| Subject: Re: hep-th/0112090
Date: Thu, 13 Dec 2001 22:59:19 +0200 From: "Dimiter G. Chakalov" <dchakalov@surfeu.at> To: Joao Magueijo <j.magueijo@ic.ac.uk> CC: l.smolin@ic.ac.uk BCC: [snip] On Thu, 13 Dec 2001 13:12:27 +0000 (BST), Joao Magueijo
wrote:
Thank you for your reply. I wish you and Lee great success in your work. Just a few words (which you may find terribly boring, I'm afraid). I believe that the Planck scale is a very special entity: there are some numerically finite values that would describe it, but they are like absolute zero temperature. It's like a wall that must exist in some way or another, but can't be reached by any physical system. In fact, the whole physical world is wrapped by such numerically finite but physically unattainable "boundaries". This is a very old philosophical issue, Titus Lucretious Carus has argued thatthere must exist some limit (lower bound) in dividing an object, and hence 'atom' (or Planck scale, as we would say), otherwise there will be no difference between 'big' and 'small'. I know that 3^-2 times 12^-2 gives +/-6, and am happy, but I have no idea what is the heck going on. Same in renorm recipes, by subtracting one infinity from another you get a finite value. Orthink about the requirement for unitarity: if fulfilled, it says that 'something will happen', but we again operate under an assumption that cannot be rigorously proved nor verified: you can't make infinite number of trials,and yet "something out there" is taking care of your calculus, as if "it" had proved that in the limit the sum of probabilities will indeed reach unity. Anyway, what I'm trying to say is that the Planck scale should be used as a cut-off after serious considerations. Nothing can go "below" it, so nothing can *physically* reach it and jump over it. The fact that such animal exists is a great mystery to me. That's how things look from my camel:-) I'm sure you and Lee can see better. Regards, Dimi
======== Suject: Variant Speed of Light
Dear Joao, Regarding your book "Faster Than the Speed of Light: The Story of a Scientific Speculation": I'm wondering what do you think of the opinion of George Ellis in Nature. See my VSL idea at http://members.aon.at/chakalov/Mario.html As to whether the physics editor at Nature is in fact "a first class moron", http://www.amazon.com/exec/obidos/tg/stores/detail/-/books see my feedback to Nature, http://members.aon.at/chakalov/Nature.html I don't think the physics editor at Nature is "a first class moron", he just doesn't care. It happens with physicists who have build a socialism around them, have their pay check secured, and don't have to fight for the daily bread. I hope this will never happen to you. Regards, Dimi
================ Subject: Revising relativity?
Dear Joao, In my email of Tue, 15 Apr 2003 15:21:30 +0300, http://members.aon.at/chakalov/Magueijo.html#VSL I asked for your opinion on the critical comments by George Ellis regarding your book "Faster Than the Speed of Light: The Story of a Scientific Speculation". See again "Einstein not yet displaced", by George Ellis, Nature 422, 563-564 (10 April 2003). It seems to me that in your latest article "Gravity's Rainbow", gr-qc/0305055, you and your co-author Lee Smolin have again ignored many objections to your hypothesis of doubly special theory of relativity. You and Lee wrote: "We found that cosmological distances, in an expanding universe, become energy dependent. Thus the physical distance associated with a given comoving distance depends on the energy scale at which it is measured. Seen in another way, the age of the universe isenergy dependent. We used this fact to show how the horizon problem may be solved without inflation or a varying speed of light." It is not at all clear what do you mean by "cosmological distances, in an expanding universe, become energy dependent" and "the age of the universe is energy dependent". In your gr-qc/0305055, you and Lee did not even mention Judes & Visser's "Conservation Laws in Doubly Special Relativity", gr-qc/0205067, which I quoted as [Ref. 1] in my email of Fri, 03 Jan 2003 16:19:10 +0200 (printed below). May I ask just two questions. Q1: How would you define 'energy' and 'curvature' – and thus gravity – into some "non-linear realizations of relativity (also known as DSR)"? Also, you and Lee wrote: "Related effects may also be detectible in the near future in CMB observations." Q2: What is the topology of space, according to your DSR hypothesis? See the 'cosmic equator' and the problems of pinpointing the space topology at http://members.aon.at/chakalov/Tegmark.html#note Take care, Dimi
Subject: Re: Revising relativity
RE: Revising Relativity -- Physicists try to outdo Einstein,
by Graham P. Collins, Scientific American, November
2002.
Dear Mr. Collins, In addition to the request for clarification (cf. the email from Dr. Alfred Schoeller below), may I ask you to find one shred of evidence that the doubly special theories of relativity or DSR theories [Ref. 1]could provide correct laws of conservation of energy and momentum in GR. The proof of the pudding, as we call it. It is well-known since 1950s that, because of the invariance under the general coordinate transformation in GR, it becomes ambiguous how to define the time variable, and subsequently the Hamiltonian conjugated to it. The problems resulting from this ambiguity are severe, to say theleast [Ref. 2]. Do you believe that DSR theories, as outlined by Amelino-Camelia and Magueijo & Smolin, can shed some light on the puzzle of the energy of the gravitational field? Is there any other 'proof of the pudding' for DSR theories that you might suggest? I will be happy to learn the opinion of the professional physicists as well. Sincerely yours, Dimiter G. Chakalov
References [Ref. 1] Simon Judes, Matt Visser.
