Exploring Singularities in Quadratic Gravity Models

Recent research titled "Tilt in Quadratic Gravity" explores solutions within both Einstein-Hilbert General Relativity (GR) and Quadratic Gravity (QG) for the anisotropic Bianchi V model. The study, authored by Waleska P. F. de Medeiros, Matheus J. Lazo, Daniel Müller, and Dinalva A. Sales, was submitted on March 15, 2024, and revised on August 23, 2024.

The authors highlight the significance of QG, particularly following its effective application in strong gravitational fields, as evidenced by its compatibility with the Cosmic Microwave Background Radiation (CMBR) data from the Planck satellite. The primary focus of the research is the numerical time evolution leading to singularities and the behavior of various kinematic variables, including vorticity, acceleration, and expansion.

Key findings indicate that universes with higher and lower matter densities tend to fall into distinct singularity attractors: the Kasner attractor and isotropic singularity attractor, respectively. Notably, the Kasner singularity is characterized by zero vorticity in both GR and QG frameworks. In contrast, the isotropic singularity attractor in QG may exhibit divergent vorticity.

The study concludes that under specific assumptions, the isotropic singularity attractor favors QG over GR, revealing a geometric singularity with divergences in all kinematic variables, which decrease to finite values over time. This research contributes to the understanding of gravitational theories and their implications for cosmological models, particularly in the context of the early universe and singularity behavior.

For further details, the paper can be accessed at arXiv:2403.10377.