From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: re: Carlip's comments on gravity cut-off in quantum electrodynamics with further speculations on the nature of knowledge and the Mind of God.
Organization: Whole Earth 'Lectronic Link
Date: Wed, 6 Jan 1993 15:55:57 GMT


Sarfatti replies to:

From: carlip@landau.ucdavis.edu (Steve Carlip)
Newsgroups: sci.physics,alt.sci.physics.new-theories,sci.skeptic
Subject: Re: Carlip's comments on The Force that is not a force.
Date: 6 Jan 93 08:13:34 GMT
Organization: Physics, UC Davis
I had said originally that I was probably going to regret getting into
this.  Sure enough :-)

*Why "Sure enough"? This suggests impatience with discussion. If that is
the case, why bother? It also expresses a kind of condescending arrogance
which is really not good scientific manners. A good role model would be
John Wheeler who is always the perfect gentleman - but that's WASP "old
money" blue blood breeding which is fast vanishing.*

(Attributions: >*[stuff]* is Sarfatti, >[stuff] is me; don't ask me why.)

*because it's easy and I don't know how to do the > stuff*

In article <C0D2Au.Hro@well.sf.ca.us> sarfatti@well.sf.ca.us (Jack
Sarfatti) writes:

>*[...] Is there any law against using this new
>medium for brain-storming, refining half-baked ideas. Why do you want to
>crush free inquiry. This is not the Physical Review!  What would have
>happened to Feynman if Wheeler tried to crush him at the beginning? I feel
>sorry for your research students if you have any!*

I'm sincerely sorry if I gave that impression.  I enjoy half-baked ideas
and brainstorming as much as anyone.  My only reservation is that,
particularly in a medium involving a lot of people who are not experts,
it's important to clearly specify which parts of an argument are
established and which parts are speculation (and if possible, just how
speculative the speculation is).

*Nonsense! You sound like a certified public accountant! This is a free-
for-all forum right out of Socrates' Athens and caveat emptor. Who has time
and online money for all the niceties you suggest which would constrict the
free flow of spontaneous thought needed for creation. The editing can come
later. You do not understand the nature of this new medium in which the
transient fluctuations in the collective mind obey the laws of chaos. This
is a vast cognitive sea of competing memes. You are only a terminal
receiving patterns of meaning from the God Head.*


The point of my last posting was simply that the idea of a Planck
length cutoff has been around for a long time, but that no one had yet
managed to move much beyond speculation (and not for lack of trying).

I wrote:
The speculation that Planck length effects cut off divergences in quantum
>field theory has been around for years, and a lot of interesting work has
>been done, but no one has yet managed to find a way to consistently
>implement such a cutoff.

>*Why not? Please amplify on this. What do you mean by "consistently"?*

Lots of things.  The biggie is that if you want to look at Planck length
physics, you really have to include quantum gravity, and no one knows how
to do that.

*True enough, but irrelevant to my simple observation. I was pointing out
that rather than assume an infinite bare mass and charge assume zero and
then by requiring that the vacuum create the observed ones we get pretty
close to the observed ration between electric and gravitational couplings
without any ultra-violet divergences - using Feynman's formulae. You are
insisting I solve the whole problem before being allowed to make a simple
observation - a very silly attitude.*

But even if you ignore this, there are some very nontrivial technical
problems that aren't obvious at the one-loop level (that is, in
lowest order perturbation theory)

*Are you talking about QED in a classical metric or quantizing the metric
itself? You did not clearly distinguish the two problems and I was only
talking about the first.*

For instance, a simple momentum cutoff violates gauge invariance;

*Do you mean in QED? By gauge invariance you mean conservation of electric
charge. So this violation is good not bad because my whole idea is that net
electric charge is created at Planck scale in which the virtual positrons
disappear down the quantum wormholes leaving only the electrons. At this
scale we violate Lorentz invariance as well as gauge invariance. This is a
virtue not a vice. When I say we violate Lorentz invariance I do not mean
we go back to Galilean invariance - there is no longer any kind of smooth
symmetry.*

there are alternative regularization methods,but which one do you choose?

