Post AlDR10QSB2RTyhy3Wa by steve@discuss.systems
(DIR) More posts by steve@discuss.systems
(DIR) Post #AlCK4RG1yn4nE9p3Me by mcc@mastodon.social
2024-08-21T15:02:40Z
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Was watching a video about physics last night and at a certain point they explained the Stern-Gerlach experiment and I got so angry I had to turn it off for the night
(DIR) Post #AlCK4S9gdrb00lrV7A by mcc@mastodon.social
2024-08-21T15:03:03Z
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ME: Quantum physics isn't "weird", or mystical, or unknowable in some way that means we have to abandon the scientific ideal of understanding the universe. Quantum physics follows specific mathematical rules, and it follows them rigidly; it's just the math happens to not follow our intuition of everyday objects.PHYSICISTS: *Explain literally anything about quantum spin*ME: This is BULLSHIT and you are MAKING IT ALL UP
(DIR) Post #AlCK4Sre0Ql2D6QbdA by mcc@mastodon.social
2024-08-21T15:04:23Z
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Will make another go at the video today. I'm hopeful/unhopeful because when I found the videos I was like "oh thank goodness, finally someone is going to explain to me how quantum spin works" and so far their explanation for how quantum spin works is "somehow"** They have repeated that one word in almost every critical sentence of the video
(DIR) Post #AlCK4UNEOTcOtMDLVI by mcc@mastodon.social
2024-08-21T16:07:51Z
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Okay so the video was pretty good https://www.youtube.com/watch?v=pWlk1gLkF2Y and did a better job of explaining spin than anything else I've ever seen (it's sort of in a series of 3, in the next one they're gonna take a go at the spin statistics theorem… looking forward to that, that's another thing I've tried and failed to comprehend before) but I'm still lost and I'm not sure if I'm lost the expected amount or more lost than normal
(DIR) Post #AlCK4VtAlClLaiAMvg by engravecavedave@mastodon.social
2024-08-21T15:09:13Z
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@mcc I remember being in a Facebook group of Physics student memes during my Physics Bachelor's and at some point someone innocently asked "What is spin?" wanting a genuine answer but the entire group got dumbfounded when they realised that there's no coherent explanation for it and it became an inside joke/meme in the group for months."What is spin? Oh, it's the angular momentum of a particle but not really."
(DIR) Post #AlCK4VyqQ7IdsIotlo by mcc@mastodon.social
2024-08-21T16:31:15Z
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Here is what I am trying to figure out:* PBS SpaceTime Guy suggests the spinor nature of fermions is best understood as the behavior of lines of connection between particles, rather than behavior of particles themselves. He notes "twisting" the lines of connection produces spinor behavior (2 rotations to return to original state) whereas a regular rotation doesn't. Fine. Here is my question:Does this "lines of connection, not an object" kind of rotation *also* explain non-orientation?(1/3)
(DIR) Post #AlCK4XETlTOrl58tmK by dunderhead@social.vivaldi.net
2024-08-21T15:21:13Z
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@mcc dunno if you have seen before but Supriyo Datta has a wonderful lecture series about nanoelectronics where spin transport is covered.
(DIR) Post #AlCK4XXccIiEiS6BcG by mcc@mastodon.social
2024-08-21T15:28:14Z
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@dunderhead I will look for that, thank you. I am always curious for more youtube/nebula documentary content.
(DIR) Post #AlCK4YlU4FOYVjalrU by mcc@mastodon.social
2024-08-21T16:32:09Z
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He gives this useful visualization where he shows that the cube-with-attached-streamers example (which I've seen before) can be expanded to like, a high-N N-gon with a streamer on each face. So I imagine a 3D grid of 26-gons, each streamered to its adjacent/adjacent-diagonal neighbors. Then I imagine every n-gon simultaneously spinning with *random* orientations and speeds. Do they avoid tangling?PBS-ST-G suggests thinking about phase, not rotation. But does my 26-gon idea *work*? (2/3)
(DIR) Post #AlCK4Zrtxs7fvvbPVI by masukomi@connectified.com
2024-08-21T15:04:31Z
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@mcc For other folks like me who don't know what the Stern-Gerlach experiment was / is.https://en.wikipedia.org/wiki/Stern%E2%80%93Gerlach_experiment
(DIR) Post #AlCK4aSPm7KVlAgZPs by mcc@mastodon.social
2024-08-21T16:32:41Z
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I ask because that way non-orientedness stops being "shocking" because orientation is an irrelevant local symmetry anyway, and I could think about the unoriented spin value as like "rotation energy".---I also was gonna ask questions about how spin fits into LQG braid matter and "holographic" universe hypotheses but such such questions are absurd and "cranky" I think I should not try to ask them until I understand the normal one. Maybe I'll see if my PhysicsForums login still works (3/3)
(DIR) Post #AlCK4aUtctJZsrqYHg by clacke@libranet.de
2024-08-21T16:12:44Z
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"demonstrated the quantization of angular momentum"THE HECK, now I'm angry too. That's not a thing. Don't you dare.@masukomi @mcc
(DIR) Post #AlCK4bUvuEwEzGs5yq by aphyr@woof.group
2024-08-21T15:04:45Z
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@mcc Stern-Gerlach was like day *one* of my first QM course and I remember thinking "Oh, okay, great. They just wanted to come right out of the gate and shatter any expectation we had that our intuition is right."
