Cosmological applications of F(R,T) gravity with dynamical curvature and torsion

Abstract

We investigate the cosmological applications of Myrzakulov $F(R,T)$ gravity. In this theory ones uses a specific but non-special connection, and thus both curvature and torsion are dynamical fields related to gravity. We introduce a parametrization that quantifies the deviation of curvature and torsion scalars form their corresponding values obtained using the special Levi-Civita and Weitzenb{\"{o}}ck connections, and we extract the cosmological field equations following the mini-super-space procedure. Even for the simple case where the action of the theory is linear in $R$ and $T$, we find that the Friedmann equations contain new terms of geometrical origin, reflecting the non-special connection. Applying the theory at late times we find that we can acquire the thermal history of the universe, where dark energy can be quintessence-like or phantom-like, or behave exactly as a cosmological constant and thus reproducing $\Lambda$CDM cosmology. Furthermore, we show that these features are obtained for other Lagrangian choices, too. Finally, early-time application leads to the de Sitter solution, as well as to an inflationary realization with the desired scale-factor evolution.