*describe them! Put up or shut up!*

And having made a choice, you'll find it extremely difficult to preserve
conservation of probability, or even positivity of probability, in a cut
off theory.

*Again a virtue not a vice! You have a naive blind belief in the sacred
absolute validity of conservation laws - as Wheeler taught it's "higgledy
piggledy" at the Planck cut-off - of course probability conservation is
violated there as is everything else that requires smoothness. Roger
Penrose thinks this nonunitarity at Planck scale somehow explains
irreversible collapse of quantum states at our low energy levels - though I
don't see the math of it - yet it is an intriguing half-baked idea
especially if the Planck scale is the "Mind of God" or "IT FROM BIT" in
which Thought Creates Reality in some deep sense that we primitive monkeys
are only beginning to fathom in our ascent from the primordial slime to
Mount Olympus.*

Fundamentally, the problem is this.  New physics should certainly appear
at the Planck scale, and it is plausible that one of the effects of this
new physics might be to eliminate divergences.  But to model such effects
as a sharp cutoff --- which means essentially saying that all interactions
turn off abruptly at some scale --- is probably much too simple to permit
complete consistency.  A Planck length cutoff is fine if you're interested
in refining your speculations, but taking it too literally is risky;
there's no basis for believing nature is _that_ simple.

*It seems there is a pretty good basis for believing nature is that simple.
At least we should exhaust thqat possibility.*

>Is your cutoff at exactly the Planck length (no extra factors of two or
>pi)?  Why?

>*Good question. The self-consistency condition should be that the bare
>mass, charge etc. are exactly zero (not infinite) and all observed mass
and>charge is self-created out of the virtual fluctuations of the vacuum
>starting at the Planck scale. The factors of 2 etc. are determined by this
>self-consistency.

OK, then if the electron, the muon, and the tau all have vanishing bare
mass and bare charge, why are their dressed masses different (and their
dressed charges the same)?

*The Feynman formulae were only for QED. The next step would be to put in
the weak coupling. Then, if this idea is right - one would get some sort of
polynomial for self energy whose roots are the elementary observed masses.
The vacuum polarization polynomial would only have one root (or rather
degenerate ones).*

>If the metric is nontrivial, Lorentz invariance breaks down independent of
>how strong the fluctuations are.

>*NO! You are wrong there. You violate the equivalence principle that GR is
>locally flat (smooth, differentiable, etc.) when quantum
metric>fluctuations are small.*

Among possible spacetime geometries, only flat spacetime has Lorentz
invariance as an exact symmetry.

*I think you are confusing "Lorentz" with "Poincare". The latter includes
the translations. Classical GR has exact local Lorentz symmetry in the
sense of tangent space. Physically we can always find a set of local
inertial "free floating" frames in a small enough spacetime region
determined by the sensitivity of our tidal force detectors.*

Perhaps we're arguing over terminology, though; the equivalence principle
says that you can make the deviations from Lorentz invariance small by
looking at a small enough region of spacetime, and I agree that this is
likely to break down in quantum gravity.

[...]
>*Lenny Susskind and others have published that the particle world lines
>have a fractal dimension. A Frenchman has published similar stuff on
>metric. I do not have references handy.*

Please let me know if you find the reference on gravity.

I think the guy is from Nice Observatory.

For particle world lines, Susskind is almost certainly talking about paths
in quantum mechanics

*Yes, that is what I meant.*

rather than quantum field theory; I believe it is a fairly widely known
result that in field theory, even continuous field histories are of measure
zero in the path integral (see, for instance, Glimm and Jaffe).

*OK I don't doubt it. So you are saying that fractal idea no good since
fractals demand continuity without differentiability? But I bet there is
something analogous to fractal order even when you renounce continuity -
but I do not understand the math of distributions well enough to prove it.*

Steve Carlip
carlip@dirac.ucdavis.edu
Comments by Sarfatti