> Suppose I posited a model of double slit experiment where the position of detection depended on the interactions of wf's of atoms in the screen with the wf of the detected particle. Would this run afoul of the results of Bell experiments? TIA, AG
On Tue, Feb 16, 2021 at 10:35 PM Alan Grayson <agrays...@gmail.com> wrote:> Suppose I posited a model of double slit experiment where the position of detection depended on the interactions of wf's of atoms in the screen with the wf of the detected particle. Would this run afoul of the results of Bell experiments? TIA, AGWhy are you asking us? The only thing anybody around here knows is Trump physics, you said so yourself.
>>Why are you asking us? The only thing anybody around here knows is Trump physics, you said so yourself.> One of the key properties of Trumpism is conscious (so it seems) distortion of facts. In this case, I never made the claim you allege.
> I didn't ask for "your" opinion; rather, anyone's opinion. Moreover, and more important, you have a strong tendency to distort or ignore facts, which reminds me of Trumpism. For example, I refer you to your opening comment which alleged something I never claimed. Do you also think the election was rigged? AG
just few links!
https://kups.ub.uni-koeln.de/6889/
http://philsci-archive.pitt.edu/15798/
https://plato.stanford.edu/entries/qm-manyworlds/
https://www.sciencedirect.com/science/article/abs/pii/S135521980700024X
http://users.ox.ac.uk/~everett/docs/Hemmo%20Pitowsky%20Quantum%20probability.pdf
http://philsci-archive.pitt.edu/8558/
https://www.tau.ac.il/~vaidman/lvhp/m117.pdf
https://core.ac.uk/download/pdf/295730424.pdf
On Wed, Feb 17, 2021 at 11:04 AM Alan Grayson <agrays...@gmail.com> wrote:> I didn't ask for "your" opinion; rather, anyone's opinion. Moreover, and more important, you have a strong tendency to distort or ignore facts, which reminds me of Trumpism. For example, I refer you to your opening comment which alleged something I never claimed. Do you also think the election was rigged? AGOK I was right the first time, you sir are an ass.
On 2/17/2021 2:07 PM, Bruce Kellett wrote:
On Thu, Feb 18, 2021 at 7:26 AM 'scerir' via Everything List <everyth...@googlegroups.com> wrote:
This is an interesting paper. I was amused to see that after a long discussion, their conclusions section says essentially the things I have been saying for ages.
Bruce
Yes it says what you've been saying, but it's the thing that I think Hossenfelder said better.
Hemmo and Pitowsky write:
if probability is supposed to do its
job, it must be related at least a-posteriori to the statistical pattern in which
events occur in our world in such a way that the relative frequencies that actually
occur in our world turn out to be typical. We take this as a necessary condition
on whatever it is that plays the role of probability in our physical theory. Now,
the quantum probability rule cannot satisfy this condition in the many worlds
theory (nor can any other non-trivial probability rule), since in this theory
the dynamics logically entails that any combinatorially possible sequence of
outcomes occurs with complete certainty, regardless of its quantum probability.
But Hossenfelder notes, correctly, that advocates of MWI say you must take the probability of an outcome to be it's relative frequency as single outcome among all the branches, not just whether of not it occurred. To may it must be "typical" is ambigous. Flipping a 100 head in a row, isn't typical, but it's possible and we have a theory of how to assign a probability to it and how to test whether that assignment is consistent. It's a possible sequence, and it "occurs" in the sample space, but that doesn't make its probability=1.
In Sean Carroll's monthly "Ask me anything" blog he wrote this:
0:40:16.3 SC: Sherman Flips says, "How does the weight assigned to a given branch of the wave function correspond to the number of micro-states that are in superposition in that branch?" So, you gotta be a little bit careful. Basically, it is that number, but I wanna be careful here because number of micro-states is a slightly ambiguous concept in quantum mechanics. If what you mean is the number of dimensions of Hilbert space that correspond to that branch, that's what it means, the number of different directions in Hilbert space that you can add together in some principled way to make that particular vector corresponding to that branch. Whether you wanna call a dimension of Hilbert space a micro-state or not is up to you.