(DIR) Post #AlCK4c41nl0kk7I7gO by BillyGlennHoya@libranigans.com
2024-08-21T15:12:24Z
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@mcc
(DIR) Post #AlCK4cICx2LzS5vRmi by mcc@mastodon.social
2024-08-21T16:42:35Z
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And yeah, yeah, I get it, it's okay for quantum numbers to just be arbitrary "things" that have no classical analogues, the video mentions even Pauli wants me to think of spin as "classically non-describable two-valuedness", I'm usually okay with thinking this way. But if that's what spin is then *why does it impart mechanical angular momentum, literal macroscopic classical angular momentum, when you apply it correctly*?? I have always struggled to let this go and I kind of feel like I shouldn't
(DIR) Post #AlDQFkAsmT23xw9FT6 by clacke@libranet.de
2024-08-22T05:33:33Z
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why does it impart mechanical angular momentum, literal macroscopic classical angular momentum@mcc This thread is the first time I heard this and I thank you for it. It sounds absolutely bonkers and I will watch that video this weekend.
(DIR) Post #AlDQFlrSVegRCH4lTE by jamiemccarthy@mastodon.social
2024-08-21T17:16:26Z
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@mcc Where can I learn more about imparting classical angular momentum?
(DIR) Post #AlDQFoDVkdVmVFPP7Y by mcc@mastodon.social
2024-08-21T17:20:47Z
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@jamiemccarthy An example would be 0:48 in the "electrons do NOT spin" video above, where he describes, but does not fully explain, an experiment involving the basic "an EM field can make a metal thing rotate" behavior.I have also seen an experiment described where you fire a beam of particles with a specific quantum spin at a macroscopic object and eventually it starts rotating. Because I don't have a cite on this experiment, it is possible that I have misunderstood it.
(DIR) Post #AlDQFrTDegrKapmUWO by tess@mastodon.social
2024-08-21T16:57:11Z
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@mcc to be fair, a lot of QM is... "somehow shit is like this, and that's why we exist... somehow"
(DIR) Post #AlDQFsGqgAYf4l07sW by mcc@mastodon.social
2024-08-21T16:57:39Z
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@tess Yeah, it… I think there's some point at which that's valid but maybe one can get *too* used to doing it.
(DIR) Post #AlDQFsvcEbAT7C4gQC by triple@typo.social
2024-08-21T16:07:24Z
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@mcc Could you provide the link of the video so I can be mad too?
(DIR) Post #AlDQFtbnhkubE1oNAu by mcc@mastodon.social
2024-08-21T16:09:49Z
1 likes, 1 repeats
@triple I am watching this series:https://www.youtube.com/watch?v=pWlk1gLkF2Y (spin)https://www.youtube.com/watch?v=EK_6OzZAh5k (spin statistics and the pauli exclusion principle)https://www.youtube.com/watch?v=26ZmKqLNSZ8 ("anyons", I think this might be speculative nonsense but I don't think I'm going to understand it until I've watched the first two)"PBS SpaceTime" has sensationalist video titles but IME they are quite good on scientific rigor
(DIR) Post #AlDQFu4rxgAEgBPaU4 by bobayaga@blahaj.social
2024-08-21T16:55:20Z
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@mcc Ah, now it makes sense
(DIR) Post #AlDQFu5Zv2jOiNk9aa by cobweb@corteximplant.com
2024-08-21T16:32:24Z
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@mcc @triple I love space time and watch all of them! They’re really really compelling videos but yeah sometimes my head gets near explosion levels
(DIR) Post #AlDQFus90TZz90SwHw by nex@chaos.social
2024-08-21T17:17:13Z
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@mcc I don't see how this analogy could be helpful here; I also didn't get the impression that O'Dowd was trying to imply anything like that.To me this is a completely ordinary rotation, it's just that some objects (spin n + .5 where n is integer) behave like that under rotation — this seems familiar when you've used quaternions for 3D graphics or similar.Watching this could help: https://www.youtube.com/watch?v=pKKy2mmsziI
(DIR) Post #AlDQFvYgSJbhGwMuau by nex@chaos.social
2024-08-21T17:17:37Z
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@mcc Btw., I just rewatched the SpaceTime video (first saw it years ago) and found it quite well made — which was definitely in part due to having seen it and similar lectures about the topic before. So I've already developed a certain tolerance to this weirdness, but still I still had to occasionally pause the video at a few points to mentally catch up. That's how I discovered that other video: YT suggested it as related and I watched it in those breaks.
