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No closure yet. ;-) On Thursday, January 8, 2004, at 02:52 PM, Paul Zielinski wrote: Jack Sarfatti wrote: I am trying to get some closure on this debate of at least 2 years that has been interesting in that it has deepened my heuristic understanding of Einstein's magnificent achievement and of the "cheap" attempts to replace it as in Hal Puthoff's "PV" approach to "metric engineering" (exotic UFO warp drive). I support a lot of Hal's scientific work BTW, but not this particular item. PZ: Let's be clear that I also view Einstein's theory as a magnificent achievement, even if the position I have been arguing here is eventually vindicated. It is certainly a beautiful theory. A little too beautiful, perhaps. JS: Not possible IMHO. PZ: The question in my POV is, from the standpoint of gravitational *physics*, is it the proper point of departure for heuristic development of a viable theory of quantum gravity? And, does classic GR, with its Einsteinian "equivalence principle", faithfully reflect the true nature of physical gravitation? JS: In my opinion it does. There is no problem with Einstein's original idea of the equivalence principle i.e. The non-tensor g-force is locally equivalent to an inertial force. This is always true, independent of the local tensor curvature at the same "point". Also, the g-force can be locally eliminated by switching the test particle from a non-geodesic LNIF to a geodesic LIF that is "coincident" with it at the same "point". Paul Zielinski is concerned with distinguishing artificial gravity with real gravity. PZ: In relation to a dialectical examination of the true character of Einstein's equivalence hypothesis and its implications for the energy-momentum content of the permanent gravitational field. JS: I think I have solved all that - at least to my satisfaction. Einstein's ideas have survived your critique IMHO. The latter, would only happen when the local 4th rank curvature tensor did not vanish. Paul seems to think there is a logical contradiction in the foundations of Einstein's thinking that is glossed over in MTW (1973) "Gravitation". I do not think Paul is correct here. PZ: I have been arguing that there is an interpretive inconsistency in the MTW treatment. JS: I fail to see there is any problem here once it is clear that the "total experimental arrangements" (Niels Bohr) for measuring "gravity force" (g-force) on a single test particle in a non-geodesic LNIF and, in contrast, for measuring "local tensor curvature" at 4th rank level (relative tidal acceleration between two geodesic test particles each with ZERO g-force) are "incompatible" or "complementary" in Bohr's sense, there is no longer any conceptual problem at all here! It is curious that Bohr's "quantum measurement" ideas work as well for General Relativity as they do for Quantum Theory. This may be a clue for the correct theory of quantum gravity. Note my claim that Einstein's GR is a MACRO-QUANTUM theory based upon "Vacuum Coherence" missing in most approaches although not in Chapline's and Volovik's independent approaches. PZ: I am saying that the MTW "committee" apply both a modern interpretation, in which the question of non-vanishing Riemann curvature is taken seriously as a mark of inequivalence between inertial and permanent gravitational fields, and also the classic Einsteinian interpretation, in which it is not -- all depending on the context. JS: That distinction has absolutely no impact on Einstein's local equivalence principle as I define it above. PZ: From the standpoint of interpretive consistency, it is a chimerical mish-mash. JS: I do not think so at all. The relevant form of Einstein's equivalence principle is that: I. A "point" test particle on a time-like non-geodesic world line has a "weight" or "g-force" proportional to the 3rd-rank non-tensor connection field for parallel transport. Make the test particle jump to a time-like geodesic (neutralize the charge) and the g-force vanishes. In this sense, gravity is locally equivalent to an accelerating frame dependent "inertial force". PZ: Yes, this is the local translational aspect. This is also true in Newtonian theory -- but the Newtonian *interpretation* is of course very different. The point here is that the GR inertial and gravitational *forces* can cancel at a point without cancellation of the entire