Exploring Tilted Source Solutions in Quadratic Gravity

Researchers have explored tilted source solutions in 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, examines the numeric time evolution towards the past singularity and the behavior of kinematic variables such as vorticity, acceleration, and expansion of the source substance.

The findings indicate that in QG, universes with higher and smaller matter densities fall into the Kasner or isotropic singularity attractors to the past, respectively. The Kasner singularity attractor to the past always has zero vorticity for both GR and QG theories. However, in QG, the isotropic singularity attractor may exhibit divergent vorticity.

The study also reveals that only in QG can a geometric singularity with divergences in all kinematic variables of the substance be found, which decreases to finite values in the future upon time reversing. This suggests that an initial kinematic singularity substance approaches a perfect fluid source in QG, favoring QG over GR under the conditions assumed in the research.

These insights could have significant implications for our understanding of the early universe and the behavior of strong gravitational fields, potentially influencing future research in cosmology and theoretical physics.

For more details, refer to the paper titled "Tilt in quadratic gravity" by Waleska P. F. de Medeiros, Matheus J. Lazo, Daniel Müller, and Dinalva A. Sales, available on arXiv with the identifier 2403.10377.