlled without excessive heat from room temperature controllers? Are all the control ingredients --- not just the quantum dots themselves --- but their measurement needs, operational environment (magnetic field, temperature, etc.), and software/firmware reliability consistent with such scaling? In this talk I will discuss approaches developed by HRL Laboratories to answer these and other questions, landing at the conclusion that systems using Si/SiGe exchange-only qubits have a path to scale to millions-of-qubits-per-microchip. This path depends on the spin qubit community continuing to pursue these scaling challenges alongside qubit fabrication and fidelity advances. As such, I will discuss ongoing ways the community can share devices, software, and hardware to accelerate viable paths to scaling.