4 ms·

I'm not convinced. (But also I'm not a physicist). Don't get me wrong, they are all great experimentalists and their experimental work helped move the science

I'm not convinced. (But also I'm not a physicist). Don't get me wrong, they are all great experimentalists and their experimental work helped move the science forward in the understanding and control of the atomic scale. But their "Bell's experiment" variations have been used to "disprove" and cast aside wide branches of theoretical research, and this will probably remain as one of the biggest failure of modern science. If you model the experimental settings in your theory, it's indeed quite simple to reproduce the QM probabilities (and therefore violations of CHSH inegalities), with a local hidden variable theory. In fact here is 60 lines of numpy code to set-up virtual experiments to convince yourself (try various settings for the polarisers angles alpha and beta) https://gist.github.com/unrealwill/2a48ea0926deac4011d26842627b69c9 https://gist.github.com/unrealwill/2a48ea0926deac4011d268426... (Straight implementation of Marian Kupczynski "Closing the Door on Quantum Nonlocality" https://www.mdpi.com/1099-4300/20/11/877 https://www.mdpi.com/1099-4300/20/11/877 (around eq.7-8) if you need more explanation).

enviclash 4y ago
I am also not an expert on the topic, but citing a MDPI paper to argue against a Nobel prize seems also unconvincing.
quixoticaxolotl 4y ago
> it is indeed quite simple to reproduce ... with a local hidden variable theory This is not the whole truth. Bell's inequality assumes a few reasonable assumptions for hidden variable theories besides locality (https://plato.stanford.edu/entries/bell-theorem/ https://plato.stanford.edu/entries/bell-theorem/) and it is true that sacrificing these assumptions can yield a local hidden theory consistent with Bell's inequality / CHSH inequality violations. But the whole point of these assumptions is that we want them. Bell's inequality is the definitive experimental test that a standard classical theory is not waiting in the wings for us, and those assumptions are central to classical mechanics. The issue with a theory that sacrifices things like parameter independence or similar is that they will remain mathematical curiosities, much like interpretations of quantum mechanics, because there is no way to test them. And they'd be stranger than quantum mechanics, so you don't get any relief either. So, yes, you can do this. But it has no practical value. This is not the experiment's fault in any way. However, if you are arguing that you can have a local hidden variable theory that satisfies all of Bell's assumptions and violates the inequality, then you have some severe issues in your argument somewhere, because it is categorically impossible. > 60 lines of numpy code In the event you are arguing for a local hidden variable theory that satisfies all of Bell's other criteria: firstly, there is no guarantee the simulation has any fidelity to the real world at all. Thankfully, you don't have to settle for simulation. I was fortunate to take 180Q at UCLA, an undergraduate class where we were required to derive the CHSH inequality and perform simple experimental violations by ourselves. The tools needed to run a simple test are commercially available and affordable - you can do it yourself at home. I was able to achieve experimental violation when I did so back in 2015/2016, and documented the results here: https://github.com/AkshatM/Physics180Q/blob/master/Final%20Paper/Akshat%20Mahajan%20-%20Physics%20180Q%20Final%20Report.pdf https://github.com/AkshatM/Physics180Q/blob/master/Final%20P... Of course, if you are arguing we can sacrifice an assumption of Bell's besides locality, then the above is moot. But it would still be rather pointless.
Strilanc 4y ago
Your code is not properly enforcing the communication constraint between the two players. Try to enter code that passes the bell tester widget included in this blog post and you'll find the problem: https://algassert.com/quantum/2015/10/11/Bell-Tests-vs-No-Communication.html https://algassert.com/quantum/2015/10/11/Bell-Tests-vs-No-Co...
- GistNoesis 4y ago
  Of course it can't be written into your bell tester. It's not hiding anything. It works because of the post-selection. But this selection is done in a locally compatible way. It works because you as the (virtual) experimenter can specify/choose explicitly a precise definition of what a measurement is, (which you can't do in your widget). My code is showing an example of the general structure of how you could/should define what a measurement is, in such a way that you preserve both the locality of the world, and the observed violation of the Bell inequalities (according to your definition of what a measurement is). I'd argue that it's in essence doing what, one way or the other, the real world measurement apparatuses of the experimenters are doing.

enviclash 4y ago

I am also not an expert on the topic, but citing a MDPI paper to argue against a Nobel prize seems also unconvincing.

quixoticaxolotl 4y ago

> it is indeed quite simple to reproduce ... with a local hidden variable theory This is not the whole truth. Bell's inequality assumes a few reasonable assumptions for hidden variable theories besides locality (https://plato.stanford.edu/entries/bell-theorem/ https://plato.stanford.edu/entries/bell-theorem/) and it is true that sacrificing these assumptions can yield a local hidden theory consistent with Bell's inequality / CHSH inequality violations. But the whole point of these assumptions is that we want them. Bell's inequality is the definitive experimental test that a standard classical theory is not waiting in the wings for us, and those assumptions are central to classical mechanics. The issue with a theory that sacrifices things like parameter independence or similar is that they will remain mathematical curiosities, much like interpretations of quantum mechanics, because there is no way to test them. And they'd be stranger than quantum mechanics, so you don't get any relief either. So, yes, you can do this. But it has no practical value. This is not the experiment's fault in any way. However, if you are arguing that you can have a local hidden variable theory that satisfies all of Bell's assumptions and violates the inequality, then you have some severe issues in your argument somewhere, because it is categorically impossible. > 60 lines of numpy code In the event you are arguing for a local hidden variable theory that satisfies all of Bell's other criteria: firstly, there is no guarantee the simulation has any fidelity to the real world at all. Thankfully, you don't have to settle for simulation. I was fortunate to take 180Q at UCLA, an undergraduate class where we were required to derive the CHSH inequality and perform simple experimental violations by ourselves. The tools needed to run a simple test are commercially available and affordable - you can do it yourself at home. I was able to achieve experimental violation when I did so back in 2015/2016, and documented the results here: https://github.com/AkshatM/Physics180Q/blob/master/Final%20Paper/Akshat%20Mahajan%20-%20Physics%20180Q%20Final%20Report.pdf https://github.com/AkshatM/Physics180Q/blob/master/Final%20P... Of course, if you are arguing we can sacrifice an assumption of Bell's besides locality, then the above is moot. But it would still be rather pointless.

Strilanc 4y ago

Your code is not properly enforcing the communication constraint between the two players. Try to enter code that passes the bell tester widget included in this blog post and you'll find the problem: https://algassert.com/quantum/2015/10/11/Bell-Tests-vs-No-Communication.html https://algassert.com/quantum/2015/10/11/Bell-Tests-vs-No-Co...

GistNoesis 4y ago
Of course it can't be written into your bell tester. It's not hiding anything. It works because of the post-selection. But this selection is done in a locally compatible way. It works because you as the (virtual) experimenter can specify/choose explicitly a precise definition of what a measurement is, (which you can't do in your widget). My code is showing an example of the general structure of how you could/should define what a measurement is, in such a way that you preserve both the locality of the world, and the observed violation of the Bell inequalities (according to your definition of what a measurement is). I'd argue that it's in essence doing what, one way or the other, the real world measurement apparatuses of the experimenters are doing.