gravitational field together with its physical energy content. JS: Your last sentence seems to garble things. The TOTAL g-force IS an inertial force not just a tensor piece of it. It does not "cancel" an inertial force. This may be the root of your confusion? The LNIF connection field is of the form g-force = Indexed coeffcient (Third rank tensor + inhomogeneous term) with summation convention, i.e. big sum of terms Apply the local tetrad transformation to get (g-force) in LIF = 0 The gravity force is the TOTAL SUM of the tensor part and the inhomogeneous part. It is an error to think that the inhomogeneous part is the "inertial force". g-force = inertial force is local EEP The 4th rank curvature tensor is irrelevant at this level. In math terms g-force per test particle mass = d^2x^u/ds^2 = (^u|vw)(dx^u/ds)(dx^w/ds) (^u|vw) = tensor + non-tensor u,v,w are LNIF indices a,b,c are LIF indices at SAME point event P Use the tetrads to switch from LNIF to LIF i.e. eu^aeb^vec^w(^u|vw) = (^a|bc) = 0 The tensor piece cancels the non-tensor piece in the LIF But when you take partial derivatives of the connection to get curvature you cannot maintain this clean separation. You have missed this mathematical fact IMHO. You cannot consistently think of the tensor part of the connection field as the "real gravity" with the non-tensor part as the "fake gravity". PZ: A good model for this is the rest-frame behavior of a charged particle freely moving in a *pure* electrostatic field, as treated in standard GR, which is there interpreted as *inertial compensation*: the net apparent translational forces on the particle vanish in this frame, but the *electrostatic field* does not. JS: I do not understand what you just wrote. I think it is wrong. The rest frame of the charge here is an LNIF on a timelike non-geodesic with a net g-force, or "weight", on the charge from the local EM field that is equal and opposite to the electrostatic reaction force from the charge on the EM field (or equivalently on the distant charges making the EM field). That is, the total momentum of charge and EM field is conserved. There is no "free float" weightlessness in the LNIF rest frame of the charge. Off the top of my head (I could be making a mistake?): I think you need to use for the point test particle something like P = p - (e/c)A = 0 by definition in the LNIF "rest frame". with DP/ds = Dp/ds - (e/c)DA/ds = 0 in the rest LNIF where D/ds is a covariant proper time derivative? Your example is wrong IMHO. A tiny strain gauge on the charge in the electrostatic field shows a "weight". The non-geodesic time-like motion depends on e/m. In no way could the electrostatic force on a charge be confused with a gravity force. There is no "universality". Your example is equivalent to us standing on the surface of the Earth. We have no net charge, but there are induced electric and magnetic multi-pole forces on neutral bodies that have a similar effect as in your less complex example. Of course there are approximations here, e.g. "point particle", "world line" that break down in quantum gravity, also lack of a torsion-spin coupling. PZ: Yes. Here we are at the least ignoring local rotational effects. JS: Note that there is no way to put a test particle on a non-geodesic without an electric charge in an external EM field. Neglect weak and strong charges for simplicity for now. PZ: OK. JS: Note that I is independent on the contingency that the 4th rank curvature tensor vanishes or does not vanish on the world line of the single test particle. Therefore, the decomposition suggested by Zielinski PZ: ?! JS: guv = guv(artificial) + guv(real) makes no physical sense at all IMHO. PZ: I agree this makes no physical sense. However, I NEVER SUGGESTED ANY SUCH THING. JS: I am pretty sure I can produce e-mails from you with that equation? PZ: I am NOT proposing a linear decomposition of the unified g_uv of this sort; I am proposing a linear decomposition of the GRADIENTS g_uv, w of the metric components g_uv with respect to the coordinates x_u ONLY. JS: OK even for the gradients the distinction is no good at the next curvature level. BTW I seem to remember you also wrote the split at the metric level. Perhaps it was a typo. PZ: Neither do bimetric theories entail any such decomposition: they define two separate metrics, a "deformable" physical metric g_uv, and a "transformable" kinematical