Remotely Establishing Polarization Entanglement over Noisy Polarization Channels

TL;DR

This paper demonstrates a method to reliably distribute and transfer entanglement between different degrees of freedom of photons over noisy channels, achieving high fidelity and robustness for quantum networks.

Contribution

The authors experimentally implement a deterministic entanglement purification protocol that transfers energy-time entanglement to polarization entanglement over noisy channels.

Findings

Achieved polarization entanglement fidelities up to 97.6%.

Enabled noise-resilient entanglement distribution for quantum networks.

Successfully transferred entanglement from energy-time to polarization DOF.

Abstract

The faithful distribution of entanglement over noisy channels is a vital prerequisite for many quantum technological applications. Quantum information can be encoded in different degrees of freedom (DOF) of photons, where each encoding comes with its own advantages and disadvantages with respect to noise resilience and practicality in manipulation. In this work, we experimentally implement a deterministic entanglement purification protocol that allows us to faithfully distribute entanglement in one DOF over a noisy channel and then remotely transfer it to another DOF for manipulation. In particular, we distribute robust energy-time entanglement and transfer it to polarization entanglement at the communicating parties. The remotely obtained polarization state is independent of the polarization noise during distribution and reaches fidelities to a Bell state of up to 97.6%. Our scheme enables robust and efficient polarization entanglement distribution in the presence of arbitrary polarization noise, which is relevant for future large-scale quantum networks.