Testing Einstein's 'Spooky Action at a Distance' 375
smooth wombat writes "Travelling to a time in the past is, as far as we know, not possible. However, Einstein postulated a faster-than-light effect known as 'spooky action at a distance'. The problem is, how do you test for such an effect? That test may now be here. If all goes well, hopefully by September 15th, John Cramer will have experimented with a beam of laser light which has been split in two to test Einstein's idea. While he is only testing the quantum entanglement portion, changing one light beam and having the same change made in the other beam, his experiment might show that a change made in one beam shows up in the other beam before he actually makes the change."
Been there, Done that (Score:5, Insightful)
Re:Been there, Done that (Score:5, Informative)
Of course. Slashdot is getting weird by the day. First off, it was not Einstein's idea. Eisntein was against it and this was made famous in a paper he wrote with two other physicists who agreed with him. It's called the Einstein-Podolsky-Rosen paradox [wikipedia.org] or EPR paradox for short.
Re:Been there, Done that (Score:5, Informative)
See this:
http://www.analogsf.com/0612/altview.shtml [analogsf.com]
The idea is to see if an interference pattern will spontaneously change from a single slit to a double slit merely by moving the position of where entangled photons are destroyed.
I think there is a reasonable chance this will work. This is interesting as it in principle allows FTL communication.
After that his ideas get REALLY interesting.....
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dupe, sort of.
Ack Gad! Finally... (Score:2)
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http://faculty.washington.edu/jcramer/ [washington.edu]
I love his articles.
He's a quack selling snake oil (Score:4, Insightful)
Where do you get a laser that produces entangled pairs with the ability to separate the pairs into 2 coherent beams?
Then from TFA we have this:
This guy doesn't think that the detector for B will "fiddle" with the photons at A before they reach their fiddler?He also seems to be getting money from people who believe his BS. Not to mention publicity.
If someone honestly believed they could send information back in time, the logical thing to do is fund the experiment any way you can while keeping it secret. You recover the funds by playing the stock market using future data (minutes to hours is the required time frame here). You keep it secret so "they" don't come after you - for whatever "they" you may be concerned about.
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That part is easy. A UV laser produces photons that when fired though a LiO3 crystal are split to provide two momentum correlated photons. This is routinely done in labs all round the world and specifically by Ms Dopfer for her Ph.D. back in 1998. Cramer is attempting to see if the pattern change she observed in her experiment will arise if you don't demand a coincidence between the arms.
Rea
Re:"Faster than light"... (Score:4, Informative)
Nobody has ever found a way to use entangled particles to send FTL messages. In principle it is impossible. I have never even heard anybody else but this guy musing about ways it might be possible.
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As a serious question, I still don't understand why light speed is the limit - my understanding of relativity goes that it starts with the assumption that light is the fastest thing and then moves from there. This is them backed up by all the observations we have, so it is so far an excellent theory.
So the thought experiment I like is, suppose there was an intelligent fish that was blind and used sound to communicate. This fish was intelligent enoug
Re:Been there, Done that (Score:5, Funny)
Well, I looked it over, contemplated it, thought about it in depth for a while and I came to the conclusion that I have no fucking idea what that proves, and now I have a headache, thank you.
Re:Been there, Done that (Score:5, Insightful)
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while we're wasting time, let's test relativity theory
and einstein had little to nothing to do with it. he didnt even believe in it. "spooky action at a distance" was meant as a derogatory term.
Quit it (Score:5, Informative)
It's called the EPR Paradox in the scientific community.
Einstein was no fan of it, and he believed it was a way to point out how silly the idea of Quantum Mechanics was, but he was very much the discoverer of it.
This is as important to understanding Einstein as "God does not play at dice", his basic objection to the probability implications of QM and EPR.
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But we all know that since Einstein believed in God he must be a narrow-minded, naive, simpleton. Someone like that couldn't possibly have validity in modern science so these people are wasting their time trying to confirm Einstein's theories.
[/sarcasm]
It is interesting how most people get flamed for their religious beliefs on Slashdot, but nobody is flaming Einstein here.
