Bell inequalities and the profound implications of quantum mechanics

.
Timestamps
00:00 Introduction
00:35 Toy model
04:32 Real experiments
08:10 Assumption 1
10:27 Assumption 2
18:36 Assumption 3
19:58 Conclusion

The original paper by John Bell

Inspiration for using this state instead of the traditional Bell State

Non-local models with Bohmian mechanics

A preliminary attempt to "rebuild modern physics" with non-locality

Although I didn’t mention it in the video, another reason that non-local theories must break both assumptions of relativity is because otherwise one has time paradoxes. Still, there are attempts (see link below) to break only the second postulate but I’m not certain how they get around these concerns.

There's a lot of work one on the subtleties that occur when breaking the assumptions, most of which I’m not familiar with. So, if I made a mistake please let me know!

[aintaintaword]

Came up in my recommendations, props for bringing this up! Suggestion to invest in a mic, it's very important

[danielasher]

No doubt this superb presentation would fill a father with pride.

[nightspore]

This was a very interesting presentation, and I have definitely subscribed. One suggestion, however. A presentation on youtube unfolds in real time and while, yes, you can always rewind, it is much better to build in a bit of redundancy or explanatory expansion. Your presentation moves along like the inexorable lockstep of an elegant proof in a mathematics text, which is very smooth but can be quite hard to follow, even though it may seem clear and elementary to you. It’s a matter of forgetting what you understand and putting yourself back in the position you were in when all this was new to you. The result may seem rougher and less elegant, but will be far more understandable on an initial run-through. Otherwise you may find yourself only appealing to those who are already familiar with the material. The best youtube science channel I have found in this regard is ScienceClic. Otherwise, I am looking forward to a lot more from you.

[laughy]

Awesome use of graphics and narration to visually explain this uninuitive topic. You understand what you're talking about and it shows, no doubt your channel will grow!

[mrdeer]

Smooth voice, gentle background music, interesting content. You got my interest. Please keep them coming.

[penguinista]

Excellent, thought provoking presentation! Thank you.

[spydula]

Wow! Love this! I really enjoyed the flow of the presentation! Looking forward to see what topics you cover next! :D

[doug]

Nicely done and very interesting video. I look forward to more of your work!

[ErikBongers]

Very good that you clarified that the down-pointing measuring device still measures spin-up in the direction of the arrow. This is where Veritasium caused confusion.

[herbiejinkles]

Really well done video, great visuals and step by step explanation.

[mathwisdom]

I appreciate the graphs by which you show the effects of Lorentz transformations and how either event (measurement of spin) can precede the other. This for me is a great illustration of the problem but also suggests a solution. Typically the two particles were created together which is how they got entangled. That frame of creation is then a natural distinguished frame. Their entanglement is an encoding of the distinguishedness of that frame.

[BabaBabelOm]

I thought your presentation was done magnificently.

[vauchomarx]

Beautiful presentation! A few questions/clarifications came to my mind though:
1) Isn't non-locality at least partially acceptable without breaking the cosmic speed limit? If two entangled particles were locally created, the fact that they correlate instantaneously across distances wouldn't mean that they exchange instant information, but that they simply share locally created, but more specific information than we'd come across in the macroscopic world. It's a bit like a pair of shoes always containing a right and a left shoe, even if the shoes are away from each other.
(Maybe this seems less outrageous to me given that I find Superdeterminism actually plausible.)
2) One thig I never understood about EPR experiments: While we can measure the spin state of two particles and find a non-local correlation, how could we actually _know_ that the correlations still hold true if we only measure _one_ particle? Sure, this is the implication of orthodox QM, but it's also part of what Einstein, Podolsky & Rosen criticised…

[stormtrooper]

Nicely done video, and even better explanation of Bell’s inequalities!
I know it must be hard to conceptualized or animate some of the diagrams, but can I ask politely(for many of us who watch on a phone or have a bad vision) for a bigger fonts on a text that is shown! Sometimes the experimental results and the assumptions were barely readable by me. Don’t get me wrong, and cheers!

[vitsirosh]

Make a video about quantum decoherence next

[aaronwalker]

Great vid, great explanation. Love the 3Blue1Brown vibe!

[michaelccopelandsr]

My idea so I get to name it! Voyager 1 is now in interstellar TIME! (Mikey's Time) Think of it like Alvin and the chipmunks. "Vyger's" message is fine. It's just sped up now that it's outside our suns time bubble or "Terran Time." It would be faster still if "Vyger" sent a message from beyond the Milky Way's time bubble. That name is still up for grabs. Outside the Local Group TIME is open, too. Now that "Vyger" is in interstellar space, it's also in the Milky Way's STANDARD, faster moving, interstellar TIME or "Mikey's Time."
•Our sun's TIME bubble: "Terran Time" we know and have measured.
•Milky Way's TIME bubble or "Mikey's Time." The rate/flow of TIME outside any influence but within the Milky Way: We just got there and are still figuring. Wild guess I'd say time will increase in speed, now and until Vyger is outside the Ort cloud .007-.07% faster, maybe. Just for reference.
•Local Group's TIME bubble or the rate/flow of time outside of any influence but within the Local Group: Name still open and unknown. Wild guess .08% to a couple seconds faster, maybe. Used just for reference.
•Outside any influence in True interstellar TIME: Name still open and unknown. ???? Here is where surfing time is SO choice.
A minute is a minute in all. It's the rate/flow I'm talking about.
Pass it on, please and thank you.

[djohnsto]

It's pretty good! I had trouble hearing the audio though - The narration has too much bass, or is muffled, droning, or something... I had to crank the volume to understand the speech until it was uncomfortably loud. I like the style though - A second version with better audio, and maybe "time-outs" for side explanations or re-iterations would be good too. Well done!

[michaelccopelandsr]

TIME is fascinating. I worked the subway stations for nearly 10 years. From one end of the city to the other. Every so often I would notice the city would be saying that, "Today just flew by" or "The day was just dragging along."  How can an entire city complain about the same TIME paradox unless it was effected by it. Maybe a TIME distorted bubble the earth passes through in its revolution around the sun. Maybe random waves of TIME distortion hitting the earth? Maybe they're randomly given off by the sun. Maybe they're from outside our Terran system and reach us in intervals. ???? There is SO MUCH MORE to TIME than we realize. TI-I-I-IME, is on my side. Yes, it is!

[ganymede]

Quick tip. Watched to 4:28 and you are talking about axes A, B, and C. But these labels don't appear anywhere on screen so you are asking me to remember something, increasing the cognitive load on the viewer. In fact you are using colours for axes so you could talk about the Red, Green, and Blue axes. Or just keep A, B, C labels on screen. I've been on a Manim binge with various creators. What separates the good from the bad is details like this. The best explainers put in a ton of work to make the smoothest possible journey for the viewer.