QG2 - Quantum Gravity Phenomenology |
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Speaker |
Mercati, Flavio |
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Coauthors |
Henrique Gomes, Tim Koslowski, Andrea Napoletano |
| Talk Title |
Gravitational collapse in Shape Dynamics |
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Abstract |
I study the gravitational collapse of (massive or null) thin shells of dust in the ADM Hamiltonian formalism, in a particular foliation, namely, Constant-Mean-extrinsic-Curvature in the case of a spatially compact universe, and its analogue in the case of asymptotically flat space: maximal slicing. I obtain exact solutions to Einstein's equations at the nonlinear level, which take fully into account the backreaction of matter on geometry. My result is interesting because, on top of providing an exact solution of GR, it also represents a solution of the newly discovered theory of Shape Dynamics. This theory is classically equivalent to General Relativity but highlights a different (dual) symmetry to refoliation invariance: spatial Weyl invariance. For this reason Shape Dynamics is expected to differ at the quantum level from the standard covariant quantization schemes of GR, and suggests that the fundamental degrees of freedom of GR are spatial conformal and diffeorphism invariant, not 4D diffeo invariant. |
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