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couldn't agree more

Best professor at Sixty Symbols!

Indeed, I just love his way of speaking.

He's just the best

I want a beer during the lecture to drown-out the ignorance of the lecturers.

Yeah, I should play him to put put me to sleep at night.

ironic that Pound Sterling inflation made Ed study Cosmic Inflation in London back in the 70s. Wonder what scientists will come from this round of inflation in 40 years time edit, I think the anecdote came from another Sixty Symbols extra video, it might not have been Ed tho

It's funny to know other people are falling asleep to it too! Not because it's boring. On the contrary, I have absorbed so much of it. It's just very relaxing :)

This isn’t how it’s done in these lab experiments, but an example of when two particles with entangled polarisations would be produced is by the decay of a spin-0 particle, such as a pion, into two photons.

@@NuclearCraftMod How do they test the photons after they have been created?

@@lundysden6781 I’m not exactly sure, but essentially you put a polarising filter in front of a photodetector. If a photon is detected, you know it got through the filter, and vice versa.

I want to know too. I think some experiments have been explained only on the level of thought experiment by "don't worry about how this is done". I've learnt equipment and method of delayed choice quantum eraser and it really WAS essential to adjust my assumptions. Others who may believe 'observer' means 'conscious entity' would obviously never make that mistake... Plus with entanglement i don't quite know the equipment but some ask "how do you know the states weren't just determined, if they aren't observed" and i know one rarely explained answer is that the axis of spin is chosen, and the other particle reflects the choice in degrees of freedom to maintain probabilities consistent with that. I e. The probability along a chosen "axis"

@@NuclearCraftMod How do they separate the two photons? I think they don`t have to do anything because the two photons travel immediately in opposite directions?

Totally agree! We really are so lucky

Yeah what would we do without these brilliant people since not one of them are brilliant-enough to realize that Bell’s Inequality is incorrect!

@@tuckquest Strong words! Please elaborate. I mean the Nobel prize for physics was just given to three scientists who proved Einstein was wrong about quantum events, and experiments have proven Bell's Inequalty to be true.

I'm 40 :(

Yeah and Bell’s Inequality is still as wrong as ever.

How is this philosophical discussion relevant in the context of optical / photon based QM experiments that have been performed? No way gravity affected 33% predicted by fixed state variables vs 25% predicted by QM and 25% confirmed by experiment. Gravity it's 40 orders of magnitude weaker than E&M for example. Do you have a time-varying model of these fixed state variables that gives the same QM predictions and compatible with other extensive QM experiments?

@@irrationalpie3143 ~ Photons were first modeled by Maxwell, who showed they obeyed a set of four simultaneous equations involving sinusoidal time-varying electromagnetic fields. Feynman later employed an even simpler mathematical representation of a photon as a rotating vector. In those models, timekeeping was still modeled as uniform, so that no time dilation entered the analysis. The question of what parameter affects the probabilistic deviations is initially answered by attending to the time-varying parameter. For a photon, it's the phase of the E-field when it interacts with a polarizer. One can appreciate this better by considering much longer-wavelength radio frequency waves interacting with an antenna. Anyone who has wrestled with the challenge of positioning a TV antenna knows well that moving an antenna half a wavelength makes the difference between capturing a signal or not. For photons, the time-varying component is sinusoidal. For any one photon in a Bell Test setup, the phase of any one photon when it interacts with matter along the path is essentially unknown. But it's not just photons. Anything with a time-varying aspect will decohere out of perfect phase-locked synchrony because time-keeping is local, varying from one location to the next due to the presence of gravitational gradients. Mathematically, this means that λ(x,t) cannot be treated as an odd function governed by a uniform time-keeping. Bell's math employed the simplifying assumption that λ(x,t) ≡ -λ(-x,t) for all x and t. But the age, t, of the particle descending a gravitation gradient differs from the age of its twin ascending the same gravitational gradient. The particle at +x is not the same age as its twin at -x. They differ by some relative phase shift corresponding to gravitational time dilation. Plug this detail into the math (amounting to taking a gravitational path integral instead of a conventional Minkowski integral) and λ(•) doesn't vanish, but yields a non-vanishing "beat frequency" term. There never was any "spooky action at a distance" but (under GR) there manifestly is not-so-spooky time-keeping at a distance.

He's so lucky.

But don't all our relativistic theories have to be local? So isn't it kind of besides the point for a lot of physics?

Wouldn't giving up localism be even more non-intuitive than giving up realism?

