Statut  Confirmé 
Série  SOUTENTH 
Domaines  hepph 
Date  Vendredi 8 Septembre 2017 
Heure  14:30 
Institut  LPT 
Salle  Amphi 1, bat 210, 2eme etage, LPT 
Nom de l'orateur  Lionni 
Prenom de l'orateur  Luca 
Addresse email de l'orateur  luca [dot] lionni [at] th [dot] upsud [dot] fr 
Institution de l'orateur  LPT Orsay 
Titre  Colored discrete spaces: higher dimensional combinatorial maps and quantum gravity 
Résumé  In any dimension, the Euclidean EinsteinHilbert action, which describes gravity in the absence of matter, can be discretized over random discrete spaces obtained by gluing families of polytopes together in all possible ways. In the physical limit of small Newton constant, only discrete spaces which maximize the mean curvature survive. In two dimensions, this results in a theory of random discrete spheres, which, in the continuum limit, converge towards a fractal continuous space called the Brownian sphere, which is interpreted as a quantum spacetime. In this limit, the Liouville continuous theory of twodimensional quantum gravity is recovered. Previous results in higher dimension regarded random triangulations (gluings of tetrahedra or higher dimensional generalizations) or gluings of simple building blocks of small size. For these polytopes, we recover at best the twodimensional results. This work aims at providing combinatorial tools, which would allow a systematic study of more complicated building blocks and of the continuous quantum spacetimes they generate in the continuum limit. We develop a bijection with stacked discrete surfaces and explain how it can be used to characterize the discrete spaces that survive in the physical limit of small Newton constant. 
Numéro de preprint arXiv  
Commentaires  
Fichiers attachés 
Pour obtenir l' affiche de ce séminaire : [ Postscript  PDF ]

[ English version ] 