[HN Gopher] New work extends the thermodynamic theory of computa...
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New work extends the thermodynamic theory of computation
Author : dlojudice
Score : 90 points
Date : 2024-05-14 13:24 UTC (9 hours ago)
(HTM) web link (www.santafe.edu)
(TXT) w3m dump (www.santafe.edu)
| dlojudice wrote:
| Every computing system, biological or synthetic, from cells to
| brains to laptops, has a cost. This isn't the price, which is
| easy to discern, but an energy cost connected to the work
| required to run a program and the heat dissipated in the process.
|
| Researchers at SFI and elsewhere have spent decades developing a
| thermodynamic theory of computation, but previous work on the
| energy cost has focused on basic symbolic computations -- like
| the erasure of a single bit -- that aren't readily transferable
| to less predictable, real-world computing scenarios.
| yodon wrote:
| If you're going to directly quote the first two paragraphs of
| the article, it's generally considered good form to indicate
| you're quoting from the article (for example by starting your
| text with ">")
| gryn wrote:
| if you find this interesting you'll also find the publications of
| J.P Cruthfield interesting, he seem to have worked in this same
| institute up to 2004 before moving to UC Davis. he has 20+ years
| worth of papers on the topic, I keep procrastinating reading them
| esp the ones about what he calls epsilon machines.
|
| I don't really understand this topic, but find the premise
| interesting enough.
|
| here's a paper about
|
| the intrinsic cost of modularity
| https://journals.aps.org/prx/abstract/10.1103/PhysRevX.8.031...
|
| Anatomy of a Bit: https://arxiv.org/abs/1105.2988
|
| Modes of Information Flow https://arxiv.org/abs/1808.06723
|
| stuff related to Landauer's bound
| https://arxiv.org/abs/1812.11241 https://arxiv.org/abs/1909.06650
| https://www.researchgate.net/publication/350794561_Refining_...
| idontknowtech wrote:
| From the headline, I thought this was yet another attempt by some
| silicon valley bro to handwave furiously about everything being
| thermodynamics. Thankfully, this was not the case.
|
| I'm kinda surprised nobody's done this before, given how
| important estimating wastage is.
| gs17 wrote:
| The thermodynamic "limit" is pretty small compared to any other
| waste in a system (from Wikipedia):
|
| > At room temperature, the Landauer limit represents an energy
| of approximately 0.018 eV (2.9x10^-21 J). Modern computers use
| about a billion times as much energy per operation.
| colmmacc wrote:
| One of Feynman's lesser known works is his lectures on
| computation.
|
| https://www.amazon.com/Feynman-Lectures-Computation-Frontier...
|
| Feynman is not as expert on the topic as he is on his core
| research, but his gift for great explanation carries over and
| makes the material more accessible. The lectures are ground in
| thermodynamics and the related information theories, and there's
| a very accessible lecture in there too about Maxwell's Daemon.
| Most of the material is very foundational and still correct, so
| it's a good read for anyone who is interested in the area. I'm
| glad I read it before I had to deal with more complicated and
| statistical approaches to computation and entropy.
| gnatman wrote:
| Fenyman worked with Thinking Machines on their first
| supercomputer, The Connection Machine in the 80s. Here's some
| great background and anecdotes from the founder, Danny Hillis:
|
| https://longnow.org/essays/richard-feynman-connection-machin...
| winwang wrote:
| He also proposed using quantum computers to solve "hard"
| physical systems.
|
| https://arxiv.org/pdf/2106.10522
|
| Though, I'm unsure if he were the first to do so in a semi-
| public manner.
| anonzzzies wrote:
| This is important for our resources and connected to the (at
| least for me) very interesting field of reversible computing.
| rulalala wrote:
| Is SFI alive after all his founders are long gone? I think so,
| but really it is increasingly difficult to discern its current
| unique contribution to the global scientific landscape.
| pmayrgundter wrote:
| Adjacent work from Fields & Levin 2021 on the thermodynamics of
| cellular process, arguing that due to the information processing
| demands and classical thermo minimal power requirements per
| operation for loose estimates of protein control, aggregate
| cellular metabolism power requirements are off by 10-15 orders of
| magnitude of available. They then conclude that cellular
| processes are using quantum coherent processes for major work
| internally and externally (p17).
|
| https://chrisfieldsresearch.com/quantum-cells-pre.pdf
| delichon wrote:
| So perhaps like consciousness.
|
| https://www.youtube.com/watch?v=R6G1D2UQ3gg
| darby_eight wrote:
| I smell Penrose bullshit in the air
|
| Of course the brain uses quantum mechanics, it exists in the
| real world. What has yet to be demonstrated is any link to
| consciousness.
| delichon wrote:
| The link addresses your point.
| darby_eight wrote:
| I am not watching a video
| spacetimeuser5 wrote:
| If Levin wouldn't produce so much fluff on pseudoscientific
| concepts like "selves" and "computational psychiatry", he would
| have had the mice regenerate better and already proceed to
| humans, like Sinclair.
|
| How would quantum theory explain the thermodynamics of
| increased mental clarity reported by humans on 3-5 day of
| fasting induced ketosis? Or multiple biocomputational benefits
| of mTOR inhibition (by e.g. rapamycin for longevity purposes),
| reduced rate of metabolism?
|
| Extrapolating to modern mechanotech, this would be similar to
| an airplane flying faster and better upon regular reduction of
| fuel to it. Imagine a computer running more loads and faster
| upon regular reduction of AC power to it. Thus linear
| application of thermodynamics seems rather ridiculous and
| quantum theory may not save, because it disintegrates beyond
| the Plank's scale.
| slwvx wrote:
| The underlying paper:
| https://journals.aps.org/prx/pdf/10.1103/PhysRevX.14.021026
|
| I skimmed it; it's not super accessible.
| nico wrote:
| What are irreversible problems? Any good/fun and maybe practical,
| examples?
| sponaugle wrote:
| From a boolean logic point of view - AND is irreversible, since
| (1 .AND. 0) is 0, as is (0 .AND. 0.) Going from the result (0),
| you can't reverse and get the starting inputs.
|
| NOT however is reversible, since 1 .NOT. -> 0, and you can get
| back to 1 with another .NOT.
| nico wrote:
| Thank you for the examples
|
| It seems like AND is similar to calculating a binary
| derivative (https://news.ycombinator.com/item?id=40328821)
|
| In a certain way you could say you can integrate AND
|
| For example 1 AND 0 = 0
|
| Now if I only have 0 as a result, it means one of the
| arguments was 0, and the other is either 0 or 1
|
| So the "integral" of AND(0,x) = 0, is (0, (either 0 or 1)) or
| just x = (either 0 or 1)
|
| [0 or 1 meaning one means either. It doesn't mean 0 OR 1,
| which would be 1]
|
| This is analog to the result of an integral being expressed
| as a function + C (constant). The C part is the uncertainty
| of the result, just like having (0 or 1) for AND
|
| The (0 or 1) part can also be expressed as a probability
| distribution, for example p(0)=0.5,p(1)=0.5 which then you
| can use to "sample" the integral of AND by randomly taking a
| (0 or 1) and using it as argument to AND(0, x)
| spacetimeuser5 wrote:
| >>Every computing system, biological or synthetic, from cells to
| brains to laptops, has a cost.
|
| Obviously so, fetching tiny potatoes from point A to point B by
| monkeys has a cost.
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