​@@denglish5275Yeah, but you still better off sacrificing locality but holding to causality! Causality is more vital

​@@jackkendall6420 I think not, as long as you don't give up causality

He said something about cos^2 last video, and cos(90) is 0. So I believe there is 0 correlation between up/down and left/right at a 90deg angle.

It's just been kept neatly on a shelf that's all. some people don't have to destroy books to read them

Plot Twist: He started reading the book but couldn't understand it so he gave up and shelved it for 40 years.

Particles do travel. Look up "wavepacket" and wavepacket "group delay"

Yes there is. Bell’s Inequality is incorrect.

Take a look at the ER = EPR idea.

@@davidgillies620I see. So it's not _like_ a wormhole, it _is_ a wormhole? It sounds incredibly unstable, but then entanglement is delicate, so I suppose it's not a crazy idea. Thanks.

You don’t even know how close you are to the truth in what is wrong with Bell’s Inequality.

@@tuckquest Please tell us

There is an invariant spacetime interval between the two measurement events that is independent of the reference frame chosen. If this interval is “spacelike”, there is no way in which light, or any other massless particle, could travel from one detector to the other in the time required.

The entanglement experiments can / have been done with massive particles. Same result. What NuclearCraft says applies generally, I'm just giving a specific example (particles that have mass) to make sure we don't dwell on things like "photon experiences no time".

I know you! We had an argument a couple years ago. I can't remember what though. It might have had something to do with the RAND corporation or something funding a scishow episode

Bell’s theorem still applies. It rules out local hidden variables, while de Broglie-Bohm uses non-local hidden variables.

@@NuclearCraftMod Bell's theorem is inapplicable to a theory that doesn't use hidden variables. It does still apply to theories that do.

@@protocol6 It isn’t a theory that really “applies” to any particular interpretation. It just states that your interpretation of choice can’t have local hidden variables.

@@NuclearCraftMod If you are going to nit-pick word usage, it's a theorem, not a theory. Its result only logically follows when all of its premises and unstated assumptions are true. Bell starts with the premises that you have both locality and hidden variables and then proves, mathematically, that both can't be true simultaneously. The proof, assuming there are no flaws, invalidates any theory or interpretation where both are true but does nothing to the rest either way. The test results suggest the logic isn't flawed. That's nice to know but I don't consider it relevant if you aren't seriously positing a local hidden variable theory. Bell's argument would technically be valid regardless of the truth of its premises but it's conclusion would be in error if any were false. Other theories aren't constrained by the resulting inequality, therefore the inequality is untrue for them. The test results suggest it's always untrue. The OED defines "applicable" as "that can be said to be true in the case of somebody/something" and has "relevant" is a synonym. American Heritage is more blunt and define it simply as "relevant or appropriate."

Look up the Veritasium video on this (about 7 years old). He explains it very well and addresses this question in the video.

Quantum entanglement can be “deeper” than classical correlations. For example, not only are the spins opposite each other along some particular direction, they are opposite each other in _every_ direction. This is what ultimately leads to the fact that a local hidden variable theory can’t describe QM, while it can easily describe classically correlated measurements.

They don't have any state until measured (wave function collapse)

@@lyreco7910 i get the collapse part, the particle collapses into spin up/down randomly and thus the other is revealed to be in the opposite state. But where's the action itself? These two systems in superposition can evolve independently of each according to a predetermined process that is set off at random initial conditions

There is something called superdeterminism Sabine Hossenfelder has videos about it

KZfaq is large.

There are papers (self published, not mine) showing it's possible to get the same results as in the Bell experiment, but with classical mechanics and noise. I think the same, entanglement is no mystery, only synchronized particles left like that (entangled) from when they were close together (so a hidden variable (just like a pair of gloves). [1] viXra:1609.0129 submitted on 2016-09-10 08:33:32, (1827 unique-IP downloads) A Classical System for Producing “Quantum Correlations” Authors: Robert H. McEachern Category: Quantum Physics [2] viXra:1707.0162 submitted on 2017-07-11 12:04:39, (463 unique-IP downloads) What Went Wrong with the “interpretation” of Quantum Theory? Authors: Robert H. McEachern Category: Quantum Physics [3] viXra:1804.0123 submitted on 2018-04-11 06:36:53, (588 unique-IP downloads) Resolving the EPR Paradox and Bell's Theorem Authors: Robert H. McEachern Category: Quantum Physics

So how does Planck’s constant emerge from classical mechanics? I would feed it in as a bit of additional Brownian or Lucretian motion.

