Quantum physics: Unconnected node teleportation a step towards quantum internet

The teleportation of quantum information between two non-neighbouring nodes in a three-node quantum network is demonstrated in a paper published in Nature this week. This achievement is an important step towards creating a quantum internet.

Quantum teleportation can transfer quantum information from one location to another, and has potential applications in secure communications, quantum computing and the development of next-generation internet. Experimental demonstrations of this effect reported to date have been between two connected nodes. Teleportation between non-connected nodes will be critical for the development of a quantum network, such as a quantum internet.

The quantum network operated by Sophie Hermans, Ronald Hanson and colleagues involves three nodes called Alice, Bob and Charlie connected by optical fibres in a line, with direct links between Alice and Bob and between Bob and Charlie, but not between Alice and Charlie. Teleportation first requires sharing of entangled quantum states between the neighbouring nodes. A quantum swapping operation at the middle node Bob then creates entanglement between Alice and Charlie, enabling the direct teleportation of quantum information between them. Realising every step of the protocol while preserving the delicate quantum information required improvement in the preparation, manipulation and readout of the quantum states.

The sharing of information between non-connected nodes demonstrated here may represent a step towards building a quantum network that communicates via the teleportation of quantum information, the authors propose. However, potential ubiquitous teleportation around a quantum network remains some way away, suggest Oliver Slattery and Yong-Su Kim in an accompanying News & Views article. Further improvements to multiple features of the system will be needed to enable multiple rounds of teleportation and to produce large-scale quantum networks, the authors conclude.