On Dec 7, 2010, at 4:05 PM, Paul Zielinski wrote:

*I wasn't talking just about the mathematical equations, but also about the physical reasoning behind the equations.*

Me: The two really powerful ideas in physics today are

1) local gauging of fermion fields - as a generalization of Einstein's relativity principle

New dynamical fermion-boson interactions still keeping the total dynamical action invariant under the extended global to local symmetry group.

this includes Einstein's gravity from T4 --> T4(x)

Maxwell's EM from U1 ---> U1(x)

Weak-Strong Forces from SU(2) SU(3) ---> SU2(x) SU3(x)

2) spontaneous broken vacuum/ground state symmetries for the emergence of new long range order - the above total dynamical action remains invariant, only the vacuum/ground state has smaller symmetry than the dynamics.

this includes seed rest masses of leptons & quarks, W-mass

superfluid helium

superconductors

crystal formation

ferromagnets et-al

absolute cosmological rest frame - Hubble flow, isotropic CMB - absolute temperature as measure of time since Big Bang.

Z wrote: *For example, Weyl's second gauge theory. What is the *physical* reasoning behind local gauging of the electron phase? In 1929 Weyl (and others) first posited electron phase invariance as a gauge symmetry, and then used physical arguments about the local nature of propagating disturbances being limited by the speed of light in order to motivate local gauging. Do you take that seriously?*

Of course.

Z: *And if you don't, what more is Weyl's local gauging of the electron phase than a mathematical recipe that for some unknown reason seems to work?*

The key is that it does work even if we do not fully know why. Obviously local gauging is motivated by the light barrier for classical signals.

On Tue, Dec 7, 2010 at 3:50 PM, JACK SARFATTI wrote:

On Dec 7, 2010, at 3:37 PM, Paul Zielinski wrote:

*OK fine, but I think it's important not to neglect theory. Measurement in physics involves more than operations. And here I am echoing the older and wiser Albert Einstein.*

Be specific I have no idea what you mean. I am not proposing to neglect

Guv + kTuv = 0

etc.

On Dec 7, 2010, at 5:22 PM, Paul Zielinski wrote:*By treating gravity as a "gauge field" and showing a formal analogy with gauge fields in particle physics. Or by treating gravity as a quantum field in flat spacetime.*

On Tue, Dec 7, 2010 at 4:45 PM, Paul Murad wrote:

*Regarding gravity, if it is not a force and it is curvature of a spacetime continuum, then how could the physics community develop a unification of forces if gravity is not one of them?*

Ufoguy...

Me: The four spin 1 gravity tetrad fields e^I = (Minkowski GIF TETRAD)^I + A^I(LIF)

are formally SO(1,3) vector fields on a non-dynamical background.

A^I is the locally gauged INDUCED T4(x) field.

Physically we know they are only LIFs with different LIFs in non-overlapping coordinate charts separated by more that the curvature radii.

The dynamical physical curved spacetime comes from

ds^2 = (Minkowski Metric)IJe^Ie^J

Note that A^I is GCT invariant.

Non-rigorously ds ~ (e^IeI)^1/2

On Dec 7, 2010, at 5:43 PM, Paul Zielinski wrote:

I think your Kibble-Utiyama gauge gravity model comes under the first heading.

But at the same time you insist that gravity is not a force.

Does that mean that the "forces" of the Standard Model are also not really forces?

Jeez Z you make the most ridiculous inferences. Of course not. Don't you see the difference I am driving at? Let me spell it out again for the jillionth time.

Real forces come from NON-UNIVERSAL compact internal symmetry groups U1, SU2, SU3

e.g. leptons don't carry the eight strong SU3 charges

Gravity pseudo-inertial forces, IN CONTRAST, come from the UNIVERSAL non-compact "spacetime" symmetry groups - the lowest one is T4 is all we need locally gauge for Einstein 1916 GR -- followed by SO(1,3) Einstein's 1905 SR - both subgroups of Poincare group, which in turn is a subgroup of the conformal light cone group.

Roy's question is thus answered, but Roy lacks the concepts to properly grasp the answer and even to ask intelligible questions in the field.

If not, what's the difference? That one is based on an "external" gauge symmetry, while
the other is based on an "internal" one?

By Roy, I think you grokked it!