Spinfoam Fermions: PCT Symmetry, Dirac Determinant, and Correlation Functions

Abstract

We discuss fermion coupling in the framework of spinfoam quantum gravity. We analyze the gravity-fermion spinfoam model and its fermion correlation functions. We show that there is a spinfoam analog of PCT symmetry for the fermion fields on spinfoam model, where a PCT theorem is proved for spinfoam fermion correlation functions. We compute the determinant of the Dirac operator for the fermions, where two presentations of the Dirac determinant are given in terms of diagram expansions. We compute the fermion correlation functions and show that they can be given by Feynman diagrams on the spinfoams, where the Feynman propagators can be represented by a discretized path integral of a world-line action along the edges of the underlying 2-complex.

26 pages, 9 figures

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• Fermion coupling to loop quantum gravity: canonical formulation
• Toward matter dynamics in spin foam quantum gravity
• Spin foams
• Kinematics of arbitrary spin matter fields in loop quantum gravity
• Quantum Entanglement Dynamics of Spacetime and Matter
• (2+1) Lorentzian quantum cosmology from spin-foams: opportunities and obstacles for semi-classicality