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- Xref: sparky sci.physics:22156 alt.sci.physics.new-theories:2702 sci.skeptic:22072
- Newsgroups: sci.physics,alt.sci.physics.new-theories,sci.skeptic
- Path: sparky!uunet!well!sarfatti
- 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.
- Message-ID: <C0Fw99.KA5@well.sf.ca.us>
- Sender: news@well.sf.ca.us
- Organization: Whole Earth 'Lectronic Link
- Date: Wed, 6 Jan 1993 15:55:57 GMT
- Lines: 189
-
-
- 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
-
-