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A rudimentary quantum network link between Dutch cities

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Re: A rudimentary quantum network link between Dutch cities

#31

Post by itishappy »

bawolff wrote: post #6

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?

As I understand, quantum key distribution cannot be beaten by classical equivalents and they're only good or better because our current quantum computers kinda suck. So the major use case at the moment is proving the tech and developing the infrastructure. The "killer app" of the quantum internet in my mind is as simple as just sending qbits around. Currently every network call involves an observation that collapses the system wavefunction. If you're looking to actually network quantum devices (say, to run distributed quantum computations) then you need quantum infrastructure.

Re: A rudimentary quantum network link between Dutch cities

#32

Post by dekhn »

solarkraft wrote: post #7
bawolff wrote: post #6

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?

What are the classical equivalents?

manually distributing codebooks of pre-shared keys

Re: A rudimentary quantum network link between Dutch cities

#33

Post by dwnw »

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.

Re: A rudimentary quantum network link between Dutch cities

#34

Post by vtomole »

bawolff wrote: post #6

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?

A quantum internet is absolutely necessary for creating a useful quantum computer, the same way the internet (LAN) is needed to create a supercomputer. A supercomputer is essentially many computers connected together. A quantum computer that solves problems we care about will be similar: https://arxiv.org/abs/2212.10609.

Re: A rudimentary quantum network link between Dutch cities

#35

Post by seanhunter »

ikari_pl wrote: post #10
bawolff wrote: post #6

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?

I'd prefer @ziofill to answer, but I think: - security - if we use quantum entanglement/teleportation to the extent I've read about how it works, then even if you still need a fiber optic cable connecting the two parties, the data is unreadable if you're not looking at physically the same wave/photons, meaning that man in the middle attack (like the ones with bending an optic cable to break it's internal reflection)…

People have dealt with the second one in sibling comments but I somewhat doubt the first one is true when you take into account sidechannel attacks on the encoding and decoding part of the transmission.

Yes I get through quantum magic you can theoretically tell if your secret has been intercepted in the quantum state because it would cause a wave form collapse but the wave form wouldn't collapse if they were listening in to your quantum computer squeaking and buzzing and decoding those noises or timings or reading its heat signature etc, or getting your operator drunk and finding out their dog's name or partner's birthday and using it as their password, or kidnapping them and hitting them with things until they voluntarily give you their password etc. All those types of attacks would still work and still be just as undetectable as they are in classical encryption. ie all the most effective forms of attack are still just as effective in a quantum case.

I think it's a very interesting area of research but this whole idea of uncrackable codes is a stretch.

Re: A rudimentary quantum network link between Dutch cities

#36

Post by robblbobbl »

vtomole wrote: post #34
bawolff wrote: post #6

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?

A quantum internet is absolutely necessary for creating a useful quantum computer, the same way the internet (LAN) is needed to create a supercomputer. A supercomputer is essentially many computers connected together. A quantum computer that solves problems we care about will be similar: https://arxiv.org/abs/2212.10609 .

Cool thanks

Re: A rudimentary quantum network link between Dutch cities

#38

Post by dwnw »

pclmulqdq wrote: post #30
Havoc wrote: post #23

Earlier quoted context omitted.

It says over fiber. I assume that has to be a straight shot point to point non-routed? Or could this deal with repeaters and routers etc

All of the quantum networking stuff is point-to-point. It's not clear to me whether fiber amplifiers are even allowed on these links.

Amplification would absorb one photon and replace it with one or more new photons. Definitely not quantum.

Personally, I always wonder why point-to-point connections are called "networks". The information is not quantum at any node, even if there are multiple nodes in a system.

Then there's "quantum internet", which makes no sense at all. What are we going to do, run direct fiber from every computer to every other computer directly? You can't hop safely or anything. Don't get me started on the total bullshit that is the "quantum repeater", now we need "quantum switch" too?

We call serial port connections things like "link", "connection", etc. We typically don't call them networks until we start linking them all together with simple routing logic that doesn't inherently require access to all the unencrypted information the packets contain and such.

To me these are all just signs that the whole scheme is/was and will forever be mostly crankery.

Quantum networking is an oxymoron. It doesn't allow end-to-end encryption and in exchange gives back extremely fragile single link security properties.

Re: A rudimentary quantum network link between Dutch cities

#39

Post by eigenket »

dwnw wrote: post #38
pclmulqdq wrote: post #30

Earlier quoted context omitted.

All of the quantum networking stuff is point-to-point. It's not clear to me whether fiber amplifiers are even allowed on these links.

Amplification would absorb one photon and replace it with one or more new photons. Definitely not quantum. Personally, I always wonder why point-to-point connections are called "networks". The information is not quantum at any node, even if there are multiple nodes in a system. Then there's "quantum internet", which makes no sense at all. What are we going to do, run direct fiber from every computer to every other co…

I don't think it's completely clear (to me) that quantum networking is an oxymoron. I would enthusiastically agree that its very complicated and the real world use cases are incredibly limited.

As far as your routing/switching qualms go I think they are mostly addressed by entanglement swapping? Person A and person B can each make an entangled pair and send me half, and I can (locally) do stuff which leads to the halves they keep at home becoming entangled. Then they can use teleportation or whatever to do whatever they want between themselves without me knowing anything about it.

Re: A rudimentary quantum network link between Dutch cities

#40

Post by dwnw »

eigenket wrote: post #39
dwnw wrote: post #38

Earlier quoted context omitted.

Amplification would absorb one photon and replace it with one or more new photons. Definitely not quantum. Personally, I always wonder why point-to-point connections are called "networks". The information is not quantum at any node, even if there are multiple nodes in a system. Then there's "quantum internet", which makes no sense at all. What are we going to do, run direct fiber from every computer to every other co…

I don't think it's completely clear (to me) that quantum networking is an oxymoron. I would enthusiastically agree that its very complicated and the real world use cases are incredibly limited. As far as your routing/switching qualms go I think they are mostly addressed by entanglement swapping? Person A and person B can each make an entangled pair and send me half, and I can (locally) do stuff which leads to the hal…

Lots of handwaving there. Particularly with "and I can (locally) do stuff"

Good luck with all of that.

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