Cosmological dynamics from covariant loop quantum gravity with scalar matter

Han M, Liu H, Qu D, Vidotto F, Zhang C (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Physical Review D American Physical Society

Book Volume: 111

Article Number: 086012

Journal Issue: 8

DOI: 10.1103/PhysRevD.111.086012

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.

Authors with CRIS profile

Hongguang Liu Chair for Theoretical Physics III (Quantum Gravity) Cong Zhang Chair for Theoretical Physics III (Quantum Gravity)

Involved external institutions

Florida Atlantic University US United States (USA) (US) Perimeter Institute for Theoretical Physics CA Canada (CA) Western University CA Canada (CA)

How to cite

APA:

Han, M., Liu, H., Qu, D., Vidotto, F., & Zhang, C. (2025). Cosmological dynamics from covariant loop quantum gravity with scalar matter. Physical Review D, 111(8). https://doi.org/10.1103/PhysRevD.111.086012

MLA:

Han, Muxin, et al. "Cosmological dynamics from covariant loop quantum gravity with scalar matter." Physical Review D 111.8 (2025).

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