Rovelli's Quantum Gravity Book

On Jun 11, 2005, at 4:58 PM, iksnileiz@earthlink.net wrote:

Jack Sarfatti wrote:


Paul

Rovelli calls the "tetrad field" the "gravity field" in his new book on Quantum Gravity".


Z: OK, that makes sense to me. I agree with you that the non-trivial part B of the tetrad field may be the key to separating observer-dependent and objective aspects of the Einstein field, and arriving at a satisfactory understanding of gravitational energy.

J: Rovelli starts from there, but he has no idea that ALSO the dimensionless

Bu^a ~ BuLp(argVacuumODLRO)^,a for the 4D Diff(4) macro-quantum supersolid world crystal

analogous to

v = (h/m)GradargGroundstateODLRO for the 3D macro-quantum superfluid

g(curved metric)uv ~(flat)uv + B(uIv) + B(uBv) for "spin 2"

Note that elastic linear B term and the plastic nonlinear B^2 term.

Also, B while not a spin2 Diff(4) first rank tensor field all by itself, is a Minkowski spacetime spin 1 Yang-Mills vector field.


Z: Maybe Alex can explain to you why he and I propose to draw a fundamental distinction between raw mathematical spacetime CSs, on the one hand, and physical spacetime CSs ("moving CSs") that in GR represent observer reference frames, on the other.

J: Yes, he did, but I am not convinced that his idea is any better than mine, which is that a local frame (inertial or non-inertial) is an equivalence class of local coordinate charts at P that do not change the motion of the detector. Similarly, I mean a local event as a coincidence of at least two processes, like Rovelli's "collision" of two point particles, that is clearly an active Diff(4) invariant "object". See Rovelli's explanation of Einstein's solution of the "hole problem".

For example, any transition overlap function between 2 local charts for same "coincident" P that leaves c^2(LC)00^i, i = 1,2,3 invariant is not physical. Note that points A & B in Rovelli's are same P = {~|A,B,C ...} That is A ~ B if B = active Diff(4) on A etc.

That is, think of EM and weak and strong fields Au ... as animals living on Leviathan the Great White Whale Moby Dick which is the geometrodynamic tetrad field e = I + B.

The Ashtekar idea is a much more fancy way of doing what I have done more simply, i.e. the basic field is the tetrad = flat + curved,


Z: Yes, but you have to be careful about how the coordinate-basis tetrad is physically interpreted. There is more than one possible interpretation.

J: Rovelli et-al show a completely coordinate-free Cartan form tetrad e. In fact the tetrad e is a 1-form independent of coordinates. Torsion and curvature are 2-forms. No problem!

e = eu^a&adx^u

e is a dimensionless Cartan 1-form

&a is a 1-co-form vector field basis in the tangent fiber with dimension 1/length

dx^u is a 1-form basis in base space with dimension length

You can make them anholonomic (non-coordinate) sticking in Lie brackets - all well-known techniques.

e.g.

[dx^a,dx^b] = Wab^cdx^c

Wab^c = Jim Corum's object of anholonomy with dimension length


Z: As I'm sure you know, the tetrad starts out simply as a coordinate-independent basis for a any 4D vector space defined at each point on the spacetime manifold.

J: Yes, and what it represents physically is the state of linear elastic warping B(uIv) and nonlinear plastic cracking B(uBv) of the perfect Minkowski Planck lattice that is the pre-inflationary massless conformal false vacuum without any gravity and inertia at all!

e.g. the state of warping and cracking of the 4D active Diff(4) invariant supersolid Higgs vacuum at P is given by the base space reciprocal lattice vector field

eu(P) = eu^a&a = (Iu^a + Bu^a)&a

where &a = nab&^b and [eu(P)] is a length^-1 i.e. eu - &u = Bu = crystal distortion reciprocal lattice "phonon" wave vector away from equilibrium along the u axis (u = 0,1,2,3), e^u - dx^u = B^u is the lattice distortion with dimension of length.

nab = flat Minkowski metric of pre-inflation unstable false conformal massless twistor vacuum without gravity and inertia because vacuum ODLRO = 0

but Ashtekar & Co do not use local gauge invariance & vacuum ODLRO directly the way I do.


Z: OK.


J: They do not seem to even be conscious of vacuum ODLRO - but maybe I have underestimated them there.


Z: Maybe not.


J: We will see as I read Rovelli's book.


Z: OK.


Z: What they are doing in loop gravity is overly-complicated (complexification of the tetrad, taking self-dual "instanton" part etc. Where all the Pundits go wrong is not realizing that there even is a macro-quantum theory whose rules are different from micro- quantum theory. I get diff(4) invariance + background independence non-perturbatively trivially!