metric gamma_uv over a flat background manifold. JS: Angels dancing on the head of a pin IMHO. PZL So your guv = guv(artificial) + guv(real) is a straw man of your own invention. Jack, you will at least have to clear up this basic confusion if you want real closure of the debate! JS: I handled the gradients above. II. Measurement of the local 4th rank curvature tensor, outside the regime of quantum gravity, uses the time-like geodesic motion of a pair of neighboring test particles each feeling ZERO g-force, according to Einstein's "geodesic deviation equation" for stretch-strain relative tidal accelerations. PZ: This a merely an assertion. In fact it is, strictly speaking, false. The correct version is: "... Measurement of the local 4th rank curvature tensor, outside the regime of quantum gravity, CAN USE the time-like geodesic motion of a pair of neighboring test particles..." This is a very important detail. This is explained at length in Ohanian & Ruffini, "Gravitation and Spacetime", Sec 1.9. You do not HAVE to use a pair of test particles. JS: I do not have immediate access to 1.9. What is the relevant quote? Any valid alternative cannot contradict the method with a pair of test particles. This measurement on a pair of test particles is completely independent of the measurement of g-force on a single test particle. PZ: Yes. JS: Indeed, the two kinds of measurement are "incompatible" in the sense of Bohr's principle of complementarity. PZ: OK, I have to agree that you seem to be injecting Bohrian complementarity into this discussion of GR. This is a very serious issue IMO. In my POV it is a license for *semantical incoherence*. It reduces all discussion of interpretation of a formal-empirical framework in terms of concrete models to a matter of subjective preference ("personal belief" -- W. Heisenberg). It encourages equivocacy and pedagogical caprice. This attitude represents a troglodyte theory of science that is no longer taken seriously amongst professional philosophers of science. From my POV it betrays a serious lack of understanding of the epistemologically essential role that concrete physical models -- and the semantic integrity of such models -- pay in scientific explanation, empirical prediction, and heuristic development. It is what is fundamentally wrong with so-called "modern physics", IMHO. Ironically, the born-again realist Einstein later himself emphatically rejected this "pseudo- positivist" approach. And as you know, Jack, the late-Einsteinian neo-realist torch was later taken up by David Bohm. So Jack, where do you really stand on all of this? Are you now finally unmasked as a Copenhagenist? JS: Not really, only on Tuesdays, Thursdays and Sundays. ;-) I am a pragmatist. If the shoe fits, wear it. III. What about the nonlocality of energy and momenta of the pure gravity field? This has to do with the issue of gravity waves. You need to split the near field from the far field. You need to define a global flux integral over a space-like slice for total Pu (also Muv for angular momentum), for example, using an "effective" non-tensor for ONLY the far field dynamical degrees of freedom! PZ: The point is that moving matter exchanges energy-momentum with the field. It can do this in the standard theory by gravitational radiation. JS: What "moving matter"? Take a gravity wave detector in the Hubble flow for example. PZ: A gravitational pulse propagates through the vacuum in a lawful manner. JS: Wait! An EM wave propagates relative to a fixed space-time geometry in Special Relativity. A gravity wave IS wiggly space-time geometry. So what is the reference frame for the wiggles? You need to split the degrees of freedom of gravity into propagating and non-propagating pieces. PZ: It carries energy momentum. Yet, according to the canonical theory, while it is in flight, we cannot say exactly where the energy-momentum carried by the pulse is. It is, strictly speaking, everywhere and nowhere. At the same time, we are told that the pulse propagates at two separate speeds; one (the propagation speed of the curvature component) is objective, while the other (the propagation speed of the gradient component) is frame-dependent. My take on all this is that "modern physicists" are so punch-drunk with Alice-in- Wonderland quantum mechanics that they are now ready to swallow just about anything. You could almost convince them