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Nobelist Smoot: entropic geometry explains cosmic acceleration

  1. Mar 31, 2010 #1

    marcus

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    It's possible someone else slipped this into arxiv, as an April foolery, pretending it was by Smoot. You have to judge for yourself. Some elements of parody or jovial self-parody are faintly discernible.

    http://arxiv.org/abs/1003.5952
    Go with the Flow, Average Holographic Universe
    George F. Smoot
    14 pages
    (Submitted on 31 Mar 2010)
    Gravity is a macroscopic manifestation of a microscopic quantum theory of space-time, just as the theories of elasticity and hydrodynamics are the macroscopic manifestation of the underlying quantum theory of atoms. The connection of gravitation and thermodynamics is long and deep. The observation that space-time has a temperature for accelerating observers and horizons is direct evidence that there are underlying microscopic degrees of freedom. The equipartition of energy, meaning of temperature, in these modes leads one to anticipate that there is also an entropy associated. When this entropy is maximized on a volume of space-time, then one retrieves the metric of space-time (i.e. the equations of gravity, e.g. GR). Since the metric satisfies the extremum in entropy on the volume, then the volume integral of the entropy can readily be converted to surface integral, via Gauss's Theorem. This surface integral is simply an integral of the macroscopic entropy flow producing the mean entropy holographic principle. This approach also has the added value that it naturally dispenses with the cosmological constant/vacuum energy problem in gravity except perhaps for second order quantum effects on the mean surface entropy."
     
    Last edited: Apr 1, 2010
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  3. Mar 31, 2010 #2

    marcus

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    Serious or not, this essay appears intended for wide audience--different standards than for peer-review professional journal publication.

    Smoot has already written a couple of articles on this topic for journal publication. See the Easson Frampton Smoot papers in the MIP poll. This essay purports to be doing something different: taking on the job of communicating these (fairly new nontrivial) ideas to the general educated reader.

    Some of the imagery is alarmingly speculative & sci-fi. The Star Trek holodeck metaphor. At times so over-the-top as to make me suspect an element of erudite April foolishness. But I can't say for sure: Maybe someone else can clarify.
    Smoot is ordinarily a first rate science-communicator (as well as a top cosmologist) but the author of this essay (whoever it was) let their imagination gets the best of them. There are typos, showing it was put together hastily (uncharacteristic of Smoot, and another indication that it may have been a joke.)

    Despite these reservations I recommend having a look.
     
    Last edited: Apr 1, 2010
  4. Apr 1, 2010 #3

    Physics Monkey

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    I didn't care for this paper. I have no interest in a lengthy analysis, but I'll give a flavor of my initial objections. Readers here may already know of my skepticism regarding this entropic force business. I continue to question what this line of thought has contributed to our understanding.

    As an early example, on page 4 Smoot makes a big deal out of the agreement between the number of ops (a la Lloyd) and the entropy of cosmic event horizon. I think this is disingenuous as the author is basically using the same formula twice. The horizon entropy is given by 1/H^2 (c=1) while the maximum number of ops is supposed to be rt, but if you use r ~ 1/H and t ~ 1/H then of course these two formulas will agree. How is that surprising or deep? For example, its not clear we could even get a disagreement. One way we might get a disagreement is to use a different cosmological distance measure. In fact, I would think this kind of reasoning by Smoot would annoy people like marcus who are, in my opinion, rightly critical of the uncritical use of various distance measures in cosmology.

    I also agree that the analogies used border on the silly. I realize this is more of a popular article, but the analogies just don't work for me without more serious content to back them up. I also don't think things really improve later in the paper, but I won't get into it.

    I don't want to be too harsh, but I still fail to see the point. Smoot hasn't changed my mind with this latest article.
     
  5. Apr 1, 2010 #4

    marcus

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    I don't want to be harsh either, but I think the point is hostile satire. I'm sure there are people who resent the fact that Erik Verlinde (a former string star) has taken up this thermodynamic view of geometry.

    And the same people must resent even more that a Nobel laureate has come down in favor of exploring the idea, which helps to emphasize that it is worth investigating. Smoot definitely co-authored the two March papers (Easson Frampton Smoot, on entropic acceleration and inflation.) This would be threatening to someone who wanted to dismiss and isolate Verlinde's initiative.

    If you read it as hostile satire it is actually quite funny in a buffoonish "Onion" or college humor magazine sort of way.

    The abstract is written completely straight. But when you open the PDF and look at the article itself the first phrase is sophomoric humor:
    "In the early 1970s...the four laws of black home mechanics..."
     
    Last edited: Apr 1, 2010
  6. Apr 1, 2010 #5

    atyy

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    Good thing Greg and Math Is Hard got me :mad: before I saw this paper :rofl:
     
  7. Apr 1, 2010 #6

    marcus

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    I thought the PF Wedding was delightful. A sweet idea. And where better than Bora Bora?!

    But this "Go with the Flow" hoax is a bit too malicious for my taste. The title maligns Smoot by suggesting that when he, together with Easson and Frampton, took up this thermodynamic geometry idea and applied it to cosmology they were just "going with the flow".

