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Testing Einstein's 'Spooky Action at a Distance' 375

Posted by samzenpus
from the this-worked-in-a-different-timeline dept.
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."
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Testing Einstein's 'Spooky Action at a Distance'

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  • by sconeu (64226) on Wednesday July 18, 2007 @10:10PM (#19909609) Homepage Journal
    Didn't the Aspect Experiment [roxanne.org] back in the '80s demonstrate this effect?
    • by MOBE2001 (263700) on Wednesday July 18, 2007 @10:38PM (#19909805) Homepage Journal
      Didn't the Aspect Experiment back in the '80s demonstrate this effect?

      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.
    • by msevior (145103) on Wednesday July 18, 2007 @11:11PM (#19910055)
      Actually no. This new experiment is VERY interesting. The new experiment proposed by John G. Cramer aims to test an idea that might allow quantum signaling.

      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.....
      • Re: (Score:3, Informative)

        by brunascle (994197)
        i knew [slashdot.org] that name sounded familiar.

        dupe, sort of.
      • by mrmeval (662166)
        All of his writing including pointers to his novels are here.

        http://faculty.washington.edu/jcramer/ [washington.edu]

        I love his articles.

      • by gr8_phk (621180) on Thursday July 19, 2007 @09:46AM (#19913455)
        He is talking about an issue I've raised before - there is no way to tell the difference between a particle whose entangled twin has been "measured" and one that has not. If you can tell the difference, this would allow faster than light communication. I contend there is no difference - physics has a lot to explain here. But he claims to have an experiment to confirm it - great. However:


        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:

        Now brace yourself for the backward-causality part: Because Signal B followed a shorter route to its detector, the fiddling in Signal A could theoretically show up in Signal B before Cramer actually fiddles with Signal A. It would be as if Cramer's actions had an effect that worked backward in time.
        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.

        • Re: (Score:3, Informative)

          by msevior (145103)
          "Where do you get a laser that produces entangled pairs with the ability to separate the pairs into 2 coherent beams?"

          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
    • by Brad1138 (590148) * <brad1138@yahoo.com> on Wednesday July 18, 2007 @11:19PM (#19910117)
      Didn't the Aspect Experiment back in the '80s demonstrate this effect?

      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.
  • Causality (Score:5, Interesting)

    by GWLlosa (800011) on Wednesday July 18, 2007 @10:11PM (#19909621)
    Does this mean that once the effect shows up in the one light beam, before he does it in the other light beam, he is somehow locked in to his future actions? If not, what happens if he just turns off the device?
    • by Anonymous Coward on Wednesday July 18, 2007 @10:17PM (#19909657)
      Does this mean that once the effect shows up in the one light beam, before he does it in the other light beam, he is somehow locked in to his future actions? If not, what happens if he just turns off the device?

      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.
    • by Nyeerrmm (940927)
      This is just a completely uninformed gas, but I would guess it would be a case where it only happens briefly, after the experimenter has reached what amounts to a point of no return. In other words, perhaps the change occurs only after the action is already 'locked in' but hasn't actually occured. I'd suppose if this is true its probably on the order of femtoseconds, or something like that.

      Anyway, I'm not particularly knowledgable on quantum stuff, as I'm sure this post shows, but that would be my guess.
    • Re: (Score:3, Funny)

      by RuBLed (995686)
      If he turns off the device as soon as he sees a result, he would be transported to the realm of Q where he would be tortured and made to drink the soup of earth's first would be inhabitants.. He would only be released when he agrees that he would not turn off the switch thus Q would send him back one second before he turns off the switch thus he would not turn off the switch he turned off in the future... or something like that..
    • by Bluesman (104513)
      He won't :-)
    • by pelrun (25021)
      There's an inherent fallacy in such a proposed experiment. Where is the case in which the experiment actually performs the action? As stated, the action can never be performed. If the action is never going to be performed, then the result is never going to be observed.