0:41:00.7 SC: There's another way of thinking about things if you just had like a bunch of spins. So you have a bunch of two-dimensional Hilbert spaces, one for each spin, spin up or spin down, but the dimensionality of the combined Hilbert space is not 2N. If you have N spins, it's 2 to the N. So you don't have one dimension of Hilbert space for each dimension of the subspaces; you exponentiate them. That's why it depends on what you mean by micro-state, but basically, that is what the weight means. You're on the right track thinking about that.
So he's definitely branch counting, but not describing the mechanism whereby the amplitude of one component of a superposition is translated into a different dimensionality of the combined Hilbert space.
On Thu, Feb 18, 2021 at 10:51 AM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 2/17/2021 2:07 PM, Bruce Kellett wrote:
On Thu, Feb 18, 2021 at 7:26 AM 'scerir' via Everything List <everyth...@googlegroups.com> wrote:
This is an interesting paper. I was amused to see that after a long discussion, their conclusions section says essentially the things I have been saying for ages.
Bruce
Yes it says what you've been saying, but it's the thing that I think Hossenfelder said better.
That might be a matter of opinion. Sabine talks about MWI introducing something equivalent to collapse in the measurement process, I have said that asking the question "which branch will I end up on?" introduces a dualist notion of personal identity. This is exactly the 'collapse' that Sabine sees in MWI.
Hemmo and Pitowsky write:
if probability is supposed to do its
job, it must be related at least a-posteriori to the statistical pattern in which
events occur in our world in such a way that the relative frequencies that actually
occur in our world turn out to be typical. We take this as a necessary condition
on whatever it is that plays the role of probability in our physical theory. Now,
the quantum probability rule cannot satisfy this condition in the many worlds
theory (nor can any other non-trivial probability rule), since in this theory
the dynamics logically entails that any combinatorially possible sequence of
outcomes occurs with complete certainty, regardless of its quantum probability.
But Hossenfelder notes, correctly, that advocates of MWI say you must take the probability of an outcome to be it's relative frequency as single outcome among all the branches, not just whether of not it occurred. To may it must be "typical" is ambigous. Flipping a 100 head in a row, isn't typical, but it's possible and we have a theory of how to assign a probability to it and how to test whether that assignment is consistent. It's a possible sequence, and it "occurs" in the sample space, but that doesn't make its probability=1.
That is to confuse ordinary probability in a chancy universe with the fact that these outlying branches certainly occur in MWI. I thought the point made by Hemmo and Pitowsky was relevant. They pointed out that no matter what sequence you have observed up to this time, you have no guarantee that the next N results you observe won't be contrary to Born rule expectations.
Thus previous experience is no guide to the future in MWI. I know this is true also in ordinary classical probability theory, but the difference is that in MWI, one or more of your successors is bound to see the atypical sequences -- that is not guaranteed in classical probability theory. It *might* happen, but it is not *bound to* happen. This difference is important.
And the statistical limiting theorems that David Albert quotes point to the significance of this difference.
In Sean Carroll's monthly "Ask me anything" blog he wrote this:
0:40:16.3 SC: Sherman Flips says, "How does the weight assigned to a given branch of the wave function correspond to the number of micro-states that are in superposition in that branch?" So, you gotta be a little bit careful. Basically, it is that number, but I wanna be careful here because number of micro-states is a slightly ambiguous concept in quantum mechanics. If what you mean is the number of dimensions of Hilbert space that correspond to that branch, that's what it means, the number of different directions in Hilbert space that you can add together in some principled way to make that particular vector corresponding to that branch. Whether you wanna call a dimension of Hilbert space a micro-state or not is up to you.
