On Fri, Sep 1, 2023 at 10:26 PM John Clark <johnkcl...@gmail.com> wrote:
> On Thu, Aug 31, 2023 at 6:29 PM Bruce Kellett <bhkellet...@gmail.com> > wrote: > > *> OK. So spell out your non-realist, but local, many worlds account of >> the violations of the Bell inequalities. It seems that you want it both >> ways -- Bell's theorem says that MWI must be non-local, but you claim that >> it is local? "Realism" has nothing to do with it.* > > > > "Realism" has* EVERYTHING* to do with it, and I spelled out exactly why > in a post on May 4 2022 when somebody said they wanted to hear all the gory > details and this is what I said: > I am not complaining that your explanations are too short, or too long. I am complaining because they do not answer the question I posed: "Spell out your non-realist, but local, many worlds account of the violations of the Bell inequalities." Let me summarize your argument. You appear to agree that Bell's theorem, given its assumptions, shows that no local hidden variable account of these correlations is possible. You then expect at least one of two things must be true: 1) The universe is not realistic. 2)The universe is non-local. It is not clear how you get to this dichotomy, but once you have it, you claim that MWI is non-realistic,..., so it has no need to resort to any of these non-local influences to explain experimental results. This conclusion is flatly illogical. Accepting one arm of the dichotomy does not mean that the other is false -- both could be false, or both could be true. In other words, the theory could be both non-realistic AND non-local. I said that realism has nothing to do with the argument over Bell inequalities. It simply serves to point out that ordinary one-world QM is also non-realistic in your sense. So it is not a special feature of many worlds. Since everything in QM is non-realistic, "realism" has no particular bearing on the violations of Bell inequalities. Your initial dichotomy is, therefore, meaningless. In his book "Something Deeply Hidden", Sean Carroll gives a better version of a similar argument (p.102ff). The argument still fails, as we shall see, but let's examine it further. Sean accepts that what Bell showed was that, under certain superficially reasonable assumptions, the quantum mechanical predictions are impossible to reproduce in any local theory. The assumptions that Carroll points to are that the experimenters are free to choose what measurement to make (no superdeterminism!) and, secondly, that measurements have definite outcomes. He rejects this latter assumption as being untrue in Everettian theories because all possible outcomes are realized in the branches of the wave function, The universe as a whole doesn't have any single outcome for a measurement: it has multiple ones. In rejecting this supposed assumption of Bell's, Sean goes on to argue that Bell's theorem is simply irrelevant for MWI -- it doesn't apply. Because He has removed Bell's theorem from consideration, Sean then concludes that MWI is local. But, once again, this conclusion does not follow. MWI could be non-local for reasons unconnected with Bell's theorem. Arguing that Bell's theorem does not apply does not guarantee that your theory is local. Many people have tried this argument, but it is patently invalid. There is another objection to Sean's argument. He claims that many worlds invalidates Bell's assumption that experiments have just one outcome. But in that whole history of physics, that has always been true. There has never been a case in which an experimenter has seen more than one outcome in a single experiment. Bell's theorem applies in many worlds exactly as it applies in single world theories. The reason is that when Alice and Bob perfore a series of polarization measurements on entangled particles to ascertain the correlation, all their measurements and calculations take place in a single world. In no case do they see more than a single result for each measurement, and in order to maintain agreement with universal physical observations, the alternative outcomes postulated by MWI must occur in separate, disjoint worlds. These 'other worlds' cannot impinge on either Alice or Bob, or their calculations, So even if Bell's theorem does assume a single outcome and a single world, that is all we ever have, even in MWI. So Bell's theorem applies in full force in MWI as in the single world case. Consequently, the correlations that Alice and Bob observe can have no local (or local hidden variable) explanation. If you disagree with this argument, then I invite you to provide a counterexample by providing a local account of the correlations. Bruce " If you want all the details this is going to be a long post, you asked > for it. 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 > which 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 at least 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."* > *==* > Back in 2022 in response to my post in the above you complained that it > was too long and detailed even though previously you had complained that my > explanation was too short and lacked detail. And I have no doubt that today > you will complain that my explanation was still too long and detailed. And > then, ignoring the fact that Many Worlds does *NOT* say everything > happens it says everything *PHYSICALLY POSSIBLE * happens, you > complained that in my example I failed to include instances where 2 > polarizers oriented oriented in opposite directions produced up-up and > down-down, and this is what I said: > == > "*NO, up-up and down-down is never allowed!* If I set my polarizer in the > "up" alignment (and I am free to pick any direction I like and call it > "up") and a undetermined photon makes it through then then I know with 100% > certainty that my photon is now polarized "up", and I know for a fact that > if you set your polarizer to the corresponding "down" position then there > is a 100% chance the brother photon that is entangled with mine will make > it through your polarizer and a 0% probability it will not. *Set the > polarizers to any angle you like but you will NEVER ever ever see up-up or > down-down. * > > If instead of orienting your filter in the "down" position you only > misaligned it from mine by 30° then is a 75% chance the photon will make > it through your polarizer, if it does then you know with certainty that > your photon is now, not in the "up" direction, but in a direction 30° from > "up". And you know one other thing, you know that your photon and mine are > no longer entangled because *misaligned polarizers destroy entanglement.* > By the way, I use quotation marks because "up" and "down" are completely > arbitrary directions, as long as consistency is maintained between what is > called "up" and "down" any direction can be chosen" > == > If you have complaints about anything I've said in the above, which I'm > sure you will, feel free to say so, but please don't complain that my > explanations are too short and lack detail, and then complain that they're > too long and have too much detail. > -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAFxXSLS-Kfp1dR_rpz4oMW-ArOQPk4b3rdj7ndErdN2Ysp1xTA%40mail.gmail.com.
