Hi Saibal,

Yes, trans-Plankian physics is likely to be quite different from our cis-plankian one. However I think the main reason 't Hooft claims the no-go theorems of quantum physics are "in small print" is because his "reading glasses" are no longer current :-), I am afraid. His arguments for the prevalence of simple deterministic models at this scaled have varied over the years (as his little
examples) and some of these are quite clever, I'll agree.

However, as you very well point out, any transplankian theory worth looking into has to reproduce a recognizable picture of the cisplankian world we know
and that means: quantum mechanics (non-locality and all) in some
discernible limit (and General Relativity too in some other limit) and all indications is that this cannot be done from deterministic models alone.
't Hooft has been working around this for the last 10 years or so and
he doesn't have much to show for it. Considering that it took him less
than 2 years to come up with a renormalization prescription for non-abelian gauge theories in his youth I suspect "god's dice" are loaded against him this time.

However he is always fascinating to read and hear. I saw him at Harvard
this winter for the Colemanfest and he had the most fabulous animations...

Godfrey Kurtz
(New Brunswick, NJ)

-----Original Message-----
From: Saibal Mitra <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Cc: everything-list@eskimo.com
Sent: Sat, 13 Aug 2005 01:34:19 +0200
Subject: Re: subjective reality

Hi Godfrey,

't Hooft's work is motivated by problems one encounters in Planck scale
physics. 't Hooft has argued that the no go theorems precluding
deterministic models come with some ''small print''. Physicists working on ''conventional ways'' to unite gravity with QM are forced to make such bold
assumptions that one should now also question this ''small print''.

As you wrote, 't Hooft has only looked at some limited type of models. It seems to me that much more is possible. I have never tried to do any serious work in this area myself (I'm too busy with other things). I would say that anything goes as long as you can explain the macroscopic world. One could imagine that a stochastic treatment of some deterministic theory could yield
the standard model, but now with the status of the quantum fields as
fictitional ghosts. If photons and electrons etc. don't really exists, then
you can say that this is consistent with ''no local hidden variables''.

Saibal



> Hi Saibal,
>
> You are correct that Gerard 't Hooft is one of the world exponents in
> QFTh.
> But Quantum Field Theory is but one small piece of QM and one in which > non-local effects do not play a direct role (as of yet). Understandably
> 't Hooft's forays into Quantum Mechanics have not, however, been
> very insightful as he himself confesses (you can check his humorous
> slides in the Kavli Institute symposium of last year on the Future of
> Physics).
>
> So far he has supplied mostly some interesting simple CA models from
> which one
> can indeed extract something akin to superpositions but that in no way
> bypasses
> the basic facts of entanglement and non-local correlations.
>
> He may very well be the very last hold out for a deterministic (an thus
> classically mechanistic) point-of-view but I would not count him out
> just yet. If any one around has the brain to deal with this its him!
> That much I will grant you...
>
> (Now I have met 't Hooft! 't Hooft was a neighbor of mine and I tell
> you: Bruno is no 't Hooft! ;- )
>
> Best regards
>
> Godfrey Kurtz
> (New Brunswick, NJ)
>
> -----Original Message-----
> From: Saibal Mitra <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
> Cc: everything-list@eskimo.com
> Sent: Fri, 12 Aug 2005 21:11:30 +0200
> Subject: Re: subjective reality
>
> Godfrey Kurtz wrote
>
> > More specifically: I believe QM puts a big kabosh into any
> non-quantum
> > mechanistic view of the physical world. If you
> > don't get that, than maybe you don't get a lot of other things,
> Bruno.
> > Sorry if this sounds contemptuous. It is meant
> > to be.
>
>
> There aren't many people with a better understanding of QFT than 't
> Hooft.
>
>
>
> http://arxiv.org/abs/quant-ph/0409021
>
>
> http://arxiv.org/abs/gr-qc/9903084
>
>
> http://arxiv.org/abs/quant-ph/0212095
>
>
> http://arxiv.org/abs/hep-th/0105105
>
>
> http://arxiv.org/abs/hep-th/0104219
>
>
> http://arxiv.org/abs/hep-th/0104080
>
>
>
>
> Saibal
>
>
>
>
> ________________________________________________________________________
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