Z: I'm inclined to agree.

J: Micro-QM is linear, nonlocal, unitary with signal locality. Macro-QM is nonlinear, local, non-unitary with signal nonlocality. Gravity + dark energy is a "More is different" macro-quantum phenomenon.
Vacuum ODLRO makes quantum theory (QT) and general relativity (GR) completely consistent with each other.

Z: I think it's an interesting and very promising approach.


J: BTW John Baez in Ch 5 last part also waffles on gravity energy problem, p. 452 Notes to Part III


Z: YES. So does Penrose in "Road to Reality".

J: I think I gave the real answer as to why this is really a pseudo-problem:

BTW from my "Rovelli Notes"
The non-trivial warp part B of the Einstein-Cartan tetrad components e = I + B comes into being and becoming from the simultaneous local gauging and spontaneous vacuum symmetry breaking of the spacetime translation group T4, therefore there is no reason at all, from Noether’s theorem, to imagine that either total energy or total linear momentum of the pure gravity field as the spacelike integral of a local density should be conserved as the lapse function "time" pushes forward from one spacelike slice to another in the ADM 3+1 foliation. Indeed, the Hamiltonian of the pure gravity field is strictly zero because of the constraint structure of Einstein’s field equation. For example, the Wheeler-DeWitt equation in the superspace whose points are 3D geometries is

H(pure gravity)(BIT Wave Function of Multiverse) = 0

leading to the “problem of time” in idealistic non-Bohmian attempts at quantum gravity that are only thoughtlike BIT with no rocklike hidden variable IT. In the Bohmian interpretation, the super-geodesic equation of motion for the IT hidden variable is separate from the above Wheeler-DeWitt equation for the pilot BIT wave functional that need not depend on any time parameter.

All you can say is

Sum of all Tuv = 0 locally, i.e. matter + gravity + exotic zpf vacua


Z: Or, more generally, you can introduce *some* kind of source field for vacuum G_uv. This provides an objective localizable physical "container" for the energy lost through gravitational radiation -- which is not the situation in orthodox GR.

J: No, you are confusing apples (zero point dark energy) and oranges (classical gravity waves). Residual zero point energy "exotic vacua" of both dark energy (Pioneer 10 & 11 anomaly a_g = -cH) and dark matter (Galatic Halos flat stellar rotation curves) & stability of extended electron Bohm hidden variable and Ken Shoulders mesoscopic "charge clusters" does give a local tuv(zpf) but that has nothing at all to do with classical gravity waves in weak field approximation on a flat background.



With

TOTAL Tuv^;v = 0

Therefore, any total energy-momentum = 0

Universe is a "free lunch".

In my view the search for quantum gravity is a serious error. Gravity is emergent in the inflationary vacuum phase from micro- quantum theory to macro-quantum theory. God plays dice in the unstable pre-inflationary micro-quantum vacuum that has no gravity and no inertia in it. The rules change completely in the Big Bang. God loads the dice significantly in order for gravity and dark energy to emerge into Being and Becoming. Our post-inflationary expanding accelerating universe in the multiverse of parallel worlds next door is a vibrating “super-solid” or “world crystal”.



It's certainly a promising alternative to the usual perturbative approach. The macro-quantum ghost of the departed Maxwellian aether.

It's not "departed", we are fish swimming in it, or rather the "fish" are themselves phase ripples in it - solitons i.e. vacuum geons like Chapline & Laughlin's "dark energy stars" on micro-scale of "mass without mass" (Wheeler) in which the zero point energy false vacuum cores give effective strong short range gravity G* ~ 10^40G on the fermi scale of 10^-13 cm ~ e^2/mc^2.

The only flag I would raise here is about the stability of the vacuum LRO. According to your BEC model, why is the gravitational vacuum observed to be so stable? What exactly would it take to disrupt and destabilize this LRO?

This means you still do not understand the key idea. Ask why is the superconductor ground state stable? It's the same problem! The Goldstone phase of Vacuum ODLRO is "rigid" that's part of "More is different". That's why space-time is stiff. If you do not do your homework and read the key "superfluid" papers in PW Anderson's "A Career in Theoretical Physics" you will never really understand the idea here. Soft condensed matter physicists are very familiar with this idea.

And what about light propagation? How does light propagate through the vacuum BEC? Could the characteristics of the vacuum BEC be responsible for the permeability and dielectric constant of the vacuum?

That's Puthoff's dead end. I will not go there. I get guv that's enough. Light is ds^2 = 0. I follow Einstein there. Hal has wasted 20 years or more on that and has gotten nowhere important. I think Ibison is finally persuading him to look in my direction?