The CHSH Game: Lecture 7 of Quantum Computation at CMU

Quantum Computation and Quantum Information
Lecture 7: The CHSH Game
Carnegie Mellon Course 15-859BB, Fall 2018
www.cs.cmu.edu...
Course discussion board at www.diderot.one
Email [e-mail] for access
Weekly work: www.cs.cmu.edu/...
Taught by Ryan O'Donnell
Thumbnail image by Eels and Ticha Sethapakdi

[@michaelgrimaila3726]

The volume is too low !

[@Ehsan_alizadeh24]

Thank you so much for this extraordinary explanation Ryan!

[@randomvideos3628]

This is how slides should be made and explained. This should be the standard.

[@OlliWilkman]

51:16 to add to the story, Alain Aspect was finally one of the 2022 Nobel laureates in physics for the work mentioned here.

[@bibek2599]

thanks for the wonderful explanation.

[@sasidharankumar3713]

What if Alice measures Yellow and Dotted, Bob is not going to get Green Dotted right? So How come Yellow and Green measure same in the graph?

[@wagsman9999]

Very nice explanation. Thanks.

[@ittayd]

I think you're missing what if they have two coins that they "entangle" in such a way that the coins are both at the same angle to the horizon and then they look at them at angles that are similar to the measurement basis. Alternatively, what if they have two qbits that are not entangled, but simply at the same state (0 or 1) without alice & bob knowing. The idea is that there can be probability misses here that makes the answers align correctly. There should be the explanation that then the measuring will still come below 85%.

[@TeoZarkopafilis]

louder

[@jacekaleksandergruca]

I can't see what the CHSH inequality has to do with all this.

[@yangsiyuan4]

Padding may be showing :D

[@mimArmand]

@52:32 Funny tho, because 80% is as far from 75% as it is from 85%! so not sure how it proves one and disproves the other?!

[@mimArmand]

@@roberttech4035 Based on the video, Quantum mechanics prediction is %85.. the results are %80.. Classical prediction is %75.. Looks like both QM and classical are wrong, isn't it?!

[@roberttech4035]

​@@mimArmand No. In the CHSH game, the maximum success rate achievable by classical methods is mathematically proven to be 75%. However, quantum experiments have shown a statistically significant deviation from this classical limit. While quantum computation is in its early stages and it's challenging to achieve ideal results, even a 5% difference observed over 200 experiments indicates an underlying quantum phenomenon at play. As pointed out, the p-value suggests that the probability of this deviation being purely coincidental is extremely low.

[@mimArmand]

​@@roberttech4035 I agree, but I think you either didn't read my previous comment or are ignoring what I'm trying to say! There is no doubt that hidden variable theory with the exact parameters specified in the simplest version of it is out of question as you explained. but it's important to mention that the results are not in agreement with the expected values from QM perspective either ( a %5 discrepancy ) AND also that it does not disprove any other possible mechanism ( It simply disproves ONE possible explanation of what is going on ), but it does NOT prove or show what IS going on! We simply disproven one explanation, but we have NOT proven any other one yet! We simply do not know what is going on, I don't understand why everyone uses this to "prove" that universe is non-local, while it doesn't do that in ANY way! go read the paper and tell me where it proves that universe is non-local! it's all just a hype and propaganda which is unfortunate to see in a scientific environment.

[@davidschneide5422]

This quantum comment will remain in a state of liked/unliked until it's read.