| Subject: The
Frontiers of Physics:
Loop Quantum
Gravity?
Date: Mon, 26 Dec 2005 01:09:19 +0200 From: Dimi Chakalov <dimi@chakalov.net> To: Graham P Collins <gpc@nasw.org> CC: editors@sciam.com, experts@sciam.com Dear Dr. Collins, I like very much your note on p. 19, and regret that you didn't comment on L. Smolin's essay [Ref. 1]. I noticed two discrepancies: 1. The very title of the segment "Evolution of geometry in time" [Ref. 1] would make Hermann Minkowski spin in his grave like a helicopter. We operate with one entity, 4-D spacetime. It is unacceptable to break them apart and talk about evolution of "geometry" in time. 2. The statement "the evolution, which at first glance appears to be smooth and continuous, is in fact discontinuous" [Ibid.] is not based on*facts* at all, because "time does not exist in between the ticks; there is no "in between," in the same way that there is no water in between two adjacent molecules of water." Since neither time nor space exist "in between" [whatever], we cannot know whether the evolution is continuous or discontinuous. Now, if we consider both options, continuous-and-discontinuous, I believe we shall come to the case examined at http://www.God-does-not-play-dice.net/Rosinger.html We have localized "expressions" that literally build spacetime as a *perfect* continuum, since their common source is NOT present in the spacetime build from its explications/flashes: it is "between" any two "adjacent" atoms of geometry, as we know since the time of Plato. I invite you and your colleagues to try the experiment at the link above. Merry Christmas and all the best wishes for 2006. Regards, Dimi Chakalov
[Ref. 1] L. Smolin,
Atoms of Space and Time, in: The Frontiers of
p. 63, Evolution of geometry in time: "Another way to represent moves is
to add the time dimension to a spin network
-- the result is called a spin foam.
"But notice that the evolution, which
at first glance appears to be smooth and continuous, is in fact discontinuous.
"Although speaking of such sequences
as frames of a movie is helpful for visualization, the more correct way
to understand the evolution of the geometry is as discrete ticks of a clock.
At one tick the orange quantum of area is present; at the next tick it
is gone -- in fact, the disappearance of the orange quantum of area defines
the tick. The difference in time from one tick to the next is approximately
the Planck time, 10^-43 second. But time does not exist in between the
ticks; there is no "in between," in the same way that there is no water
in between two adjacent molecules of water."
========== Subject: Re: Typo
in quant-ph/0512125
v1
Dear Professor Bub, I take for granted that Special Relativity is indeed a "principle theory", but it seems to me that QM isn't. There should exist a Lorentz-invariant, reversible, bi-directional, and smooth transition from the hidden unobservable quantum reality to the normal world of tables and chairs, and back to the hidden unobservable quantum reality, http://www.God-does-not-play-dice.net/Brody.html The "back bone" of this bi-directional transition is not known to me. My efforts to speculate on its possible physical and geometrical nature are at http://www.God-does-not-play-dice.net/Rosinger.html http://www.God-does-not-play-dice.net/Hauser.html#Leifer Put it differently, the "back bone" of spacetime is something that is "between" spacetime points; see Lee Smolin's metaphor 'there is no water between two adjacent molecules of water' at http://www.God-does-not-play-dice.net/Smolin.html Best wishes to your birthday. Dimi Chakalov On Mon, 19 Dec 2005 13:02:55 +0200,
Dimi Chakalov wrote:
========== Subject: How
can an Eskimo choose one vacuum from the Landscape?
Dear Dr. Mersini, Regarding your recent paper [Ref. 1], it seems to me that the crux of the matter is the "selection" of one Schrödinger cat state, under the requirement for understanding the nature of quantum reality 'out there', http://www.God-does-not-play-dice.net/Kiefer.html#Chris_3 If true, we need a new kind of "background", http://www.God-does-not-play-dice.net/Rosinger.html Just a hint: the number of possible brain states is also in the range of googles, yet the brain keeps all of them in some "potential" cat state. If the universe works like a huge brain, all She has to do is to pinpoint one vacuum, set the appropriate initial and boundary conditions, and let the *evolving* "constants" and dark matter/energy develop in such a way that we can communicate by email after 13.7 billion years. Please notice that this is not some "anthropic" metaphysics a la Steven Weinberg -- the initial idea goes back to Leibnitz and Pauli & Jung. An Eskimo cannot comprehend the notion of "trunk", http://www.God-does-not-play-dice.net/qualia_1.html#1 Hence she would try to understand quantum cosmology only by studying "the nose". I'm glad that Lenny Susskind [Ref. 2] opened this 'can of worms':-) Kindest regards, Dimi Chakalov
"The puzzle of finding a selection
criterion for our universe which would predict one vacuum among something
like (10^100 - 10^500) solutions...
