Complete hyperentangled Bell state analysis for polarization and time-bin hyperentanglement

TL;DR

This paper introduces a complete protocol for analyzing hyperentangled Bell states in polarization and time-bin degrees of freedom, enabling unambiguous state discrimination for advanced quantum communication.

Contribution

It presents the first complete hyperentangled Bell state analysis scheme for polarization and time-bin entanglement, improving resource efficiency and potential for long-distance quantum communication.

Findings

Unambiguous discrimination of 16 hyperentangled states achieved

Polarization state distinguished deterministically with cross-Kerr nonlinearity

Protocol applicable to high-capacity, long-distance quantum communication

Abstract

We present a complete hyperentangled Bell state analysis protocol for two-photon four-qubit states which are simultaneously entangled in the polarization and time-bin degrees of freedom. The 16 hyperentangled states can be unambiguously distinguished via two steps. In the first step, the polarization entangled state is distinguished deterministically and nondestructively with the help of the cross-Kerr nonlinearity. Then, in the second step, the time-bin state is analyzed with the aid of the polarization entanglement. We also discuss the applications of our protocol for quantum information processing. Compared with hyperentanglement in polarization and spatial-mode degrees of freedom, the polarization and time-bin hyperentangled states provide saving in quantum resources since there is no requirement for two spatial modes for each photon. This is the first complete hyperentangled Bell state analysis scheme for polarization and time-bin hyperentangled states, and it can provide new avenues for high-capacity, long-distance quantum communication.