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The present phase of stagnation in the foundations of physics is not normal

backreaction.blogspot.com

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Re: The present phase of stagnation in the foundations of physics is not normal

#131

Post by dwaltrip »

naasking wrote: post #68
walrus1066 wrote: post #21

Earlier quoted context omitted.

'Physics is notoriously bad at having curiosity about strange, unconventional, or truly novel ideas.' There is certainly no shortage of these! What we are short of, are ideas that are: - falsifiable - testable by experiment, with current technology

Maybe we're short on those precisely because the strange ideas aren't given enough attention. Bell's Theorem was a landmark result that didn't come out of the Copenhagen interpretation, but because John Bell was fascinated by the de Broglie-Bohm interpretation. The point is, unconventional perspectives give you new ways of looking at a problem that can yield new experiments.

That could be the case. I think the bigger issue is that many unsolved questions today are difficult to explore without expensive, highly-sophisticated equipment and larger teams of people.

Re: The present phase of stagnation in the foundations of physics is not normal

#132

Post by tbabb »

kgwgk wrote: post #128
tbabb wrote: post #124

Earlier quoted context omitted.

> I am not sure what premise of Copenhagen is being contradicted. Before measurement, the state of the particle system is Σ α_i|i>. Copenhagen says, "after you measure the system, all but one of the α_i go to zero". The authors don't do that, and in fact say that you can't. Unless I am misunderstanding something, they keep all the α_i around at all times and project the measurement for each particle separately, regar…

Please see what I added to my previous comment. You could in principle do it in the "right" order and you would get the same result. They routinely solve quantum optics problems using standard QM and the experimental results match the predictions. What he shows in that paper is that the order of the measurments is irrelevant [1]. So he does solve the problem in the reverse order where it can be done easily writing a…

Yep, I'm with you that we don't need to bring causality into it.

And yes, you don't need to ask "when does the wavefunction collapse" to manipulate joint probabilities of measurements that happen at disparate locations and times. In fact, that's my objection: If you do ask, you find that there is no consistent answer! (And I suggest it's because wavefunction collapse is not a thing the universe does).

Re: "interference tagging"-- do you have a link to some material? (I'd love to understand something specific before commenting).

EDIT: Also, I didn't see Appendix B at first-- The authors do understand and even advocate the Everettian view! Though I still don't quite understand/agree with their earlier timidity about finding and interpreting conflicts with Copenhagen.

Re: The present phase of stagnation in the foundations of physics is not normal

#133

Post by rivp931 »

rthomas6 wrote: post #104
tylermw wrote: post #3

Love this comment left on the post by Peter Shor (of Shor's algorithm--the algorithm that kicked off the quantum computing frenzy). I assume it's him and not an imposter. "It's not just that scientists don't want to move their butts, although that's undoubtedly part of it. It's also that they can't. In today's university funding system, you need grants (well, maybe you don't truly need them once you have tenure, but…

I wonder if some rich people could start a form of charity where they just pay a few incredibly brilliant people a good salary to go do whatever research they want for the rest of their lives. Sort of like patronage. Just bypass the whole grant funding cycle and work on whatever you want, because you're a genius and want to study things other people don't like or understand.

A first problem is how to recognize these incredibly brilliant people. The current answer to this is the tournament to tenured professorship. If you select those who already succeed in this system, you are not really doing anything new, so something different should be done but it is not clear what.

A second difficulty is the "rest of their lives" part. It's quite hard to believe ROI would not be required when rich people are involved in some way or other. Charity is PR, and so the system will optimize for PR.

Re: The present phase of stagnation in the foundations of physics is not normal

#134

Post by starbeast »

pdonis wrote: post #115
EGreg wrote: post #43

Earlier quoted context omitted.

This is one of the best arguments for UBI. Imagine how much humanity would innovate in science, open source and other public gift economies if everyone didn’t have to worry how they will eat and pay rent next month.

The argument you are making assumes two things that strike me as highly implausible: (1) That enough people would use their new free time to innovate instead of just watching TV or playing World of Warcraft or something like that. (2) That enough people would still choose to do the unpleasant but necessary tasks that provide the resources needed for everyone to eat, have housing, etc. Not to mention all the other stu…

I don't know why you find it implausible given that there are plenty of people who already do both those things while having enough money not to.

Re: The present phase of stagnation in the foundations of physics is not normal

#135

Post by sgt101 »

konschubert wrote: post #111
YeGoblynQueenne wrote: post #70

Earlier quoted context omitted.

I'm sorry, I don't know what General Relativity says, really. I'm not that kind of geek :0 What if I say there are frames of reference that are irrelevant to discovering the process that generates the observations? Edit: Um, guys? I genuinely don't know what general relativity says and I didn't get the comment above. It'd be nice if someone explained.

I think your "I'm not that kind of geek" comment came off as condescending. It also makes you sound like you're not really interested in understanding the other side's argument.

