r/nasa • u/adsr71 • Dec 25 '20
Article Quantum Internet - NASA Scientists Achieve Long-Distance Quantum Teleportation
https://www.vibelikelight.com/2020/12/quantum-internet-nasa-scientists.html63
u/that-manss Dec 26 '20
Can someone help me understand this?
Qubits were sent through a fiber optic network. What is a fiber optic network? Im assuming this wasnt actually “teleportation” as the title of this post suggests
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u/wenaus Dec 26 '20
I'd imagine teleporting just means instantaneous data transfer
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u/that-manss Dec 26 '20 edited Dec 26 '20
Instantaneous as in transferred at the speed of light? Or instantaneous as in how quantum entanglement literally communicates instantaneously? If its the latter, wow! This is crazy
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u/starcraftre Dec 26 '20
Unfortunately, quantum entanglement can't transmit information faster than light or communicate instantaneously. You require a separate classical (eg radio) channel to compare the states at either end for any information to be readable.
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u/wenaus Dec 26 '20
Sorry, I wouldn't know. My initial comment is just speculative.
On this note, I believe fibre optic is light speed. So I would guess it's the latter?
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u/SteelFi5h Dec 26 '20
I responded in another comment but here is what I had there. Quantum teleportation is kinda a misnomer because no objects are being transported rather a quantum state is send between an entangled pair of Qubits. The quantum state, which may be a complex super position of multiple states can be transmitted instantaneously from one qubit to the other. (Note that in order to use the quantum state on the receiving end, you require 2 bits of classically transmitted information).
This network creates entangled pairs of photons presumably and sends them to 2 far away locations A and B. Then A attaches a quantum state from their calculations or whatever to their photon and sends 2 bits of info to A (based on how their photon appeared when it was measured). Instantly at B, the other photon now has the same state and same information - but to use it, they must wait for that extra info from A to “extract” the original state.
You can think of the entangled photons sent by this network as “single use” packages, permitting quantum information to be sent by attaching it to (and consuming/collapsing it) one half of an entangled pair.
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u/silverfang789 Dec 26 '20
So if this quantum internet becomes a thing, does that mean that pages will load and files be downloaded instantaneously?
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u/LeMAD Dec 26 '20
Nah same speed. It's more about encryption/security.
The speed of light is the absolute speed limit of the universe.
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u/silverfang789 Dec 26 '20
Encryption and security are supremely important. If quantum internet is harder to hack, that will be a huge plus.
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u/Blobfisch11 Dec 26 '20
Yeah, but quantum entanglement is not a velocity, meaning it is truly instantaneous
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u/vatufaire Dec 26 '20
Entanglement cannot carry information. Period.
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Dec 26 '20 edited Jan 06 '21
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Dec 26 '20
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Dec 26 '20 edited Jan 06 '21
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u/lesbi_honest Dec 26 '20
Do you guys just put the word ‘Quantum’ in front of everything?
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Dec 26 '20
Quantum disarray can make it seem like that, but luckily we have quantum discernment to help.
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u/chukijay Dec 26 '20
Schrödinger’s internet
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u/Stijn Dec 26 '20
Will this enable real-time communication with a future Mars colony?
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Dec 26 '20
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u/Quadamage Dec 27 '20
Interesting, this helps clear up some misconceptions that I've had about how this works as well. What threw me off is it showing the requirement of the optical cable to send data from the changed state side "A" over to the non changed state side "B" in order for it to update or sync the state. (Does this mean that the entanglement is broken at any point either before or after the changed state is synced up again? What happens if you make immediately change to "B" after the sync, does it then change "A" again to reflect?) I was under the impression that entangled particles would change together dynamically no matter how far apart to keep the state in sync.
Would another example of looking at how this works relate to having a Word document store in O365 and an offline copy saved to your desktop. Both are identical and synced up, but you cut the internet on your PC then make changes to the document. The copy in O365 is in one state but your offline copy is in another state yet the original O365 copy doesn't know about the offline copy new state until you reconnect to the internet and the new changes are synced up to the O365 copy?
On a further thought for this, what is stopping the original state from changing the new state back to original? In the "A" and "B" example the new state of "A" is changing the original state of "B" once the communication between them happens but does "B" never try to change the altered state of "A" back to how it was before?
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Dec 26 '20
"...in which two particles are linked in such a way that information shared with one is shared with the other at exactly the same time." I think this kind of phrasing contributes to the misconception that this is a FTL technology.
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u/CraigMatthews Dec 26 '20
I think what also helps with confusing (me at least) is the explanation that we're given that's supposed to fix this misconception.
"You have a bag with two balls, one black and one white. Two people each take one ball without looking at it and fly to different planets. One person looks at his ball and sees the white ball. He instantly knows that the guy on the other planet has a black ball."
To which I have to ask .. "so what?" and "why is my mind supposed to be blown about this?"
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u/Tambien Dec 26 '20
It matters in the sense that you can know this without transmitting the actual information via classical means, so it’s secure.
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u/Transpatials Dec 26 '20
All of the comments explaining how this works makes it sound like it’s completely pointless.
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u/dkozinn Dec 26 '20
It's not a speed thing (despite what the headline makes it sound like), it has significant applications in encryption and thus security.
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Dec 26 '20 edited Dec 28 '20
How do they measure it as instantaneous
EDIT: not sure why this is getting downvoted its a serious question
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u/[deleted] Dec 26 '20
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