English

Effective $f(R)$ actions for modified Loop Quantum Cosmologies via order reduction

General Relativity and Quantum Cosmology 2023-04-20 v2 Cosmology and Nongalactic Astrophysics High Energy Physics - Theory

Abstract

General Relativity is an extremely successful theory, at least for weak gravitational fields, however, it breaks down at very high energies, such as in correspondence of the initial singularity. Quantum Gravity is expected to provide more physical insights concerning this open question. Indeed, one alternative scenario to the Big Bang, that manages to completely avoid the singularity, is offered by Loop Quantum Cosmology (LQC), which predicts that the Universe undergoes a collapse to an expansion through a bounce. In this work, we use metric f(R)f(R) gravity to reproduce the modified Friedmann equations which have been obtained in the context of modified loop quantum cosmologies. To achieve this, we apply an order reduction method to the f(R)f(R) field equations, and obtain covariant effective actions that lead to a bounce, for specific models of modified LQC, considering matter as a scalar field.

Keywords

Cite

@article{arxiv.2104.12283,
  title  = {Effective $f(R)$ actions for modified Loop Quantum Cosmologies via order reduction},
  author = {Ana Rita Ribeiro and Daniele Vernieri and Francisco S. N. Lobo},
  journal= {arXiv preprint arXiv:2104.12283},
  year   = {2023}
}

Comments

16 pages, 4 figures. V2: typo corrected in caption of Fig.4a); references added

R2 v1 2026-06-24T01:30:12.092Z