Can somebody explain quantum entanglement?

Question

I have read explanations in the past, but some things are unclear (big surprise) to me:

1. How do particles become "candidates" for entanglement? Were they somehow related before hand, or do they just have to interact at some point?

2. They apparantly exhibit their respective behaviors without respect to causality -- how is this proven and how is it possible? ("we don't yet know" is an acceptable answer)

3. How does this translate into the possibilty of "quantum teleportation"? I don't see or understand the flow of logic.

I am no math whiz -- if you can explain it without math, great -- but if you must, be gentle with me. This is one of the most fascinating subjects I can imagine.

Ron: Um, okay, the math is almost meaningless to me, but I gather that by measuring the property of one of the related particles, we can make a statement regarding the probability of the state of the other. Now that very act of measurment -- doesn't this affect the state of the particle, and doesn't the entangled particle then (if we could measure it too) exhibit an opposite behaviour? So if the act of measurement, say, exactly reverses the "spin" of particle A -- how can particle B respond with a spin in he opposite direction of its previous spin? Am I making sense?

Answer 1

1. Particles that are entangled *must* have interacted at some point in spacetime.
2. This is a misconception caused by loose and sloppy mass media writing. the basic idea is that the measurement of a certain property of one of the entangled particles "determines" instantly the entangled property of the other particle, no matter how far away it may have travelled. *This does not mean that the particle sent a faster-than-light signal to the other particle to "quick, change into a pair of red pants"!* The reason for this effect is the combination of the limits on quantum measurement with the fact that the particles have a sort of "probability machine" accompanying their measurement and due to their previous meeting, these "machines" have become related. If you want to understand this better, I suggest reading http://www.mathpages.com/home/kmath521/kmath521.htm .
3. This allows the possibility of instantly sending information from one point to another using entangled properties (using some heretofore unthought of encryption/decryption algorithm). However at this moment we are not exactly brilliant enough to figure out how to accomplish this not so easy task!

Answer 2

you're suited guess is to study-up on the EPR paradox. yet, right this is an attempt to summarize. Quantum Mechanics (QM) as all of us be attentive to it at present is named the Copenhagen Interpretation. This very specific kind of QM is composed of a few very interesting innovations that leave from Classical deterministic mechanics. right here are 2 substantial innovations correct to entanglement. a million. A QM device is in an indeterminate state, or superposition of all conceivable states, till now a length is made. The act of arising a length forces the device right into a particular state, with a definite threat for the specific consequence. This habit is immediately observable in what's called "the strict-Gerlach test." 2. Pauli's exclusion correct. specific products can no longer all occupy a similar states, yet ought to distribute themselves for the time of available states. enable's say 2 products from 2 above work together at a while, while they are co-placed, and then holiday an excellent distance aside. At some destiny time we degree the state of the two products as quickly as they have moved a approaches aside. in actuality, enable's do it in a manner that a "sign" traveling the linked fee of sunshine could no longer pass between them because of the fact the measurements are made. And, such that we degree the state of one immediately till now the different. we can locate, after making the 1st length, the 2d will continuously accept as true with Pauli's exclusion theory. yet, remember, we additionally be attentive to the state of the 1st became into in basic terms desperate as quickly as we made the dimensions. The collective device became into in a superposition of states till a minimum of one length is made. So the products are suggested to be “entangled” on the very commence of this technique. This habit has been experimentally shown, and is actual! that's frequently suggested as "Spooky action at a Distance."

Answer 3

http://en.wikipedia.org/wiki/Category:String_theory

can I explain it. uh, no. hope you find an answer---Brian