A rudimentary quantum network link between Dutch cities

Hi all! I'm one of the co-authors. Honestly it's a dream to end up on HN with my research. As mentioned in the video we made, it has been a long road (6-7 years) to achieve this absolute moonshot of a project. I think we'll look back on this demonstration as the first experiment that truly made a distributed and real-world deployed quantum network. Not only did we use a (quantum) hardware platform capable of quantum processing, we also generated the entanglement in a way that it can be used in further quantum computations. In order for all this to work on a distributed network, we had to fully design and build the architecture to support that, both hard- and software. And we did it successfully!

Besides hard-working PhD students, another key ingredient that our research institute QuTech facilitated, was the collaboration with expert hardware and software engineers, allowing us to quickly transform new ideas into (deployable) products. A great show of what's possible when academia mixes with professional engineering. But of course there was enough hacking and tinkering going on that it warrants to be on HN ;)

You can reply here if you have any questions, I'll be checking throughout the day. Thanks!

I've worked in quantum nonlinear optics during my first postdoc 12 years ago, and back then we could only dream of the efficiency of frequency conversions that are used here. So many advances in just a decade, and most of them don't even make the news.

the article: https://www.science.org/doi/10.1126/sciadv.adp6442

> “The distance over which we create quantum entanglement in this project, via 25 km of deployed underground fiber, is a record for quantum processors,” says Hanson. “This is the first time such quantum processors in different cities are connected.”

I know very little about quantum networking. I assume you are going beyond what they did here? How so? [1]

> Recently, as a sort of proof of potential and a first step toward functional quantum networks, a team of researchers with the Illinois‐Express Quantum Network (IEQNET) successfully deployed a long-distance quantum network between two U.S. Department of Energy (DOE) laboratories using local fiber optics.

> The experiment marked the first time that quantum-encoded photons — the particle through which quantum information is delivered — and classical signals were simultaneously delivered across a metropolitan-scale distance with an unprecedented level of synchronization.

> “To have two national labs that are 50 kilometers apart, working on quantum networks with this shared range of technical capability and expertise, is not a trivial thing,” said Panagiotis Spentzouris, head of the Quantum Science Program at Fermilab and lead researcher on the project. “You need a diverse team to attack this very difficult and complex problem.”

[1] https://www.anl.gov/article/quantum-network-between-two-nati...

What is actually the usecase for "quantum internet"?

Like at most i hear about quantum key distribution, but quite frankly the classical equivalents to that are just as good if not better, so what is the actual benefit?

To disperse some of the hype here around using this for "uncrackable" key exchange: QKD has been a product of choice for cybersecurity conmen for decades.

https://www.nsa.gov/Cybersecurity/Quantum-Key-Distribution-Q...

https://www.ncsc.gov.uk/whitepaper/quantum-security-technolo...

https://en.wikipedia.org/wiki/Snake_oil_(cryptography)

Stick with TLS. If you really think quantum computers are a threat to anything, use a hybrid-PQC key exchange.

My honest professional opinion is a cryptographically-relevant quantum computer will never exist, making classic cryptography superior in every case.

Good job!

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Did you hear a cat just now?