Qubit read-out in Semiconductor quantum processors: challenges and perspectives

We report the efforts, challenges and perspectives dedicated towards building a reliable spin read-out for Si spin qubit systems. We review several strategies that are pursued in the semiconductor quantum circuit community. We discuss their pros and cons with respect to their performance (speed and fidelity), their integration potential and their footprint. We then address the envisioned architecture to read-out spin qubits at large scale.