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-   -   Solution to Einstein's Field Equations where T^uv not= 0? (http://www.molecularstation.com/forum/physics-forum/38097-solution-einsteins-field-equations-where-t%5Euv-not%3D-0-a.html)

Jay R. Yablon 03-16-2006 07:27 PM

Solution to Einstein's Field Equations where T^uv not= 0?
 
Many of the widely-studied solutions to Einstein's field equations are taken
in vacuo, that is, at events where the energy momentum tensor T^uv=0. This
includes Schwarzchild and Kerr geometries, for example.

Have there been many exact solutions found where T^uv not= 0? I am speaking
of analytical solutions where the differential equations are solved exactly,
*not* numerical approximations.

I am especially interested in any exact solutions based on the usual Maxwell
energy tensor of electrodynamics T^u_v = (1/4pi) [F^ut F_vt - (1/4)
lambda^u_v F^st F_st]. I am interested in solutions both where F^uv_u=0
(free space) and also where F^uv_u=J^v (space with current sources).
Conditions of interest include static spherical symmetry in the nature of
Schwarzchild, and rotation with spherical symmetry about the z-axis in the
nature of Kerr.

To be clear, I am *not* looking for solutions where the metric is assumed to
be a Minkowski metric. Lots of analyses assume a flat-space background for
electrodynamics.

Rather, I am looking for *exact* solutions, to the extent that such
solutions are known, which derive a curved spacetime metric from the
electromagnetic field strength tensor, that is, which derive g_uv =
g_uv(F^uv) via the Maxwell tensor T^u_v, whereby T^u_v(g_uv, F_uv) simply
becomes T^u_v(F_uv) once the g_uv(F^uv) are found.

Thanks.

Jay R. Yablon

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Martin Hogbin 03-16-2006 09:19 PM

Solution to Einstein's Field Equations where T^uv not= 0?
 

"Jay R. Yablon" <[Only registered and activated users can see links. Click Here To Register...].com> wrote in message news:G_iSf.18215$[Only registered and activated users can see links. Click Here To Register...].com...

You might try posting this on sci.physics.research.

Martin Hogbin



Jay R. Yablon 03-16-2006 09:42 PM

Solution to Einstein's Field Equations where T^uv not= 0?
 
> You might try posting this on sci.physics.research.

I sent it there three days ago, but nobody is minding the store right now.
Nothing new has posted there since Monday. I expect it will post there
soon.

Jay R. Yablon



Ben Rudiak-Gould 03-16-2006 10:02 PM

Solution to Einstein's Field Equations where T^uv not= 0?
 
Wikipedia seems to have a pretty good section on this:

[Only registered and activated users can see links. Click Here To Register...]

-- Ben

Jay R. Yablon 03-16-2006 10:35 PM

Solution to Einstein's Field Equations where T^uv not= 0?
 
Thank you, that is helpful.

Jay.

--
_____________________________
Jay R. Yablon
Email: [Only registered and activated users can see links. Click Here To Register...]
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carlip-nospam@physics.ucdavis.edu 03-16-2006 11:02 PM

Solution to Einstein's Field Equations where T^uv not= 0?
 
In sci.physics Ben Rudiak-Gould <[Only registered and activated users can see links. Click Here To Register...].uk> wrote:


This looks pretty good. If you want more, the standard source is the
"exact solutions" book -- Stephani, Kramer, MacCallum, Hoenselaers,
and Herlt, _ Exact Solutions of Einstein's Field Equations_ (second
edition, 2003), Cambridge University Press. There's also an online
searchable database at [Only registered and activated users can see links. Click Here To Register...]
but this requires that you know a bit about what you're looking for.

Steve Carlip


Ken S. Tucker 03-16-2006 11:09 PM

Solution to Einstein's Field Equations where T^uv not= 0?
 

Ben Rudiak-Gould wrote:

Yes, that wiki on GR is quite good, given the
difficulty of the subject.
One can go to the Electrovacuum solution and
encounter the Rainich *issues*, but that doesn't
satisfy Jay's g_uv = g_uv(F_uv) question regarding
an exact solution.

There's more at,

[Only registered and activated users can see links. Click Here To Register...]

which focuses on antisymmetrization to relate 4 and 5D.

In Tolman's "Relativity" book, pg.265 is the classical
treatment but that approach, as far as I know, has
been largely discredited because it depends on the
self energizing of a the fundamental charge, and that
effect is theoretically weak and not substantiated by
by any experiment, that I can find.

Hopefully someone else can provide an answer to
Jay's question, apart from,

[Only registered and activated users can see links. Click Here To Register...]

which provides a sort of bench-mark to attack the
problem.

Regards
Ken S. Tucker


Jay R. Yablon 03-17-2006 12:15 AM

Solution to Einstein's Field Equations where T^uv not= 0?
 
Thank you for the suggestion re the "exact solutions" book. I browsed it on
Amazon, and it is just what I am looking for, so I placed an order for it.

Jay R. Yablon

--
_____________________________
Jay R. Yablon
Email: [Only registered and activated users can see links. Click Here To Register...]
<[Only registered and activated users can see links. Click Here To Register...]> wrote in message
news:dvcqqr$98b$[Only registered and activated users can see links. Click Here To Register...]...



brian a m stuckless 03-17-2006 11:06 AM

Solution to Einstein's Field Equations where T^uv not= 0?
 
Jay R. Yablon wrote: >
$$ No.
$$ YABsolutely no.

--Jay R Yablon.

$$ Maxwell used REAL "flat" plates in air to derive his equations.
$$ This is why GR is only "approximately" flat, at-great-distance.
$$ Even a dot has extreme "curvature", so you can imagine a point.
$$ GR is a "point-SURFACE manifold" at the end of it's WORLD-line.
$$ This is why GR is NOT a "local" theory (where it's all Newton).
$$ This is why GR is a "far-field" theory (where it's all Newton).
$$ [ The "SURFACE" of a GR-"POiNT" is "FLAT-at-a-GREAT-distance ].
$$
$$ Tom R ought derive a set from lab work ..using "CURVED" plates.
$$ [Just let the PLATEs be M1 and m1 and the air as the "AEther"].
$$
$$ Hope this helps, ```Brian A M Stuckless, Ph.T (Tivity).
GR CUT OFF it's own WORLD-line, having DECLARED no PRiOR geometry.
p.s. A GR-"geodesic" is *NOT* Uncle Al's "OTHER LONGER way round".

Re: Solution to Einstein's Field Equations where T^uv not= 0?.




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