[Ref. 2] Leonard
Susskind, The Anthropic Landscape of String Theory,
=========== From: Dimi
Chakalov <dimi@chakalov.net>
RE: S. Weinstein, Class. Quantum
Grav. 23 (2006) 4231-4236;
hep-th/0508006
Hi Steve: I like your footnote 4 on p. 4233, but cannot understand why you favor WAP1 (p. 4234): "WAP1: 'What we can expect to observe must be restricted by the conditions necessary for our presence.' "This is an uncontroversial claim, since 'we' can only observe the properties of worlds that allow our presence. So for example, we cannot observe a world or a universe in which we failed to evolve, even if that universe has earth-like planets and other DNA-based life forms." To make your claim uncontroversial, I believe you should at least try to explain the difference -- if any -- between 'what we can expect to observe' and 'the physical reality out there'. Is there a difference? 1. If you say 'no', then I will follow
the terminology suggested by
Martin
CRAP1: 'The physical reality out
there must be restricted by the conditions
That's sheer parapsychology, of course,
as I tried to explain in my email
2. If you say 'yes', please suggest
some falsifiable theory to detect the
As an example of CRAP1 vs WAP1, see
the miraculous escape of Alex Vilenkin,
"He received his undergraduate degree in physics in 1971 in the former Soviet Union but was prevented from getting into graduate school because he was blacklisted by the KGB for refusing to cooperate. He emmigrated to the US in 1976, ... " The chance to escape from KGB is perhaps close to the chance for us to wind up in the universe 'out there'. So, what helped Alex to escape from KGB? Was it WAP1 or CRAP1?:-) Dimi P.S. I'm also ready to discuss serious
issues with you and Alex, and am
http://www.God-does-not-play-dice.net/Weinstein.html Alex: Do you remember our talk over
the phone in January 1990? If you do,
D. =========== Subject: You
can't stir your coffee without disturbing a star?
Dear Dr. Unzicker, I'm highly interested in the implementation of Mach's principle and the removal of the "constant" G [Ref. 1]. But how does a free falling apple feel the mass distribution of the universe, and how does it send its feedback to the whole universe [Ref. 2]? The *dynamics* of this bi-directional "talk" is the subject of my web site. If gravity depends just on c [Ref. 1], then we need to unravel the dynamics of the "changing" c and its "reference frame", http://www.God-does-not-play-dice.net/Rosinger.html In the context of the dynamic "dark" energy, please see http://www.God-does-not-play-dice.net/Rendall.html#Frampton Your professional comments and the
feedback from your colleagues will be
Regards, Dimi Chakalov
References [Ref. 1] Alexander
Unzicker, Mach’s Principle and a Variable Speed of
"There is no reason any more to wonder
why inertial and gravitating mass are of the same nature. Describing gravity
with a varying speed of light leads to the equivalence principle as a necessary
consequence. The deeper reason for this is that gravitation is strictly
speaking not an interaction between particles but just a reaction on a
changing c.
[Ref. 2] G.F.R.
Ellis, Cosmology and Local Physics, gr-qc/0102017 v1.
