by **gill1109** » Tue Oct 05, 2021 9:51 pm

Heinera wrote:Bell did not "discover" that nature is non-local. He demonstrated that any classical theory must be non-local if it has any ambition of reproducing the predictions of QM. That is why his paper initially had a rather lukewarm reception by his contemporary physicists; they were like "So what? Nobody belives in classical theories anyways these days, except as a useful macroscopic approximation." For instance Feynman hardly ever mentioned Bell's theorem, he felt that the theorem's conclusion was something that everybody already knew.

In fact, Feynman was annoyed when he heard about it, thought about it for a few minutes, and then proved the same theorem his own way. He didn’t publish it because nobody talked about Bell’s theorem, nobody cited Bell, for four or five years. But then Clauser was crazy enough to do his experiment with his student Freedman. He had waited till he got tenure to do it, because nobody believed quantum entanglement would continue to exist at any distance. Shimony then got excited and the CHSH paper came out with an inequality which could be useful in laboratory work. The Clauser-Horne inequality also came out, it too was designed for experimentalists, in fact, it has the same philosophy as Eberhard. (Eberhard’s contribution was not only to “merge” the “-1” outcomes with the “no shows” so as to get binary outcomes instead of ternary, but also to show that a much less weakly entangled state,with appropriate measurements, required much lower detector efficiency than CHSH). A handful of people published refutations. Bell published his refutation of those refutations. Then Aspect did his experiment. A whole lot later, detector efficiency reached the Eberhard limit, and the guys at NIST and in Vienna did their “loophole free” experiments in 2015. Just before that, Delft did their experiment with 100% detector efficiency thanks to the use of Bell’s idea of event-ready detectors (heralding). Munich followed.

As Heinera says, Bell experiments confirm quantum theory, and show that entanglement generates correlations which cannot be explained in a classical way. Schrödinger already intuited that that would be the case and he found it deeply disturbing. Einstein did not believe it. Physicists decided to “shut up and calculate”. The Nobel prize has gone to theoretical physicists who were spectacularly good at that, such as Gerard ’t Hooft and Marinus Veldhorst. But only after most of the particles in the standard model had been discovered in expensive high energy labs.

[quote="Heinera"]Bell did not "discover" that nature is non-local. He demonstrated that any [b][i]classical [/i][/b]theory must be non-local if it has any ambition of reproducing the predictions of QM. That is why his paper initially had a rather lukewarm reception by his contemporary physicists; they were like "So what? Nobody belives in classical theories anyways these days, except as a useful macroscopic approximation." For instance Feynman hardly ever mentioned Bell's theorem, he felt that the theorem's conclusion was something that everybody already knew.[/quote]

In fact, Feynman was annoyed when he heard about it, thought about it for a few minutes, and then proved the same theorem his own way. He didn’t publish it because nobody talked about Bell’s theorem, nobody cited Bell, for four or five years. But then Clauser was crazy enough to do his experiment with his student Freedman. He had waited till he got tenure to do it, because nobody believed quantum entanglement would continue to exist at any distance. Shimony then got excited and the CHSH paper came out with an inequality which could be useful in laboratory work. The Clauser-Horne inequality also came out, it too was designed for experimentalists, in fact, it has the same philosophy as Eberhard. (Eberhard’s contribution was not only to “merge” the “-1” outcomes with the “no shows” so as to get binary outcomes instead of ternary, but also to show that a much less weakly entangled state,with appropriate measurements, required much lower detector efficiency than CHSH). A handful of people published refutations. Bell published his refutation of those refutations. Then Aspect did his experiment. A whole lot later, detector efficiency reached the Eberhard limit, and the guys at NIST and in Vienna did their “loophole free” experiments in 2015. Just before that, Delft did their experiment with 100% detector efficiency thanks to the use of Bell’s idea of event-ready detectors (heralding). Munich followed.

As Heinera says, Bell experiments confirm quantum theory, and show that entanglement generates correlations which cannot be explained in a classical way. Schrödinger already intuited that that would be the case and he found it deeply disturbing. Einstein did not believe it. Physicists decided to “shut up and calculate”. The Nobel prize has gone to theoretical physicists who were spectacularly good at that, such as Gerard ’t Hooft and Marinus Veldhorst. But only after most of the particles in the standard model had been discovered in expensive high energy labs.