Science a GoGo's Home Page Forums General Discussion Physics Forum Bell's Inequality, simple version

I am rereading "The Dance of the Photons" by Anton Zeilinger. The book is about quantum entanglement. In an appendix Zeilinger includes a paper by "A. Quantinger" on Bell's Inequality without math. Anybody who is interested can see how it works if they can find a copy of the book. If you can read German you can read it on line in German.

Once I have finished the book I may be back with some questions about it.

Bill Gill

I'd be very interested to have your opinion on Zeilinger's book.

I had a look at the sample pages on Amazon, there seemed to be much more of the German version available. I often regret having abandoned German in the very early stages.

Anything that can present a "simple version" of Bell's Inequality" has to be worth a look.

The book is pretty good. The first parts are helpful in understanding about entanglement. Some of the later sections threw me a little bit. They were about extensions of entanglement into quantum computing and such like. But with a little study it should be possible to follow them. The book mostly concerns entanglement of photons, but the general idea is the same for other systems.

He does explain fairly clearly how quantum teleportation works. It doesn't actually transport a particle from one place to another, it transports the state of the particle to a different particle in the other place.

I looked at his explanation of Bell's inequality, and it is fairly straight forward. He explains it with identical twins. That makes it much more understandable. I tried to paraphrase it but I couldn't come up with a way to condense it into a paragraph or 2. So you probably need to see if you can find a copy of the book.

Over all it was an interesting and helpful read.

Of course I still think that there must be some mechanism that explains how entanglement works. It really does work, but how making a measurement on the state of one particle causes the state of another entangled particle to assume a specific state is really weird. Since I don't believe in magic there has to be something that enables the coupling. I realize that it is right there in the math of QM, but I don't think the math defines the method, just the result. I haven't seen anything that explains it. Everybody just says that it is weird but that is the way it is. I expect there are researchers out there trying to come up with an answer to the question, but so far there doesn't seem to be much progress.

Bill Gill

Perhaps this will help. Especially the comments of Motl.

http://physics.stackexchange.com/questio...tween-particles

pokey, I followed your link, and I think I see what motl is saying. Since both particles are part of the same wave function, then when one of them collapses both of them collapse. However, I still have a problem with the timing. How does a part of a wave function which is spatially separated from another part of the wave function know that the whole thing has to collapse? Remember that the 2 portions of the wave function can be extremely far apart.

Looking at this quote, doesn't that just amount to the hidden variable explanation? And the hidden variable explanation has been ruled out by Bell's inequality.

And the quote says that the wave function is just a bunch of numbers. Well, when did the universe learn to count? The numbers that he references are our approximation of the wave function. The actual wave function is a property of the universe which we describe using numbers.

Bill Gill