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arXiv · 2402.07984

Cosmological Dynamics from Covariant Loop Quantum Gravity with Scalar Matter

Muxin Han·Hongguang Liu·Dongxue Qu·Francesca Vidotto·Cong Zhang
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Abstract

We study homogenous and isotropic quantum cosmology using the spinfoam formalism of Loop Quantum Gravity (LQG). We define a coupling of a scalar field to the 4-dimensional Lorentzian Engle-Pereira-Rovelli-Livine (EPRL) spinfoam model. We employ the numerical method of complex critical points to investigate the model on two different simplicial complexes: the triangulations of a single hypercube and two connected hypercubes. We find nontrivial implications for the effective cosmological dynamics. In the single-hypercube model, the numerical results suggest an effective Friedmann equation with a scalar density that contains higher-order derivatives and a scalar potential. The scalar potential plays a role similar to a positive cosmological constant and drives an accelerated expansion of the universe. The double-hypercubes model resembles a symmetric cosmic bounce, and a similar effective Friedmann equation emerges with higher-order derivative terms in the effective scalar density, whereas the scalar potential becomes negligible.

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Muxin Han, Hongguang Liu, Dongxue Qu, Francesca Vidotto, Cong Zhang. 2024-02-12. Cosmological Dynamics from Covariant Loop Quantum Gravity with Scalar Matter. https://arxiv.org/abs/2402.07984

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