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arXiv · 1610.04462

Causal spin foams

Giorgio Immirzi
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Abstract

I discuss how to impose causality on spin-foam models, separating forward and backward propagation, turning a given triangulation to a 'causal set', and giving asymptotically the exponential of the Regge action, not a cosine. I show the equivalence of the prescriptions which have been proposed to achieve this. Essential to the argument is the closure condition for the 4-simplices, all made of space-like tetrahedra.

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Giorgio Immirzi. 2017-04-30. Causal spin foams. https://arxiv.org/abs/1610.04462

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