Quantum Energies of GR: Applying Bohr-Sommerfeld

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The discussion focuses on the application of Bohr-Sommerfeld quantization to General Relativity (GR) in a semiclassical context. It establishes that the curvature of the quantum surface is quantized, leading to a WKB wave function represented as Ψ=e^{iS/ħ}. The conversation highlights the challenge of deriving the action S from the Hilbert-Einstein Lagrangian and questions the applicability of the WKB method for energies and wavefunctions in this framework. Clarifications are made regarding the notation used for action and integration over hypersurfaces.

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Karlisbad
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If we apply the Bohr-Sommerfeld quantization to GR (semiclassical)

\oint_{S} \pi _{ab} dg_{ab}=\hbar (n+1/2) :confused: :confused:

In this case if "Energies" (or whatever you call energy since in Quantum GR H=0 for the "Hamiltonian constraint" ) then using Einstein equation we see that the "curvature" (quantum version) can't be arbitrary (curvature of the surface is quantizied) and that the WKB wave function would be:

\Psi=e^{iS/\hbar} of course the question there is if we can get the action S from the HIlbert-Einstein Lagrangian, or if the WKB method for energies and wavefunctions applied here. :frown: :frown:
 
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A technical question:
What is S in your first equation?
(Obviously, not the same as S in the second one.)
 
Oh..sory "Demystifier"..i forgot to change the letter.. one "S" is the action the other is just to indicate that the integral is performed over a close Hyper-surface on R-4 space (in a similar fashion ot usual WKB formula) i will change it.
 

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