2022/03/02 by Giovanni Acquaviva, Nihan Katırcı, Acquaviva, Giovanni +1 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Geophysics and Gravity Measurements #Solar and Space Plasma Dynamics
paper · pdf · doi:10.48550/arxiv.2203.01234
openalex publication_date 2022/03/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We perform the dynamical system analysis of a cosmological model in the energy-momentum squared gravity (EMSG) of the form f(Tμν Tμν)=αln(λTμν Tμν), which is known as energy-momentum log gravity (EMLG). In particular, we show that the analytical cosmological solution of EMLG presented by Akarsu \it et al. (Eur. Phys. J. C 79:846, 2019) is a future attractor. It includes new terms in the right-hand side of the Einstein field equations, which yield constant inertial mass density and provide a dynamical dark energy with a density passing below zero at large redshifts, accommodating a mechanism for screening Λ in the past for α<0, suggested for alleviating some cosmological tensions. We show that the second law of thermodynamics requires α≤0 that allows the screening mechanism to take place. We also show that the model gives rise to an entire class of new stable late-time solutions with H→√((Λ+2α)/3) as a→∞, where the new term is due to the constant effective inertial mass density that arises from EMLG contribution of dust, whereas H→√(Λ/3) as a→∞ in the ΛCDM model. We also show the existence of new interesting features and trajectories that are absent in ΛCDM with or without spatial curvature.