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Testing Einstein's 'Spooky Action at a Distance'
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."
Didn't the Aspect Experiment back in the '80s demonstrate this effect?
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
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?
But we've already done it: Elitzur-Vaidman bomb-testing problem
At the bottom, it says that the equivalent experiment has already been performed, and TFA sounds like it is nearly the same experiment.
Look, posting this article made this other article from June 12 with exactly the same content get posted!
The theory works!
How we know is more important than what we know.
Spooky Action at a Distance describes my sex life exactly.
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, 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.
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Looking for a C/C++ job in Silicon Valley?
Qxe4
Well.... he would be successful with his "spooky action", if not for those meddlesome kids!
I, myself, am a time traveler from the past. I've been journeying into the future at a rate of sixty seconds per minute.
As others have pointed out, we are in fact time travelling all of the time. However, to time travel as I'm sure you mean, significantly faster than our surroundings, Einsteins time dilation does the trick nicely, its just a matter of propulsion technology.
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.
"...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
Suppose an astronaut travels away from the earth at 99.9% of the speed of light. According to relativity, if he ever returns then everyone on earth will have aged considerably more than he has. But he has to turn around at some point in order for this to happen, hence he has to accelerate. And it doesn't take any reference points to judge that acceleration, so you can in effect say that he has travelled into (Earth's) future, and that the entire Earth has not travelled into the past.
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.'
Einstein formulated the theory with 2 colleagues, Podolsky and Rosen.
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.
Relatively speaking, of course.
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.
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 requires it to exist later in time.
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.
Relative to what? Do you really not grasp why the Theory of Relativity is called the "Theory of Relativity"? Or for that matter, do you not understand the implications of the Copernican Revolution? Yes, the Earth is moving relative to the Sun, but that's just a matter of taking the Sun's perspective in order to simplify the math. In reality, there is no absolute perspective from which to say the Earth is moving relative to it. The only reason to say the Earth moves around the Sun instead of the other way around is the mathematical convenience. From the Milky Way's perspective, we're orbiting the core. From the Andromeda Galaxy's perspective, we're charging toward them. There is no preferred perspective.
Yes, it's fun to just speculate on Slashdot, but you are far, far too ignorant of science to make even speculate pronouncements on the future of physics.
A big criticism of quantum mechanics (still) is that nobody is exactly sure the minimum you have to do to one entangled particle to "measure" it, which determines what the person with the other entangled particle will he when he "measures" his particle. Schrodinger's cat paradox has never beeon completely satisfactorily answered. The existance of quantum entanglement is well established, though.
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.
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.