    Going along with the latest fad, or intellectual fashion. Smoot is smarter than that.
     
  8. Apr 1, 2010 #7

    atyy

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    Oh, you don't think Smoot is the author?
     
  9. Apr 1, 2010 #8

    marcus

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    I mentioned in the first post that it could be "jovial self-parody". Some people occasionally make fun of themselves, which can be grandly funny.

    I don't know yet.

    A person would need to have considerable self confidence to lampoon himself to the extent of suggesting that when he joined in with Verlinde, Jacobson, Padmanabhan (and the earlier Hawking, and Unruh stuff) he was "going with the flow".

    There used to be skits at faculty picnics where professors would dress in costume and travesty their own scholarly role or personae. Is this like that? There are several possibilities. I'm not smart enough to see what's going on.

    i tend to think that it was a hostile spoof. But I do not know if the arxiv system can be hacked or fooled like that. Could someone who is not Smoot slip a parody paper in? Jacques Distler might know.
     
    Last edited: Apr 1, 2010
  10. Apr 1, 2010 #9

    Physics Monkey

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    Haha, it would actually make me feel a lot better if this paper were an April Fool's joke. I'm worried its not ...
     
  11. Apr 1, 2010 #10

    MTd2

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    He is serious, but I find it strange that what he calls the apparent horizon the big book, and that shouldn't be the big book. That should be the holographic screen, which is is actually a the sum of the maximal surfaces that is embedded by every causal diamond of every observer and summed up.
     
  12. Apr 2, 2010 #11

    Fra

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    Physics Monkey, if I may ask, can you just briefly characterize your objections to the "entropic business", and what it is you dislike, and what's your general preferred view?

    I like the direction of the recent entropic trends, although my personal impression is that alot of the papers are using a too realistic view on this. I don't quite resonate with the mechanical analogies of fluid mechainics or thermodynamics based on objective microstructures, I think the connection is more subtle, but I still think the general trend is good and may lead to something better.

    So I'm curious to listen to your reasons for not liking it?

    /Fredrik
     
  13. Apr 2, 2010 #12

    Fra

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    In particular do I think that this view suffers from the same flaws as the old logic, namely that it only makes sense for subsystems, and thus is attempts at an external description of gravity, that may well be partly right, but I can't see how objective microstructures (and statespaces) with fixed entropic measures or timeless laws can satisfactory unify the cosmological level understanding with the high energy picture. IT seems it's an attempt still to apply the logic of high energy physics, to cosmological scenarios.

    I guess what I say is that, ordinart statistical physics of fundamental microsturctures and objective entropy measures, is using the same flawed logic as the initial condition/timless law scheme. So I think we need more that just rephrase everything in terms of entropies. It's somehow almost like the relation between newtons and lagrangian formulations of mechanics. Even there, it's clear that the action principle and the entropy maximation are related. So the dual picture is there all along.

    In this sense I think the notion of entropy itself, and it's basisc, combinatorics or probability and the continuuum, must also be questions in this progression, or I also doubt it adds much.

    I would like to hear Your objections. Maybe someone else would also enjoy seeing some possible objections outlined.

    /Fredrik
     
  14. Apr 2, 2010 #13

    Demystifier

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  15. Apr 2, 2010 #14
    A very thorough spoof. The humour and English look quite young and rather Germanic to me. Well done, whoever it is!
     
  16. Apr 2, 2010 #15

    Demystifier

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    No, he isn't. This paper is only a good joke.

    However, it is stated that the paper is written for the Gravity Research Foundation 2010 Awards for Essays on Gravitation. What if the true author will really submit the paper there? And what if the committee will not recognize that it is a joke and award the paper with one of the prizes? (I mean, when such a big scientist such as Smoot proposes such a big idea, it certainly deserves a prize, doesn't it?) It takes a lot of courage to not to go with the flow and to admit that the Emperor is naked.

    By the way, today is the birthday of H. C. Andersen, the author of the tale with the famous quote "The Emperor is naked".
     
    Last edited: Apr 2, 2010
  17. Apr 2, 2010 #16

    MTd2

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    Well, see these:

    http://arxiv.org/auth/show-endorsers/1003.1528
    http://arxiv.org/auth/show-endorsers/0801.2563

    These submitted by the same author's email, but we know are not a fake papers.

    Now, this one was also authored by Smoot:

    http://arxiv.org/auth/show-endorsers/1002.4278

    And correctly shows it is endorsed. But it was not submitted by smoot. I guess the problem is with the "Dr" identifier at the end of the submitter, which mismatches the name of the author.
     
  18. Apr 2, 2010 #17

    Demystifier

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    Hm, you got a point.

    Still, the paper does not look serious ...
     
  19. May 17, 2010 #18

    Demystifier

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    The essay of George F. Smoot we are discussing is among those which received the honorable mention (for GRF essay competition) this year.
     
  20. May 17, 2010 #19

    marcus

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    Strange. The GRF contest judges must have found it entertaining and gotten a good laugh at places. I remain a bit puzzled. (By things like the long mostly irrelevant Star Trek footnote.)

    Maybe the final published version will be edited to seem less goofy.
     
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