I don't see that there is an argument - rather that a separate chain of discussion has started. It's fair to then say "well that's all fine but what I was thinking of was X" which is what I am reading. I think that there is a big difference between frames of Einstein (I don't understand these) and frames of reason and perception (I don't understand these either) but I do see that there are two different things!

Like I don't understand either Australia or Argentina.. but I know that they are not the same!

Re: The present phase of stagnation in the foundations of physics is not normal

#136

Post by kgwgk »

tbabb wrote: post #132
kgwgk wrote: post #128

Earlier quoted context omitted.

Please see what I added to my previous comment. You could in principle do it in the "right" order and you would get the same result. They routinely solve quantum optics problems using standard QM and the experimental results match the predictions. What he shows in that paper is that the order of the measurments is irrelevant [1]. So he does solve the problem in the reverse order where it can be done easily writing a…

Yep, I'm with you that we don't need to bring causality into it. And yes, you don't need to ask "when does the wavefunction collapse" to manipulate joint probabilities of measurements that happen at disparate locations and times. In fact, that's my objection: If you do ask, you find that there is no consistent answer! (And I suggest it's because wavefunction collapse is not a thing the universe does). Re: "interferen…

> If you do ask, you find that there is no consistent answer!

I'm not sure what's the problem. Why do have to "ask" if the answer doesn't really matter? What answer more consistent than "it doesn't really matter" would you like? Anyway (standard) QM is a non-relativistic theory, QFT may be more satisfactory from that point of view.

Re: "interference tagging" - what I mean is that first you detect the photons and later check if they "did happen" to go through two slits (interference appears) or one slit (no interference). But the interference pattern is not visible for a single photon and at that point the individual events are still a superposition of both possibilities (so for the events at a certain position part of them will be in the end identified as coming trough one slit and some of them from both). Only after the second measurement is done you know how to group the previoulsy recorded events to see the interference. It's not that the later measurement causes interference to appear. Or at least it doesn't affect at all where the photons were detected, it just lets you know how to group the existing events to make it apparent (selecting only those where, once the full mesurement on the pair has been done, the path taken remains uncertain).

Edit: maybe this picture helps https://upload.wikimedia.org/wikipedia/commons/thumb/c/c8/De...

If all the events are taken together there is no interference pattern. But when they are grouped according to where the second photon is detected in two cases there is still no interference but in the other cases complementary interference patterns appear.

Re: The present phase of stagnation in the foundations of physics is not normal

#137

Post by amai »

Isn’t she just complaining that nobody is listening to her? That sounds a lot like a crackpot to me. Instead of complaining she should better work on a useful new theory explaining the masses of neutrinos or dark matter and dark energy. But of course this is much harder than writing blog posts.

Re: The present phase of stagnation in the foundations of physics is not normal

#138

Post by tbabb »

kgwgk wrote: post #129
FakeComments wrote: post #106

Earlier quoted context omitted.

No, but if you have non-locality, then you don’t need the non-definiteness of Copenhagen, and could do with something like a Bohm or MW interpretation.

Or you could do with Copenhagen... I found this quote from David Lindley in a review of Adam Becker's book referenced in this thead ( http://www.math.columbia.edu/~woit/wordpress/?p=10147 ): "The problem with Copenhagen is that it leaves measurement unexplained; how does a measurement select one outcome from many? Everett’s proposal keeps all outcomes alive, but this simply substitutes one problem for another: how do…

I don't think that criticism really understands what Everett says-- the evolution of the universal wavefunction is unitary. There is no "splitting". There is only uncertainty about what part of phase space you are in (and any measurement that tightens your certainty in one axis of phase space will broaden it along some other axis).

Re: The present phase of stagnation in the foundations of physics is not normal

#139

Post by tbabb »

kgwgk wrote: post #136
tbabb wrote: post #132

Earlier quoted context omitted.

Yep, I'm with you that we don't need to bring causality into it. And yes, you don't need to ask "when does the wavefunction collapse" to manipulate joint probabilities of measurements that happen at disparate locations and times. In fact, that's my objection: If you do ask, you find that there is no consistent answer! (And I suggest it's because wavefunction collapse is not a thing the universe does). Re: "interferen…

> If you do ask, you find that there is no consistent answer! I'm not sure what's the problem. Why do have to "ask" if the answer doesn't really matter? What answer more consistent than "it doesn't really matter" would you like? Anyway (standard) QM is a non-relativistic theory, QFT may be more satisfactory from that point of view. Re: "interference tagging" - what I mean is that first you detect the photons and late…

> Why do have to "ask" if the answer doesn't really matter?

You tell me; Copenhagen is the one that says collapse exists. It sounds like maybe we are on the same page that collapse isn't necessary to explain quantum mechanical observations? In that case, we are both Everettians :).

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