A Quantum Leap Forward in Quantum Networking

Headlines trumpeting the advances being made in quantum computing may be largely getting buried underneath mountains of updates coming from the world of artificial intelligence these days, but that has by no means slowed progress in the field. We seem to be racing toward a future where computing will be fundamentally different — and fundamentally weird. I mean, if Einstein — a guy who was so smart that some people legitimately believe he was an alien — called key aspects of quantum phenomena “spooky,” you know it is really out there.

It is not just the computing devices themselves that will be radically different when the quantum era arrives, but all of the supporting infrastructure as well, which tends to get far less attention. But a team of researchers at Penn State has focused on a technology that will be crucial in the world of tomorrow — quantum networking. Quantum computers may be very powerful, but they will be very limited if they cannot be linked together in a network like today’s internet.

Our fastest and highest capacity digital network links are presently optical, transmitting data via light waves that race through fiber optic cables. These signals are read at various points along their journey through the network, and that information is used to route them to their destination. But when it comes to quantum data, reading it is a big no-no. Quantum information is just plain weird, and the mere act of examining it alters its state, forever corrupting it. Well that certainly complicates things, doesn’t it?

Fortunately the team came up with a clever solution that not only routes quantum data without corrupting it, but also leverages existing fiber optic networking hardware and internet protocols. The trick involves sandwiching the quantum information between packets of traditional light-based data. The traditional information leads the way and, naturally, can be read without altering it. This information is used to route the quantum data that trails it without ever needing to peek at it.

At present, this approach is being used with success on a private fiber network at the university. The researchers believe that scaling their system for use in a metropolitan area would present few challenges, but beyond that, it would break down. The same issues quantum data has with routing also rear their ugly head when it comes to signal amplification. Without amplification, a signal eventually becomes too weak to be of use. However, we cannot amplify a signal without first reading it, and this new technology cannot address that problem.

This work addresses one significant problem in the field, but quantum computing is still in the embryonic stages and there is much more work to be done. It will likely still be quite a long time before anyone has a practical quantum computer sitting on their desktop.