Scientists themselves are the ones who have popularized mystical misunderstanding of quantum mechanics.This is not only a form of disinformation, but also gatekeeping. Because it means it becomes much harder to learn the fundamentals of QM without actually digging deep into the papers.Take for example this guy https://www.youtube.com/watch?v=A9tKncAdlHQHis explanation is deeply wrong on two accounts:- You CAN actually observe the path taken with up to 98% certainty before losing the interference pattern (https://sci-hub.se/10.1007/BF00734319)- "Unplugging the detector" can still cause the pattern to collapse, depending what you mean by that. Whether it collapses or not has nothing to do with whether humans are observing it. If you simply unplug the screen that the scientist is looking at, the interference pattern will stay absent. (Heisenberg 1958, Physics and Philosophy)Then there is nonsense like this https://www.youtube.com/watch?v=TfouEFuB-coWhy are PhDs engaging in this nonsense? Do they actually not understand QM, is it wishful thinking combined with sunk cost fallacy, or are they doing it simply for the money? I think the first video might be a case of doing it for the money, while Penrose is doing it because of wishful thinking that humans are special, and now he's too deep in it to backpedal without looking like a fool.Is there any physicist who actually believes the conscious observer nonsense in current year and is not bending the truth for their own personal gain? I'd like to know.Why isn't this kind of behavior called out more frequently by respectable scientists? Is it because of fear?
https://www.youtube.com/watch?v=S5FG8zZ7hlU
>>16291308It also makes the classic error of showing the one-slit patterns as two sharp peaks that are largely separate from each other.I don't know why they peddle nonsense like this. They really should know better. I imagine them justifying it to themselves by something like "yes, this is full of errors, but it's simpler to explain to people, and lots of other people have explained it the same way, so it must work pedagogically." Which is pretty stupid; misinforming people isn't effective teaching. But perhaps they don't care enough about informing the masses to think this through.This is a common phenomenon in education, where teachers repeat the explanation of better teachers, or just other teachers that came before them, and through a telephone-game effect, the explanation degenerates a bit each time it's repeated. In this case the better teacher who has been badly repeated is Richard Feynman. Here's an old video of him explaining the same topic:https://www.youtube.com/watch?v=b0EChbwSuuQHe also gives more or less the same explanation in the famous Feynman Lectures on Physics.Some notable differences:1. He's using a lot more time than his parrots. Most likely a lot of the errors in the poor explanations originated due to trying to rush the presentation.2. He isn't afraid of using basic math.3. He provides a physical model of observing the electrons, namely a light shining on the electrons as they pass through the holes. This enables him to explain why the interference pattern is being destroyed without any woo-woo; the light is simply deflecting the electrons a bit. He also talks about what happens when you weaken the light. In the video, this last part got cut a bit short (time constraints!) compared to the version in the Feynman Lectures.
>>16291627Online version of the relevant chapter of the Feynman Lectures:https://www.feynmanlectures.caltech.edu/III_01.html
>>16291627Can you tell us more about experiment in the pinned picture? I’ve been hearing about this “observer effect” everywhere for a long time and it always seemed strange to me, so what’s wrong here?
>>16291308observation is simply collision basically pinching a wave so it is restricted to one single location it's not magic
>>16291658Well we should start by distinguishing between what's a real experiment and what's a thought experiment designed to illustrate the principles of physics as we understand them. If you send light through a double slit, you do get an interference pattern, showing that light is a wave. You can do this yourself with a laser pointer. Showing that light comes in photons is harder, but that's also been done. People have done experiments where the light intensity is low enough that there should be only one photon at a time passing through the slits, and they still get an interference pattern. It was also found that electrons form interference patterns due to scattering off the atoms in a crystal, similar to the interference patterns light forms due to a diffraction grating. All this was well before Feynman gave his lectures. The first experiment showing electrons forming a true two-slit interference pattern happened around the time Feynman was lecturing.What you're probably interested in is the idea of disturbing the interference pattern by seeing which slit the electrons go through. This part of Feynman's lecture was a thought experiment. Feynman proposed to do this with a light shining on the electrons; this light would scatter off the electrons, causing a flash you could see showing which hole the electron went through. By applying the known laws of physics, Feynman could show that if the light was of a small enough wavelength to resolve which slit the electron went through, it would also disturb the electrons enough to destroy the interference pattern. Feynman also considered some other ways of figuring out which hole the electron went through, and showed why they wouldn't work. You can read about this in the text linked here: >>16291638It's been a long time since the Feynman Lectures, and I'm not sure what the closest real experiment to the thought experiment part of Feynman's lecture is. But I do know of some similar things that have been tried. (cont.)