0:41:00.7 SC: There's another way of thinking about things if you just had like a bunch of spins. So you have a bunch of two-dimensional Hilbert spaces, one for each spin, spin up or spin down, but the dimensionality of the combined Hilbert space is not 2N. If you have N spins, it's 2 to the N. So you don't have one dimension of Hilbert space for each dimension of the subspaces; you exponentiate them. That's why it depends on what you mean by micro-state, but basically, that is what the weight means. You're on the right track thinking about that.
So he's definitely branch counting, but not describing the mechanism whereby the amplitude of one component of a superposition is translated into a different dimensionality of the combined Hilbert space.
Yes. I think that the idea that Bob has been pursuing is a definite non-starter. Carroll is smart enough to see this, even though he does want to finally reduce probability to branch counting. The real trouble I see with Sean's approach is that he has to call on Born rule insights to know how many additional branches to manufacture. His approach is irreducibly circular.
On 2/17/2021 4:29 PM, Bruce Kellett wrote:
Thus previous experience is no guide to the future in MWI. I know this is true also in ordinary classical probability theory, but the difference is that in MWI, one or more of your successors is bound to see the atypical sequences -- that is not guaranteed in classical probability theory. It *might* happen, but it is not *bound to* happen. This difference is important.
I don't think it's even relevant. It isn't "bound to happen" to you. It's just a possibility for you, just as it is in the Kolmogorov sample space.
Yes. I think that the idea that Bob has been pursuing is a definite non-starter. Carroll is smart enough to see this, even though he does want to finally reduce probability to branch counting. The real trouble I see with Sean's approach is that he has to call on Born rule insights to know how many additional branches to manufacture. His approach is irreducibly circular.
But then he could just postulate the Born rule as the way to partition, or create, branches and it would work; which is what Sabine says. And that tells me that the Hemmo and Pitkowsky objection is wrong.
On Thu, Feb 18, 2021 at 1:05 PM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 2/17/2021 4:29 PM, Bruce Kellett wrote:
Thus previous experience is no guide to the future in MWI. I know this is true also in ordinary classical probability theory, but the difference is that in MWI, one or more of your successors is bound to see the atypical sequences -- that is not guaranteed in classical probability theory. It *might* happen, but it is not *bound to* happen. This difference is important.
I don't think it's even relevant. It isn't "bound to happen" to you. It's just a possibility for you, just as it is in the Kolmogorov sample space.
This is the problem with personal identity in many worlds -- the copies are all *you*, so your comment is without force. You are sneaking in the collapse that Sabine mentions; or you are making a dualist assumption -- only one of the copies is *really you*.
<........>
Yes. I think that the idea that Bob has been pursuing is a definite non-starter. Carroll is smart enough to see this, even though he does want to finally reduce probability to branch counting. The real trouble I see with Sean's approach is that he has to call on Born rule insights to know how many additional branches to manufacture. His approach is irreducibly circular.
But then he could just postulate the Born rule as the way to partition, or create, branches and it would work; which is what Sabine says. And that tells me that the Hemmo and Pitkowsky objection is wrong.
That is what Carroll and Bob are doing. But that rather defeats the purpose of deriving the Born rule from the Schrodinger equation alone. All such arguments are inherently circular.
On 2/17/2021 6:46 PM, Bruce Kellett wrote:
On Thu, Feb 18, 2021 at 1:05 PM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 2/17/2021 4:29 PM, Bruce Kellett wrote:
Thus previous experience is no guide to the future in MWI. I know this is true also in ordinary classical probability theory, but the difference is that in MWI, one or more of your successors is bound to see the atypical sequences -- that is not guaranteed in classical probability theory. It *might* happen, but it is not *bound to* happen. This difference is important.
I don't think it's even relevant. It isn't "bound to happen" to you. It's just a possibility for you, just as it is in the Kolmogorov sample space.
This is the problem with personal identity in many worlds -- the copies are all *you*, so your comment is without force. You are sneaking in the collapse that Sabine mentions; or you are making a dualist assumption -- only one of the copies is *really you*.
