On Thu, Apr 18, 2019 at 09:13:34PM -0700, [email protected] wrote:
>
>
> On Thursday, April 18, 2019 at 9:20:36 PM UTC-6, [email protected] wrote:
>
>
>
> On Thursday, April 18, 2019 at 8:08:58 PM UTC-6, [email protected]
> wrote:
>
>
>
> On Thursday, April 18, 2019 at 6:53:33 PM UTC-6, Brent wrote:
>
> Sorry, I don't remember what, if anything, I intended to text.
>
> I'm not expert on how Einstein arrived at his famous field
> equations. I know that he insisted on them being tensor equations
> so that they would have the same form in all coordinate systems.
> That may sound like a mathematical technicality, but it is really
> to ensure that the things in the equation, the tensors, could have
> a physical interpretation. He also limited himself to second
> order
> differentials, probably as a matter of simplicity. And he
> excluded
> torsion, but I don't know why. And of course he knew it had to
> reproduce Newtonian gravity in the weak/slow limit.
>
> Brent
>
>
> Here's a link which might help;
>
> https://arxiv.org/pdf/1608.05752.pdf
>
> AG
>
>
> I'm coming to the view that what I have been seeking these many years -
> namely, a mathematical derivation of Einstein's field equations, somewhat
> like a mathematical theorem -- doesn't exist. It's more a case of a set of
> highly subtle physical intuitions about how the universe functions, which,
> when cobbled together, result in the field equations. For this reason,
> most
> alleged explanations of GR involve, at some point, essentially pulling the
> field equations out of the proverbial hat. As with the Principle of
> Relativity and the Least Action Principle, the latter say applied to
> asserting geodesic motion for freely falling bodies, they're not provable
> as "true", but assuming them "false" would be a dead-end for physics and
> would, as well, make our lives miserable. AG
>
>
> One possible exception to the above is the Einstein-Hilbert Principle of Least
> Action, from which, it is alleges, Einstein's field equations can be derived.
>
> https://en.wikipedia.org/wiki/Einstein%E2%80%93Hilbert_action
>
> But what it is, and how it would work, is above my pay grade. Maybe someone
> here can shed some light on this topic.
>
> AG
Roy Frieden has a derivation of Einstein's field equations from his
Fisher information principle - sorry its above my pay grade too, so
don't ask me to explain, but it could be related to you Hilbert action
derivation.
@Book{Frieden98,
author = {B. Roy Frieden},
title = {Physics from Fisher Information: a unification},
publisher = {Cambridge UP},
year = 1998,
address = {Cambridge}
}
--
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Dr Russell Standish Phone 0425 253119 (mobile)
Principal, High Performance Coders
Visiting Senior Research Fellow [email protected]
Economics, Kingston University http://www.hpcoders.com.au
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