that the moon is made of green cheese if some Copenhagenist techno-priest says so. What energy-momentum conservation principles apply to the matter-field system? There is no sensible answer to this basic physical question in orthodox GR. This is a real problem: Einstein himself saw this, and so did Schrodinger, Bauer, and Laue, among others, in the early days of GR. JS: What do you mean? In orthodox GR Tuv^;v = 0 PZ: Even Roger Penrose wrote a whole article on this a few years ago in "Philosophy of Vacuum" ("The Mass of the Classical Vacuum"). Even Penrose understands that this is a serious problem in orthodox GR. JS: Do you have that digital? Please send it to me ASAP. Thanks. PZ: Now we have Lee Smolin chasing his tail trying to find "quasi-local" conserved quantities in GR. All such efforts are doomed IMO for the reasons I have been arguing: there is a fundamental problem with the Einstein equivalence hypothesis. The solution of this problem, I am arguing, must go to the roots of Einstein's "relativistic" thinking. It will require a radical deconstruction of the early Einsteinian philosophy -- of the depth undertaken, ironically, by none other than Einstein himself, starting in the early 1920s. WILL THE REAL ALBERT EINSTEIN PLEASE STAND UP? JS: Note that the elimination of dynamical degrees of freedom of the electromagnetic field by Wheeler and Feynman, extended to the gravity field by Hoyle and Narlikar, only applies to the far field on the light cone not to the near field off the light cone! PZ: OK. JS: What about Freud's identity as in Yilmaz's theory? It is not relevant because it attempts to replace curved space-time covariant divergences by global flat space-time ordinary divergences. PZ: The Freud theorems (Freud decomposition and Freud identity) are purely mathematical propositions that are true for all geometrodynamic theories of the GR type. These do not depend on specific versions of the RHS of the field equations. JS: Agreed. Nothing I said contradicts that. PZ: From my POV there are serious questions regarding Einstein's unphysical use of covariant divergences, and this is part of the problem. JS: "The Question is: What is The Question?" Wheeler It is useful in treating gravity waves in asymptotic flat space-times, but it is not more than that. Yilmaz is mistaken to try to elevate it as a basis for a new theory. PZ: But Yilmaz doesn't do that, Jack. He simply uses "it" as a mathematical *point of departure* for an alternative development and interpretation of GR. You have simply not understood his argument. JS: A delicate distinction. ;-) PZ: IMO this is no different from Bohm's use of a trivial decomposition of the Schrodinger wave function as a *point of departure* for his neo-realist interpretation of QM. JS: No comparison IMHO, but that is another long story. PZ: Or do you now have a problem with that? Was Bohm "mistaken to try to elevate it as a basis for a new theory"? In your current opinion? JS: Loaded question based on a false comparison IMHO. There is a local stress-energy density covariant tensor for the pure gravity field, it is simply tuv(Gravity) = [(Witten's String Tension)/(QED dimensionless coupling)]Guv(Einstein) PZ: That is not phenomenological GR! There is no "string tension" in GR! There is no "QED dimensionless coupling" in GR! JS: You are wrong. It is there, but hidden because many theoretical physicists today are really "elegant tailors" more into the gloss of fashion than substance. They are too quick to take G = h = c = k = 1 and thereby miss some deep connection a bit under the surface of phenomenological GR. I am offering a constructive theory like Lorentz and Fitzgerald but for GR in the sense of Sakharov and PW Anderson's "More is different". I am offering a "kinetic theory" to Einstein's 1915 "thermodynamics". Einstein always was interested in doing that. PZ: You are arguing all over the shop! JS: I am asking you to scratch the surface. There is a deeper insight of Einstein's GR as an emergent MACRO-QUANTUM coherent vacuum theory. PZ: In any case, if there are such things in a deeper theory, and your statement above JS: tuv(Gravity) = [(Witten's String Tension)/(QED dimensionless coupling)]Guv(Einstein) PZ: is valid, then by correspondence this tensor tuv(Gravity) should show up at the macro-level -- which supports my argument. How do you answer this? JS: Exotic vacuum dark