cross-posted from: https://rss.ponder.cat/post/16876
What exactly are they trying to accomplish? The article talks about sending entangled photons down a fiber optic… but that just sounds like ordinary fiber with extra steps.
Quantum networks allow you to transmit quantum states between physically separated quantum processors.
And what’re you going to quantum do to quantum stop me? Quantum suck it, nerd.
I’m guessing for quantum cryptography. It would allow you to have perfect crypto (assuming the non quantum hardware isn’t hacked (a big if)).
You can have post-quantum cryptography using classical computation, though
(“Simply” pick a problem with no quantum acceleration. I think Elliptic Curves Cryptography works, but I’m not an expert)
Quantum crypto is different than cracking encryption with a quantum computer. The point of quantum crypto is that the key exchange is perfectly secret. If it is observed, the people exchanging keys will know due to entanglement bs that I’m too dumb to understand.
But you basically get the perfect uncrackable encryption of one time pads without having to manage one time pads.
You can break elliptic curve cryptography with quantum computers. Post-quantum cryptography is instead based on something called the lattice problem, sometimes called lattice-based cryptography.
Sabine Hossenfelder has a PhD in Physics and gives some good information about what quantum internet is, and what it is not: https://www.youtube.com/watch?v=u-j8nGvYMA8
Basically, this is not a means of transferring data faster than the speed of light.
It does allow for an ultra secure connection, but that connection is so fragile and susceptible to noise that this would not be useful for transferring any large amounts of data.
Most likely this would be used for exchanging keys/tokens which could then be used with a more reliable connection for transmitting larger amounts of data.
Personally, I think there is a much bigger issue with the quantum internet that is often not discussed and it’s not just noise.
Imagine, for example, I were to offer you two algorithms. One can encrypt things so well that it would take a hundred trillion years for even a superadvanced quantum computer to break the encryption, and it almost has no overhead. The other is truly unbreakable even in an infinite amount of time, but it has a huge amount of overhead to the point that it will cut your bandwidth in half.
Which would you pick?
In practice, there is no difference between an algorithm that cannot be broken for trillions of years, and an algorithm that cannot be broken at all. But, in practice, cutting your internet bandwidth in half is a massive downside. The tradeoff just isn’t worth it.
All quantum “internet” algorithms suffer from this problem. There is always some massive practical tradeoff for a purely theoretical benefit. Even if we make it perfectly noise-free and entirely solve the noise problem, there would still be no practical reason at all to adopt the quantum internet.
