On Sunday, March 6, 2022 at 5:57:28 AM UTC-6 Lawrence Crowell wrote: > 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 meant pre-measurement. It is still early in the morning and my morning coffee has not fully kicked in. Sorry if the language is a bit garbled. LC > > 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/ad225803-92fa-4d13-9a67-aab626fbafcan%40googlegroups.com.
