Re: Curvature vs matter by KST

Ken S. Tucker wrote:
On Jul 25, 9:17 pm, Tom Roberts <tjroberts...@xxxxxxxxxxxxx> wrote:
Ken S. Tucker wrote:
Suppose you go into a
block of Lead (Pb), and select your "point"
between the nucleus and the electrons, would
you call that a vacuum.
You need to keep your theoretical context constant during a discussion.
You were discussing CLASSICAL theories, either GR or some extension to
it. You cannot expect to jump into a quantum context and continue the
discussion without silliness.

why is T_uv a point on a continuum?

It isn't. The point you selected is a point on the manifold, and the values of T_uv are continuous for neighboring points in the manifold.

I repeat: you need to be more precise in your thinking and writing. You intermixed wildly different concepts there. Your question makes no more sense than if you had asked "why is T_uv purple?"


Moreover, there are several problems with your claim taken at face value:
1) such a point is NOT in vacuum because of the EM fields present

Ok, how do you (Tom) intend to decribe
those "EM fields" in the metric given at
point "p", equidistant from "+" and "-",
+.....p.....-

You can describe any point you wish. But if you want it to be in vacuum then it must be in vacuum, and AS I SAID there is no such point inside an atom or inside a block of lead.

And, of course, the EM fields are not "described in the metric" at all. EM fields are COMPLETELY DIFFERENT from the metric.

And inside an atom there ARE no specific points at which the + and - charges are located, and there IS no point "equidistant from '+' and '-'".

I repeat: you need to be more precise in your thinking and writing. And you must have at least a basic understanding of what you are trying to write about.


1a) not to mention the nonzero density of electrons -- there _IS_
no "point between the nucleus and the electrons" as the latter
"fill" the entire region near the nucleus; and in lead there is
no empty space between the atoms, either (except in occlusions,
but those are large enough that there is a region with zero
density).

Of course there is, put your point there.

If you are going to discuss atoms, then you must use a theoretical context that includes quantum mechanics. Clearly you do not understand quantum mechanics, or you would know that there is NOT any point inside an atom at which the charge density is zero. The electrons have a continuous density function which is nonzero throughout the atom (and for some distance outside its nominal radius).


2) the value at a point is useless -- one really needs to discuss
regions

Not using T_uv, it's a function at a point.

Sure. But it is not just the value of T_uv that matters: you are considering curvature tensors which involve derivatives of the metric, and that requires a NEIGHBORHOOD of the point, not just the point itself. So you need to discuss a region, not just an isolated point.


3) in classical theories, matter is assumed to be continuous

NOTE, we have fully enabled all conditions.

"We" haven't. And you haven't "enabled all conditions" consistently.

I repeat: to have a sensible discussion you must pick ONE theoretical context and use it throughout. Your attempts to switch between GR and QM, or to somehow "combine" them are useless. To have any hope at all of discussing them together, you must first understand them both.


Tom Roberts
.

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