@@RoGeorgeRoGeorge There are many, many papers, published and unpublished, constructing such models. Looking at the papers you link to, admittedly very quickly, they are constructed for one, specific experiment (except that the PDF slides refer to the Bohmian particle model, which is a well-defined, general construction). I think I don't see an explicit claim that a similar model could be constructed for any other experiment, but I think I see an implicit claim. I'm pretty sure the 2018 paper exploits the detection loophole, which it would do well to mention; whether or not I'm wrong about that, it needs to include a more abstract analysis of how the model works that would place it more clearly in the physics literature on Bell inequalities. My feeling is, for what it's worth, that the 2016 paper is far too ad-hoc: it doesn't lay out in detail how a similar model is to be constructed for an arbitrary experiment. With a more abstract analysis, we would perhaps have a better idea of why such noise models might sometimes be more useful than a QM model for an experiment. It's perhaps interesting that in the recent physics literature there is a move towards classical-quantum models of experiments that model some aspects of the noise classically and other aspects QMically because of the lower computational costs for classical noise modeling. In general, my feeling is that we have to take seriously that none of the models available have moved the needle for physicists for QM and the measurement problem. Why not? Ad-hoc models definitely haven't worked. For the de Broglie-Bohm interpretation, there are many books that try to make a positive case for it but I'll just say here that most physicists aren't convinced by them. Ed Nelson, in the 60s and 70s, produced an interesting, sophisticated approach to noise that McEachern would be well to look at, but that didn't quite work, though there are still a few people working on it. There's Stochastic Electrodynamics, from the late 50s, same thing. Entering this game in any kind of serious way is a real mind-bender. I think my papers /might/ get past all that and more, but I'll be surprised if they convince many physicists of that. I've tried my best. The construction in my papers, in particular, is not ad-hoc; it's more in the way of de Broglie-Bohm's approach, but it uses completely different transformations. There is, as well, a specific critique in the JPhysA 2022 paper of the way that quantum mechanics and quantum field theory model experiments that include a lot of signal analysis, which requires just one less collapse of the quantum state than there are measurements of the signal (that's many, many billions, for modern experiments). Well, I won't try to retype a 25 page paper and a 24 page paper here; sorry to say, people tell me they're not an easy read. Anyway, Koopman is worth a look for anyone interested in classical mechanics.

For all still pondering this, you need to understand one simple thing: There is no possible way to measure one of a pair of entangled particles and know from the measurement alone (i.e., without the use of a separate channel limited by light speed) whether the other particle of the entangled pair has already been measured, has yet to be measured, is concurrently being measured, or for that matter will ever be measured. All you can tell is that, if it's entangled "twin" was, is, or will be measured, and, very importantly, if the measurement is of the same fundamental property in the same way, what this measurement must be. That is all, no more and no less. That is the very reason why although that particular aspect is known about the other particle, and if measured will be present in the other particle, it does not provide any way to transfer information.

@@SteelBlueVision I guess I just wondered if you measure one particle, is there a way to set up the other particle to just know that the first particle was measured. So you don’t have to know anything about the outcome of the measurement, just that it was measured.

@@SteelBlueVision If that is the case - you don't even know which particles are being measured- then we know these physicists have ever even been doing these experiments properly in the first place? You would first need to entangle the particles then separate them into pairs two particles in each pair and then measure them in succession without doing anything that could or would effect its "spin" properties before measurement. Basically winds up being entanglement the myth if you can never know which particles were even entangled and this is something experiments cannot disprove yet. Additionally how are we testing two discrete particles at the same exact time to know that measurements are indeed breaking the speed of light? A lot of stuff about the experiments themselves is left on the back burner for most videos talking about the topic. There are already 3 videos in this particular Nobel Prize and no details about how a measurement of two particles is managed down to the femtosecond (or less) in the here and now, never mind back when the first experiments were done decades prior. Are we sure entanglement is acting faster than light? I don't know. I guess I'm going to have read them for myself, but that means I also have to find them myself and a video like this should have relevant links, I think.

@@Jack__________ If I understand your question correctly, there is no way to do this. That is, there is no way to know that the other particle of an entangled pair has been measured, other than to communicate this information separately and be limited by a sub-luminal communication channel. Be able to instantly know that the other particles has been measured would violate the laws of quantum-mechanics and cause causality problems, due to the ability to communicate information at speed faster than the theoretical speed of light.

Yeah, except they are wrong. Bell’s Inequality is flawed mathematically.

Prove it or shut up.