Einstein field equations

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SUMMARY

The discussion centers on the implications of the Einstein Field Equations (EFE) in relation to conservation laws such as mass, energy, mass-energy, linear momentum, and angular momentum. It establishes that the EFE can be derived from the principle of least action using the Hilbert Action, which inherently assumes the validity of these conservation laws. Additionally, it highlights the use of Killing's Equations to identify symmetries and conserved quantities from the metric solutions of the EFE. The Einstein tensor's conservation is confirmed through the identity {G^{\mu\nu}}_{ ;\nu}=\kappa\ {T^{\mu\nu}}_{ ;\nu}=0, affirming the conservation of the energy-momentum tensor.

PREREQUISITES
  • Understanding of Einstein Field Equations (EFE)
  • Familiarity with the principle of least action
  • Knowledge of Lagrangian mechanics
  • Basic concepts of Killing's Equations and symmetries in physics
NEXT STEPS
  • Study the derivation of Einstein Field Equations from the Hilbert Action
  • Explore the implications of conservation laws in Lagrangian mechanics
  • Learn about Killing's Equations and their applications in identifying symmetries
  • Investigate the role of the energy-momentum tensor in general relativity
USEFUL FOR

Physicists, mathematicians, and students of general relativity who are interested in the foundational principles of conservation laws and their relationship to the Einstein Field Equations.

Alain De Vos
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Can one deduce from the einstein field equations:
-Conservation of mass
-Conservation of energy
-Conservation of mass-energy
-Conservation of linear momentum
-Conservation of angular momentum
-Principle of least action
?

And does curvature of space-time has a "potential" on certain conditions ?
 
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You can obtain the Einstein's Field Equation from the principle of least action using the Hilbert Action...
 
Matterwave said:
You can obtain the Einstein's Field Equation from the principle of least action using the Hilbert Action...

Also, principle of least action derives many conservation laws using virtue of symmetries in lagrangian mechanics, if you derive field equation from lagrangians, you atomatically assume that conservation laws are valid.
 
Otherwise, once you have solved for the metric from the EFEs you can use Killing's Equations to find symmetries/conserved quantities by solving for the respective killing vector fields.
 
The Einstein tensor

G^{\mu\nu}=R^{\mu\nu}-(1/2)Rg^{\mu\nu}<br />

obeys {G^{\mu\nu}}_{ ;\nu}=\kappa\ {T^{\mu\nu}}_{ ;\nu}=0 identically as a consequence of satisfying an action prinple. What is conserved is the complex T, the energy-momentum tensor.
 
Last edited:
In an inertial frame of reference (IFR), there are two fixed points, A and B, which share an entangled state $$ \frac{1}{\sqrt{2}}(|0>_A|1>_B+|1>_A|0>_B) $$ At point A, a measurement is made. The state then collapses to $$ |a>_A|b>_B, \{a,b\}=\{0,1\} $$ We assume that A has the state ##|a>_A## and B has ##|b>_B## simultaneously, i.e., when their synchronized clocks both read time T However, in other inertial frames, due to the relativity of simultaneity, the moment when B has ##|b>_B##...

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