energy + dark matter add up to Omega ~ 0.96 with our kind of matter a mere Omega ~ 0.04. This is IMHO a crucial fact and test of my Vacuum Coherence theory of Einstein's gravity. I do not think the recent Blanchard argument that dark energy is a mirage will hold up. I agree with Martin Rees on that. Guv(Einstein) = Ruv - (1/2)Rguv In the non-exotic vacuum Guv = 0 exactly. PZ: Yes, because R_uv = 0 and R = 0. But we still have the Weyl components of Ruvwl to play with. JS: Note that if you try to write tuv(Gravity) = tuv(Gravity)near-field +tuv(Gravity)far-field the two terms on the RHS are not covariant tensors separately. PZ: In orthodox GR. JS: This may have been part of the confusion. PZ: What "confusion"? You are unwittingly supporting the Yilmaz thesis by correspondence! Perhaps this is the "confusion"? This has nothing to do with near-field vs. far-field. There are NO less-than-global *exactly* frame-independent vacuum energy-momentum densities *anywhere* in orthodox GR. JS: Straw Man. The generally covariant vacuum stress-energy density tensor is tuv(vacuum gravity) = [(String Tension)/(QED coupling)]Guv(Einstein) -- ZERO in non-exotic vacuum, i.e. no dark energy and no dark matter in the small region around P. In exotic vacua with positive zero point energy pressure (attractive dark matter Omega ~ 0.3) and negative zero point energy pressure (repulsive dark energy Omega ~ 0.7) tuv(Gravity) = - (Witten String Tension)/(QED dimensionless coupling)/\zpfguv /\zpf = (Loop Gravity Area Quantum)^-1[(Loop Gravity Area Quantum)^3/2|Vacuum Coherence|^2 - 1] Witten String Tension = hc/(Loop Gravity Area Quantum) The discrete stringy link "edge" in a spin network is dual to the Loop Gravity Area Quantum) ~ Bekenstein BIT. guv = Einstein's Special Relativity Metric + (Loop Gravity Area Quantum)(Phase of Vacuum Coherence)(,u,v) where passive general coordinate transformations at a fixed event P emerge from local gauge transformations on the Goldstone Phase of the Vacuum Coherence field. PZ: Ah hah! So this is indeed closely analogous to the Feynman spin-2 case, where he gets macro-covariance from the micro- gauge invariance of the underlying quantum field. JS: No! because my decomposition is NON-PERTURBATIVE. The second term on RHS is NOT SMALL compared to first. PZ: This does NOT give you Einstein equivalence in the correspondence model! That's the point I have been trying to get over to you. Read Feynman! JS: False comparison IMHO. PZ: The viability of Einstein equivalence, the unified g_uv, and the entire Riemannian manifold model, is all simply contingent on the symmetries of the underlying quantum field -- in your case a virtual BEC. But the same Feynmanian arguments apply. This was all laid out by Feynman in his "Lectures on Gravitation". He thought that the success of the Einstein geometric model was the result of a mere mathematical "coincidence". JS: You only get GR by summing an infinite number of Feynman diagrams of certain topological class. This is non-perturbative like in BCS theory. PZ: So you are in fact unwittingly supporting my "Venutian" (Feynman 1963) position by correspondence! Or so it seems to me. JS: ,u is ordinary partial derivative. PSI = |Vacuum Coherence|e^i(Goldstone Phase of Vacuum Coherence) Higgs Field = |Vacuum Coherence| Curvature comes from stringy "vortex core" topological defects in the U(1) order parameter PSI as shown by Hagen Kleinert. More specifically curvature from disclination defects and torsion from dislocation defects in 4D "world crystal" lattice, whose discrete symmetry groups inside the unit cell on scale (Loop Gravity Area Quantum) are different vacuum phases. This theory can be extended to hyperspace with supersymmetry matrix dimensions of M-theory in which gauge force charges are reduced to Kaluza-Klein geometrodynamics. PZ: This all looks very interesting. The only problem I have with it so far -- within the limits of my current comprehension -- is your stubborn insistence on Einstein equivalence at the macro-level, which does not IMHO seem to be supported by any reasonable correspondence model that is based on your virtual BEC/Goldstone phase theory of gravity. JS: Sure it is. One can get the tetrads and hence vanishing connection field in LIFs. Indeed Hagen Kleinert works all that out in detail. PZ: Neither can it be. Z. |
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