>>16291627That one is indeed much better (I had to find the original one since I can't stand the "noise reduced" audio).https://www.youtube.com/watch?v=Ja0HSFj8ImcBecause it doesn't talk about "observation" and "detectors", it actually describes the original apparatus without vague references to unexplained "detectors", and highlights how the interesting aspect of the original experiment is that if we modeled the electron as a particle, it means that the electron somehow knows whether there was another slit available to it or not at the time it was boiled off from the source. So the experiment shows quantum weirdness even before trying to figure out which way any particular electron is going through, it's just enough to block the electrons that aren't going through one of the slits to demonstrate this effect.
>>16291308what books do you recommend for learning QM? can i just go about classical mechanics and then jump to QM?
>>16291693Here's one famous experiment called the delayed-choice quantum eraser experiment.https://arxiv.org/abs/quant-ph/9903047In this experiment, a strong laser was sent through a double slit, and then passed through a crystal that converted photons from the laser beam into two photons of a lower frequency. The two photons were polarized at right angles to each other, allowing the experimenters to separate them. For one of the photons, the experimenters measured the position distribution using a detector with adjustable position.The second photon can be thought of as the measurement apparatus. The experiment was set up so that depending on how the second photon bounced off or passed through a series of beam splitters, the experimenters were able to determine by which detector the second photon arrived at either(a) which slit the original photon had passed throughor(b) how splitting the photon in two had disturbed the interference pattern.All this happened after the first photon had been detected.When they had the disturbance information, they were able to look at what the first photon's position was in the cases where the second photon went to a particular detector. In this position distribution, there were alternating bands where the first photon showed up more and showed up less. It should be emphasized that without the disturbance information from the second photon, there were no such alternating bands detectable. That's because the places the first photon struck more in the cases where the second photon went to one detector were struck less by the first photon in the cases where the second photon went to the other detector.In the cases where the detector that the second photon arrived at instead revealed which slit the original photon went through, they were not able to reconstruct any alternating pattern.
>>16291724I don't know. I haven't studied it myself.I just know a little bit from casual googling every now and then.
>>16291725Here's something I don't understand.If we had the two slit experiment, and we covered one of the slits after the electron had passed the slits but before it had impacted the screen, would we see an in interference pattern or not?
>>16291740If you performed that repeatedly, you would see an interference pattern. Changing the slits after the electron has already passed won't make a difference.
>>16291724The Feynman Lectures >>16291638 could be a fun way to get your feet wet. The first two volumes are about classical mechanics and are worth reading as well. Then read Griffiths and/or Sakurai when you get serious.
>>16291749Suppose I wanted to simulate what would happen if instead of two open slits or one slit open and one covered, I had any two arbitrary shapes between firing each electron. What equation describes that?
>>16291761A simple approach would be to treat each place where the particles could pass as a point source of waves, and perform a sum or integral to add up their contributions to the wave that reaches a particular point on the screen.
>>16291770I see. So we wouldn't have to care about quantum mechanics at all. Since the interference pattern is the probability distribution, we would just have to compute the interference pattern for wave-like behavior and then just assign particles randomly according to the distribution pattern.
>>16291784I mean, that's more or less what quantum mechanics says (at least when applied to a single particle). You have a partial differential equation (the Schrodinger equation) describing how the wave behaves, and taking the square of the amplitude of the wave gives you the probability distribution for finding the particle.
>>16291308You cannot predict where particles will land, even when you create scenarios where it should be 50/50 even knowing all possible variables you are unable to really predict it, nature is just fundamentally random/indeterministic
>>16291308>Sources are all YouTube Wtf is your problem?
>>16291693>it would also disturb the electrons enough to destroy the interference pattern.This is repeatedly said without justification. How precisely is the electron disturbed and why does that destroy the interference pattern?
>>16291740depends if youre letting it go through both slits or only one
>>16292164When the light bounces off the electron, it changes the electron's momentum.
>>16292433Why does that destroy the interference pattern? The electrons are already hitting the slots with randomized momentum. A single electron doesn't make a pattern so presumably the detector is interrupting all the electrons in the experiment.
>>16291308>Do they actually not understand QMThat's it. That's the answer. They're making it more complicated and mysterious than it is.
>>16292642It's the momentum after leaving the slits that's important. In order to go from the slits to a given place on the screen, it has to have momentum in that direction.