Re:Quit it (Score:4, Informative)
"It was, of course, a lie what you read about my religious convictions, a lie which is being systematically repeated. I do not believe in a personal God and I have never denied this but have expressed it clearly. If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it."
Albert Einstein, in a letter March 24, 1954; from Albert Einstein the Human Side, Helen Dukas and Banesh Hoffman, eds., Princeton, New Jersey: Princeton University Press, 1981, p. 43.
Re:Quit it (Score:5, Interesting)
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Einstein wasnt doing the work on EPR to further our knowledge of the universe, or anything like that. he was doing it specifically to discredit quantum physics, by showing the absurd conclusions that naturally flowed from it. he had made up his mind already, and wouldnt budge, showing a clear bias againstly any new-fangled theories that would shake his perception of reality (which is quite ironic, since he was on the other side of the fence just a few decades prior).
now i
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The A.P.A. and M.L.A. manuals instruct the reader to use one space after the full stop. Perhaps the public schools have followed suit?
This practice is distasteful, true, but if successive generations want to remove helpful verbal timing cues from the language, then how is anyone to stop them? Usage changes over time in a multicultural environment, and this is not a bad thing, although we can a
Re:Been there, Done that (Score:5, Funny)
Re:Been there, Done that (Score:5, Funny)
Re:Been there, Done that (Score:5, Funny)
Unless you'd like to avoid this, of course, in which case I take payment in Visa, Mastercard, or hookers.
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On the other hand, it is known he went to get some help in formulating the tensor equations for the general theory of relativity (I don't
Causality (Score:5, Interesting)
Re:Causality (Score:5, Funny)
Fire and brimstone coming down from the skies. Rivers and seas boiling.
Forty years of darkness. Earthquakes, volcanoes...
The dead rising from the grave.
Human sacrifice, dogs and cats living together - mass hysteria.
Re:Causality (Score:5, Interesting)
As you said, event B requires event A. Event B precedes event A.
Let's say event A occurs when I press a button, just for the sake of simplicity. So if this formula is correct, event B will happen BEFORE I press the button. This is hurting my brain a little, but I think this would imply that event B could not happen unless I was truly planning on pressing the button. I can't "fake" the universe out by pretending to hit it, witness B, and then stop. Because if I were to do that, B would never happen. And... uhhh...
OW. See, as much as I support the fields of science and research into all things, I'm concerned about screwing with time. It makes my head hurt and the possible consequences scare me a little. Teleportation gives me similar worries.
Re:Causality (Score:5, Insightful)
Re:Causality (Score:4, Interesting)
I sure hope Niven's wrong about that.
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Re:Causality (Score:4, Insightful)
Consider: Researcher prepares to activate device, but researcher views results first. He already plans to perform an action (activate or not activate) in a way designed to contradict the results. He views the results, then takes the appropriate contradictory action. He succeeds in contradicting the theory. What does he prove? Not much, I think. How do you prove that the experiment was successful in sending an appropriate signal rather than it showing some false signal based upon noise or some other failure? In other words, how do you backtrack (forward-track?) the results to determine that the point of failure was actually the researcher's decision rather than some other mechanical issue?
Far more interesting would be an experiment in which a random number generator is in control of the device activation. Perform a long series of tests. Review the results afterwards. Does the activation always match with the pre-recorded results? Now that would be interesting. It still seems impossible to "backtrack" and prove no mechanical errors, but it would be possible to compile statistically important results this way.
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Think of it this way: Think of the universe as one big information computation machine. Everything is merely information, there is no real "current" state of said information, yet at the same time, there is the concept of a flowing time. Time moves as information becomes absolute, information thats processed becomes absolute. Its possible for information to exist in lots of states,
Re:Causality (Score:5, Insightful)
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Anyway, I'm not particularly knowledgable on quantum stuff, as I'm sure this post shows, but that would be my guess.
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An equivalent experiment with normal causality would be something like "wait until the stone turns red before painting the stone red" - if the only thing which could turn the stone red is you painting it, then you'll sit there watching a non-r
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Problems with classical intuitions. (Score:5, Insightful)
I'd guess we could never create such a paradox even if the effect is real.
