Robust-fidelity hyperparallel controlled-phase-flip gate through microcavities

Hyperparallel quantum information processing outperforms its traditional parallel one in terms of channel capacity, low loss rate, and processing speed. We present a way for implementing a robust hyper-parallel optical controlled-phase-flip gate through microcavities. The gate acts on polarization and spatial degrees of freedom (DOFs) simultaneously, and the incomplete and undesired interactions between photons and quantum dots are prevented. Interestingly, the unity fidelity of the gate can be achieved in principle, and the success of the gate is heralded by the single-photon detectors.