Causal structure in spin-foams

• URL: http://arxiv.org/abs/2109.00986v1
• Date: Thu, 2 Sep 2021 14:37:42 GMT
• Title: Causal structure in spin-foams
• Authors: Eugenio Bianchi and Pierre Martin-Dussaud
• Abstract summary: In spin-foam models for quantum gravity, the role played by the causal structure is still largely unexplored. We propose a causal version of the EPRL spin-foam model and discuss the role of the causal structure in the reconstruction of a semiclassical spacetime geometry.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The metric field of general relativity is almost fully determined by its causal structure. Yet, in spin-foam models for quantum gravity, the role played by the causal structure is still largely unexplored. The goal of this paper is to clarify how causality is encoded in such models. The quest unveils the physical meaning of the orientation of the two-complex and its role as a dynamical variable. We propose a causal version of the EPRL spin-foam model and discuss the role of the causal structure in the reconstruction of a semiclassical spacetime geometry.

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