> On 26 Oct 2019, at 22:56, 'Brent Meeker' via Everything List > <[email protected]> wrote: > > What creates the problem at microscopic level is that the stress-energy > tensor on the right hand side will be due to the wave function of a quantum > particle and so would only have a probabilistic interpretation. We an do > semi-classical computations by replacing the wave function by it's expected > value at each point. But that avoids the point that the metric stuff on the > left hand side needs to be represented by a probabilistic function to match > the right hand side.
Yes. We could say that both theories (EFE and SWE) works well at both scales (microscopic, macroscopic). The problem is that they are different and logically incompatible, at both scale. So, scale is not the problem, except that EFE equation are needed for the macroscopic, and the quantum is needed for the microscopic. Many heuristics can combine them, like when working on black hole, but we have just no theory making them fitting together coherently. Put in another way, the problem is that EFE, (GR) resist to quantisation. Two impressive attempts do exist (Loop Gravity, which follows GR logic, and quantise the whole space time structure), and string theory, which consider the particles to be strings, and explains quickly the graviton. But both attempts get into very mathematical and physical difficulties. Bruno > > Brent > > On 10/26/2019 1:19 PM, Alan Grayson wrote: >> Where do the several postulates of GR imply that the field equations fail to >> apply at some small dimensions of space and time? It's commonly claimed that >> GR does not apply at the microscopic level, but I see nothing in the several >> postulates of GR that imply this result. AG >> -- >> You received this message because you are subscribed to the Google Groups >> "Everything List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] >> <mailto:[email protected]>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/everything-list/3bd1beb2-da6b-4608-be01-92c50ebd3944%40googlegroups.com >> >> <https://groups.google.com/d/msgid/everything-list/3bd1beb2-da6b-4608-be01-92c50ebd3944%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/93daa11d-4d5d-cb1d-154b-6a9e97e4e73e%40verizon.net > > <https://groups.google.com/d/msgid/everything-list/93daa11d-4d5d-cb1d-154b-6a9e97e4e73e%40verizon.net?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/DB86B10B-57E4-4ECD-9239-1502F3A7E974%40ulb.ac.be.
