Researchers in the Netherlands have successfully connected three separate quantum processors in what is effectively the world's first multi-node quantum network. This paves the way for the large-scale quantum internet that governments and scientists have dreamed of for decades.
QuTech, a quantum research institute based in Delft, has published new work in which three nodes that can store and process quantum bits called qubits are linked, and according to QuTech researchers, this is the world's first primitive quantum network.
Connecting quantum devices is not new, as many researchers around the world are currently working on similar networks, but so far they have only succeeded in connecting two quantum processors.
Accordingly, establishing a multi-node connection is an essential step towards greatly expanding the network size. Much of the research effort aims to create a quantum internet that could someday extend across the planet's surface. The quantum internet exploits the laws of quantum mechanics to allow quantum devices to communicate with each other.
The quantum internet is expected to enable a host of applications that cannot be operated by current classical means, such as impenetrable communications. The quantum internet can connect small quantum machines together to create a large quantum group with more computing power than more sophisticated classical supercomputers.
Entanglement is one of the main quantum properties that underpin the quantum internet, a phenomenon that occurs when two quantum particles are coupled in such a way that they are essentially interconnected, regardless of their physical distance from each other.
When two quantum particles are entangled, their properties become linked, which means that any change in one particle is inevitably reflected in the other. In quantum communication, this means that scientists can use entangled particles to simultaneously transfer information from the first qubit to the second paired qubit, even if the two are in separate quantum devices.
The QuTech research team is developing a system based on intermediate nodes, similar to current Internet routers, that can maintain entanglement over greater distances. The QuTech team also developed the first quantum network protocol, with an indication that each process has been successfully completed. The new network provides a test platform for developing new quantum internet hardware, software, and protocols, but the experiment must also evolve from a proof-of-concept to a practical solution for scaling up quantum networks.
The future quantum internet consists of a myriad of quantum devices and intermediate nodes. QuTech research is supported by the European Union's Quantum Internet Alliance, but the European Union is not alone. China and the United States are equally interested in developing quantum networks, and they have achieved milestones in this field.