(DIR) Post #AlDQFwAcBHwrAa7CiW by nex@chaos.social
2024-08-21T17:18:31Z
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@mcc Suppose you're helping someone learn square roots and they're currently learning for their first test for which they need them.If you told them to take the square root of -1 as a practice example, you'd *want* them to say “this is BULLSHIT!”, right? I think this is a normal an necessary step towards understanding 😄
(DIR) Post #AlDQFwtHVDg3P70sL2 by mcc@mastodon.social
2024-08-21T17:22:01Z
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@nex Imaginary numbers are easier for me to understand because numbers are not real. Imaginary numbers are fake but natural numbers are also fake. It doesn't really matter if they behave one way or another. They behave how we decide to define them.But magnets are real. They interact with things I can see and touch. So it is harder for me to just go "I guess it's just an arbitrary mathematical object with arbitrary mathematical properties"
(DIR) Post #AlDQa6zXenPgWVYWdk by tess@mastodon.social
2024-08-21T17:01:06Z
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@mcc that's the thing tho - if you dig down you can keep answering "why" to a point, but then... Why SU(3)xSU(2)xU(1)?At some point, are the fundamental symmetries that give rise to the standard model feel arbitrary; the values of the masses of the particles, the strength of the fundamental forces, and the coupling constants feel arbitrary; this is (in part) why we still have string theorists.
(DIR) Post #AlDQa7iYxPQSm8cToW by clacke@libranet.de
2024-08-22T05:38:53Z
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@tess @mcc I wonder if it's a statistic certainty that a universe within certain parameters produces string theorists.
(DIR) Post #AlDQa8bVf7NVWYKMSW by mcc@mastodon.social
2024-08-22T05:37:06Z
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@clacke Note I am not sure I am completely right in my description. But the videos are interesting.There are another two plus one just on spinors.https://mastodon.social/@mcc/113000879836189669
(DIR) Post #AlDQaA3CHf7U0iHzFo by mcc@mastodon.social
2024-08-21T19:08:21Z
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@josh_clone @tess fr tho screw the copenhagen interpretation
(DIR) Post #AlDQaB2WbeAz4uyxqS by mcc@mastodon.social
2024-08-21T19:08:33Z
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@josh_clone @tess the Feynmann Interpretation, I will tolerate
(DIR) Post #AlDQjbl2demuY6IlJQ by mark@mastodon.fixermark.com
2024-08-21T17:09:50Z
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@BillyGlennHoya @mcc these guys don't get enough credit for asking some very fair questions. I hear that lyric and I'm reminded of the story Richard Feynman would tell about how he got into physics because he had questions about how a ball in his little red wagon worked that his dad couldn't answer... And after years of working in the field he came back to his dad with an explanation of momentum and inertia and his dad hit him with something to the effect of "Sounds like you just gave names to the stuff we don't know; you didn't actually explain it."
(DIR) Post #AlDQjg5kWbjFzU1M92 by mcc@mastodon.social
2024-08-21T17:11:11Z
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@mark @BillyGlennHoya Me: Fuckin gauge perturbation of U(1). How does it work
(DIR) Post #AlDQjgtjWliAUVPH3Q by Catfish_Man@mastodon.social
2024-08-21T17:38:08Z
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@mcc @mark @BillyGlennHoya and it goes even further than magnets! Chappell Roan sings about not only not knowing how kaleidoscopes work, but knowing she'll never know
(DIR) Post #AlDQjhXR99TETdyywK by ianholmes@mastodon.social
2024-08-21T17:58:05Z
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@mcc @mark @BillyGlennHoya Fuckin prosody, how does THAT work
(DIR) Post #AlDQjhcOqhRMj2Iwfw by mcc@mastodon.social
2024-08-21T17:39:36Z
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@Catfish_Man @mark @BillyGlennHoya It makes a lot more sense if you just disassemble one but maybe let's just let Chappel Roan keep her sense of wonder
(DIR) Post #AlDQjiJeFu2EtAXU5Q by mark@mastodon.fixermark.com
2024-08-21T17:59:01Z
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@ianholmes @mcc @BillyGlennHoya Couldn't tell you; I haven't followed Pokémon since Red and Blue.
