Quantum Information Transmission via Classical Network Technology

In a significant stride towards the development of a quantum internet, a team from the University of Pennsylvania has successfully transmitted quantum information over classical internet protocols, routers, and fiber optic cables. This groundbreaking achievement, published in the journal Science, could pave the way for a future quantum internet that leverages existing network technology.

The team, led by Yichi Zhang, combined classical and quantum-based data into a hybrid data packet. To ensure the quantum information remained intact during the five-hour test, an error detection system was integrated into the IP header to identify and mitigate external disturbances before they affected the quantum information. Remarkably, the hybrid data packets were routed correctly without accessing the sensitive quantum information.

This demonstration follows a similar experiment led by the University of Geneva, where classical internet protocols, routers, and fiber optic cables were used for the transmission of quantum mechanical information. The experiment showcased the potential of using existing infrastructure for quantum communication.

Hannes Bernien, a quantum researcher at the University of Innsbruck, believes that a quantum internet protocol will resemble classical internet protocols in many ways. However, he emphasises that a quantum network will always require its own infrastructure due to incompatibility with classical network components. He further highlights that the networking of quantum computers or quantum sensors is what makes a quantum internet truly interesting.

Several studies have already shown that conventional fiber optic cables can transmit quantum information. A team from England, Poland, and the Netherlands established quantum communication over a 250-kilometer commercial fiber optic cable, while quantum networks that transmit information securely are commercially available over distances up to about 100 kilometers.

The potential benefits of a quantum internet are vast. A quantum internet could potentially address key challenges in communication and data processing in the future, offering secure data transmission and the interconnection of quantum computers. It could also enable cloud computing by connecting many small quantum computers using a quantum network.

As we move closer to realising a quantum internet, researchers are focusing on developing more efficient and scalable hybrid networks. The team from Pennsylvania sees their work as a foundation for further developments in hybrid networks with higher data rates and greater scalability.

In the largest setup, the team from Pennsylvania routed quantum information from two possible source addresses through two routers to three possible destination addresses. This demonstration suggests that future quantum internet could potentially leverage existing network technology, bringing us one step closer to a secure, interconnected quantum world.