Towards Conditional Quantum Phase Gates Based on Strongly-Coupled Charged Quantum Dot-Micropillar Cavities

The realization of quantum-photonic networks is a key challenge for optical quantum technologies. To scale such networks to many nodes and long distances, an efficient interface between stationary and flying qubits is necessary. One of the front-runners towards this goal is a spin-photon interface realised with a single charged QD with a localized electron spin that is strongly coupled to a micropillar cavity [1] . Through the strong spin-photon coupling, the polarization state of the optical field is controlled by the QD spin, thus modulating the cavity’s transmission properties. Controlling the polarization state over a wide angle is particularly useful for realizing high-fidelity polarization states and conditional phase quantum gates (e.g. CNOT) for photon-based quantum computing.