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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.


Feb
15
comment Harvesting hydrogen from a star
@Floris e.g. this blog post shows that if you naïvely extrapolate past economic trends you find human energy use will pass the Sun's total output in less than 2000 years. I don't think this figure is particularly plausible, but I do think it's plausible that it could happen eventually. (Not good or bad, just plausible.)
Feb
15
comment Harvesting hydrogen from a star
@Floris the question is coming from the somewhat dystopian perspective that societies' energy requirements can run out of control. Our society is coming close to wrecking our planet because of exponentially increasing energy requirements; the thought experiment is about what would happen if this exponential economic growth continued to the point where we'd end up wrecking the Sun as well. If this happens elsewhere it should be detectable, so I'm hoping this weird dystopian thought experiment can be turned into a testable hypothesis.
Feb
15
asked Harvesting hydrogen from a star
Feb
14
comment What is the interpretatation of individual contributions to the Shannon entropy?
Aah, I'm not sure if it works. My idea was to set up a situation where you can send either signal $A$ or $B$, but where there's a cost to send one of the signals but not the other. Then by trying to maximise (total information transmitted)/(expected cost) you might end up maximising $-p(A)\log p(A)$ to get $p(A)=1/e$ as the optimum. But the exact thing I thought of doesn't work, so I need to think more about it.
Feb
14
comment What is the interpretatation of individual contributions to the Shannon entropy?
Interesting - thanks. I've thought of another case where it comes up as well, which I've been meaning to post as an answer. Let me see if I have time to do that now.
Feb
12
comment Help explore a self-feedback camera-monitor chaotic system
There are some papers on video feedback by James Crutchfield. I'll try to dig them out when I'm at a computer, or that might be enough for you to find them for yourself.
Feb
11
awarded  Nice Answer
Feb
11
comment Why aren't there any clear planets/ stars?
@JohnRennie yeah, but even if they didn't they would still be opaque due to Rayleigh scattering.
Feb
11
comment Why aren't there any clear planets/ stars?
It's a good question, and neither the question nor the correct answer have anything whatsoever to do with the linked "why is water clear?" question. The actual answer is that even things like water or hydrogen gas, which are clear in small quantities, are no longer clear if you scale them up to the size of a planet. I hope someone has the time to write up a good answer explaining this.
Feb
7
comment Sun in front of horizon after sunset; mirage or reflection?
I suspect that it's a reflection - I think the atmosphere is bending the light such that you can't see the Sun directly, but you can see the rays that have been bent by the atmosphere and then reflected off the sea. But I'm not at all sure about this. +1, it's a good question.
Feb
7
revised Random musing, is $\langle\psi^*|\psi\rangle$ = $\langle\psi^*|I|\psi\rangle$, where I is the identity operator a legit operator?
deleted 17 characters in body; edited title
Feb
5
comment What is the interpretatation of individual contributions to the Shannon entropy?
Oh sorry. The first was just a Wikipedia link. Yes, the point is that paper makes the Rényi entropy feel like a physically and informationally meaningful thing, whereas to me the Tsallis seems like a mysterious equation that comes from nowhere. (But if you know an interpretation I'd like to hear it.)
Feb
5
comment What is the interpretatation of individual contributions to the Shannon entropy?
it's not just a related quantity, it's a more general one that includes yours, but anyway. Yes I meant to post two links. The second is an interpretation of the Renti entropy. I don't know a good interpretation of the Tsallis entropy, it always seemed a bit arbitrary to me.
Feb
5
comment What is the interpretatation of individual contributions to the Shannon entropy?
@NikolajK your other thing seems related to the Rényi entropy. I do know a nice interpretation of the Rényi entropy, though its exact relation to your formula would need some thought.
Feb
5
comment What is the interpretatation of individual contributions to the Shannon entropy?
@NikolajK it's not so much "I don't know an interpretation" (although I don't) as "here's a reason why you wouldn't expect there to be an interpretation."
Feb
5
answered What is the interpretatation of individual contributions to the Shannon entropy?
Feb
3
comment What does a long strip of explosive sound like when detonated?
Probably quite a bit like a roll of thunder, which is essentially the same thing.
Feb
2
comment Unmixing of gases: What is the relevant temperature for my Entropy?
@mart typically the heat bath is just the atmosphere or water surrounding the thing that's doing the unmixing. Known practical practical methods for unmixing macroscopic quantities of fluids are so far from the theoretical maximum efficiency that the temperature of the heat bath makes no difference to the energy they need. The point is just that in priciple, if you had access to a heat bath at a lower temperature than the system, then in principle you could design a Maxwell's demon type thing to take advantage of it and unmix more efficiently.
Jan
31
answered Is $ds^2$ just a number or is it actually a quantity squared?
Jan
28
comment Confusion in understanding the concept of beats
You might find the diagrams and explanation at en.wikipedia.org/wiki/Beat_(acoustics) helpful.