New method of quantum entanglement increases the information that can be carried(phys.org)
phys.org
New method of quantum entanglement increases the information that can be carried
http://phys.org/news/2015-06-method-quantum-entanglement-vastly-photon.html
3 comments
I wonder how long before we see major internet nodes connected via quantum entanglement.
Entanglement can't be used for communication. https://en.wikipedia.org/wiki/No-communication_theorem
I was going to post that link. This is the standard theory, isn't it? Most physicists subscribe to this, regardless of their interpretation of quantum mechanics (Copenhagen, De Broglie–Bohm, and so on?)
Yes basically if you build say 2 entangled bytes you'll basically get random data out of them every time you measure / set their state you'll basically get random data.
The only way to make the data "make sense" is to share the measurements between both observers on a side channel.
But and that's the big but which i don't understand and couldn't get a decent explanation from anyone who i know has some / more understanding that i do in QPT.
Yes i understand if you got 2 observers Alice and Bob both of them with a pair of say you got a pair of 12 entangled quantum bytes.
Bob can't tell by random measurement if Alice has done something since the state of his 12 qbytes is "random", however if the interpreted say say's Hello World! or I Just Changed It why Bob can't superimpose additional information he has such as the knowledge of the English language to interpolate that Alice actually did something.
On top of that the no information theorem is also tied to the no-cloning theorem which conflicts with well with how some one would explain quantum teleportation.
The explanation I managed to find is that the no-cloning and no-teleportation theorems do not prevent quantum teleportation but rather classical one which means that you cannot encode a quantum state into a classical system and then clone/teleport that information into another quantum system, but you can do it from one quantum system to another which is where my brains starts to scream.
http://courses.cs.washington.edu/courses/cse599d/06wi/lectur...
The only way to make the data "make sense" is to share the measurements between both observers on a side channel.
But and that's the big but which i don't understand and couldn't get a decent explanation from anyone who i know has some / more understanding that i do in QPT.
Yes i understand if you got 2 observers Alice and Bob both of them with a pair of say you got a pair of 12 entangled quantum bytes.
Bob can't tell by random measurement if Alice has done something since the state of his 12 qbytes is "random", however if the interpreted say say's Hello World! or I Just Changed It why Bob can't superimpose additional information he has such as the knowledge of the English language to interpolate that Alice actually did something.
On top of that the no information theorem is also tied to the no-cloning theorem which conflicts with well with how some one would explain quantum teleportation.
The explanation I managed to find is that the no-cloning and no-teleportation theorems do not prevent quantum teleportation but rather classical one which means that you cannot encode a quantum state into a classical system and then clone/teleport that information into another quantum system, but you can do it from one quantum system to another which is where my brains starts to scream.
http://courses.cs.washington.edu/courses/cse599d/06wi/lectur...
I don't understand the limitation that "neither Alice nor Bob is allowed, in any way, to affect the preparation of the initial state." Why shouldn't Alice create the initial state?
If we can use the quantum entanglement to determine if some Eve has intercepted a message between Alice and Bob, then why can't we use the fact of tampering as the data pipe? Why shouldn't Alice create the initial state and Bob use the quantum entanglement to communicate back? Use two constant photon streams between the two, one from Alice to Bob, one from Bob to Alice. The photons that are emitted are identical--it's notionally a carrier wave. Alice checks to see if Bob "tampers" with the photons. The actual data encoded in the photon itself isn't important.
Say I fire a laser beam to the Moon. It's going to take a second and a half to get there. I send one half of my entangled pair to the Moon and I send the other half down a fiberoptic delay line. In 1.5 seconds, I start checking whether or not my entangled photons have been tampered with, and that is the data stream back from the moon.
If we can use the quantum entanglement to determine if some Eve has intercepted a message between Alice and Bob, then why can't we use the fact of tampering as the data pipe? Why shouldn't Alice create the initial state and Bob use the quantum entanglement to communicate back? Use two constant photon streams between the two, one from Alice to Bob, one from Bob to Alice. The photons that are emitted are identical--it's notionally a carrier wave. Alice checks to see if Bob "tampers" with the photons. The actual data encoded in the photon itself isn't important.
