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"Spooky" Science Points Towards Quantum Computing
Stony Stevenson writes to tell us that University of Michigan physicists have been able to establish an "entanglement" between two atoms trapped more than a meter apart in different enclosures using light. This shows how two different atoms can have a sort of communication, something Einstein referred to as 'spooky action-at-a-distance'. "By manipulating the photons emitted from each of the two atoms and guiding them to interact along a fibre-optic thread, the researchers were able to detect the resulting photon clicks and entangle the atoms. Professor Monroe explained that the fibre-optic thread was necessary to establish entanglement of the atoms. But the fibre could be severed and the two atoms would remain entangled, even if one were 'carefully taken to Jupiter'."
My armchair reaction was, "Do they even have equipment precise to the nanosecond that you would need to determine that information had traveled one meter, faster than light speed?"
Apology to Ubuntu forum.
I don't have a great deal of understanding of advanced physics, so I'll throw this out. Could extra dimensions as proposed by string theory help explain this type of stuff?
Except for ending slavery, the Nazis, communism, & securing American independence, war has never solved anything.
We should probably not use words like "communication" to describe entanglement, because it only confuses people. Connection and correlation do not equal classical communication.
How entanglement works though is that you have two billiard balls that are not red or blue but both simultaneously. That is unless you measure it.
So you take your boxes too each side of the world and look in one that sets that ball to say red, the other turns blue instantly, and when you say instantly you really mean it, it is faster than light, faster than what should be the infinite speed, it is instant.
That is weird.
However, your example is accurate in describing why quantum entanglement doesn't break causality. You see you can't predict what colour the ball is going to be so you can't go to one end with eight boxes and say 'right ill make this byte the number 172.' then set your balls to 10101100 leading to the other boxes instanteously being set as well.
All you can do is measure the 8 boxes find out which are red and blue at either end confirm that they are entangled, thats it. No information transfer no causality breaking.
This is also why the initial posts idea falls down. You might know which particle is entangled with which but you can't measure its status without breaking the entanglement. So you could say tell the person 'measure it in 10 minutes and see if its broken down.' and yes you confirm that the entanglement breaks down instantaneously but you rather defeat the point by already giving the information. Either that or the person can guess when it breaks down but measuring it causes it to break down and bam you defeat the point again.
Entanglement has some kind of instant effect but it can not be used to send information and thus causality is preserved.
Once again, I'll quote the dude.
"Half of what we know about physics is wrong. The trouble is, we don't know which half." -Gary Skouson (AFAIK)
Exam 4/C again. Maybe I'll do better this time.
People think Quantum Physics is spooky, but I don't get it -- I really don't. Can anyone please explain to me (or point me at a link) that will tell me how this is any different than having two billiard balls, one is red and one is blue. Without looking at them, you put them both into boxes and ship them off to opposite sides of the globe. Now, one box is opened, and the ball is blue. So you know when the other box is opened, the ball they got will be red.
:-)
It's ``spooky'' to some since the ball decides -randomly- at the point of observation which color to display. The color is not known or set (or defined), in any way, before that observation. (so the `other' ball has no way of knowing what that -random- choice was, but somehow still manages to choose the proper color). [ie: in your example, the balls already have their color before they're separated; in quantum mechanics, they randomly choose the color upon observation].
First thing that pops to mind is ``how do they -know- that it's random?''; maybe the balls had their colors pre-set all along (like in your example). Well, there are various logical puzzles you can play where if things are -random- you'd get one result, and if things are pre-set, you'd get another result---and it does appear like the choice is -random- and not pre-set.
Google for ``Free Will Theorem''; it's a fun read
There's a lot of stuff about "no hidden variables" (ie: it's not that ``there's something [a deeper knowledge of things] we don't understand yet'' that's hidden from us... it's that the choice truly is random (there are no `hidden variables'); and somehow the other particle knows about that random choice at faster than speed of light). You cannot use this to send information though (since the choice is random---you only know what the other particle's choice is... but you can't force it to choose something in particular).
To resolve the confusion (and how I like to view things), it helps to picture the two particles as really being different sides of the -same- particle, that, from our perspective, just exists [we can observe] at two different locations. Picture the world from the particle's perspective---if you're moving at the speed of light, time stands still for you, therefore, from your perspective, you can traverse the universe at infinite speed---from your perspective, you can instantly react to events anywhere in the universe (from the outsider's perspective, they just see you as moving at the speed of light...). I guess it's one of those things that are hard to explain, but easy to visualize.
"If anything can go wrong, it will." - Murphy
This sort of thing is exactly why I think (brace yourselves, everyone) that all science outside of pure maths should abandon "laws." Not the rules themselves, just the notion that they are %100 pure-real-deal. Having laws in science causes bizarre rationalizations whenever a study yields results that contradict a law, such as some of the explanations of this study. I have a far easier time accepting that quantum entanglement breaks the "laws" as we know them than I have accepting that than something like "allowing things to happen before they are caused."
There is more to science than physics!
www.iomalfunction.blogspot.com
This small side-effect is probably fascinating only to me, but wouldn't a system of communication based on this kind of entanglement mean that the medium for communication would be a limited resource (i.e. when you run out of entangled particles you can no longer communicate with the other party)?
It strikes me as very odd that something used only for communication ("entangled particles") might someday be counted along with things like "food" and "oxygen" as vital, but limited resources for long-distance travel. In fact, it seems like they may eventually be the most vital resource: things like food and oxygen are relatively sustainable in that they can be grown, purified, distilled, extracted, etc. but entangled particles from earth would be impossible to reproduce or replace without direct contact with earth (or at least, direct contact on the order of a very very long fiber optic cable).
Anyway, just a musing.
Or
4. Our knowledge of the universe is quite limited at this point and we can in fact exceed the speed of light without violating causality.
Furthermore, in time it's quite likely to be found that Special/General Relativity and the mathematics that explicate them including Minkowskian geometry do hold true, but only in a limited context (close to light speed), and have little to no relevance once C has been exceeded.
// MD_Update(&m,buf,j);