======= Subject: Sweeping
the garbage under the rug: The "semiclassical limit"
Dear Lee, It seems to me that you're trying to sweep the garbage under the rug: your so-called "semiclassical limit" [Ref. 1] does not match the *classical limit* of quantum gravity. The alleged "experimental test" of
your speculations is supposed to be performed with GLAST, the Gamma-ray
Large Area Space Telescope, and with the Cosmic Ray Detector at Auger
Observatory (refs. [4] and [5] in [Ref. 1]). Hence
you need to fix the the *classical limit* of your quantum
The classical limit of *any* quantum theory -- quantum gravity included -- is the limit at which we obtain "points", by following the rules of diff calculus known from Leibnitz or the rules of Archimedes, http://www.God-does-not-play-dice.net/Kiefer.html#Claus The resulting "points" correspond to the classical world at which GLAST and AUGER operate. Your "semiclassical limit" does not, http://www.God-does-not-play-dice.net/Kiefer.html#Loll To the best of my knowledge -- please correct me if I'm wrong -- none of your colleagues has managed to derive even the *semiclassical* limit of her/his version of quantum gravity. See the recent efforts of A. Ashtekar et al., who have completely bypassed the crucial issue of Hamiltonian constraint observables, http://www.God-does-not-play-dice.net/Kuchar.html#A1 Paradoxically enough, you have explained the insurmountable problems of the *semiclassical* limit for Hamiltonian constraint observables in your gr-qc/0104097 v1 from August 30, 2000, http://www.God-does-not-play-dice.net/Aaronson.html#70 And yet today you're optimistic. Have you solved the problems explained by you in gr-qc/0104097 v1 from August 30, 2000? If not, why don't you invite Karel Kuchar to help you sort out your mess? See http://www.God-does-not-play-dice.net/Etera.html#Lee You can read this email also at your dedicated web page at http://www.God-does-not-play-dice.net/Smolin.html Soon on CD ROM. Take care, Dimi
Reference [Ref. 1] Lee Smolin,
Falsifiable predictions from semiclassical quantum
"In this letter, I report predictions
for these experiments coming from the quantum theory of gravity. These
predictions are generic, in that they rely only on general features of
gravitational theory, that are independent of dimension and the specifics
of matter couplings, as well as the presence or absence of supersymmetry.
They only involve calculations at semiclassical level, to leading order
in lPl.
"We then arrive at the conclusion
that given the very mild assumptions made here, quantum gravity predicts
a deformed realization of special relativity [8, 9] in the semiclassical
limit.
"Remarkably, it appears that the AUGER and GLAST experiments together could be sufficient to distinguish these three cases." ===============
Rhetorical question. Of course Lee Smolin moved to the Perimeter Institute and start advertising, with some help from Dan Christensen. That's a lot of cash, isn't it? Besides, Lee Smolin wanted "(...) an open atmosphere where anybody can criticize anybody, honestly and directly. You also want a supportive atmosphere, where people are generous and sympathetic about difficulties and failures." This is what the Perimeter Institute is supposed to be. I sent my critical remarks one year ago to many physicists at the Perimeter Institute, stressing the vision of the Founder, Mike Lazaridis. He used to dream that one day he might be in a position to create a setting where scientists could boldly devote themselves to unlocking nature’s deepest secrets, and invested an enormous amount of his own money. I very much respect people like Mike Lazaridis, and tried to be very honest and direct in my critical remarks (email of Tue, 28 Jan 2003 15:39:35 +0200). Nobody replied, even to confirm the receipt of my email. Then I wrote to many physicists there, again very honestly and directly. Dead silence. I cannot be "generous and sympathetic about difficulties and failures" anymore. The Perimeter Institute was not founded for advertising misunderstandings and keeping quiet to criticism. I could not have missed the latest loop quantum gravity extravaganza, in the January 2004 issue of Scientific American [Ref. 1]. Lee Smolin had 10 (ten) pages to present his bubbles of spacetime, some 1099 "atoms of volume" in every cubic centimeter of space [Ref. 1, p. 61], and to explain how time "proceeds in discrete ticks of about a Planck time, or 10-43 second" [Ref. 1, p. 58, pp. 62-63]. The first gentle touch of scientific style emerges on p. 62, Sec. 