Hybridizing Spin, Charge and Photon on a Quantum Chip

As we witness the transition of quantum information science from the singular objective of quantum supremacy to the eclectic world of NISQ algorithms, the metrics for success have become rapidly more complex. The simultaneous need for long coherence times, fast gates, accurate readout and high connectivity has both highlighted the respective advantages of various quantum hardwares and accentuated their shortcomings. Hybrid device developments, where technologies across different qubit incarnations are combined to compensate for their inherent physical limitations, have enjoyed much success in recent years. In this lecture, I will review one such example where the technique of circuit quantum electrodynamics (cQED) was successfully grafted from superconducting qubits to semiconductor quantum-dot spin qubits. We will cover the physics and technical developments that have led to the first observations of strong-coupling between a single electron charge in gate-defined quantum dots and a microwave photon [1] and strong-coupling between a single electron spin and a single photon [2]. As time permits, applications of the hybrid device to valley physics in silicon will also be covered [3, 4].

[1] X. Mi et al., Science 355, 156 (2017).
[2] X. Mi et al., Nature 555, 599 (2018).
[3] X. Mi et al., PRL 119, 176803 (2017).
[4] X. Mi et al., PRB 98, 161404(R) (2018).