Deterministic Preparation of a Hyper‐Entangled Three‐Photon Asymmetric W State Assisted by the Single‐Sided QD‐Cavity System

Abstract

Hyper‐entangled states that encode qubits in multiple degrees of freedom of a quantum system can provide a decisive advantage in quantum information processing, such as improving the capacity of communication and speeding up the computation. Assisted by quantum dots in single‐sided optical microcavities, nonlinear interaction of optical circular polarizations is induced and a deterministic scheme for preparing a three‐photon hyper‐entangled asymmetric W state with polarization degree of freedom and spatial degree of freedom is proposed. The preparing process is composed of three steps: the preparation of a three‐photon polarization entangled asymmetric W state; the preparation of a three‐photon spatial entangled asymmetric W state; the preparation of a three‐photon hyper‐entangled asymmetric W state. It can be generalized to generate a three‐photon general W state according to practical requirement.