Re: Is string theory in trouble?
- From: markwh04@xxxxxxxxx
- Date: Thu, 22 Dec 2005 20:55:35 +0000 (UTC)
Jochen.Fromm wrote:
> Take a look at this NewScientist.com Article
> http://www.newscientist.com/channel/fundamentals/mg18825305.800.html
Speaking from the perspective 25 years past today: history is going to
look upon this time and see that the truly fundamental papers that
would lead to the foundation of something new were Hojman and Shepley
in 1990 (No Lagrangian? No Quantization!), Jacobson in 1995 (the one
that derived GR from Thermodynamics + Bekenstein), and c. 1990 Morris,
Thorne and Friedmann (the one that introduced the idea of doing quantum
theory in the presence of time travel and global non-hyperbolicity).
String theory doesn't even address any of the fundamentals underlying
the issue of combining the time-as-a-dimension-not-a-process view of GR
(particular in the presence of time travel loops or other global
non-hyperbolicity) with time-as-an-arena-for-change view of quantum
theory. It takes for granted the underlying precepts general to quantum
theory (Hilbert spaces, operators, etc.), not even addressing where
these come from or whether and how they fit within a more general
picture (e.g. classico-quantum hybrids) -- the issue ultimately
addressed by H&S 1990. It -- along with all other approaches to
"quantum gravity" tacitly assume that gravity needs to be quantized as
a fundamental force (and that it comes out of the framework "for free"
in virtue of the presence of a spin 2 field -- an assumption which (as
any researcher in strong gravity knows) is nothing more than a
conflation), whereas Jacobson shows in clear and decisive fashion that
gravity, itself, does NOT need to be quantized as a fundamental field
any more than phonons do. It comes out nearly for free, *without* the
need for any spin 2 fields ... i.e., GR + Quantum Theory *without*
quantum gravity.
And the main issue that string theory addresses, which always seems to
be conflated with these (the actual) fundamentals: the issue of
bringing about a unified theory of matter and forces will not even
prove to be anything more than peripheral to the overall issue of
combining GR and QT. It's a valuable issue that needs to be addressed
in its own right, and will lend perspective on where fermions come from
and where they fit in with the Yang-Mills gauge bosons, but don't think
for even the slightest moment that this will have any bearing on the
more fundamental questions pertaining to the matters raised above.
So, it is no surprise that the "theory" has never been cast in the
frame of a fundamental universal theory (like Newtonian physics with
Newton's laws, SR with the 2 main postulates, thermodynamics with its
3+1 laws); as the article cited pointed out. It was never intended for
it to take on that cloak.
.
- References:
- Is string theory in trouble?
- From: Jochen.Fromm
- Is string theory in trouble?
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