I don't think so. Every copy post-test is some copy of you pre-test. The Everett explicitly writes the post-test wave function with all the you's in it. I don't see that as any more problematic than referring to possible you's pre-test. In any probabilistic theory only one possibility is realized
...that doesn't mean we have to assume there was some realism-spirit that got passed to it.
<........>
Yes. I think that the idea that Bob has been pursuing is a definite non-starter. Carroll is smart enough to see this, even though he does want to finally reduce probability to branch counting. The real trouble I see with Sean's approach is that he has to call on Born rule insights to know how many additional branches to manufacture. His approach is irreducibly circular.
But then he could just postulate the Born rule as the way to partition, or create, branches and it would work; which is what Sabine says. And that tells me that the Hemmo and Pitkowsky objection is wrong.
That is what Carroll and Bob are doing. But that rather defeats the purpose of deriving the Born rule from the Schrodinger equation alone. All such arguments are inherently circular.
I agree with that. Do you agree that it would work to simply add the Born rule to MWI as a postulate?
Brent
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On 18 Feb 2021, at 04:39, Bruce Kellett <bhkel...@gmail.com> wrote:On Thu, Feb 18, 2021 at 2:21 PM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:On 2/17/2021 6:46 PM, Bruce Kellett wrote:
On Thu, Feb 18, 2021 at 1:05 PM 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
On 2/17/2021 4:29 PM, Bruce Kellett wrote:
Thus previous experience is no guide to the future in MWI. I know this is true also in ordinary classical probability theory, but the difference is that in MWI, one or more of your successors is bound to see the atypical sequences -- that is not guaranteed in classical probability theory. It *might* happen, but it is not *bound to* happen. This difference is important.
I don't think it's even relevant. It isn't "bound to happen" to you. It's just a possibility for you, just as it is in the Kolmogorov sample space.
This is the problem with personal identity in many worlds -- the copies are all *you*, so your comment is without force. You are sneaking in the collapse that Sabine mentions; or you are making a dualist assumption -- only one of the copies is *really you*.
I don't think so. Every copy post-test is some copy of you pre-test. The Everett explicitly writes the post-test wave function with all the you's in it. I don't see that as any more problematic than referring to possible you's pre-test. In any probabilistic theory only one possibility is realizedThat is where you keep slipping in the implicit collapse (or dualist identity hypothesis). In MWI it is just not the case that only one possibility is realized.
...that doesn't mean we have to assume there was some realism-spirit that got passed to it.If you don't like dualism, then you are left with an implicit collapse hypothesis. There are no other options in MWI.
<........>
Yes. I think that the idea that Bob has been pursuing is a definite non-starter. Carroll is smart enough to see this, even though he does want to finally reduce probability to branch counting. The real trouble I see with Sean's approach is that he has to call on Born rule insights to know how many additional branches to manufacture. His approach is irreducibly circular.
But then he could just postulate the Born rule as the way to partition, or create, branches and it would work; which is what Sabine says. And that tells me that the Hemmo and Pitkowsky objection is wrong.
That is what Carroll and Bob are doing. But that rather defeats the purpose of deriving the Born rule from the Schrodinger equation alone. All such arguments are inherently circular.
I agree with that. Do you agree that it would work to simply add the Born rule to MWI as a postulate?I have difficulty seeing how that could work. For the Born rule to work, the dynamics have to 'see' the amplitudes rather than just the eigenstate basis vectors. But this does not happen in Everett. The set of histories arising in N repetitions of the spin measurement is the same for any two-component initial state -- there is no differentiation of the histories according to the Born probabilities.You have attempted to remedy this by assuming that the number of branches on each trial splits in the Born rule ratios. But this is inconsistent with unitary evolution and the MWI. You might be able to construct a many worlds theory that has the Born rule as an independent postulate -- but the resultant theory will not be quantum mechanics as we know it. I doubt that it can even be unitary.Bruce
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On 19 Feb 2021, at 08:27, 'scerir' via Everything List <everyth...@googlegroups.com> wrote:
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