Timeline for Lagrangian for Relativistic Dust derivation questions
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
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| Nov 30, 2011 at 4:26 | history | edited | Ron Maimon | CC BY-SA 3.0 |
typo
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| Nov 30, 2011 at 0:13 | comment | added | Ron Maimon | @Ondrej: In general you should wait before accepting an answer, there might be better answers coming. This stuff is not original to me, so there is no need to praise. The point I was making is that dust is just as non-fundamental as dissipative fluids, so if you're ok with Navier Stokes being non-Lagrangian, why not dust? If you couple the standard model to GR, you do just add the Lagrangians up, and there are no obvious restrictions on the matter from gravity. For string theory, which is a more fundamental theory, you need consistency, and there are strong restrictions on the allowed matter. | |
| Nov 29, 2011 at 20:32 | comment | added | Ondřej Čertík | Ron, thanks a lot for this amazing answer! I will go carefully and think about it for some time before asking more questions. But I have one now: I think that the dissipating Navier Stokes equations are in some sense only an approximation for the microscopic phenomena, so it is ok that it cannot be derived from a Lagrangian. But the fundamental interactions (on the classical level) seem to be possible to derive from a Lagrangian, don't they? | |
| Nov 29, 2011 at 20:28 | vote | accept | Ondřej Čertík | ||
| Nov 29, 2011 at 19:47 | history | answered | Ron Maimon | CC BY-SA 3.0 |