'Predictions and Tests': "An important test is whether one can derive classical general relativity as an approximation to loop quantum gravity. (...) Do spin networks describe the geometry of space and its evolution in a way that agrees roughly with the "smooth cloth" of Einstein's classical theory?" Of course not. Lee Smolin's extravaganza cannot recover -- even approximately -- the "smooth cloth" of Einstein's General Relativity. According to loop quantum gravity, we should not be able to see much further the end of our nose, and the very existence of 3-D space is almost a miracle. Says who? Lee Smolin, in his book "Three Roads to Quantum Gravity". See Ch. 14, "What chooses the laws of nature?", pp. 204-206. To the best of my knowledge, Lee Smolin has not yet identified the origin of this deadly flaw of his bubble theory. In the past three years, after the release of his book mentioned above, this ultimate task should have been the very first item on his what-I-must-do-today list. You can't say "in the end experiment will decide" [Ref. 1, p. 65], because your bubble theory has failed in the very first 'test of the pudding'. You have not yet connected to the reality of 3-D space, Lee. Get real. With scrupulous intellectual honesty, of course. Once you pinpoint the origin of the problem (with scrupulous intellectual honesty), please do not forget to publish your proof of the exact reason why you cannot recover the continuum, -- the mysterious bundle of points which deliver the physical interactions to "the nearest" points, with some finite speed that does not exceed the speed of light in vacuum. All you can do is to find out why you cannot recover the continuum (with scrupulous intellectual honesty). What to do, then? "Then physicists would have to turn to more radical postulates, such as those of string theory" [Ref. 1, p. 65]. Brilliant idea. If you really wish to go into string theory, don't miss Leonard Susskind's "The Anthropic Landscape of String Theory" [Ref. 2]. There might be a dedicated vacuum waiting patiently to be attached to each and every bubble in a cubic centimeter of space, and once you do that, you might solve the dark energy puzzle [Ref. 3]. Alternatively, you may recall that
I have suggested a new reference object for solving the paradox
of continuum, but since you don't read my email and don't accept references
to web pages, try the string theory. With scrupulous intellectual honesty,
just like Carlo Rovelli.
D. Chakalov
[Ref. 1] Lee Smolin, Atoms of Space and Time, Scientific American, 290(1), 56 (January 2004). [Ref. 2] L. Susskind, The Anthropic Landscape of String Theory, hep-th/0302219. Leonard Susskind: "It is much more likely that the number of discrete vacua is astronomical, measured not in the millions or billions but in googles or googleplexes." [Ref. 3] George Musser,
Four
Keys to Cosmology, Scientific American, SPECIAL REPORT, February
2004.
P.S. Lee Smolin posted a new article, "Scientific alternatives to the anthropic principle", hep-th/0407213 v3, in which he wrote (p. 38): "What is clear is that some falsifiable version of the theory must be found. If not, the theory cannot be considered a scientific theory, because there will be no way to establish its truth or falsity by a means which allows consensus to be established by rational argument from shared evidence." How about the fourth road to quantum gravity? See "Three Roads to Quantum Gravity", p. 206. The main puzzle is the existence of 3-D space, as he acknowledged. I'm sorry he missed the fourth road to quantum gravity. Well, it happens. D. Chakalov
====== From: "Dimi Chakalov" <dimi@chakalov.net>
Dear Colleagues, I mentioned loop quantum gravity (Sci American, January 2004) and string theory at http://members.aon.at/chakalov/Smolin.html Kindest regards, Dimi Chakalov
===== Subject: Re: Scrupulous intellectual
honesty: The nature of time
On Sat, 23 Feb 2002 11:36:43 +0000 (BST), Lee Smolin wrote: > could you state your objection clearly? I find a lot
of
The web page is, again, http://members.aon.at/chakalov/Rovelli.html Regrettably, you didn't say what was "lot of mis-information". Please be specific, as a physicist. > In particular, there has been a lot of progress about
dynamics, as a
To the best of my knowledge, there has been no progress whatsoever on the issue of dynamics in 3+1 dimensions. Just "an essential germ of truth", as acknowledged by Ashtekar, http://members.aon.at/chakalov/Ashtekar.html > So far as I can tell, you do not formulate a clear objection,
you
