Teleportation of a ququart system using hyperentangled photons assisted by atomic-ensemble memories

Abstract

A single photon encoded in both the spin and the orbital angular momentum has recently been experimentally demonstrated [X.-L. Wang et al., Nature 518, 516 (2015)] with linear optics using the hyperentangled state, which can be viewed as a bipartite four-dimensional (ququart) entanglement. Here, we investigate this process from a general point of view. By exploring a controlled phase flip induced by atomic ensembles in one-side optical microcavities, we propose teleportations of general ququart systems including a two-atomic-ensemble system, a two-polarized-photon system, one photon with the polarization and spatial degrees of freedom (DOFs), and a hybrid photon-ensemble system using two hyperentangled photons. The output information may also be encoded by different physical systems up to the special requirements of a receiver. These schemes are also adapted to teleportation of a ququart system with only phases or real probability amplitudes, which is beyond previous superdense teleportation [Nature Commun. 6, 7185 (2015)]. With these restrictions, half of the classical communication cost may be saved and experimental complexities are also reduced. Our theoretical schemes are feasible in modern physics and show the possibilities of transferring complex quantum systems for scalable quantum applications.