On Friday, March 4, 2022 at 4:34:12 PM UTC-6 Bruce wrote: > On Sat, Mar 5, 2022 at 2:50 AM John Clark <[email protected]> wrote: > >> On Thu, Mar 3, 2022 at 7:03 PM Bruce Kellett <[email protected]> wrote: >> >> >> Just exchange the 2 slits in the experiments that I described with a >>>> polarizer and then the world would split because of polarization >>>> differences not because of which slip the photon went through, or if you >>>> prefer exchange the photons with electrons and the 2 slits with a >>>> Stern-Gerlach magnet, and then the world will split because of differences >>>> in spin of the electron; after that everything I said was still hold true, >>>> and nowhere would there be a need to invoke non-local influences. And you >>>> can build any Bell-type experiment you like with polarization or with spin, >>>> >>> >>> *> Yes. But you have to show how non-separable states can exhibit >>> locality. Or, at least, you are required to show in detail how >>> the correlation arise locally, in many worlds, or in any other theory.* >>> >> >> Well OK but.... if you want all the details this is going to be a long >> post, you asked for it. >> > > Yes, I asked for a detailed account of how MWI produces the correlations > for the entangled singlet state. The trouble is that you have not provided > this. Your post is long and rambling, full of a lot of unnecessary detail, > but the bottom line is the claim that since MWI is not realistic, it can be > local. You have made that claim many times before, but the current post > comes no nearer to giving a local explanation than any of your previous > posts. > > What is required is a local account, invoking many worlds as necessary, > that can explain how the correlations are built up. In the usual Alice/Bob > setup, when Alice measures her particle, she splits into two branches: in > one of which she sees spin_up and in the other, spin_down. Similarly, Bob > splits on his measurement into Bob_up and Bob_down branches. When Alice and > Bob come together, each splits again according to which branch of the other > they meet. So there are then four branches, up-up, up-down, down-up, and > down-down for the results of Alice and Bob respectively. For all > polarizer orientations apart from parallel or orthogonal, these four > branches must exist. But for parallel or orthogonal polarizers only two > branches are possible for an initial singlet state -- Alice and Bob must > get opposite results, for parallel polarizers, and the same result for > orthogonal polarizers. In other words the up-up and down-down branches do > not exist for parallel polarizers. How is this magic achieved in many > worlds? > > Things are more complicated in the general case of polarizers at an > arbitrary relative angle, theta. The question then is how do we manage the > correlations between consecutive trials in order to preserve the > cos^2(theta/2) probability. (Over a sequence of N trials, the proportion of > up-down branches for polarizers at the relative angle theta must be > approximately cos^2(theta/2)). > > In a sequence of N trials, both Alice and Bob split into 2^N copies, each > copy has a unique sequence of up and down results. When Alice and Bob meet, > the usual MWI procedure means that there are (2^N)^(2^N) branches, as each > of the 2^N branches for Alice meets the 2^N branches for Bob. Out of all > these branches, only one has the matching sequence of up and down from each > end required to get the correlations correct, How does MWI get rid of all > the (2^N)^(2^N)-1 incorrect branches? > > This is the question you are required to answer in detail, without > generalized fudging or appeals to magic. > > Bruce > > The issue is the extent to which there is subjectivity. With MWI we have this idea an observer is in a sense "quantum frame dragged" along eigenstates corresponding to all possible measurements, but is able to make a conscious account of only one. This observer witnesses this post-measurement state as a separable state that is local. However, if the observer is frame dragged along all possible paths there is a statistical ensemble of separable states, but we know this is not a separable state in total. What is an account of a separable state is then subjective to the observer.
This is to be compared to qubism, where the probability outcome is a subjective Bayesian update. There are some things to be said for Qubism IMO, though it has some almost solipsistic implications. Qubism is a ψ-epistemic interpretation while MWI is ψ-ontological, in that with qubism assigns no particular existence to the wave function. The quantum wave of course has no operator assigned to it that gives an eigenvalue, but there is the density operator ρ = |ψ〉〈ψ| that defines probabilities. Probability is in qubism based again on Bayesian statistics considers these subjective. With MWI the wave function is treated more as a real, real in the existential sense than mathematical, object, but it is highly nonlocal. This splitting off of worlds is not tied to any point in space or spacetime, and if the wave is determined by field operators acting on a Fock basis, then field locality is not global. The subjectivity of the wave as separable