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awarded  Nice Answer
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comment Entanglement in time
Specific foliations are irrelevant. If two classical events are mutually subject to Bell’s Inequality, then a foliation that makes their separation look time-like enables that relationship to be interpreted as classical causality. However, the same relationship under a space-like foliation becomes inexplicable under classical causality. By far the simplest and most self-consistent physical interpretation of this situation is that the events are linked by a single space-time relationship, entanglement, that only appears to be “causal” or “spooky” depending on the foliation used to observe it.
Oct
19
comment Why do fermions come in generations, but not bosons?
Heterotic, thanks, that's great info and much appreciated!
Oct
19
comment Quantum entanglement of spin along multiple orthogonal axes
Suggestion: Shrink your measurement system, including the observer, down to the size of a small molecule. Run the numbers, and see if it's still heresy to say that new entanglement relationships emerge after a detection. If you don't see any emerge, watch out: Somewhere in your setup you inadvertently violated one of the universe's global conservation laws.
Oct
19
comment Entanglement in time
Bell's Inequality converted the metaphysical "spooky action" debate of Bohr and Einstein into meaningful experiments with fully classical setups and outcomes. If properly selected, these setups and outcomes prove the existence of a quantum entanglement relationship between them. However, the setups and outcomes are classical events subject to the space-vs-time interpretation ambiguity of special relativity. The entanglement relationship that links and mutually influences these events must bridge the same spacetime interval between events, and so is subject to frame-dependent order-of-events.
Oct
16
comment The distance between touching objects
Jim... thank you, and my sincere apology for incorrectly and unfairly associating your comment with that vote. I was wrong to do that. The Android StackExchange app has a very unfortunate bug that completely erases an author's ongoing edits to an answer if someone else, as best I can tell, comments on it or downvotes it. Since I lost my entire first full draft to just that bug, I confess to having been unfairly grumpy... :)
Oct
15
awarded  Nice Answer
Oct
15
comment What does it mean for two objects to “touch”?
Hi Ruslan: Yep, kind of hard to rotate point particle, isn't it? There's a great story about how Pauli cost one poor fellow a Nobel Prize by excoriating his idea of a "rotating electron" so viciously that the fellow flip-flopped completely and forever after attacked anyone else who repeated the idea... even after Pauli then flip-flopped and took the, er, compromise solution that even though a point particle cannot "rotate," it can somehow have a quantized version of angular nomentum. The word games get amusing, since it's considerably less than clear how either phrase can possibly apply.
Oct
15
comment The distance between touching objects
Jim, the idea you quote above about electromagnetic repulsion is a very common one in chemistry, but it is also wrong. The repulsion due to Pauli exclusion. Check out the Feynman Lectures if you want the gruesome details.
Oct
15
comment The distance between touching objects
Jim or whoever, a -1 for a relevant link minutes after my initial post, seriously? Given that my phone app dumped the rest of my answer (see above) before I could post it, that seems a bit unsporting. I had to use my laptop.
Oct
15
revised The distance between touching objects
Completed my initial answer (after my phone app dumped it!)
Oct
15
revised The distance between touching objects
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Oct
15
revised The distance between touching objects
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Oct
15
answered The distance between touching objects
Oct
15
comment Why do fermions come in generations, but not bosons?
If I could just suggest: Perhaps the more interesting facet of the symmetries question might be why, if they do exist, they are so badly broken. The breaks are like windows (or perhaps detectors) into some broader reality where things aren't as smooth as simple symmetries would suggest... and that has to make them interesting and insightful, assuming we can ever figure out the root causes of the breaks.
Oct
15
comment Why do fermions come in generations, but not bosons?
Regarding string theory and @Heterotic's intriguing comment that it does (or can) predict generations: Can anyone elaborate on that specific point? Is there a simple (heh!) example somewhere that shows how e.g. a vibrating string might lead to some fixed number of harmonics? Ben Crowell, any pointers on that? To me, the generations issue is still one of the top outstanding and most fascinating mysteries still remaining in physics. It's just so "not obvious" that it has to be telling us something hugely important.
Oct
15
comment What is the speed of time?
Hi @BenCrowell, sorry, I just laughed out loud when I saw this one -- touche! Wow, this answer is so old I'd forgotten I ever wrote it! It is a bit loosey-goosey, isn't it? Likely a late nighter. Er, I hope you only bumped into it because someone just edited it or something?... Once, a fellow over in chemistry looked up every answer I'd every given there, just so he could down vote half of them after I'd given an answer he disliked on something unrelated! And sorry about dumping on string theory (again) in my one comment, but it really is just frustration. HOW does ST predict generations?
Oct
15
reviewed Approve suggested edit on resource-recommendations tag wiki
Oct
14
comment Why do fermions come in generations, but not bosons?
Your comment about string theory being capable of predicting generations, but also leading to too many models, is at the heart of why I get very frustrated with it. A formal framework is also necessarily a language in which assertions can be made, and string theory is no exception. A predictively interesting language, such as the symmetries Dirac used to predict antimatter, should only be capable of making a limited number of such assertions. The number of vacuua in string theory in contrast implies that its fundamental semantic units— string vibrations — are too rich too predict anything.
Oct
13
awarded  Nice Question