PeterDonis's latest activity
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PeterDonis replied to the thread High School A Recent Article claims that a paper's findings show "collapse" in real-world environments. Is this serious?.I don't either. Unfortunately such misdescription of what a paper actually supports is par for the course at phys.org. They can't... -
PeterDonis replied to the thread Graduate Quantum interpretations and indistinguishable elementary particles.Not at all. You just need to be clear about what "individual physical system" your wave function is describing. As in the example I gave...
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PeterDonis replied to the thread Graduate Quantum interpretations and indistinguishable elementary particles.Usage of that term, unfortunately, is very vague and hand-wavy in much of the literature. There is one such usage that kinda sorta has...
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PeterDonis replied to the thread Graduate How valid is the Block Universe theory?.Generally we don't recommend using AI as a source. The last six words of your post quoted above are a good quick summary of why.
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PeterDonis reacted to PAllen's post in the thread Graduate Is the variation of the metric ##\delta g_{\mu\nu}## a tensor? with
Like.
I don’t see why you would expect that last to be true in general. Starting from T with indexes down, in one case you have the metric... -
PeterDonis replied to the thread Undergrad Special Relativity in a closed universe.If by "special relativity" you mean "my own personal intuition about length contraction", yes, but looking at the whole circumference...
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PeterDonis reacted to Demystifier's post in the thread Graduate Is the variation of the metric ##\delta g_{\mu\nu}## a tensor? with Like.
After some thinking, I believe it's only a problem in notation. To make the explanation simpler, I find convenient to use an index-free...
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PeterDonis replied to the thread High School Calculating an impossible reference frame as my own homework problem.I'm not sure your scenario can even be analyzed, since it appears to contain internal contradictions. I've pointed a few of them out in...
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PeterDonis replied to the thread High School Calculating an impossible reference frame as my own homework problem.I don't understand what this means either.
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PeterDonis replied to the thread High School Calculating an impossible reference frame as my own homework problem.It's impossible for any ship to have a path through spacetime that's shorter than the path of a light ray. The length of a light ray's...
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PeterDonis replied to the thread High School Calculating an impossible reference frame as my own homework problem.It's impossible for any ship to move along with the CMB. The CMB moves at the speed of light. And CMB radiation is moving at the speed...
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PeterDonis replied to the thread High School Calculating an impossible reference frame as my own homework problem.I don't understand what you mean by this. What does the length in spacetime of the ship's path have to do with the apparent speed of the...
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PeterDonis replied to the thread Undergrad Special Relativity in a closed universe.But the change in topology does create something that is not present in SR on ##R^4##: a preferred frame. To see how this works...
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PeterDonis reacted to Dale's post in the thread Undergrad Special Relativity in a closed universe with Like.
In such a universe the first postulate does not hold. So you have to be careful with any "these frames contradict" type of reasoning...
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PeterDonis reacted to Dale's post in the thread Graduate How valid is the Block Universe theory? with Like.
I wouldn’t say it was even a new interpretation so much as a new derivation. His main contribution was taking Lorentz aether theory...