36 Multi-Node Quantum Network

For taking another step closer to an unhackable internet

Governments and scientists have been dreaming of it for decades: a large-scale quantum internet that would open the aperture on a range of applications, like unhackable communications, cloud computing with complete privacy and warp-speed computations. And that’s just the stuff they’ve thought of.

Researchers had previously only been able to connect two quantum processors that shared a direct physical link. But a truly scalable quantum network must be able to relay quantum information through intermediate nodes, like to routers in the regular old internet. Then in April, a team at Dutch research center QuTech—a collaboration between Delft University of Technology and TNO—made the jump: Using a complex system of mirrors and laser light, it created a rudimentary quantum network by connecting three independent nodes (named Alice, Bob and Charlie) across 10 to 20 meters (32 to 66 feet).

The QuTech team wasted little time on celebration. It’s now at work on a project to make a link between greater distances: connecting Delft and The Hague, about 10 kilometers (6 miles) apart. Researchers are also working on adding more quantum bits to their network and eventually making it more accessible.

"Once all the high-level control and interface layers for running the network have been developed, anybody will be able to write and run a network application without needing to understand how lasers and cryostats work," says Matteo Pompili, PhD student and a member of the research team. "That is the end goal."

Quantum Basics
While conventional computers store and process data as a series of 0s and 1s, a future quantum internet will make use of quantum bits that can be 0 and 1 at the same time.