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arXiv · 2301.13525

Higher-order curvature operators in causal set quantum gravity

Gustavo. P. de Brito·Astrid Eichhorn·Christopher Pfeiffer
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Abstract

We construct higher-order curvature invariants in causal set quantum gravity. The motivation for this work is twofold: first, to characterize causal sets, discrete operators that encode geometric information on the emergent spacetime manifold, e.g., its curvature invariants, are indispensable. Second, to make contact with the asymptotic-safety approach to quantum gravity in Lorentzian signature and find a second-order phase transition in the phase diagram for causal sets, going beyond the discrete analogue of the Einstein-Hilbert action may be critical.\\ Therefore, we generalize the discrete d'Alembertian, which encodes the Ricci scalar, to higher orders. We prove that curvature invariants of the form $R^2 -2 \Box R$ (and similar invariants at higher powers of derivatives) arise in the continuum limit.

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Gustavo. P. de Brito, Astrid Eichhorn, Christopher Pfeiffer. 2023-01-31. Higher-order curvature operators in causal set quantum gravity. https://arxiv.org/abs/2301.13525

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