Source of Heralded Atom-Photon Entanglement for Quantum Networking

Area of Science:

• Quantum Information Science
• Quantum Communication
• Atomic Physics

Background:

• Photon loss is a major challenge in quantum networks, limiting communication distance and fidelity.
• Current error mitigation strategies using measurement-only heralds are slow and susceptible to false positives.

Purpose of the Study:

• To implement a novel entanglement herald at the sending node to improve quantum communication.
• To enhance the efficiency and fidelity of atom-photon entanglement in quantum networks.

Main Methods:

• Utilized a single atom undergoing cascaded two-photon emission into two optical fiber cavities.
• Generated entanglement between photon polarization and atomic spin, with the second photon acting as a herald.
• Implemented the entanglement herald at the source to mitigate errors before transmission.

Main Results:

• Achieved a 68(3)% in-fiber efficiency for atom-photon entanglement.
• Demonstrated an 87(2)% fidelity for the generated atom-photon entanglement.
• Showcased the potential for improved long-distance quantum communication by extending range or increasing fidelity.

Conclusions:

• The developed entanglement herald significantly improves atom-photon entanglement efficiency and fidelity.
• This source shows promise for robust, long-distance quantum communication in noisy environments.
• The sending-node herald approach offers a viable solution to overcome photon loss limitations in quantum networks.