      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
    • It's simple. If you see the change, then in the future, he DID make the change. Just like in Bill and Ted, he wouldn't have gotten his dad's keys if he didn't go back in time, from the future of that point.
    • Re: (Score:2, Interesting)

      by Anonymous Coward
      Two points, A and B. An actor at point A causes a result at point B. The laws of the universe don't prevent the result from preceding the cause, but they do prevent the actor from knowing the result before acting. By the time the actor can know what the result is, he will already have acted, or not. Information about the result can't travel back to point A before the actor acts.
    • by chub_mackerel (911522) on Thursday July 19, 2007 @01:38AM (#19910931)

      Does this mean that once the effect shows up in the one light beam, before he does it in the other light beam, he is somehow locked in to his future actions? If not, what happens if he just turns off the device?

      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.

    • Re: (Score:3, Interesting)

      by AdamWeeden (678591)
      Go watch Deja Vu [imdb.com]. The movie is not going to win any Oscars, nor are the physics 100% pristine, but it does have an interesting proposal on effects preceding causes and causal feedback loops.
  • by Kagura (843695) on Wednesday July 18, 2007 @10:12PM (#19909625)
    But we've already done it: Elitzur-Vaidman bomb-testing problem [wikipedia.org]

    At the bottom, it says that the equivalent experiment has already been performed, and TFA sounds like it is nearly the same experiment.
  • by QuantumG (50515) <qg@biodome.org> on Wednesday July 18, 2007 @10:17PM (#19909653) Homepage Journal
    Look, posting this article made this other article from June 12 [slashdot.org] with exactly the same content get posted!

    The theory works!

    • Does that mean 'spooky action at a distance' becomes 'slashdot dupe' in all the textbooks?
      Personally, I prefer ballsy scientific names after people like Heisenberg and Avogadro.
    • by Z0mb1eman (629653)
      You get bonus points for your username.

      (or you would if I had mod points right now :p)
  • Amazing (Score:5, Funny)

    by INeededALogin (771371) on Wednesday July 18, 2007 @10:21PM (#19909691) Journal
    Spooky Action at a Distance describes my sex life exactly.
  • 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.

    • If, the egg were to somehow mysteriously not fall to the ground.

      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)

    by phantomfive (622387) on Wednesday July 18, 2007 @10:25PM (#19909717) Journal
    John Cramer, the designer of the experiment, is really quite a colorful guy. He last got the attention of the press by simulating the sound of the big bang using Mathematica. Useless research of course, but who wouldn't laugh hearing that the big bang sounded like "large jet plane 100 feet off the ground flying over your house in the middle of the night?" At heart this guy is a physics hacker (in the true sense of the word hacker).

    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)

      by xPsi (851544) on Wednesday July 18, 2007 @11:37PM (#19910251)
      I worked with John on the STAR experiment at RHIC in the pion interferometry group. Your description of him as a physics hacker (in a good way) is right on. I do sometimes wonder about his sanity when I read about his latest projects (e.g. see TFA) -- but he is by no means a crank or crackpot. Oddly enough, he also does dog shows as an owner. His personality would fit right into Christopher Guest's movie Best in Show (I also mean that in a good way). So think of him as a dog trainer/quantum mechanic/science fiction author. He's basically a nerd renaissance man.
    • Thank you for the informative post. I have mod points, but I couldn't in good conscious bump you up to 5 when you add a headhunting link to your post in the guise of a signature. (I have display of .sigs disabled, which is why I am sure it is not your signature.) I know it's borderline - which is why I couldn't in good conscious give a negative mod, either - but if we start accepting sly stuff like this without comment it just moves the borderline more into the spammy side of the net.
      • Thanks for the comment, I didn't realize it bothered people. I'll move the link into my 'real' sig, however, it does feel a little hypocritical since your own sig is just an advertisement for a website.