Classical relativity imposes one set of constraints, and quantum mechanics another. Einstein was bothered because it seemed like the classical limits (think "light cone") would be inapplicable here. Quantum physics requires us to consider the actual mechanisms by which we measure and communicate as PART of the experiment.
Even if it works out that information at point B shows up "before" (in the same reference frame) an action at point A causes that message to be sent... it's possible that there's no practical way to detect this fact and use it in any way that would make for a "paradox." It may be that the best we can do is *record* the fact that such a backward transmission happened.
Example: Your instrument records a signal at B "before" the timestamp of the interference of the beam at A. This shows that entanglement is real, and gets you out of the "light cone" limits of classical relativity, which is what bothered Einstein. But if you go further and try to create a logical paradox, by using this information at A to stop the sending of the signal, then you will likely run into other, quantum mechanical limits... E.g. the actual means by which you detect the signal at B and send that information back to A will likely overwhelm or destroy whatever time differences we're talking about, bringing them back within classical limits...
This would be similar to things like the particle/wave experiments, where the experimental apparatus itself affects the outcome of the experiment.
So while something like "instantaneous" or even slightly "backward in time" messages may seem spooky in some ways may be possible, I'd bet that the time differences we're talking about wouldn't be large enough to make for any of the paradoxes people imagine using sci-fi based "time travel" notions.
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Very neat and interesting! (Score:5, Informative)
At the bottom, it says that the equivalent experiment has already been performed, and TFA sounds like it is nearly the same experiment.
Re:Very neat and interesting! (Score:5, Interesting)
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Well there you go.
I think it is already working!! (Score:5, Funny)
The theory works!
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Personally, I prefer ballsy scientific names after people like Heisenberg and Avogadro.
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(or you would if I had mod points right now
Amazing (Score:5, Funny)
Re:Amazing (Score:5, Funny)
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Re:Amazing (Score:5, Funny)
Re:Amazing (Score:5, Funny)
Whose sex was exceedingly brisk.
So fast was his action
That the Lorentz Contraction
Reduced his tool to a disk.
Re:Amazing (Score:5, Funny)
(No, not really. =\ )
Yellow journalism (Score:2)
While he is only testing the quantum entanglement portion, changing one light beam and having the same change made in the other beam, his experiment might show that a change made in one beam shows up in the other beam before he actually makes the change.
Yeah, sorta like me doing an egg-drop experiment "might show that gravity has no effect on a free-falling egg". If, the egg were to somehow mysteriously not fall to the ground.
I'm not knocking scientific experimentation, but this looks like just another test for the finer details of a well-understood phenomenon: quantum entanglement. Wake me up if anything even slightly unexpected happens.
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It wouldn't be a mystery why it didn't hit the ground. It would be flying. Why it was flying would be the mystery. The secret to flight is learning how to fall towards the ground and missing. --THHG2TG
A True Hacker (Score:5, Informative)
He also writes science fiction [wikipedia.org], so you can tell he completely enjoys science. Betcha anything he's doing this experiment, not because he thinks it will work, but just 'cause he wants to see what will happen. I can totally agree with that. It's the right reason to do research.
--
Looking for a C/C++ job in Silicon Valley? [slashdot.org]
Re:A True Hacker (Score:5, Informative)
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There are reasons to put the sig in the actual post, your sig may fit in very well with the post, and when you change it you don't want it to change everywhere; or sometimes search engines don't look at sigs. Sigs are just a chance to say something brief to the world, from the bottom of your heart, on an
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BTW, in case you were unaware of it, there exists http://jobs.slashdot.org/ [slashdot.org] to post wanted ads.
So say this works. (Score:2, Interesting)
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Not me. I'll be playing Alpha Centauri all the way to . . . Alpha Centauri.
Dammit. If WOW were a solar system, that would have been a lot funnier.
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To bad we'll never see that in this lifetime..