Say I fire a laser beam to the Moon. It's going to take a second and a half to get there. I send one half of my entangled pair to the Moon and I send the other half down a fiberoptic delay line. In 1.5 seconds, I start checking whether or not my entangled photons have been tampered with, and that is the data stream back from the moon.
>If we can use the quantum entanglement to determine if some Eve has intercepted a message between Alice and Bob, then why can't we use the fact of tampering as the data pipe?
You can't; quantum key distribution requires a classical channel as well. See https://en.wikipedia.org/wiki/Quantum_key_distribution#BB84_...
>After Bob has measured all the photons, he communicates with Alice over the public classical channel.
Edit: also, "I don't understand the limitation that "neither Alice nor Bob is allowed, in any way, to affect the preparation of the initial state." Why shouldn't Alice create the initial state?"
If Alice creates the initial state, she can send a message encoded within.
You can't; quantum key distribution requires a classical channel as well. See https://en.wikipedia.org/wiki/Quantum_key_distribution#BB84_...
>After Bob has measured all the photons, he communicates with Alice over the public classical channel.
Edit: also, "I don't understand the limitation that "neither Alice nor Bob is allowed, in any way, to affect the preparation of the initial state." Why shouldn't Alice create the initial state?"
If Alice creates the initial state, she can send a message encoded within.
I was thinking of that too. Do you think that would add additional latency as the entanglement needs to boot and initialize? It also feels like we would be wasting some bandwidth because the tampering of the pipe will give us 1-bit of information rather than the pipe providing us with four.
But hey, it is FTL anyway.
But hey, it is FTL anyway.
It is not FTL. There is no way to use this to communicate FTL.
Was my explanation lacking?
Was my explanation lacking?
Alice and Bob are friends born on planet X who now live on planets Y and Z respectively each a light year away from X on opposites sides. Bob's mom on X dies, and the news on intergalactic social media is beamed to planets Y and Z where Alice and Bob learn of the news. In an instant after the year it takes the news to reach him Bob realizes that 2 light years away Alice will be sad, she might take a few days off work, her already strained relationship with her father will worsen, and that more than likely she will be returning to X...all sorts of meaning and information is communicated. Is the information "from Alice"? What information is "from Alice"?, when she and Bob next meet on planet X and tells him in person how devastated she is, was it Alice that really generated that information? Was it Alice's nervous system? Was it the event of the death itself or the transmission of it? Alice didn't "will" her sadness into existence nor the communication of it, nor any meaning in her life to be communicated, I don't think we communicate anything a priori because that would be useless. Do humans really generate any information at all that doesn't come from entangled systems?
>Is the information "from Alice"?
No.
> when she and Bob next meet on planet X and tells him in person how devastated she is, was it Alice that really generated that information? Was it Alice's nervous system?
Yes. The info may also have had an earlier cause, but that is completely screened off by Alice (in the technical sense of screen; see http://plato.stanford.edu/entries/causation-probabilistic/#S...).
>Do humans really generate any information at all that doesn't come from entangled systems?
I think you don't understand what entangled means; if I take two envelopes and put a 1 in the first and a 0 in the second, the envelopes aren't "entangled". Entanglement has a specific meaning, and doesn't just mean correlation. See https://en.wikipedia.org/wiki/Bell's_theorem
Anyway, you seem to have some confusion over determinism and physics, but it doesn't really have to do with FTL.
No.
> when she and Bob next meet on planet X and tells him in person how devastated she is, was it Alice that really generated that information? Was it Alice's nervous system?
Yes. The info may also have had an earlier cause, but that is completely screened off by Alice (in the technical sense of screen; see http://plato.stanford.edu/entries/causation-probabilistic/#S...).
>Do humans really generate any information at all that doesn't come from entangled systems?