>>16292642>Why does that destroy the interference patterbecause it's colliding with it duh if i ram into you you and i will both have altered momentum
>>16291308gatekeeping nuclear energy / bombs
https://youtu.be/IBP1oxHxnpk?si=nhKmqh4MjMbb2zpPinterference just comes from particles moving randomly
>>16293531Interesting talk, but I don't think it solves anything. A model of the type he proposes can predict "given the initial conditions of the universe, what's the probability I put my hand in a fire?" and "given the initial conditions of the universe, what's the probability I get burnt?", but it can't answer "given the initial conditions of the universe and given that I stick my hand in the fire, what's the probability I get burnt?" That's a critical flaw.
>>16294467what the fuck are you talking about?
>>16291716>describesWhere do he SHOW it, where is the replicable paper?
>>16294684The models he proposes compute probability of states at time t given what the state was at the initial time t0. You can't use them to compute any sort of joint or conditional probability involving 3 or more times.
>>16294684>what the fuck are you talking about?FogBot
>>16294973well you cant do that in quantum mechanics either..
>>16295318In Copenhagen you can do the following. Start with a system in a given state at time t1. Represent its state by a vector in a Hilbert space. Apply a unitary transform to model how the system evolves between t1 and t2. At t2, you learn something. Copenhagen says the state vector depends not just on the reality of the system, but also on your knowledge of the system. So you update the state vector by applying a projection operator (you "collapse the wavefunction"). You do another unitary transform to model how the system evolves between t2 and t3. Finally you use that vector to calculate the probability of outcomes at t3.
>>16295653you can do the same in the videothe point of video isindivisible stochastic process = divisible quantum evolutionthe point is that since its a stochastic process you dont need woo woo observer bollocks to explain quantum theory. its just particles that are always in one position at any time, moving randomly along trajectories and they naturally produce the phenomena of quantum mechanics.
>>16293185Okay it alters by trajectory but that doesn't explain why the interference pattern gets destroyed instead of distorted or shifted in a systematic way. In fact, the interference pattern of a single slit actually remains whereas the dots from double slit vanish. So on the one hand the dots get destroyed but the single slit interference which overlays the double slit interference is unperturbed? I don't buy it.
>>16296067>you can do the same in the videoNo. You can't. The very concept of a conditional probability involving 3 times isn't in his model. The closest thing he shows is that a calculation of a probability involving 2 times can be approximated by assuming an intermediate collapse. That's missing the point.
>>16296100no. you canbecause the video states that an indivisible stochastic process is the same as divisible quantum mechanics so you can just translate the probabilistic stochastic representation into the complex quantum representation where it becomes divisibleconversely a divisible quantum system can be translated to a stochastic representation which would be indivisiblethe quantum and stochastic systems have the same properties because they are the same. if you translate the stochastic system into the quantum representation it becomes divisible. if you translate the quantum one back into the stochastic one it becomes indivisible again. nothing new is gained empirically from the translation because its just changing the description of the same systemthe advantage is then that if you can show all quantum behavior comes from a stochastic process there is no reason to resort tofucking ridiculous ludicris airy fairy bullshit interprwtations like qbism, copenhagen and many worlds
>>16296100and again the conditional probabilities of multi-times are not in quantum mechanics either.you can divide the AMPLITUDES but you cannot divide the PROBABILITIES different things.
>>16296248Translating to the complex quantum representation is just a mathematical technique, so it can't give you answers the original model doesn't give you.>>16296249>and again the conditional probabilities of multi-times are not in quantum mechanics either.I showed how to compute them right here: >>16295653You may not like it, but this is what quantum mechanics looks like.
yet another schizo narcissistic grandiose delusions quantum thread full of losers with emotional disorders regurgitating their memorized soiyence catchphrases and buzzwords
>>16296787>>16296787>I showed how to compute them right hereumm the conditional probabilities are still indivisible in quantum mechanics. if the probabilities were not indivisible there would literally be no interference between paths. by using unitary transformations you are cheating. like i said in orevious posts, the quantum system is just the stochastic system given a divisible form via complex representation. but the probabilities are no less indivisible than before. if they were not indivisible there would be no interference. you cannot sum up probabilities for different paths or along the intermediate parts of the trajectories and get the correct answers. its as indivisible in the quantum representation as in the stochastic one - |a + b|^2 =/= |a|^2 + |b|^2|a + b|^2 = |a|^2 + |b|^2 + interferencethat is indivisibility of the stochastic form made explicit in the quantum system which ofcourse os just the stochastic system dressed up in a tarted up complex representation>Translating to the complex quantum representation is just a mathematical technique, so it can't give you answers the original model doesn't give you.yeah and getting the same answers is exactly what we want it to do. we want to show that the stochastic version is the same as the quantum one because then it says by occams razor that all quantum mechanics is is a stochastic process where particles are always in a definite position at any time but move about randomly. gets rid of all the nonsense woo, nonsense superposition bullshit, nonsense measurement problem, nonsense many worlds, nonsense classical limit bullshitthe world becomes sensible again if you can show that quantum mechanics is just a stochastic process
i don't understand how we can be confident that there aren't hidden variables underneath. like, how are you sure that a process is truly random? how can you go "yep there's definitely nothing that determined how this ended up".like, a coin flip is "random" in a human sense. you are unable to predict what it will come up and the outcome is probabilistic. but the flipping of the coin comes from the motion of the hand, and the influence of the air and so on. if you had enough data you could predict the outcome.how can we be sure that there's not something we're unaware of behind the scenes with quantum effects?
