Efficient two-photon polarization entanglement detection by Bell state analysis

TL;DR

This paper demonstrates that a Bell state analyzer using a beamsplitter offers an efficient way to detect two-photon polarization entanglement in a single basis, simplifying the measurement process compared to traditional methods.

Contribution

It introduces the use of a Bell state analyzer for efficient entanglement detection and compares its performance with optimal witnesses using Bayesian mean estimation.

Findings

Bell state analyzer enables efficient entanglement detection in a single basis

Comparison shows the analyzer's effectiveness is comparable to multi-basis methods

Bayesian estimation quantifies the efficiency of different entanglement witnesses

Abstract

We emphasize the Bell state analyzer, a beamsplitter, as an efficient means of detecting two-photon polarization entanglement. Whereas the optimal entanglement witness for spatially separated photons requires coordinated measurement in three bases, the local Bell state analyzer enables an efficient entanglement witness in a single polarization basis. We use Bayesian mean estimation to compare the efficiency of these two witnesses. We report the method and results of this comparison.