Conservation Laws in Doubly Special Relativity.
[Ref. 2] Carlos Barcelo, Matt Visser.
Twilight for the energy conditions?
On Fri, 03 Jan 2003 11:48:25 +0000, alfred schoeller wrote:
==================== Note: Regarding the argument of Lucretius (Titus Lucretius Carus, 96 BC - 55 BC, Book I, Character of the Atoms; please see above), that there must exist some limit (lower bound) in dividing an object, and hence 'atom' (or Planck scale, as we would say), otherwise there will be no difference between 'big' and 'small': note that the bounding point, the minimum of Nature, exists without all parts. Here's the quote: Lucretius' Book I has been written some 2060 years ago, when nobody knew about background-independent models of quantum gravity. We can, of course, neglect these very old and widely known ideas, and indulge ourselves with some highly sophisticated math. After all, we live in 21st century and use math, not poetry.Of that first body which our senses now Fine, but do we use the human mind? Do we reply on the astonishing effectiveness of mathematics in the natural sciences? Let's be minimalists, and suppose only that physicists use their mind. The human mind can comprehend the phrase 'inside the universe' only by relating it to something that is opposite to it -- 'outside the universe'. The human knowledge is relational; that's the way it is. Next questions: Is this only relevant to epistemology? What if this faculty of the human mind reflects the very nature of the universe? Of course, you can again ignore this very old philosophical question, and delve into math only. But then you will have to combat your own mind. Tell him to shut up and not use any relational knowledge whatsoever. Use math, but don't use your mind, ever! Well, that's really tough, isn't it? I believe the note below, from Alfred Einstead, is a striking example of the story told by Lucretius. Another example can be found on p. 206 in Lee Smolin's book Three Roads to Quantum Gravity: the power of the universe as a whole to organize itself. Hence we need to introduce a new reference object, the universe as a whole,which is "outside" the universe, and with respect to which everything "inside" the universe makes sense. To whom? To the human mind. The same mind that uses math. Hence Lee Smolin missed a possible fourth road to quantum gravity, from the Holon. It is the bounding point, the minimum of Nature, and exists without all parts, as stressed by Lucretius quite some time ago. Note that by introducing the Holon as a holistic structure "outside" the universe, we inevitably enlarge the notion of 'universe'. If we wish to talk about The Universe as 'everything that exists', we have to address some cosmological issues: how did the inside-the-universe and its Holon emerge, and from what. A possible hint can be found in [John 1:1-4]. Try it! With mind and math [Matthew 7:7]. If this task seems too difficult,
try the puzzle of the topology of the
universe, and see where you will end up. Or the Higgs
boson(s). Try anything, your choice.
Dimi Chakalov
Re: Is Probability physically meaningless? On 8 May 2000 18:16:52 GMT, in sci.physics.research, alfred_einstead@my-deja.com wrote: One of the fundamental criterion of an empirical science is that the universal statements it makes be falsifiable -- namely that there be some kind of criterion which determines when the statement has been empirically proven false. The question which stands at the focus of the subject header is this: How does one falsify the statement Pr(E) = 1/2? where E is some kind of physical event. The traditional link given between mathematical probabilities and their application is the "frequency" interpretation, which defines the probability as the limit of the relative frequency for a chain of independent random observations of the event as the chain approaches infinity. The problem is that all observation sequences are finite, and even further, every combination of outcomes is admitted by the statement Pr(E) = 1/2? A theory can't be falsified by something it says is possible! So no chain of observations, no matter how long and no matter how unusual, can falsify the statement. So, empirically speaking, it is meaningless. A common answer which may be provided to this (but which misses the mark) is that one will (in practice) use "confidence intervals" of some sort to [sic] falsify the statement. But the problem there is that you're falsifying something other than the statement, namely that certain "unlikely" observation sequences don't occur, not the statement Pr(E) = 1/2? itself -- which leaves unanswered the original question of how to falsify it. The only way out of this I can see is the idea that perhaps it's not statistical randomness that we're looking at, but in reality, a different kind of randomness known to computer scientists, which CAN in fact be defined in terms of finite sequences -- Turing randomness: a key concept in the theory of Kolmogorov complexity. But then this raises a very important question: when we assert that the outcomes of quantum measurements (e.g., spin measurements taken on successive electrons passing through a detector), is the sequence actually Turing random? Since this question (as far as I'm aware) has never really
be directly addressed, it seems that the entire issue of whether Quantum
Physics actually incorporates randomness (meaning: Turing randomness)
vs. is still open.
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