Timeline for What is entropy really?
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20 events
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| Oct 27, 2019 at 10:40 | comment | added | More Anonymous | @WetSavannaAnimal "their sameness is an experimental observation" ... Wait there's no ingenious uniqueness theorem? Is there at least research in that direction? (seems like a worthy goal to me) | |
| Apr 13, 2017 at 12:39 | history | edited | CommunityBot |
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| Jul 28, 2016 at 17:57 | comment | added | Rococo | @WetSavannaAnimalakaRodVance not to beat a dead horse, but I asked a question about Lambertian entropy awhile back: physics.stackexchange.com/q/219830 . If you think it is valid (as you'll see there, I don't), I encourage you to add an answer. | |
| Jul 28, 2016 at 17:41 | comment | added | Hypnosifl | One quibble: Boltzmann entropy does differ by Shannon entropy by a constant factor, namely Boltzmann's constant--so Shannon entropy is dimensionless while the Boltzmann entropy has units of energy/temperature. | |
| Jul 28, 2016 at 5:45 | comment | added | Selene Routley | @TerryBollinger Frank L. Lambert is the chemist I am thinking of. | |
| Jul 28, 2016 at 4:29 | comment | added | Terry Bollinger | Rod, thanks. I'll be sure to look over that video. As an AI type I am amused at the thought of dispensing with visual processing, as the perceptive aspect of intelligence is the one that proves most difficult in most forms of artificial intelligence. Math, on the other hand is relatively compatible with computers. Here perhaps is a deeper question for you, though: Why does maximizing information density create smoothness? | |
| Jul 28, 2016 at 4:09 | comment | added | Selene Routley | ... of teaching entropy as energy dispersal - I can't find the academic chemist who has advocated this approach in chemistry education right now, but this is good one. You might like this which is my favorite lay explanation of the second law ever, even though Cox does talk of "order" which is a little bit distracting. | |
| Jul 28, 2016 at 4:06 | comment | added | Selene Routley | @TerryBollinger There seems to be a bit of a tendency to look down on visual metaphors, especially amongst the more theoretically inclined. It's a little hypocritical: and I am sure that the reaction of most mathematicians to a call to dispense with commutative diagrams would show that! We're a highly visual species with a great deal of our brain given over to sight, so to sneer at diagrams is kind of like buying a Lamborghini and keeping it undriven in one's garage (I'm not much into motoring, but that's the metaphor I can quickly come up with). That smoothness idea is very like the idea ... | |
| Jul 27, 2016 at 17:54 | comment | added | Terry Bollinger | Hi Rod. As usual, great answer! I was caught off guard when this old question flared up. A few folks got really annoyed at me for having provided a visual heuristic (smoothness = entropy) that describes the curious lack of large-scale patterns induced by encoding maximum information into matter. E.g., I once uncovered opportunities for compressing computer programs just by looking for large-scale patterns in their binary representations. Only smoothly random arrays of bits represented the highest entropy, or most compressed per bit, programs states. Thermodynamics is very much the same idea. | |
| Jul 27, 2016 at 5:12 | comment | added | Selene Routley | @DanielSank See also my comments to Innisfree | |
| Jul 27, 2016 at 5:12 | comment | added | Selene Routley | ...way too hard in seeming very artificial ways to make the second law fit. Then I read a review paper by Bennett on the subject and my mind changed radically - the state information "forgotten" by the reservoir really must end up encoded in the states of physical systems. I realized then that I really believed in the fundamental reversibility - unitary evolution - of the World at a microscopic level. The whole discussion also hurts my mind a bit since I would classify myself as a strong Platonist when it comes to mathematics. | |
| Jul 27, 2016 at 5:08 | comment | added | Selene Routley | @innisfree I agree about the SE of a pdf and data encoding; it just hurts my brain to think that the mind conceiving these things is a thermodymamic system itself and therefore to wonder whether we can really divorce abstract deduction from physical systems, since we must use a physical system to make such abstract reasoning. I remember the first time many years ago when I read about the Landauer principle broadening the thermodynamic discussion of the Maxwell daemon to show that the second law holds if one considers the daemon's mind. My first gut reaction was that this was really trying .... | |
| Jul 27, 2016 at 3:27 | comment | added | innisfree | @WetSavannaAnimalakaRodVance I understand where you're coming from in the discussion with DS, but you can calculate the Shannon entropy of a probability mass function (which has nothing to do with thermodynamics or physics, really). Great answer. | |
| Jul 27, 2016 at 3:16 | history | edited | Selene Routley | CC BY-SA 3.0 |
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| Jul 24, 2016 at 17:21 | comment | added | Rococo | Relevant: physics.stackexchange.com/q/263197 (as elaborated in my answer there, I think DanielSank's formulation is more useful, but there is clearly significant disagreement about this). | |
| Jul 24, 2016 at 8:42 | comment | added | DanielSank | Mehhhh I kinda disagree. We can usefully talk about entropy in discussions about data encoding where the underlying physics is completely irrelevant. | |
| Jul 24, 2016 at 7:36 | comment | added | Selene Routley | @DanielSank I used to be inclined to agree with this - I still agree with the second sentence, depending on one's definition of a "thermodynamic system". But in the light of the Landauer limit, even the information defined in abstract information theory must, for its realization, be encoded in the quantum state of some physical system and so entropy always, ultimately, refers to a physical system. | |
| Jul 24, 2016 at 2:33 | comment | added | DanielSank | Actually, entropy makes sense even outside of physics. We don't need a thermodynamic system to understand entropy. | |
| Jul 24, 2016 at 1:38 | vote | accept | CommunityBot | moved from User.Id=36790 by developer User.Id=2911 | |
| Jul 23, 2016 at 10:19 | history | answered | Selene Routley | CC BY-SA 3.0 |