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Spooky? (Couldn't resist) (Score:5, Funny)
future doesn't exist? (Score:2)
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When you say "hasn't happened", you're saying the future is not in the past. Your entire confusion is based on the intuition that the present must always follow causally from the past. The simplest resolution to this would simply be that your intuition is wrong. No contradictions are introduced by rejecting this assumption.
Just because something appears a certain way most o
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What happens when.... (Score:4, Insightful)
What happens when he notices the change, before he makes the change, and changes his mind and doesn't make the change?
-CF
they must be out of flux capacitors at the store.. (Score:2)
Makes my head spin (Score:5, Funny)
Wish I had mod points (Score:2)
BTW, wasn't Traf-O-Data the first foray of Gates and Allen into the biz world???
recursion (Score:2, Insightful)
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Is this ... (Score:2)
the "Einstein's Bridge" John Cramer who's proposing this test?
Just wondering...
Faster than light it ain't: (Score:2, Informative)
-- Wikipedia article on Spooky Action [wikipedia.org]
Things they need to consider.... (Score:2, Interesting)
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When sending any signal, they need to consider that the signal grows weaker the further it travels. This is obvious with 3-dimensional travel but when adding that 4th dimension, it degragates exponentially.
Signal degradation is already exponential, and already takes into account time, "the fourth dimension." It is not possible for a signal to degrade without it being away from the source of its transmission, which necessitates its having propagated away, which re
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Of course, an interesting thought experiment is to consider a universe consisting of exactly one particle...and then ask if that particle is spinning.
Paradoxes my a$$ (Score:3, Interesting)
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So it is quite possible for an event E to happen in system A, to use FTL comm to transmit the event to system B, system B to take an action depending on the information before observing E, and then finally system B to observe the event E.
The above is not violation of causality in any way. It's similar to
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Sgt. Doom, Galactic Temporal Patrol
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Re:Isn't all time travel impossible? (Score:5, Funny)
I, myself, am a time traveler from the past. I've been journeying into the future at a rate of sixty seconds per minute.
Re:Isn't all time travel impossible? (Score:5, Funny)
Re:Isn't all time travel impossible? (Score:5, Insightful)
Note that also, too, we can observe the past due to the finite speed of light. Thus, given our current knowledge it is always possible to travel to the future and observe the past, but never the other way around (except maybe at quantum scales as discussed in TFA).
This, according to my random ponderings makes me think that if its possible to travel to the past, it will also be possible to observe the future, and in fact in some respects, they could be two aspects of the same thing.
Just for the record, I'm not a physicist, so beyond the first couple of facts this is all random amateur speculation.
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Re:Isn't all time travel impossible? (Score:5, Interesting)
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Only if you assume that their is only one set of ordered images. If every possible image is in the 'book' and every page is 'adjacently linked' to every other page that differed 'only a little', then free will may determine which adjacent page you (individually or perhaps your entire universes shared consciousness) go to at each step.
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For your example, let A and B be ants on a ruler, both starting at 0cm and walking towards 30cm. At the 5cm mark A scoots ahead of B, until it has a lead of 10cm. That doesn't make B travel backwards, it merely means that B is still at 5cm while A is at 15cm. You can speed up or slow down the passage of time, but you ca
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I seem to remember Zeno thought it illogical. But that was in my past.
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There's still no going backwards into the past for eithe
Eternalism and Reverse Causality (Score:3, Insightful)
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Time travel in the alternate universe sense implies that you can skip all that and simply pop in somewhere. This implies numerous things, but for starters implies that the universe has an infinite memory for everywhere it's been (and consequently, where it will be), and that this memory is not limited to the atom, particle or anything else, since it has to be remembered even if the atom/particle was destroyed or converted to energy.
That's no more true than the idea that there is foreign currency means that we have an unlimited supply of dollars.
A branching-universe theory of time travel (which is what you meant) simply implies that time as we perceive it is an actual dimension that can be traveled on at all. No more, and no less. Either time is an actual spacial dimension, or it is not.
Anything further than that is pseudoscientific nonsense, akin to speculations about the nature of life on Mars or Jupiter from last century.
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Wacking off to anime tentacle movies OTOH.........
Actually, the worst thing about TIme Travel (Score:3, Funny)