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0 votes
0 answers
40 views

Extrinsic Curvature in a conformally-flat spacetime that is also asymptotically-flat spacetime

I would appreciate if someone can confirm or correct my understanding of extrinsic-curvature (as in the ADM 3+1 decomposition of spacetime) when dealing with a conformally-flat spacetime. (I updated ...
AmnonJW's user avatar
  • 21
2 votes
0 answers
35 views

Partial integration of the Gibbons-Hawking-York boundary term

In https://arxiv.org/abs/1402.6334 on page 16 in their Eq. (5.21), they go from the equation $$S_G+S_\chi\approx\int d^2x\sqrt{-g}XR+\int dt\sqrt{-\gamma}XK$$ to the equation $$=\int d^2x \sqrt{-g}\...
mp62442's user avatar
  • 109
3 votes
2 answers
504 views

Is the mass of curved space, additional mass?

According to Einstein, mass, say in the form of matter, curves space. It is the curvature of space that gives rise to gravity. Now I have heard there is an energy associated with the curvature of ...
John Hobson's user avatar
0 votes
0 answers
97 views

Extrinsic curvature, Gauss equation and Christoffel symbol contribution

This question is in the context of geometry of hypersurfaces and ADM formalism. In a $4$-dimensional manifold, we define a $3$-hypersurface with space-like tangent basis $e_a$, $a=1,2,3$, and a normal ...
hyriusen's user avatar
  • 175
0 votes
1 answer
391 views

Extrinsic Curvature expression (ADM Formalism)

I'm reading The ADM Formalism chapter of Baez's book Gauge Fields, Knots and Gravity and on page 429 we have the expression $$ K_{ij}=\frac{1}{2}N^{-1}(\dot{q}_{ij}- {}^3\nabla_i N_j - {}^3\nabla_j ...
Powder's user avatar
  • 403
1 vote
0 answers
230 views

How to compute the scalar $^{(4)}R_{\mu\nu} \; ^{(4)}R^{\mu\nu}$ in the ADM formalism in General Relativity?

In the Arnowitt-Deser-Misner (ADM) formalism in General Relativity, the line element takes the form $$ ds^2 = - N^2 dt^2 + \gamma_{ij} ( N^i dt + dx^i) (N^j dt + dx^j) \ , $$ where $\gamma^{ij}$ is ...
QuantumEyedea's user avatar