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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.


Jan
23
comment Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
@MarkEichenlaub it looks like the discussion resolved the rest of your questions - is that right?
Jan
23
comment Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
@MarkEichenlaub (replying to your first comment) this is just because the machine has to know the state of the cube in order to solve it; once that information's been copied into the machine's state, there's no way to erase it without generating heat. To see it another way, there are $\sim 2^{65}$ possible initial (macro)states of the cube+machine system, so there must be the same number of possible final states unless information has been lost. The cube always ends up in the same state, so the machine must end up in one of $\sim 2^{65}$ states, depending on the initial state of the cube.
Jan
23
comment Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
@immibis I guess the reference would be Landauer's paper (pitt.edu/~jdnorton/lectures/Rotman_Summer_School_2013/…), though I have to admit I haven't read it. Any recent treatment of Maxwell's demon should have a good explanation of how the demon can reduce the entropy of a gas, allowing work to be done, unless it has to erase the information that it inevitably stores about the gas as it operates.
Jan
23
comment Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
@JánLalinský this might be down to imprecision of language on my part. I meant to say "it can indefinitely reduce the thermodynamic entropy of its environment, but only through processes that involve indefinitely increasing the information entropy of its own internal state." It's not just the correlation that makes the entropy decrease, it's the fact that it can make measurements and act on them without having to generate heat. I guess the reference would be Landauer's paper, though I have to admit I haven't read the original. (See next comment for link)
Jan
22
awarded  Good Answer
Jan
21
awarded  Enlightened
Jan
21
awarded  Nice Answer
Jan
21
revised Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
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Jan
21
revised Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
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Jan
21
revised Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
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Jan
21
answered Is there a thermodynamic limit on how efficiently you can solve a Rubik's cube?
Jan
21
comment What is the relativistic mass of this spinning ball?
I can see quite a bit of conceptual stuff in the second to last paragraph.
Jan
19
comment Are the large moons of Jupiter, Saturn, and Neptune still cooling and does this give and indication of their age?
This question might (or might not) be more likely to get a good answer at earth science stack exchange. (It's on topic here as well though.)
Jan
18
revised Why is the isothermal compressibility of the ideal boson gas larger than of the classical ideal gas?
There's no need to make a note of the edit, as there's an edit history feature.
Jan
18
asked What is the argument for detailed balance in chemistry?
Jan
13
comment What would happen to matter if it was squeezed indefinitely?
The phase diagram you link to does not show what you say it shows. Increasing the pressure sufficiently will always turn water into a solid, no matter the temperature.
Jan
11
comment How did Einstein arrive at the right hand side of his general relativity tensor equation?
Related: physics.stackexchange.com/q/30218
Jan
5
comment Why are large scale structures isotropic in the Ising model?
@alarge whether it's dynamics independent is difficult to say, as I don't have any Wolff algorithm code lying around to test it with. My intuition says I could probably come up with some crazy dynamical scheme that would result in obviously anisotropic quenching though, so I suspect it isn't.
Jan
4
comment Thermodynamics, chaperones : How to model polymer fragmentation
When you say "living polymers", do you refer to living polymerisation (a purely chemical phenomenon) or to biopolymers? I'm confused because the reference to equilibrium makes it sound like you're talking about the former, but chaperones are proteins that affect the folding of biopolymers. Or is this another sense of "chaperone" that you're talking about?
Jan
2
comment Why are large scale structures isotropic in the Ising model?
@YvanVelenik no, I mean the pattern that arises if you start at a high temperature and then rapidly drop it to below the critical temperature, then run it for a longish time (using e.g. Metropolis updating) but not for long enough to reach equilibrium. If you do that you get a pattern with a characteristic scale, which looks isotropic to the eye. Though I guess it might not really be isotropic, because it probably also depends on the surface tension. (Your comments were very helpful.)