means we have a conflict with the QFT axioms. This subjectivity is not with the probabilities, so much as it is with the interpretation of post-measurement states relative to re-measurement states. I am not particularly an upholder of any interpretation of quantum mechanics. At best either one uses the one which makes the best sense of some problem, or you just "shut up and calculate." Since quantum mechanics has this funny issue with the reduction of quantum states, the discontinuous transition of a pure quantum state to statistical mixtures or a single separable state, it all involves the issue to what extent the decoherence of quantum states by coupling a larger quantum system (measurement apparatus or observer) is at all computable. This is ultimately a process of encoding quantum numbers within a system of quantum numbers. Can this emulate the system observed, think of this as a Turing machine encoding other Turing machines, or a process of Gödel numbering that then act as the subject of a predicate. The shut-up-and-calculate approach might be compared to the Euclid 5th axiom that is not decidable, consistent but not complete, but where the negation of this axiom leads to a bouquet of alternate models that are complete but not consistent with each other. LC > > > > First I'm gonna have to show that any theory (except for superdeterminism >> which is idiotic) that is deterministic, local and realistic cannot >> possibly explain the violation of Bell's Inequality that we see in our >> experiments, and then show why a theory like Many Worlds witch is >> deterministic and local but NOT realistic can. >> >> The hidden variable concept was Einstein's idea, he thought there was a >> local >> reason all events happened, even quantum mechanical events, but we just >> can't see what they are. It was a reasonable guess at the time but today >> experiments have shown that Einstein was wrong, to do that I'm gonna >> illustrate some of the details of Bell's inequality with an example. >> >> When a photon of undetermined polarization hits a polarizing filter there >> is a 50% chance it will make it through. For many years physicists like >> Einstein who disliked the idea that God played dice with the universe >> figured there must be a hidden variable inside the photon that told it what >> to do. By "hidden variable" they meant something different about that >> particular photon that we just don't know about. They meant something >> equivalent to a look-up table inside the photon that for one reason or >> another we are unable to access but the photon can when it wants to know if >> it should go through a filter or be stopped by one. We now understand that >> is impossible. In 1964 (but not published until 1967) John Bell showed that >> correlations that work by hidden variables must be less than or equal to a >> certain value, this is called Bell's inequality. In experiment it was found >> that some correlations are actually greater than that value. Quantum >> Mechanics can explain this, classical physics or even classical logic can >> not. >> >> Even if Quantum Mechanics is someday proven to be untrue Bell's argument >> is still valid, in fact his original paper had no Quantum Mechanics in it >> and can be derived with high school algebra; his point was that any >> successful theory about how the world works must explain why his >> inequality is violated, and today we know for a fact from experiments >> that it is indeed violated. Nature just refuses to be sensible and doesn't >> work the way you'd think it should. >> >> I have a black box, it has a red light and a blue light on it, it also >> has a rotary switch with 6 connections at the 12,2,4,6,8 and 10 o'clock >> positions. The red and blue light blink in a manner that passes all known >> tests for being completely random, this is true regardless of what position >> the rotary switch is in. Such a box could be made and still be completely >> deterministic by just pre-computing 6 different random sequences and >> recording them as a look-up table in the box. Now the box would know which >> light to flash. >> >> I have another black box. When both boxes have the same setting on their >> rotary switch they both produce the same random sequence of light flashes. >> This would also be easy to reproduce in a classical physics world, just >> record the same 6 random sequences in both boxes. >> >> The set of boxes has another property, if the switches on the 2 boxes are >> set to opposite positions, 12 and 6 o'clock for example, there is a total >> negative correlation; when one flashes red the other box flashes blue and >> when one box flashes blue the other flashes red. This just makes it all the >> easier to make the boxes because now you only need to pre-calculate 3 >> random sequences, then just change every 1 to 0 and every 0 to 1 to get the >> other 3 sequences and record all 6 in both boxes. >> >> The boxes have one more feature that makes things very interesting, if >> the rotary switch on a box is one notch different from the setting on the >> other box then the sequence of light flashes will on average be different 1 >> time in 4. How on Earth could I make the boxes behave like that? Well, I >> could change on average one entry in 4 of the 12 o'clock look-up table >> (hidden variable) sequence and make that the 2 o'clock table. Then change 1 >> in 4 of the 2 o'clock and make that the 4 o'clock, and change 1 in 4 of the >> 4 o'clock and make that the 6 o'clock. So now the light flashes on the box >> set at 2 o'clock is different from the box set at 12 o'clock on average by >> 1 flash in 4. The box set at 4 o'clock differs from the one set at 12 by 2 >> flashes in 4, and the one set at 6 differs from the one set at 12 by 3 >> flashes in 4. >> >> BUT I said before that boxes with opposite settings should have a 100% >> anti-correlation, the flashes on the box set at 12 o'clock should differ >> from the box set at 6 o'clock by 4 flashes in 4 NOT 3 flashes in 4. Thus if >> the boxes work by hidden variables then when one is set to 12 o'clock and >> the other to 2 there MUST be a 2/3 correlation, at 4 a 1/3 correlation, and >> of course at 6 no correlation at all. A correlation greater than 2/3, such >> as 3/4, for adjacent settings produces paradoxes, at least it would if you >> expected everything to work mechanistically because of some local hidden >> variable involved. >> >> Does this mean it's impossible to make two boxes that have those >> specifications? Nope, but it does mean hidden variables can not be involved >> and that means something very weird is going on. Actually it would be quite >> easy to make a couple of boxes that behave like that, it's just not easy to >> understand how that could be. >> >> Photons behave in just this spooky manner, so to make the boxes all you >> need it 4 things: >> >> 1) A glorified light bulb, something that will make two photons of >> unspecified but identical polarizations moving in opposite directions so >> you can send one to each box. An excited calcium atom would do the trick, >> or you could turn a green photon into two identical lower energy red >> photons with a crystal of potassium dihydrogen phosphate. >> >> 2) A light detector sensitive enough to observe just one photon. >> Incidentally the human eye is not quite good enough to do that but frogs >> can, for frogs when light gets very weak it must stop getting dimmer and >> appear to flash instead. >> >> 3) A polarizing filter, we've had these for well over a century. >> >> 4) Some gears and pulleys so that each time the rotary switch is advanced >> one position the filter is advanced by 30 degrees. This is because it's >> been known for many years that the amount of light polarized at 0 degrees >> that will make it through a polarizing filter set at X is [COS (x)]^2; and >> if X = 30 DEGREES (π/6 radians) then the value is .75; if the light is so >> dim that only one photon is sent at a time then that translates to the >> probability that any individual photon will make it through the filter is >> 75%. >> >> The bottom line of all this is that there can not be something special >> about a specific photon, some internal difference, some hidden local >> variable that determines if it makes it through a filter or not. Thus if we >> ignore a superdeterministic conspiracy, as we should, then one of two >> things MUST be true: >> >> 1) the universe is not realistic, that is, things do NOT exist in one and >> only one state both before and after they are observed. In the case of Many >> Worlds it means the very look up table as described in the above cannot be >> printed in indelible ink but, because Many Worlds assumes that >> Schrodinger's Equation means what it says, the look up table itself not >> only can but must exist in many different versions both before and after a >> measurement is made. >> >> 2) The universe is non-local, that is, everything influences everything >> else and does so without regard for the distances involved or amount of >> time involved or even if the events happen in the past or the future; the >> future could influence the past. But *because Many Worlds is >> non-realistic, and thus doesn't have a static lookup table, it has no need >> to resort to any of these non-local influences to explain experimental >> results.* >> >> Einstein liked non-locality even less than nondeterminism, I'm not sure >> how he'd feel about non-realistic theories like Many Worlds, the idea >> wasn't discovered until about 10 years after his death. >> >> >> for these purposes the words "world" and "universe" are >>>> interchangeable and have exactly the same meaning they have when used in >>>> any other context. I meant nothing new or exotic in the words. >>>> >>> >>> *> Worlds are disjoint and do not interact.* >>> >> >> There's no reason they can't be if the difference between the worlds is >> tiny because they've only been separated for a tiny amount of time. If the >> difference between the worlds is very very small it's not statistically >> improbable that they could evolve into the same state and thus merge, but >> if the difference is large it becomes ridiculously improbable for that to >> happen. >> >> John K Clark See what's on my new list at Extropolis >> <https://groups.google.com/g/extropolis> >> > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/6f0c6aeb-72c8-4378-bbd8-8093ede51639n%40googlegroups.com.
