Discrete Symmetries in Covariant LQG

Carlo Rovelli (1) , Edward Wilson-Ewing (1)

1 CPT - Centre de Physique Théorique - UMR 7332

We study time-reversal and parity ---on the physical manifold and in internal space--- in covariant loop gravity. We consider a minor modification of the Holst action which makes it transform coherently under such transformations. The classical theory is not affected but the quantum theory is slightly different. In particular, the simplicity constraints are slightly modified and this restricts orientation flips in a spinfoam to occur only across degenerate regions, thus reducing the sources of potential divergences.

Domaines: Relativité Générale et Cosmologie Quantique [gr-qc]

Carlo Rovelli, Edward Wilson-Ewing. Discrete Symmetries in Covariant LQG. Physical Review D, 2012, 86, pp.064002. ⟨10.1103/PhysRevD.86.064002⟩. ⟨hal-00694396⟩