>>16296859>by using unitary transformations you are cheating.Do you mean projection operators? I understand this guy doesn't like it, nobody really likes it, but that is a part of quantum mechanics, at least the standard version of it. You can't just throw it out (without adding something to replace it) or else you end up saying stupid things like "quantum mechanics doesn't allow you to compute conditional probabilities involving three times" which would leave you with a useless theory.
>>16296862>i don't understand how we can be confident that there aren't hidden variables underneath.We can't. You will find many people who are mistaken on this point, but they are wrong.
>>16296867again. you can compute conditional probabilities but they are not divisible. this is the same as in the stochastic representationhere is the cruxcomplex representatoon = divisibletransition probabilities in either representation = indivisibleby swapping the indivisible representation for a divisible representation you are making everything much easier but they behave in the same way because they are describing the same system but ultimately it all reduces to the behavior of the stochastic system. the complex representation isnt even a unique way of representing the stochastic behavior. its just a useful tool.
>>16296862there are hidden variables underneath its just they are randomly moving particles so they are random
>>16296862and how can we be sureits random?its parsimonythere are random stochastic processes that reproduce quantum mechanics in virtue of being randomwhy do you need anything else? why do you need an underlying explanation. the randomness is the explanation.ofcourse it doesnt mean there cannot be an underlying underlying deterministic cause... but this determinism must produce random behavior... like how in brownian motion, we can conceive of a dust moving randomly in a glass of water but the random motion could be caused by deterministic interactions between the dust particle and water molecules
>>16296897>you can compute conditional probabilities but they are not divisibleDid you forget what we are talking about again? You can't compute P(event at t3 | initial state at t1, observation at t2) in his model; you can in quantum mechanics. This means I can use quantum mechanics to make predictions about real life, which I can't do with his model. I do not care whether his condition on expressions of the form P(state at t2|state at t1) holds.
>>16291329lol yeah i was just thinking if posting that exact video
>>16291308Like I only have grade school, but I know it's not collapsed by observer, but definately some sort of meta particle is harvested by sensor, which makes it not have wavelike nature, but really when I tried doubleslit, it was always interference, so I don't know what collapse of wavefunction is, maybe my sensors didn't crashed metaparticle.
>>16296910>You can't compute P(event at t3 | initial state at t1, observation at t2) in his modelumm the exact thing that cannot be done is this computationp(s1 | s3) = sum p(s1 | s2)p(s2 | s3)and you can't do that in quantum mechanics eitherits notthat conditional probabilities dont exist. you just cannot compute them using marginalizationyeah you can compute it more easily with quantum mechanics and that is precisely the point of quantum mechanics when we look at it retroactively - the complex representation is more convenient than the stochastic oneputting forward this model is not meant to replace the complex representationit is mrant to show that quantum mechanics is nothing more than a stochastic process.. so you can continue using the orthodox formalism with the understanding you are talking about a stochastic process
>>16297386Waves.
>>16296862Bells Theorem guarantees there can be no local hidden variables.
>>16291308>Is there any physicist who actually believes the conscious observer nonsense in current year and is not bending the truth for their own personal gain? I'd like to know.https://www.youtube.com/watch?v=aow8hVpdSHQ>>16291658>I’ve been hearing about this “observer effect” everywhere for a long time and it always seemed strange to me, so what’s wrong here?https://www.youtube.com/watch?v=Zm9tUVI6Ehk
>>16297392heres the fingits pretty obvious now that waves are just a special case of stochastic behaviorwhy some of this quantum bullshid turns up in macroscopic light
>>16298111i don't understand how bell's theorem proves that.i don't understand what bell's theorem is demonstrating.
>>16297386Like a broken record, you keep ignoring the actual objection and going on about other stuff that anyone who watched the video would have seen already. Show how to compute conditional probabilities involving three times with his model or be silent.
