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| bio | website | nathanielvirgo.com |
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| location | ||
| age | ||
| visits | member for | 1 year, 7 months |
| seen | 55 mins ago | |
| stats | profile views | 822 |
I'm a post-doctoral researcher with a wide range of interests. My career is in complex systems science (or maybe cybernetics) and the origins of life, but I also have research interests in
- the foundations of statistical mechanics and its relationship to information theory
- Earth systems science
- non-equilibrium thermodynamics in general
I'm also generally interested in the foundations of quantum mechanics and in black holes, though I wouldn't say I'm an expert on those things.
It's probably worth noting that despite the fact that my research is in physics-related areas, all my degrees are in other subjects. If I occasionally seem to start talking in an alien language, this is probably why.
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22h |
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Is the wave function objective or subjective? @EmilioPisanty I know. But this other question seemed in danger of being marked a duplicate of this one. Since this question is closed, it means the question cannot be asked. But it's a reasonable question that probably has a definite answer, so that would be a bit of a shame. |
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1d |
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Is the wave function objective or subjective? @Weissman I hope I haven't changed the meaning of your question too much by editing it. Please feel free to roll back the edit if I have. |
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1d |
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Is the wave function objective or subjective? @DavidZaslavsky subjectivity has a fairly well-recognised and standard definition, so I've edited it into the question. |
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1d |
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What does the difference in odds for Bell's inequality tell us about quantum mechanics? @Xaqron can you edit the question to be more clear about what you mean by "missing data", and why this would lead to us thinking Bell's inequality is satisfied when it isn't? It's kind of hard to answer as it is, because we can't see exactly what you're thinking. |
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2d |
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What is a “gravitational cell”? The wording of the abstract, and the use of quotation marks, strongly suggests that the "gravitational cell" is something that will be described in the paper. I imagine it's some kind of gravitational analog to an electrochemical cell. The only way to find out for sure is to get a copy of the paper and read it. |
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May 17 |
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From where (in space-time) does Hawking radiation originate? @LeosOndra yes, that's exactly what I'm asking. (Note that for any real black hole there is a gas between the horizon and the observer.) |
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May 16 |
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From where (in space-time) does Hawking radiation originate? @RonMaimon would I be correct in understanding that as "close to the horizon, the photons are of such a high frequency that they pass through just about anything"? |
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May 16 |
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Boundary conditions on wave equation thanks, that's a very elegant argument. |
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May 16 |
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Boundary conditions on wave equation I guess the question is, why isn't that allowed? Since there is a discontinuity in the linear density of the rope, it's not immediately intuitively obvious that a kink can't develop at that point. (I think it can be derived from energy conservation, though.) |
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May 15 |
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From where (in space-time) does Hawking radiation originate? @Siva really? If that's true it's very interesting, and bizarre that no-one ever mentions it when explaining the Penrose diagram for an evaporating black hole. (It's different from what Ben Crowell said, AFAICT.) |
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May 15 |
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How large of a solar sail would be needed to travel to mars in under a year? I think the first step is to write your last expression as an equation: $d = \frac{1}{2}at^2$. Which variables in this equation are known, and which are the unknown(s)? |
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May 15 |
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From where (in space-time) does Hawking radiation originate? @RonMaimon ok, if it comes from a Planck-sized region rather than a single point, that's fine. I understand (qualitatively) how the Penrose diagram smooshes space-time up. But why is the star matter like a diffuse, wispy gas? Stars under normal circumstances are made of opaque plasma, and if there is nothing "special" about the event horizon from a falling observer's point of view, the star should continue to be made of opaque plasma as it falls through it. |
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May 15 |
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From where (in space-time) does Hawking radiation originate? Black hole complementarity can't resolve it (afaics) because we're talking about two different observers who are both outside the event horizon and in principle can meet and compare notes. But people say Hawking radiation doesn't contain information about the infalling matter (modulo weird stuff about non-locality and tunnelling past the horizon), which would suggest they think it doesn't interact with the matter at all. This means it either magically passes through it, or it gets generated well away from the horizon, in between the matter and the distant observer. |
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May 15 |
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From where (in space-time) does Hawking radiation originate? To clarify, the main reason I'm interested in this is that it seems as if the whole mass of the collapsing star should be in between the distant observer and the region where the Hawking radiation is emitted, so it seems that it should get in the way and prevent us from directly observing it, instead being heated up by it and re-emitting thermal radiation of the same spectrum. But the infalling matter itself is not supposed to experience interaction with the Hawking radiation, so this is a paradox. |
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May 15 |
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From where (in space-time) does Hawking radiation originate? So my questions would be (i) if the radiation is emitted from a single point, why are we predicted to observe it over periods of time much longer than one wave cycle; and (ii) there is a very large opaque object in between that point and a distant observer, namely the collapsing star. Does the radiation get absorbed by the matter, or magically shine through it, or what? |
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May 15 |
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From where (in space-time) does Hawking radiation originate? @Ron while I greatly appreciate your edit, it doesn't give me much to go on. Penrose diagram or not, if I observe a photon coming from a black hole and trace the ray back to try and determine its origin, it intersects the surface of a collapsing star. Tracing back further, I reach a point before the formation of the horizon. The rest of the question follows from that - the Penrose diagrams were just a way to illustrate it. |
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May 15 |
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From where (in space-time) does Hawking radiation originate? But the issues to do with the in falling matter were the entire point of the question! |
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May 14 |
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Definition of entropy Shannon entropy and thermodynamic entropy have an awful lot to do with each other actually. See bayes.wustl.edu/etj/articles/stand.on.entropy.pdf , for example. |
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May 14 |
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Can one get clear ice crystals from a dirty suspension? Another relevant thought: if the solid particles act as nucleation sites then each will start out embedded in its own ice crystal and they won't get separated at all. |
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May 14 |
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Our Universe Can't be Looped? @Qmechanic ok, fair enough, I didn't follow the link in the answer to the other question. |
