Quantum internet is possible using standard Internet protocol — University engineers send quantum signals over fiber lines without losing entanglement
Posted by donutloop@reddit | hardware | View on Reddit | 59 comments
Vb_33@reddit
What benefit is there to a quantum Internet over the traditional Internet?
xternocleidomastoide@reddit
I mean, technically the internet right now is all "quantum." The semiconductors and fiber optics we use now rely on quantum electrophysics. ;-)
the ultimate goal of quantum entanglement is as an enabler of safe, practically instantaneous communication.
If you have pairs of entangled atoms, you could theoretically separate them and they both would communicate their state changes simultaneously regardless of where in the world either of them are.
effrightscorp@reddit
No: https://en.m.wikipedia.org/wiki/No-communication_theorem
xternocleidomastoide@reddit
Thus the "practically"
nanonan@reddit
There's nothing practical about your proposal, but there is something impossible.
xternocleidomastoide@reddit
prac·ti·cal·ly/ˈpraktək(ə)lē/adverb
nanonan@reddit
Impossible things don't almost happen.
xternocleidomastoide@reddit
like managing basic contextual reading and comprehension, apparently.
nanonan@reddit
You seem to be unable to comprehend that you cannot in fact communicate instantaneously using entanglement.
xternocleidomastoide@reddit
Mate. this is why contextual comprehensions is so important. E.g. information in physics refers to the state/arrangement of matter and energy, whereas in CS, it's the encoding of data.
Furthermore, entanglement implies the particles' states are instantly correlated.
We can, in fact, use particle states as form of data encoding. That's literally the point of this system (e.g, encoding the collapse as proof of crypto attack).
And they do so not breaking the speed of light limit; the particles need to be transmitted. And for the type of distances involved the communication is "practicably" instantaneous.
Anyway. I have no further interest in wasting time with your Dunning Krugering...
bye
effrightscorp@reddit
They don't communicate at all
nanonan@reddit
Isn't that completely useless for communication? If I send two people identical messages, it doesn't mean they are communicating.
xternocleidomastoide@reddit
That is not what that means, at all.
If we affect one particle, the entangled particle will reflect the change automatically. Thus the observer with the other particle gets updated on what we did to our particle instantaneously.
nanonan@reddit
That would violate relativity, wouldn't it? FTL communication is impossible. I was under the impression that you cannot use entanglement to communicate at all.
xternocleidomastoide@reddit
Instantaneous quantum interactions decoupled from space-time are why Einstein couldn't wrap his head around the concept of spooky interaction.
Relativity just limits the speed of the particles. The entangled particles are interacting instantly at distance, without particles as carriers of the information between them.
Theoretically entanglement can preserve information, and thus you can use it for information sharing with an observer.
The issue is that practically we can't make scalable entanglements that don't collapse very quickly.
nanonan@reddit
It's impossible to communicate anything though, right? like I can measure the spin of my particle and know the state of the distant entangled particle, but how does that help me communicate anything?
xternocleidomastoide@reddit
by encoding information as specific changes in one of the particles, and reconstructing it on the other side by observing the inverse state changes on the entangled twin.
nanonan@reddit
You could do that at the creation of the particles, but that won't help communicate. You can't do that after.
xternocleidomastoide@reddit
it won't help communicate at faster than light speed, since the particles have to be distributed anyway so they are bound by causality/relativity.
but we are communicating the data at the moment of creation.
We simply can't, at this point, do much useful with these systems. We just exploit the collapse when we try to observe these particles as a "canary" against an cryptographic adversary/attack.
nanonan@reddit
This was your assertion, now you say it's no better than a wire or optic fiber. That's not instantaneous.
xternocleidomastoide@reddit
you still need to distribute the particles. the entanglement is instantaneous.
nanonan@reddit
The entanglement cannot be used to communicate.
Nicholas-Steel@reddit
Why can't this be used as one-time-use instantaneous communication across vast distances? You want to tell someone something so you encode your info on one or more particles that a space ship is carrying the pairing of, they can then get the info instantly regardless of where you and they are, the particles lose quantum entanglement upon receipt as their nature becomes observed.
xternocleidomastoide@reddit
I mean, yeah that is a way to share the information. But it requires the particles to move to the observer, ergo it is not instantaneous.
They are sort of being used in that way now, as I mentioned, as krypto key pairs. The 2 entangled pairs have a "state" information we set at creation, so the "trusted" source with one of the twins should match the "state" of the other particle (in reverse). If an attacker tries to observe the system, then it collapses.
(I am sure I am getting some of the details wrong, it's been ages since I looked at this stuff).
Nicholas-Steel@reddit
For that usage you described, wouldn't the system be generating and transmitting entangled particles at the same rate as data packets? That sounds expensive but I have absoloutely no clue how much it costs to run such a system lol.
xternocleidomastoide@reddit
Yup.
Right now we only seem to be using entanglement as a sort of quantum crypto key pair.
Some of the theoretical applications were in terms of doing instantaneous short distance communication that don't go through a wire. But the technological challenges are pretty big, since creating the entangled particle pair is extremely hard, and making sure their state doesn't collapse once we move them apart is also extremely challenging.