(DIR) Post #AlDQjj0XgQLX2Cbjwe by mcc@mastodon.social
2024-08-21T17:59:40Z
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@mark @ianholmes @BillyGlennHoya What's this?FERMION is evolving!FERMION became ANYON!
(DIR) Post #AlDQm2fFZUsQZrklkW by mcc@mastodon.social
2024-08-21T16:39:31Z
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@BenAveling Somewhere, Feynmann nods in approval
(DIR) Post #AlDQs9VR2zDlXB4mZM by inthehands@hachyderm.io
2024-08-21T16:50:42Z
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@mcc The terminology sure doesn’t help. “Mesons are composite gauge bosons made of quarks.” “Do right-handed neutrinos exist?” It’s like Dr. Seuss writing tech talk for ST:TNG.
(DIR) Post #AlDQsAMFsbTKAzmxto by mcc@mastodon.social
2024-08-21T16:58:23Z
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@inthehands Essentially the Big Problem in physics is that every single thing got named before they understood what it did or how it worked (naturally, since they couldn't start trying to explain how it worked until it had a name to talk about it with)
(DIR) Post #AlDQsAZj4WFOqm5itc by inthehands@hachyderm.io
2024-08-21T17:06:15Z
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@mccAs a developer, I relate to this deeply. And I admire the physicists for actually coming up with new words, however ridiculous, instead of using the same ones over and over (e.g. “port,” “static”).Still, the completely made-up ridiculous words do make the theories also •sound• completely made-up and ridiculous, even when they aren’t.
(DIR) Post #AlDQuD6MeLDpGUKZGK by mark@mastodon.fixermark.com
2024-08-21T17:02:25Z
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@mcc Yes, I love this.This is the thing I sometimes think is missing from a lot of science education--- We can get so hung up on having students memorize explanations for things that we can forget that the whole point of the explanations is that there are real phenomenon that make no intuitive sense whatsoever and the explanations are the best we can do with unifying all these otherwise disparate, random, mad world behaviors into something approaching a human-shaped story. Time dilation sounds like nonsense idea a person made up to troll you until you find out the history of people conducting experiments to figure out the speed of light and getting baffled by the observation that the damn thing doesn't change!
(DIR) Post #AlDQxetflQE0L62SBs by mcc@mastodon.social
2024-08-21T17:14:48Z
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@mark time dilation is not so bad because einstein was able to come up with a picture you can intuitively visualize¹ that demonstrates it happening. The fact he could not ever find an equivalent visualization for quantum physics seems to be why he rejected it to his death.¹ "Universe's lumpy""What?"**Einstein, reloading gun, getting back into sublight rocket** "Universe's lumpy"
(DIR) Post #AlDQxfVbUOZAEjmkJU by mark@mastodon.fixermark.com
2024-08-21T17:30:29Z
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@mcc Recently learned that Einstein was pretty bearish on black holes also. In that case, it was because (IIUC) his process was often "Think about a possible model for how the universe works, think through the consequences of that model, test those consequences against reality..." And when he applied that reasoning to the gravitational singularities in the math he went "But that would imply there would be these... holes in space. We've been looking for thousands of years and we don't see any holes; where are all the holes?"I can't remember if he lived long enough for astronomers to get back to him with "Well now that we know we should be looking for 'wild bullshit happening around nothing'... We turned our telescopes towards that and UH-OH!"
(DIR) Post #AlDR10QSB2RTyhy3Wa by steve@discuss.systems
2024-08-21T23:19:03Z
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@mcc I don’t even need quantum effects for this. I was in a classical mechanics colloquium given in the math department once and got there when the speaker showed that the answer just pops out magically if you take the reference frame to be the point of contact of a sphere rolling inside a cylinder and analyze the system based on the Coriolis torque.
(DIR) Post #AlDR11UODtBXHCoiIa by mcc@mastodon.social
2024-08-21T23:19:54Z
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@steve let me get back to you about this comment once i've thought about it for three weeks
(DIR) Post #AlDR127jraf1FFE8dE by steve@discuss.systems
2024-08-21T23:19:54Z
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@mcc (the question was “why does a golf ball roll into the hole and then pop out again?”)
(DIR) Post #AlDRGqz92ngBKfkcvw by clacke@libranet.de
2024-08-22T05:47:52Z
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@steve The sister lecture to #xkcd123. 😊@mcc