I believe my objection is painfully clear. Let me quote from my email to Rovelli at http://members.aon.at/chakalov/Rovelli.html : "Please bear in mind that the whole idea of 'relational reality' or 'correlations, not correlata' [Ref. 4] means one simple thing: the quantum reality does NOT exist in the physical time, as read with a clock, http://members.aon.at/chakalov/Stachel.html#PS http://members.aon.at/chakalov/Shimony.html " I plain English, this means that you, Rovelli, Ashtekar, and many other physicists are ignoring a very old and widely known idea about the nature of time, namely, that the physical world is NOT sufficient for explaining the nature of time. I'm sure this sounds familiar, after Plato. Now, my proposal is that the nature of time boils down to the challenge of the *geometrical* presentation of the infinitesimal. It encodes the existence of two modes of time, local and global, http://members.aon.at/chakalov/dimi.html Of course, you may ignore such unsolicited proposal on the nature of the infinitesimal, but please note that my objection is on *logical* grounds: you need a new reference object w.r.t.w. you can define quantum dynamics in a meaningful fashion. Otherwise your loop quantum gravity will encounter the paradox of Baron Münhausen: you too will have to 'lift' yourself by pulling up your hair, http://members.aon.at/chakalov/Ashtekar.html I called this new reference object 'global time mode'. You may call it whatever you want, the point is that you do need *something* w.r.t.w. you can define dynamics in 3+1 dimensions, simply because there are no background fields whatsoever in 3+1 dimensions, and there should be *none*. The nature of time is "behind" it. Can't beat Plato. Many people before you have tried and failed. Again, my objection is on *logical* grounds. Your brain needs something w.r.t.w. you can achieve the goal of loop quantum gravity in *3+1* dimensions. That's how the human brain works, yours included. Think deeply of simple things, says John Baez http://members.aon.at/chakalov/Baez.html With scrupulous intellectual honesty (Carlo Rovelli). Looking forward to hearing from you and from your colleagues, Regards, Dimi
====================== Subject: Re: Scrupulous intellectual
honesty: The nature of time
On Sun, 24 Feb 2002 17:30:25 +0000 (BST), Lee Smolin wrote:
I've been studying papers by your colleagues mentioned above, Ashtekar included, since September 1998. Please tell me what particular paper, in your opinion, contains some hint for possible solution to the problem of logical inconsistency of loop quantum gravity. Again, you need a new reference object w.r.t.w. you can define dynamics in 3+1 dimensions. But you know very well that there is nothing left 'out there' to serve as some *reference* object. > So don't refer me to web pages. Can you state your objection
to
I did quote Ashtekar's gr-qc/0112038 http://members.aon.at/chakalov/Ashtekar.html Let me do it again: "Although there is no natural unification of dynamics of all interactions in loop quantum gravity, it does provide a kinematical unification. (...) A key difference, however, is that while a background space-time metric is available and crucially used in gauge theories, there are no background fields whatsoever now. This absence is forced on us by the requirement of diffeomorphism invariance (or 'general covariance'). (...) In our case, the situation is much more drastic: there is no background metric what so ever!" As to Rovelli, I will quote from his hep-th/9910131: "If we take GR into account, this picture does not hold anymore, and the meaning of the coordinates x^mu is altered. In fact, in a general relativistic theory physical quantities that have a coordinate dependence are not gauge-invariant. Only quantities that *do not* depend on the coordinates may correspond to concretely physically observable quantities. Localization with respect to a background spacetime, or with respect to a fixed external reference system, has no meaning. What has physical meaning is only the *relative* localization of the dynamical objects of the theory (the gravitational field among them) with respect to one another. The physical picture of the world provided by GR is not that of physical objects and fields over a spatiotemporal stage. Rather, it is a more subtle picture of interacting entities (fields and particles) for which spatiotemporal coincidences only (Sic! - D.C.), and not spacetime localization, have physical significance. Once again, this modification of the meaning of the coordinates does not refer to the gravitational force alone: it refers to our entire description of the world at the fundamental level." See also my email to Rovelli from Fri, 26 Nov 1999 22:14:59 +0000, subject: Request for opinion (printed below). Neither he nor Ashtekar have replied to my email sent in the past three years, as if I'm dead. In short, you colleagues have identified the problem of time. You all must be aware of the fact that the problem is highly non-trivial, and you do need some brand new reference object w.r.t.w. you can define dynamics and the emergence of space *as well*, as you explained in your recent book, http://members.aon.at/chakalov/right.html#Smolin And yet you ignore the basic rules of logic and continue to search for something that does not exist ab initio. NB: The only possible solution to this problem is widely known, since Plato. See again http://members.aon.at/chakalov/Smolin.html and http://members.aon.at/chakalov/Zafiris.html#below Why are you ignoring it? You wrote: "So don't refer me to web pages." Is this your problem, Lee? Are you honest with me? Dimi