        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
        • heh, I forgot all about linking to my company in my sig. I must have added it many years ago and as I mentioned, I disabled display of sigs. But that's why we have the option to filter the real sigs out, because they are for off topic stuff. Putting advertisement - however benign - into the actual content where it can't be filtered is the trend that worries me.
          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)

    by INeededALogin (771371)
    This solves about every communication problem that man has ever come up. Long-distance space communication not only becomes trivial.. our future explorers will be playing WOW all the way to Alpha Centauri.
    • by Bluesman (104513)
      "our future explorers will be playing WOW all the way to Alpha Centauri"

      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.
    • by MrJynxx (902913)
      It's been a long time since I've read Enders Game, Speaker for the Dead, and Xenocide. But this kinda sounds like the ansible. That way of communication through what, thousands of light years instantly??

      To bad we'll never see that in this lifetime..
  • by LordPhantom (763327) on Wednesday July 18, 2007 @10:30PM (#19909747)
    Well.... he would be successful with his "spooky action", if not for those meddlesome kids!
  • i've always had trouble with this idea. my primary reason, is that the future hasn't happened so how can it exist before the present?
    • perhaps the future is pre-determined. You have no choice... That laser beam must be modified in x way.
    • by zCyl (14362)

      i've always had trouble with this idea. my primary reason, is that the future hasn't happened so how can it exist before the present?

      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

      • Re: (Score:2, Insightful)

        by SavvyPlayer (774432)
        If time travel were possible and we manage to survive long enough to discover it, today's world would be full of future gamblers. entrepreneurs, megalomaniacs & soldiers of fortune. Technology changes -- human nature doesn't.
  • by ChronoFish (948067) on Wednesday July 18, 2007 @10:52PM (#19909897) Journal
    "...his experiment might show that a change made in one beam shows up in the other beam before he actually makes the change...."

    What happens when he notices the change, before he makes the change, and changes his mind and doesn't make the change?

    -CF

  • as he would of just needed one to do the test in 1-5 min.ed
  • by Traf-O-Data-Hater (858971) on Wednesday July 18, 2007 @10:57PM (#19909937)
    so I've just sat down and made myself a nice cup of instant tea. The list of ingredients on the teabag's packet say it contains 'Thiotimoline, resublimated, product of China.'
  • recursion (Score:2, Insightful)

    by Mr EdgEy (983285)
    so, let's say Beam A and B are split from one beam.. you change beam A, B changes before you changed A so then B's change should change A before you changed it and it would recur ... so how would you be able to measure a change that would effectively be happening in an infinitely small amount of time?
  • the "Einstein's Bridge" John Cramer who's proposing this test?

    Just wondering...

  • "Observations on entangled states naively appear to conflict with the property of relativity that information cannot be transferred faster than the speed of light. Although two entangled systems appear to interact across large spatial separations, no useful information can be transmitted in this way, so causality cannot be violated through entanglement. This is the statement of no communication theorem."

    -- Wikipedia article on Spooky Action [wikipedia.org]
  • 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. They also need to consider the displacement that occurs as well. Obviously, the Earth is not in the same exact place a few seconds ago as it is now. As such, they would need to conpensate for that as well. They should also consider that there is bound to be interference by all of the signals bouncing aro
    • Re: (Score:3, Interesting)

      by Anonymous Coward
      You are quite obviously talking out your ass.

      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
      • Re: (Score:3, Insightful)

        by Control Group (105494) *
        Strictly speaking, he could have been referring to the Earth's rotation. Since you can always detect if you're in a rotational frame, that's motion that's real in a more absolute sense than linear motion.

        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)

    by master_p (608214) on Thursday July 19, 2007 @05:30AM (#19911967)
    I apologize for the colorful title, but I can not describe my feelings towards the so called theorem of 'no communication faster than light' in any other way. There are no time paradoxes if FTL communication exists, for the simple reason that when an event happens, it happens for all the universe. The fact that photons would not have arrived to the FTL communication target when the FTL signal reaches that target is totally irrelevant. And there is no way to perceive an event before it happens and change the outcome, for the single reason that effect always follows cause. So even if FTL communication is real, there would not be possible to avoid doing events that already have happened, for the simple reason that the events have already happened.

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