Re: Question about 5-D Kaluza Klein Theories with a Timelike ratherthan Spacelike Extra Dimension

"DRLunsford" <antimatter33@xxxxxxxxx> wrote in message
news:1bbfe146-48ec-4e7b-961a-edaa510a38de@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Feb 16, 5:23 pm, "Jay R. Yablon" <jyab...@xxxxxxxxxxxx> wrote:

I am curious if there are any reviews of theories where the extra
dimension is *timelike* rather than spacelike, i.e., with a +---+
signature, which of the problems that appear from an extra spacelike
dimension are averted, and what new perceived problems arise by
switching the extra dimension over from spacelike to timelike.

As Pauli showed in 1921, if the g55 is normalized to have time-like
signature such that g55=1, then the curvature scalar in 5 dimensions
is

P = R - W

(and not R+W), where W is the electromagnetic scalar. This forces one
to use a space-like signature in order for the theory to ape Maxwell-
Einstein. Even in that case, it is mere aping, as there is no
fundamental principle which forces one to select P as the integrand of
the variational principle, given the cylinder group which is
fundamental to the theory. There is a corollary to this - any
generally covariant theory whatsoever may be cast in Kaluza's form by
introduction of such a factitious "geometry" and corresponding
cylinder group.

-drl

DRL,

If I might:

I take it that you are skeptical about any sort of 5-D Kaluza-Klein sort
of theory, and get the impression that you look at this as a "spent,"
fruitless research path.

What, then, is your view then of the modern efforts being currently made
by the so-called 5-D Space-Time-Matter Consortium, which you can find at
http://astro.uwaterloo.ca/~wesson/ , and which includes quite a number
of respected physicists?

What, in your view, would a 5-D theory (or any "classical" theory, for
that matter) have to be able to accommodate, in order to not be a
fictitious (sic above?) geometry, and rather be a correct description of
real natural events? Gravitation, Lorentz force, Maxwell's equations,
stress-energy tensor, all under "one roof"? What else?

I recall you worked with 6-D at one time. What were the goals that you
set out to meet with that theory that would render it a "success"? Would
those same goals apply to other theories?

Thanks,

Jay.
____________________________
Jay R. Yablon
Email: jyablon@xxxxxxxxxxxx
co-moderator: sci.physics.foundations
Weblog: http://jayryablon.wordpress.com/
Web Site: http://home.nycap.rr.com/jry/FermionMass.htm

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