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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

#91

Post by kgwgk »

tbabb wrote: post #60
andrepd wrote: post #53

Earlier quoted context omitted.

>Physics is notoriously bad at having curiosity about strange, unconventional, or truly novel ideas. Physics of today would be unrecognisable to a scientist at the start of the 20th century. Indeed the physics of 1935 would be unrecognisable to a scientist at the start of the 20th century. Our understanding progressed enormously AND it did so because people put forward radical theories in complete rupture with the es…

> There is nothing "obviously wrong" about the standard Copenhagen interpretation Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? Can you tell me under what circumstances a system of particles will evolve unitarily or not? Can you shade the region of the spacetime diagram of EPR where the wavefunction is collapsed? How about in a delayed choice…

Demystifying the Delayed Choice Experiments: https://arxiv.org/abs/1007.3977

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

#92

Post by baxtr »

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…

So, maybe we need VC funding for science?

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

#93

Post by beefman »

This criticism may have some merit on the particle physics side of things, but from the 'gravity' side I see exciting recent progress. In particular, the AMPS firewall and literature that followed, including the introduction of computational complexity into physics, ER=EPR etc. With LIGO and various space telescopes soon coming online, the experimental future looks bright too.

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

#94

Post by jerf »

bluGill wrote: post #64
Koshkin wrote: post #51

Earlier quoted context omitted.

> the frame of reference is wrong According to General Relativity, there's no such thing as a "wrong" frame.

True, but there are frames of reference that make understanding (and the math) vastly simpler. I can calculate the orbits of the Saturn's moons using my location on earth as the origin. It will take me a lot of work, but I can do it.

It's a fun exercise to reframe the laws of physics in terms of your "stationary" frame on Earth and I recommend it to everybody. Consider the speed of light in the Andromeda galaxy... except under these physics we can't speak of the "speed" of light, but the permissible velocities as a function of the location in question.

Running through this exercise with some honesty can give one a greater understanding of why our physics is framed the way it is, and why it is that while all sorts of reference frames are valid, "inertial" reference frames are still important on their own merits.

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

#95

Post by jsweojtj »

T-A wrote: post #78
jsweojtj wrote: post #50

Earlier quoted context omitted.

It does not predict the fine structure constant, that is an input into the model.

https://en.wikipedia.org/wiki/Fine-structure_constant#Measur...

Exactly. Its value comes from being measured.

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

#96

Post by tbabb »

kgwgk wrote: post #91
tbabb wrote: post #60

Earlier quoted context omitted.

> There is nothing "obviously wrong" about the standard Copenhagen interpretation Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? Can you tell me under what circumstances a system of particles will evolve unitarily or not? Can you shade the region of the spacetime diagram of EPR where the wavefunction is collapsed? How about in a delayed choice…

Demystifying the Delayed Choice Experiments: https://arxiv.org/abs/1007.3977

I am not sure that paper knows it, but it is essentially showing that many worlds is correct-- that the wavefunction never collapses:

> the implications on conditional probabilities hold for other measurements throughout the entire spacetime, present and past. [emphasis theirs]

And the math in the paper which supports that statement works by keeping all the superpositions around and allowing us to project to them at any time. This is the picture of many worlds! Copenhagen says the opposite: When you make a measurement, the unmeasured superpositions go away. The paper confirms, that's nonsense! If you shade any region of the spacetime diagram where the superposition is gone ("collapsed"), you'll be wrong!

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

#97

Post by kgwgk »

tbabb wrote: post #60
andrepd wrote: post #53

Earlier quoted context omitted.

>Physics is notoriously bad at having curiosity about strange, unconventional, or truly novel ideas. Physics of today would be unrecognisable to a scientist at the start of the 20th century. Indeed the physics of 1935 would be unrecognisable to a scientist at the start of the 20th century. Our understanding progressed enormously AND it did so because people put forward radical theories in complete rupture with the es…

> There is nothing "obviously wrong" about the standard Copenhagen interpretation Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? Can you tell me under what circumstances a system of particles will evolve unitarily or not? Can you shade the region of the spacetime diagram of EPR where the wavefunction is collapsed? How about in a delayed choice…

> But by accident of history, John Bell was too shy to publish in a major journal, and no one even read his result for four years.

Why do you say that his 1964 paper (I assume) was not read by anyone for four years?

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

#98

Post by tbabb »

kgwgk wrote: post #97
tbabb wrote: post #60

Earlier quoted context omitted.

> There is nothing "obviously wrong" about the standard Copenhagen interpretation Can you tell me how to calculate whether a system of particles will cause another system of particles to collapse or not? Can you tell me under what circumstances a system of particles will evolve unitarily or not? Can you shade the region of the spacetime diagram of EPR where the wavefunction is collapsed? How about in a delayed choice…

> But by accident of history, John Bell was too shy to publish in a major journal, and no one even read his result for four years. Why do you say that his 1964 paper (I assume) was not read by anyone for four years ?

He published in a tiny journal that was only in print for a handful of years, which was read by very few people. Bell himself said that no one contacted him or even mentioned it to him until four years after its publish date, and that researcher only came across it by pure happenstance. The whole story is detailed in Becker's book; it's fascinating.

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

#99

Post by kgwgk »

tbabb wrote: post #96
kgwgk wrote: post #91

Earlier quoted context omitted.

Demystifying the Delayed Choice Experiments: https://arxiv.org/abs/1007.3977

I am not sure that paper knows it, but it is essentially showing that many worlds is correct-- that the wavefunction never collapses: > the implications on conditional probabilities hold for other measurements throughout the entire spacetime, present and past . [emphasis theirs] And the math in the paper which supports that statement works by keeping all the superpositions around and allowing us to project to them at…

The author says: "Note: in this work, we will not make any reference to why this (apparent) collapse occurs. Not only is this a much harder issue, it is simply not relevant to discussion we will present."

Also: "It is important to note that arriving at our conclusions did not require introducing new physics. We only relied on elementary quantum mechanics: not on novel ‘backwards time’ concepts, nor on any particular interpretation: we only used the Born rule ‘as is’. [...] With the remarks and intuition presented here, there really is no mystery whatsoever in any of the discussed experiments."

This experiment is not more mysterious than the rest of QM, but of course if you find the whole theory unsatisfactory you won't be satistified with this explanation either.

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

#100

Post by jgamman »

tbabb wrote: post #56
mannykannot wrote: post #52

Earlier quoted context omitted.

It is not clear to me in what way the tone of your post differs from that of the article.

Here's a snippet: > Another comment-not-a-question I constantly have to endure is that I supposedly only complain but don’t have any better advice for what physicists should do. > First, it’s a stupid criticism that tells you more about the person criticizing than the person being criticized. These feel closer in tone to "personal attack" on her critics to me than a discussion of their ideas. There is also discussion…

i think its one of the classic logical fallacies - you can't disagree with me unless you have a better idea. it's a false dichotomy in the sense I can think you are wrong without further explanation. unless there's expt evidence but most of this is opinion-based so it's not open to that sort of progress.
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