Entanglement is mostly a neat quantum musing, esp the spooky interaction at a distance, that has been freaking out physicists/mathematicians for a very long time, because we really don't understand what is going on really at the core of it.
The no communication theorem is mostly so that a lot of people can sleep well at night in terms of causality and special relativity being preserved.
anival024@reddit
This isn't anything other than classical communication with extra steps.
It's like mailing two different letters, to two different locations. When party A reads one message, they "instantly" know what letter party B must have received. But the information still took the regular time to travel that distance. You could have just as easily, and just as quickly, sent A a letter saying what letter you sent to B.
Strazdas1@reddit
the difference is that the results on the twin particle can be observed and interepreted at speeds higher than it would take to transmit photons to end-point location. Thus thereticaly FTL communication.
xternocleidomastoide@reddit
I didn't claim otherwise.
ibeerianhamhock@reddit
Particle state information can be registered as information states. We already translate different physical medium state representations to infer information sent be it wifi, Ethernet, fiber, etc. As long as you have a means to discern disparate states you can translate that into data. It wouldn’t be any different with quantum, it’s just a different medium.
Strazdas1@reddit
Yes, the whole point of quantum entanglement being such a big deal is that it violates relativity.
FTL communication is impossible with current tech. It is also a pre-requiting to having gaming be cloud-based.
anival024@reddit
You have to send the particles out normally. There's nothing "instant" about the communication. If you flip a coin and see it lands on heads, you instantly know the other side is tails. That doesn't mean information traveled faster - the coin had to be flipped, land, and the light showing you it landed heads up had to travel back to you at normal speed. Even if the coin is 1 lightyear thick, you're not gaining any information about the bottom side of the coin in anyway that violates the speed of light.
xternocleidomastoide@reddit
I didn't say anything about how the particles are distributed. Just about the entanglement doing its spooky thing.
anival024@reddit
Quantum entanglement does not allow for faster communication.
You may as well say you wrote A on one piece of paper, B on another, mailed them to two separate locations. They're "entangled" in the same way anything else in quantum physics is, but opening one envelope and instantly knowing what the other contains doesn't transmit information faster. You still had to send the envelopes via traditional means. There's nothing special about entanglement for communication.
Nicholas-Steel@reddit
Except you can keep updating the contents in the envelope... until you open it to read it at which point its contents become known and the quantum entangled particle loses its quantum nature :P
xternocleidomastoide@reddit
yes, the entangled particles are still limited in how fast they can move and be distributed/placed.
Jacko10101010101@reddit
they has no idea what they are talking about! and confuses other people!
i think 80% of the people here didnt got it right !
TopCheddar27@reddit
And you understand quantum mechanics with that grammar?
Quatro_Leches@reddit
there is no known benefit to quantum computing in general.
EmergencyCucumber905@reddit
Simulating quantum mechanics allowing us to more quickly design and test new drugs, better materials, better batteries?
megablue@reddit
eavesdropping proof
throwaway12junk@reddit
It's a poorly written article. The actual experiment was maintaining a point-to-point q-bit encryption over a traditional fiber optic line.
catsuitvideogames@reddit
It's tomshardware. Lousy outlet pretending to write expert articles. Quantum key exchange over public fiber optics has achieved done years ago. But you still need repeaters for any practical use.
Nicholas-Steel@reddit
Unfortunately a repeater needs to know what the quantum signal is in order to repeat it, and that will ruin it.
Plank_With_A_Nail_In@reddit
Thats not what it was it was about retransmission without reading the state of the particles being measured.
The article is fine its only issue is that its too long for the tiny amount of information contained in it.
Illustrious_Crab1060@reddit
being able to detect MIM attacks
Pugs-r-cool@reddit
Is man in the middle really such a big issue nowadays? We have the entirety of PKI to fight against it, I don’t see why quantum computers are necessary.
The majority of MiM attacks happen through insecure public wifi, and unless we invent wifi but quantum, changing how we exchange keys shouldn’t make a difference.
justice_for_lachesis@reddit
sharing encryption keys is a safe way.
nanonan@reddit
Public key systems already allow this.
einmaldrin_alleshin@reddit
Public key systems are vulnerable to a man in the middle during the key exchange. Usually you confirm the key's authenticity either through a trusted third party, or by physical exchange.
Quantum key exchange could possibly do without either
anival024@reddit
None.
eldog@reddit
um, doesn't quantum entanglement require no "sending"? This sounds like bullshit.
megablue@reddit
thats science fiction and you misunderstood the possible usage of quantum entanglement in the real world
razirazo@reddit
Folks at /r/VXJunkies has done this way before. Not only without losing entanglement, but also managed to get delta-field encabulator on parity as well the side fumbling reliably prevented.
AnechoidalChamber@reddit
The heck is that subreddit?
throwaway12junk@reddit
It's a joke roleplay subreddit lol. The whole schtick is making up nonsense technobabble and and roleplaying as completely serious.
No_Sheepherder_1855@reddit
https://www.reddit.com/r/VXJunkies/comments/1n2spn0/can_anyone_at_the_antwerp_conference_yesterday/
wtf is happening
AnechoidalChamber@reddit
I have no clue mate...
shrugs
All I know is I'm gonna stay away from that sub. xD
To each their own!
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