Goddammit, I thought they were talking about talking entanglement into another level, and manipulate the state of each of single particles at any distance without really having them entangled to begin with. I saw perspectives for while, that could have been so effective for long distance communication. And many other things.
Rob Lister said:
http://focus.aps.org/story/v10/st29
Well, it does, and that's why Einstein didn't like QM. Relativity and QM contradict eachother.
Thomas said:
I don't see where that article indicates that information is being passed at greater than light speed.
Edited to add... and so far Relativity and QM do not contradict each other. Relativity does have the problem of breaking down at arbitrarily short distances (String theory potentially resolves this by adding a "granularity" to space, if you will). None the less, no QM phenemena has been observed which actually violates Relativity.
Let me rephrase it then, quantum mechanics are considered a non-deterministic theory (acausal), and relativity is a deterministic theory (causal).scotth said:
If you have any arguments against that quantum mechanics should break with determinism, I would like to hear them, because I don't really like that it does. Nor did Einstein.
CurtC
Illuminator
Nobody knows what actually happens? That's pretty much true with any aspect of QM. However, we are able to mathematically predict the effects with an extremely high degree of precision. Quantum entanglement wasn't an experimental result that was discovered by accident - the theory predicted it, and the result was verified. In that sense, we understand what happens really really well, and you can't use that to communicate information at greater than c.
Do the particles communicate with each other at a speed greater than c? Well, maybe. The theory says that the state of the remote one is instantly determined, which sounds pretty much like that to me. But this can't be used to send information.
Do the particles communicate with each other at a speed greater than c? Well, maybe. The theory says that the state of the remote one is instantly determined, which sounds pretty much like that to me. But this can't be used to send information.
This is not true at all. Signal power drop-off is a result of shotgunning waves (photons) out in a broad spread, and when they get 50 light years out, there's not enough of them left to distinguish the signal from noise. This is also known as the inverse square law. But with your quantum communication, the photons would have to be rifle-shot exactly to their intended destination. This is just another aspect of the same problem.
scotth said:
I love your confidence that the physics of the early 21st century has solved all the issues in physics apparent to our hypothetical space aliens. Especially the issues that are currently the subject of high-level debate in our own journals. Your statement that information cannot be passed via quantum entanglement, for example, is not supported by the various national research foundations, or they wouldn't have funded experiments in this area.
Are you claiming to know this area better than the NSF? I can put you in touch with Dr. Dehmer if you like.
scotth said:
Yes. And your central assumption is that, as this would "violate causality," it must be impossible.
The NSF and similar funding agencies (in particular ONR) are willing to investigate the possibility of global causality violation. Such theories have been proposed (by Bohm and others) as early as 1951 and are still active research areas today.
What do you know that the head of the NSF Physics Division doesn't? Why is he willing accept non-localist interpretations of QM as potentially valid, while you are not?
drkitten said:
Don't confuse what I said with CurtC's post.
I said that FTL communication has been recently investigated and shown not to be possible. I also indicated that I would try to find some articles on that.
I'll also add, that I remember that it was shown in theory why it would not actually work, and that experiment actually agreed with that quite nicely.
scotth said:
Yes, and I said that the NSF and ONR consider the jury to still be out on whether or not it's possible.
What do you know that the NSF doesn't?
I remind you of Clarke's Laws : "When a distinguished but elderly scientist says something is impossible, he is very probably wrong."
scotth said:
Check out the recent NSF/ITR proposals, especially the physics-heavy ones, and see if any of them satisfy you.
More directly, I refer you to the paper "Superluminal solutions to the Klein-Gordon equation and a causality problem," (Phys. Lett. A.) by Borghardt et al. (although they're operating out of the Ukraine, and so don't have US-based funding), where they're explicity investigating the possibility of causality violations. There's similarly a large body of extremely recent (2003-4) work investigating the apparent superluminality of quantum tunnelling.
None of the researchers have yet found a clear-cut case of superluminal information transfer, but they all clearly regard the question of causality violation as an open one.
back onto topic...
I'm a supporter of SETI and think the idea is good in principal but I've always had reservations about the methodology in relation to the very narrow band of radio wavelengths they monitor.
I agree some assumtions need to be made to narrow the field from the effectively infitinite EM spectrum to something manageable with modern technology but I've always found the justification for the range chosen a bit to "airy fairly" for my liking.
I'm looking for a link to the bands monitored and the justificiation for it to make sure my feeble mind isn't deceiving me again...
Here's one with a nice graph
I'm a supporter of SETI and think the idea is good in principal but I've always had reservations about the methodology in relation to the very narrow band of radio wavelengths they monitor.
I agree some assumtions need to be made to narrow the field from the effectively infitinite EM spectrum to something manageable with modern technology but I've always found the justification for the range chosen a bit to "airy fairly" for my liking.
I'm looking for a link to the bands monitored and the justificiation for it to make sure my feeble mind isn't deceiving me again...
Here's one with a nice graph
Dancing David
Penultimate Amazing
Rob Lister said:
Very little mass, my point is that it is about detecting other possible lifeforms with what we have, there are good reasons that radio waves will continue in use for a long while. mainly the transparency of the universe.
Dancing David
Penultimate Amazing
drkitten said:
I think someone told me that these properties could not be used for data transefer.
Dancing David said:
Yes. And I'd love to know how that person who told you knew that that was the case, when the researchers are still doing the experiments and investigating the questions.
I repeat : what does he know that the scientists currently working in the area don't? How does he know the results of the experiments before they are performed?
Dancing David
Penultimate Amazing
I believe that it was Zombiefied, and his point was that the superluminal properties are essentialy a random component of the 'sum of histories', and so while superluminal properties exist and are somewhat established they are an effect of the standard theory and not a new expansion of the theory.
I am not saying that current reasearch is not ongoing, just that this was a response to comment I had made.
The main issue I have with some of the superliminal research is that we cant really do the experiments over a distance that really demonstrates anything other than a local phenomena.
(Sorry, I have probably made a msih mosh of the whole thing and totaly misrepresented what I was told, I was pointing out that the speed of light is not actualy a constant, it is an average over the history of the photon. This apparently was not sufficient to allow for data transmission faster than the speed of light. I was making reference to the Italian studies where a photon arrived at the receptor in a frame of reference 'earlier' than the standard theory would predict.)
I am not saying that current reasearch is not ongoing, just that this was a response to comment I had made.
The main issue I have with some of the superliminal research is that we cant really do the experiments over a distance that really demonstrates anything other than a local phenomena.
(Sorry, I have probably made a msih mosh of the whole thing and totaly misrepresented what I was told, I was pointing out that the speed of light is not actualy a constant, it is an average over the history of the photon. This apparently was not sufficient to allow for data transmission faster than the speed of light. I was making reference to the Italian studies where a photon arrived at the receptor in a frame of reference 'earlier' than the standard theory would predict.)