>>16296862We don't know that. The only argument for no hidden variables is that because of Bell's theorem, you would need to have FTL distribution of randomness information.Since heuristically, if you wanted to parallelize computation, you would want to limit the bandwidth between different parts of the universe (like in Second Life, each parcel runs on a different server), then a priori it might seem more likely that the universe would generate true randomness rather than having each neighborhood connected with each other to share some of that randomness.But then again there is the fact that a logical procedure by itself can not generate randomness, so maybe it makes sense that every neighborhood of the universe feeds from a central RNG.>>16298380Have you read the paper? What did you not understand about it?https://cds.cern.ch/record/111654/files/vol1p195-200_001.pdf>>16298315Thanks, I'll check it out.
>>16298315>>16298593Yeah, I remember watching this guy like 2 years ago. You or someone else must've recommended it to me back then.I don't remember what I concluded about his dimensional analysis argument (not feeling like going into it right now), but the main flaw in his argument is that either photons are waves or photons and electrons are waves, so:1. if photons are waves and electrons are particles, then why do electrons interfere with each other in a double slit experiment?2. if both photons and electrons are waves, then how the hell do photomultipliers manage to produce discrete clicks when exposed to weak sources of light?QM, no matter how problematic it might be, at least manages to predict both behaviors.
>>16291308Fundamentals of QM are literally just a couple of posulates combined with linear algebra. QM at a basic level is extremely accessible. It's not really gatekept, the public has overall a pretty intuitive understanding of QM nowadays.
>>16298637I feel like there are pretty fundamental disagreements between scientists and it's all shoved into "interpretations" as if wildly different models were somehow equivalent just because they give roughly similar predictions.For example, as a layman I've never heard explanations for the following:When do the particles stop behaving like waves and start behaving like particles? When it interacts with enough other particles that the system becomes "macroscopic"? What does that mean, when is it too many? Is it a gradual thing or a discrete thing? How does quantum coherence play into this?In the dual slit experiment, why does the electron's field interacting with the particles that make up the slits, not start behaving like a particle immediately? How does nature know that we cannot reverse engineer the slit that the particle went through by detecting minute forces induced in those other particles? I realize those other particles will behave probabilistically as well, but you will be able to narrow down the chances that it went through one or the other slit. So it must be a gradual thing. But how is this expressed mathematically?Also I've had a thought experiment in mind.In a dipole antenna, photons are emitted in a linear pattern. The photons will be emitted first from the middle, then from one side of the dipole, then from the middle again, then from the other side, etc. So when they get to a receiving dipole, if both antennas are cross-polarized, then presumably at any one time the receiving dipole will only actually catch a fraction of the photons (at most) that it would if they were polarized correctly. Actually, I don't see why it would induce any signal at all, but they do in practice, so my model must be wrong in some way. But anyways, the photons themselves have a polarization too, right? So would it be possible to emit a wave in which the pattern of the photons is polarized one way, but the photons themselves another? I guess not, but not sure.
>>16298651>not start behaving like a particle immediately?*not cause it to start behaving like a particle immediately (talking about the electron in the double slit experiment with electrons, not about the field itself becoming a particle).
>>16298651You're not wrong. That guy you replied to is completely delusional if he thinks that anyone, let alone a layperson, has an intuitive understanding of quantum mechanics.
This thread is super interesting. There seems to be a good PRX review on indivisible stochastic processes making up quantum mechanics where they derive measurement phenomena, uncertainty relations, interference, etc. specifically they say that interference is the quantitative failure of the indivisible process to be approximated by the divisible one (i.e. you can’t just sum up the probabilities of each possible path, since they interfere.)It’s quite satisfying to me because I am mainly focused on stochastic processes/Focker Planck equation, so quantum mechanics being just another stochastic process would fit how I think of the rest of the world anyway.
>>16298671Although I do suppose that it’s not much easier to think of quantum mechanics as an indivisible process. What would such a process even look like intuitively? It’s something where we can’t think of particles taking paths through time by making many little “divisible” steps. Much like QM it would say that only discrete samples at discrete times make sense for the random paths that particles take. I think this just shifts the same stresses of unintuitive quantum axioms from the interpretation of the wavefunction to the indivisible process.At least the heat equations sample paths are markov, divisible, stationary, continuous etc. it still wins out in terms of simple interpretability to the stochastic processes apparently making up the Schrödinger equation.
>>16298380I could explain it to you but I don't put effort into my 4chan posts anymore. You'll have to figure it out for yourself. It's not that hard.
>>16298734I'll spare you the effort. It doesn't prove anything like that and it can't prove anything like that
