Near-perfect quantum teleportation between continuous and discrete encodings

Abstract

Quantum teleportation between polarized single-photon and phase-opposite coherent states is studied using a hybrid entangled resource and entangled coherent states. The polarized single-photon qubit represents a discrete-variable (DV) quantum system, whereas the phase-opposite coherent-state qubit constitutes a continuous-variable (CV) system. While teleportation from CV to DV can be achieved with near-unit success probability, the reverse process is usually limited to a maximum success probability of $1/2$. We demonstrate that, by employing cross-Kerr nonlinearity together with passive linear optical components such as polarizing beam splitters, beam splitters, and phase shifters, almost perfect teleportation from DV to CV encodings can also be achieved.

Figures (2)

• Figure 1: Schematic of the proposed scheme for quantum teleportation from DV to CV quantum system. $|E\rangle_{1,2}$ is the shared entangled resource where mode 1 is with Alice and mode 2 is sent to Bob. Alice initially has DV information state in mode 0 which she passes through a polarizing beam splitter (PBS-I) to become mode 3. Modes 1 and 3 is passed through a cross Kerr medium (CKM) to give output modes 6 and 5. Alice then passes modes 4 and 5 through another PBS-II that outputs modes 7 and 8. VNM is performed on mode 7 while mode 6 is either $|\alpha\rangle$ or $|-\alpha\rangle$ which is further discriminated by the combination of a symmetric beam splitter (BS) and two photon counting detectors D-I and D-II.
• Figure 2: Variation of average fidelity over information parameters $a$ and $b$ of teleportation for DV to CV encodings. The fidelity increase monotonically and sharply to approach unity asymptotically for appreciable large coherent amplitude.