====
Dear Professor Rovelli, I am trying to comprehend how you [Ref. 1] and Prof. A. Ashtekar are trying to 'isolate time' or 'bring time' into quantum gravity. May I ask a question? Since 1986, the main hope of the Ashtekar approach is that it may yield solutions to its own analogue of the Wheeler-DeWitt equation. This analogue involve functions of spin-connections, or loops in 3-space, and hence the picture is totally 'self-acting'. It is like Barron von Muenhausen who tried to lift himself and his horse by pulling himself up by his hair. In other words, you can't 'hold' on anything, for there is no background there. If so, what could possibly 'bring the time' that we can measure with clocks from "spatiotemporal coincidences only" [Ref. 1]? With kind regards, Dimiter G. Chakalov
[Ref. 1] Carlo Rovelli. The century of the incomplete
revolution: searching for general relativistic quantum field theory. Sun,
17 Oct 1999 19:43:18 GMT,
============= Subject: A non-quantum
theory giving a precise description of THE whole universe
On Sat, 23 Feb 2002 11:36:43 +0000 (BST), Lee Smolin wrote: "So far as I can tell, you do not formulate a clear objection, you just make accusations that there is a problem and ask people to disagree with you. This is not a very constructive way to proceed." I believe have formulated a clear objection to your philosophy in my email from February 9, 2002, which you choose to ignore. Four and a half years later, in your latest quant-ph/0609109 v1, you stated that are searching for some "non-quantum theory giving a precise description of a whole universe". My objection, again, is that your presentation of 'the whole universe' is wrong. You wrote in quant-ph/0609109 v1: "The dynamics of this cosmological theory might be deterministic or stochastic, but it must be non-local." 1. If the theory should describe 'the whole universe', then the dynamics of this cosmological theory cannot be deterministic nor stochastic. Why? Because you need a brand new "reference" object w.r.t.w. you can define 'the whole universe'. See the catch? On the one hand, you need some reference object w.r.t.w. you can define 'the whole universe', because otherwise your brain cannot work: human knowledge is relational (cf. my email from February 9, 2002). On the other hand, this brand new "reference" object should be included in the universe, because the latter is ONE entity ('the only true isolated system', as Chris Isham says in his "Lectures on Quantum Theory"). Further, you wrote in quant-ph/0609109 v1: "One would choose a subsystem and then represent the rest of the universe, including possible non-local variables relating the subsystem to the rest of the universe, by a statistical ensemble." Any "subsystem" plus "the rest of the universe" should sum up to 'the whole universe as ONE'. You haven't provided the proper description of this ONE entity, and your approach is wrongly formulated from the outset. I believe can show that (i) you cannot solve the measurement problem "in the context of a theory with a realistic ontology" (quant-ph/0609109 v1, p. 1), and (ii) the underlying dynamics of 'The ONE' is neither deterministic nor stochastic. If you're interested, please write me back, and I'll refer you to the relevant web pages and your statements in "Three Roads to Quantum Gravity". If you are not interested, please ignore my email. BTW I quoted from your book (p. 205) at http://www.god-does-not-play-dice.net/Brown.html#Simone Dimi
Note: L. Smolin
stated in "The case for background independence",
hep-th/0507235 v1: Only you do need a new background to define the Dynamic Dark Energy. There is no way to avoid the ultimate need for 'background', hence the logical conclusion is to embed a brand new "background" into the theory of the whole universe, as I've been trying to explain to L. Smolin since February 2002. There is no other choice. Capiche? As John Baez stressed six years ago, "Of course, in a full-fledged theory of quantum gravity, we may have to interpret the term "geometrical structures" in a novel way." My proposal can be read here. The math was available upon request, but nobody showed any interest whatsoever.
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