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StatisticsWow ... my brain just exploded.
I'm going to have to read this again when I get home from work so I can digest it more slowly. Thanks!
Faster Than Light
Have you seen the experiment with Faster Than Light transmission? I was going to post it as news until I noticed it was dated from 2000. The dude Lijun Wang was working for NEC at the time and transmitted energy through a laser-irradiated vapor. While verbally this is nothing special (I can shine a laser pointer through shower steam) the finding was that the particles effectively emerged before they entered the medium. There's a pretty detailed discussion of it at MadScientist.org.
So this makes me wonder. If something emerged before it entered - is that simply an fluke in our notion of perception? Or is that similar to a quantum state where something exists in two places at once? If you're familiar with this experiment, how closely interrelated is such a principle with entanglement (I'm thinking in terms of the phase velocity [from the mad scientist article])?
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RE: The problem with quantum theory, put simply, is that it's really weird.
The problem with quantum theory, put simply, is that it's really weird.
Yes, quantum mechanics is weird. But, if you drink the water, it starts to make sense. Seriously, though, quantum describes practically all of what happens at the atomic level.
If I'm reading this right (wyldeling, please jump in with your physics guru-ness), engtangled photons will impact one another irregardless of their separation in time or space. "It's all incredibly counterintuitive," Cramer acknowledged.
You are reading this correctly. To be pedantic, though, you should use the word "effect" not "impact", as impact implies an actual collision which is not what is happening here.
When I first read the headline for this, my BS meter went off the scale, as it looked like science via press release to me. After I read the article, though, the pastoral aroma has dissipated somewhat. I would like to clarify what you said about it, though.
While thinking about this experiment, the idea to keep in mind is that because the speed of light is finite the flow of information from one part of the universe to another should also be finite. Because of this, we can partition space-time into regions that cannot influence each other, and our ideas of causality are built upon this precept. The idea of entanglement seems to violate this by connecting two regions of space-time that are otherwise causally disconnected (i.e. they are seperated by a space-like interval). Two particles are entangled if their combined quantum state cannot be broken down into a product of individual states. (I know gobbledegook, but hold on.) It helps to think of this in terms of probability theory. For example, if you have two random variables X and Y, their joint probability, P(X,Y), can be rewritten as P(X,Y) = P(X) P(Y) only if they are independent. In the similar manner, the joint state of two particles, S(a,b), can be rewritten as S(a,b) = S(a) S(b) if and only if they are not entangled. Physically, this means that there is some form of communication between two particles that are entangled despite any physical seperation, and this communication is instaneous because they are part of a larger whole (the joint state). So, if you wiggle one particle, you can measure the effect on the other at the same time.
In the experiment they've described, they'll take a photon, split it into two photons (which are entangled), and send one down a short path to a detector and the other down a long path, resulting in a 50 ms difference in their arrival times. When the one sent down the long path has arrives at the detector, they will do something to it to force into a specific state. Now, if entanglement allows for communication into the past, the first photon to arrive at the detector should have been effected in a detectable manner. This is the part that is fishy to me, but, as a good scientist, he has designed an experiment that will be capable of determining if it is possible, or not.
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