Metric-Affine Myrzakulov Gravity Theories

In this paper, we review the so-called Myrzakulov Gravity models (MG-N, with N = I, II, …, VIII) and derive their respective metric-affine generalizations (MAMG-N), discussing also their particular sub-cases. The field equations of the theories are obtained by regarding the metric tensor and the general affine connection as independent variables. We then focus on the case in which the function characterizing the aforementioned metric-affine models is linear and consider a Friedmann-Lemaître–Robertson–Walker background to study cosmological aspects and applications. Historical motivation for this research is thoroughly reviewed and specific physical motivations are provided for the aforementioned family of alternative theories of gravity

Impact of Collisional Matter on the Late-Time Dynamics of f(R,T) Gravity

We study the cosmic evolution of non-minimally coupled f ( R , T ) gravity in the presence of matter fluids consisting of collisional self-interacting dark matter and radiation. We study the cosmic evolution in the presence of collisional matter, and we compare the results with those corresponding to non-collisional matter and the Λ -cold-dark-matter ( Λ CDM) model. Particularly, for a flat Friedmann–Lema i ^ tre–Robertson–Walker Universe, we study two non-minimally coupled f ( R , T ) gravity models and we focus our study on the late-time dynamical evolution of the model. Our study is focused on the late-time behavior of the effective equation of the state parameter ω e f f and of the deceleration parameter q as functions of the redshift for a Universe containing collisional and non-collisional dark matter fluids, and we compare both models with the Λ CDM model. As we demonstrate, the resulting picture is well accommodated to the latest observational data on the basis of physical parameters