Entanglement

[Conk]

So I know of entanglement with characteristics of a pair of particles with properties such as spin and polarization, but i've not heard the story behind entanglement with properties with out and "equal and opposite" say, spin up and spin down, and the opposing polarization of an electron, horizontal or vertical, or any opposing set of degrees in between.

So is there entanglement for other properties? or are the equal and opposites the only ones with such a "spooky action at a distance"

[jake-the-peg]

As I recall the EPR paradox was first formulated with continuous rather than discrete observables such as to potentially contradict the Heisenberg uncertainty principal.

In this formulation one imagined a radioactive decay such that two identical particles are emitted in opposite directions with identicle energies (entangled) . You could in theory measure the position of one and the momentum of the other with unlimited accuracy, infering the position and momentum of the other hence violating HUP.

The analogue of this experiment was done in 1982 in the univeristy of Paris by Alain Aspect and that's worth looking up. But he used light polarization as I recall.

If you really want to know more about this stuff Leonard Susskind (string theorist) has an entire course on Quantum Mechanics filmed and available for free download on stanford Itunes U
http://itunes.stanford.edu/

It's given to post graduates but if you can handle complex numbers and matrices it's not too hard - although a bit of linear algebra is helpful

I think he gets into entanglement proper in about the 4th lecture

[Conk]

I've run into the Aspect experiments before, and it only follows suit to what i would call "plausibly identical" particles, such as when you pluck the string on a guitar and the string does not actually make one wave, but two reciprocal waves that overlap just slightly at their extremities, and are cause by the movement which i would illustrate as thus 1. (<--0-->)2. with 1. and 2. being the wave crests, and 0 being the "string" or mid point of vibration, being that wave 1. and wave 2. are "the same" as they are from the same source, they act identically (ideally). But as one crests, the other troughs, and vice versa, which is the same as the up/down, and horizontal/vertical relation in the entanglement phenomenon. As far as the superposition of states would go in the math, that's not unique to quantum mechanics and probabilities deals with a coin toss the same way as a particle, the future is always a superposition in the realm of math.

Entaglement is to me a falsehood cooked up by the mystery which is really known as "the future"
The only real mystery in the quantum, as Feynman stated, is the double slit experiment, which i find beautiful in it's simplicity, elegance, and bizzare nature.