Complete hyperentangled Bell states analysis for polarization-spatial-time-bin degrees of freedom with unity fidelity

TL;DR

This paper presents a simplified, high-fidelity method for complete hyperentangled Bell state analysis across multiple degrees of freedom without auxiliary resources, enhancing quantum information processing capabilities.

Contribution

The scheme achieves complete Bell state analysis in polarization, spatial, and time-bin DOFs with unity fidelity, avoiding strong coupling and auxiliary photons.

Findings

Unity fidelity in Bell state analysis is theoretically achievable.

The scheme requires fewer linear optical elements than previous methods.

No auxiliary photons or DOFs are needed for complete analysis.

Abstract

Hyperentangled states can outperform their classical counterparts on solving certain tasks. Here we present a simplified scheme for completely distinguishing two-photon hyperentangled Bell states in polarization, spatial, and time-bin degrees of freedom (DOFs). Unity fidelity can be achieved in principle without strong couple limitation between photon and quantum dot (QD), and the incomplete and imperfect QD-cavity interactions are prevented by single-photon detectors. In addition, auxiliary photons or DOFs are not required in our scheme. The necessary linear optical elements are fewer than the parity-check-based one.