Quantum Entanglement

I was reading about the quantum entanglement ...

"Quantum entanglement is a quantum mechanical phenomenon in which the quantum states of two or more objects have to be described with reference to each other, even though the individual objects may be spatially separated. This leads to correlations between observable physical properties of the systems. For example, it is possible to prepare two particles in a single quantum state such that when one is observed to be spin-up, the other one will always be observed to be spin-down and vice versa, this despite the fact that it is impossible to predict, according to quantum mechanics, which set of measurements will be observed. As a result, measurements performed on one system seem to be instantaneously influencing other systems entangled with it."


A question. If we have two or more objects for which we KNOW that they are in the "mirror" state correlation between themselves to begin with, that is, if one of them has a spin on the axis "x" upward then another has a spin on the axis "x" downward, that is, we know that those two particles cannot both have the same spin on the certain axis, how exactly an observation of the one particle to be with a spin upward makes an observation of another particle's spin to be downward as nonlocal phenomenon, if we have not know which spin particular particle had until we have observed one or another?

"However, classical information cannot be transmitted through entanglement faster than the speed of light."

I think in regard of this statement that we are , possibly, neglecting the big picture.


Anton

Let us say that we have produced a two entaglemented photons, each with opposite spin.

As I understand the only one photon with it's particular spin would be able to pass through some medium, field, material, while other photon with opposite spin would not be able to pas through that medium, field, material.

If, hypothetically, both of the photons would pass that would mean that both of them has the same spin ( hey, it is a strange world of internet forums).

Would that mean:

1) the end of the world is near?

2) that cannot happen because so called entanglement is a consequence of the universe which "follows" the law of conservation of energy?

Anton

This post has been edited by Mate on Jun 16 2007, 04:31 PM

Haha, I can see the headlines now: A century of confusion comes to a close after someone finally points out the obvious.

I get the feeling that a lot of people in the field spend their time thinking of the elegance of the math rather than what the math actually describes.

It points out that no matter what we can eventually know, we will never be able to predict or control the future exactly.

I think you missed his point. Entangled particles are essentially mirror images of each other, so once you observe one you have information on both of them.

It's akin to flipping a coin and getting heads, then having your mind blown because its tails on the other side.

Wulf,

correct, that is what I meant. You said it more simply.

Anton

But isn't this after the fact, of having observed both of the sides? If you're already at the stage of flipping the coin, then there's no reason to have your mind blown.

So let's say you can predict the future, by saying it's going to be one side or the other. Can you say which side will come up, that it won't land on its edge, or what location it will be in when it happens?

This post has been edited by Eric England on Jun 16 2007, 05:33 PM

The crazy thing is that the act of observing the coin flip determines the face of the coin on the opposite side. Statistically the odds of the face being heads or tails is 1:2, however when we observe one side the probability of the opposite side having the opposing face becomes 1:1.

It is almost as if the act of observing the outcome of the coin flip determines the face on the unobserved side.

I have come to one idea about an experiment about so called quantum entanglement, but this imaged set up can only work under certain circumstances, about which I was trying to find a relevant information on the net, but with no luck. Too much results and pages, which amounted to an avalanche of irrelevant informations which very efficiently buried my initial enthusiasm to search through that gigantic pile of everything.

After some thinking what to do I concluded that instead torturing myself with this that it would be much better for me if I pass that job on you.

So, the question is..

Is it possible to change a spin of photon at will, so to speak?

Anton

Edit...I removed another question.

This post has been edited by Mate on Jun 17 2007, 04:38 PM

Is it really so crazy that the once you've arrived at 1 of 2, the other always comes up? What would actually be crazy, is if you have a coin with heads and tails, heads came up and you turned it over, and heads was on the other side too.

What you're observing is the fundamental nature of the RELATIVE. Two things that never change, but infinitely intermingle with each other.

That sounds like a good prediction of the future.

WHAT IS PHASE?

WHAT KIND OF WAVE GETS ENTANGLED?

Yes. It's a "certain uncertainty".

I think the power of the observer is highly overrated. We too easily assume that our observations affect the phenomenon we observe. To take it a step further and assume we can add our will to this process, is just another short-coming in our ability to be objective.

How can we even begin to say that what we observe is different, that what it actually is before we observe it?

Physics is far too subjective (ego-centric) at this point.

Eric England,

but the underlying point IS that they never change. If they never change, about what so called quantum entanglement nonlocal phenomenon we are talking about?

The most simple assumption ( in the line of Ockham's Razor ) would be that there is no nonlocal "causation" between two entanglemented photons, but there is only a simple correlation between two photons which are the "mirror" images of themselves.

Should not we take Ockham's Razor instead assuming some nonlocal phenomenon here, while there is no, as far as I know, some direct experimental evidence which would validate the hypothesis of so called quantum entanglement?

What would validate QME hypothesis would be, for example....

We produced two entanglemented photons, A and B, and they went in a different directions.

On the path of the photon A is a barrier made from some material through which the photon A can pass through only if it's spin is up on the certain axis( for example ).

On the path of the photon B is also a barrier through which the photon B also can pass only if it's spin is up on the certain axis.

But the path of the photon A to a barrier is significantly shorter, so when the photon A eventually passes it's barrier the photon B is still propagating to it's barrier.

If the photon A passes it's barrier that would mean that the photon B would not pass it's barrier because the spin of photon B is down if the the spin of the photon A is up.

Now, if it would be possible to change the spin of the photon A from up to down after the photon A passed it's barrier, but before the photon B approached its barrier, and if that change of the spin of the photon A from up to down would , apparently, change the spin of the photon B from down to up, and we observe that in the manner that the photon B also passes it's barrier, then that would be, indeed, a nonlocal phenomenon observed.

Is it possible to arrange an experiment alike this?

Anton