I think you don't understand what entangled means; if I take two envelopes and put a 1 in the first and a 0 in the second, the envelopes aren't "entangled". Entanglement has a specific meaning, and doesn't just mean correlation. See https://en.wikipedia.org/wiki/Bell's_theorem
Anyway, you seem to have some confusion over determinism and physics, but it doesn't really have to do with FTL.
But it can be used for security: http://www.nature.com/news/2008/080827/full/news.2008.1067.h...
Right. So connected the usual way, but using QM for security.
They already teleported information via similar means, so I would hope this doesn't mean FTL communication is impossible.
It does mean that, actually.
https://en.wikipedia.org/wiki/John_G._Cramer
This guy seems to believe otherwise and many other scientific breakthroughs were declared as impossible before they were done, it is unwise to cling to limiting beliefs like that as that kind of attitude prevents technological advancement.
In fact, it can be speculated that messages could be sent in the future as well as in the past, and other parallel universes as well.
This guy seems to believe otherwise and many other scientific breakthroughs were declared as impossible before they were done, it is unwise to cling to limiting beliefs like that as that kind of attitude prevents technological advancement.
In fact, it can be speculated that messages could be sent in the future as well as in the past, and other parallel universes as well.
All his experiments have failed. See https://faculty.washington.edu/jcramer/NLS/NL_signal.htm
People have been trying to use QM to show FTL communication since QM was discovered, it doesn't work.
>In fact, it can be speculated that messages could be sent in the future as well as in the past, and other parallel universes as well.
Yes, you can speculate whatever you want, that doesn't make it any truer.
People have been trying to use QM to show FTL communication since QM was discovered, it doesn't work.
>In fact, it can be speculated that messages could be sent in the future as well as in the past, and other parallel universes as well.
Yes, you can speculate whatever you want, that doesn't make it any truer.
It's only 2015, I think it's a little ridiculous to make far sweeping conclusions about whole realms of science supposedly not working based on limited current understanding of science.
It is only 2015, and the conclusions you reach must make sense according to what is known in 2015.
And our current understanding of science is only limited in comparison to wild speculation. Those limits also happen to be the strongest point in its favor.
And our current understanding of science is only limited in comparison to wild speculation. Those limits also happen to be the strongest point in its favor.
Scientists know very little about QM despite it being known for 80 years due to political, resource and human IQ restraints. The human knowledge in this area is not even in infancy yet.
The experiments on Quantum Entanglement have only begun to intensify in recent years. With the advent of AI and commercial interest in the field due to communication opportunities, this may change rapidly.
When you say FTL communication is impossible that is a mere speculation at best, and a remarkably short sighted and laughable one in retrospect to paradigm shifts in the history of human technology. Scientific conservatism like that is a silly and shameful attempt to signal high status, which has held back human progress many times in the past. FTL communication is a major necessity and this field needs to be explored and pushed into hard without being held back by naysayers with dubious motives.
The experiments on Quantum Entanglement have only begun to intensify in recent years. With the advent of AI and commercial interest in the field due to communication opportunities, this may change rapidly.
When you say FTL communication is impossible that is a mere speculation at best, and a remarkably short sighted and laughable one in retrospect to paradigm shifts in the history of human technology. Scientific conservatism like that is a silly and shameful attempt to signal high status, which has held back human progress many times in the past. FTL communication is a major necessity and this field needs to be explored and pushed into hard without being held back by naysayers with dubious motives.
Again: what part of QM is little known about? It's made predictions accurate to tens of decimal places, none of its predictions have been disproven.
We've known about QM for 80 years. It's given accurate predictions for all that time. What exactly do you think is limited in currnt understanding of science?
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As I understood the description, they're not claiming that the process of entanglement encodes the information being transmitted, but rather that more information-carrying dimensions can now be entangled, so now those extra dimensions can also enjoy the proposed security benefits. For a system relying on those features, the throughput is effectively increased because more channels are eligible.