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."
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:Been there, Done that (Score:1, Informative)
What this experiment will ostensibly prove is the EPR Paradox (if I recall my college Q physics), but I'm betting it won't work. It's always sounded great, but I've always strongly suspected it is based upon faulty math...
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:Been there, Done that (Score:3, Informative)
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.
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.
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.
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.....
Re:recursion (Score:2, Informative)
Re:Been there, Done that (Score:3, Informative)
dupe, sort of.
Re:A True Hacker (Score:5, Informative)
Faster than light it ain't: (Score:2, Informative)
-- Wikipedia article on Spooky Action [wikipedia.org]
It won't work! (Score:2, Informative)
In quantum entanglement you have to objects with an entangled quantum state. That is, one of their properties is always the same (or always the opposite, depending on the kind of entanglement). On the other hand, this property is not already fixed when the objects get separated. Only when you measure the state of one particle you actually stipulate its state, and due to entanglement the state of the other partcle as well. As this happens instantaneous an the objects might be separated by a great distance, you get this 'spooky action at a distance'.
But, as been shown before, since you have no influence on the outcome of the measurement, there is no data tranmission involved (and also no reverse causality).
The article claims, that one can actually set the state of one object at will, thereby forcing the other object to have the same predetermined state. The problem is, that while you can actually force a light beam to behave like a particle (when you look at it how it behaves as a particle) or to behave like a wave (when you look at it how it behaves as a wave), and this actually has an effect on the entangled beam, it is not possible to measure if a light beam behaves like a particle or a wave!
Let's say you make the two slit experiment and observe which slit the beam will choose (thereby forcing the beam to behave like a particle). If you make the same experiment on the entangled beam, you will observe, that it will go through the same slit. (This is an ordinary EPR experiment without faster than light communication and reverse causality). If, on the other hand, you choose to look at the entangled beam as it behaves as a wave, it will behave as a wave. It still has both, the particle and the wave nature!
Unlike the spin, that could be either up or down, the particle or wave nature of a quantum object are two properties that coexists!
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.
Re:Paradoxes my a$$ (Score:2, Informative)
Um, when theory of relativity speaks about observations it speaks about causality itself. The observation B of an event A, is any event B that was caused by A.
To observe an event is to be affected by it in any manner.
"The theory of relativity states that there is no universal simultaneity for OBSERVING an event."
Um. That would not have been a new idea. The new idea that relativity brought is that there can be no universal standard for simultaneity itself, because time is dependent on the observer. Any two events C and D can be considered simultaneous according to *some* frame of reference if each is outside the other one's lightcone. According to different frames C may be thought to precede D or D to precede C -- but *that* doesn't violate causality because those event couldn't have affect one another anyway.
But FTL communication means that event C could be communicated to point-event D, even though in a different (but equally valid) frame of reference, point-event D precedes C. Event D could then use FTL to communicate itself to C. As such -- causality violation.
Unless not all frames of reference were created equal, as theory of relativity suggested.
Re:He's a quack selling snake oil (Score:3, Informative)
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.
Read:
[analogsf.com]http://www.analogsf.com/0612/altview.shtml [analogsf.com]
Now I have real problems with the causality violation part of his idea, but getting a spontaneous change in interference pattern would be really very interesting indeed.
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:3, Informative)
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 dont mean any disrespect to Einstein (as i'm clearly not worthy to do so), but i personally think his work with quantum physics is a rather dark spot on his personality.
John Cramer... (Score:1, Informative)
I predict another inconclusive result.
Re:Been there, Done that (Score:2, Informative)
http://einstein.stanford.edu/ [stanford.edu]
MISSION UPDATE -- JUNE 2007
GP-B SUCCEEDED IN COLLECTING THE DATA TO TEST EINSTEIN'S PREDICTIONS ABOUT GRAVITY
Over four decades of planning, inventing, designing, developing, testing, training and rehearsing paid off handsomely for GP-B. The 17.3-month flight mission succeeded in collecting all the data needed to carry out this unprecedented, direct experimental test of Einstein's general theory of relativity--his theory of gravity.