Deterministic entanglement purification and complete nonlocal Bell-state analysis with hyperentanglement

TLDR

Entanglement purification is essential for long‑distance quantum communication. The authors propose a deterministic entanglement‑purification protocol that exploits hyperentanglement. The protocol deterministically purifies polarization‑entangled photon pairs using hyperentanglement and is applicable to practical transmission scenarios. The protocol yields maximally entangled pure states without destroying less‑entangled pairs, exponentially boosts communication efficiency, and enables perfect nonlocal Bell‑state analysis.

Abstract

Entanglement purification is a very important element for long-distance quantum communication. Different from all the existing entanglement purification protocols (EPPs) in which two parties can only obtain some quantum systems in a mixed entangled state with a higher fidelity probabilistically by consuming quantum resources exponentially, here we present a deterministic EPP with hyperentanglement. Using this protocol, the two parties can, in principle, obtain deterministically maximally entangled pure states in polarization without destroying any less-entangled photon pair, which will improve the efficiency of long-distance quantum communication exponentially. Meanwhile, it will be shown that this EPP can be used to complete nonlocal Bell-state analysis perfectly. We also discuss this EPP in a practical transmission.