Dynamical Systems Analysis of f(Q) Gravity

Modified gravity theories can be used for the description of homogeneous and isotropic cosmological models through the corresponding field equations. These can be cast into systems of autonomous differential equations because of their sole dependence on a well-chosen time variable, be it the cosmological time, or an alternative. For that reason, a dynamical systems approach offers a reliable route to study those equations. Through a model-independent set of variables, we are able to study all f(Q) modified gravity models. The drawback of the procedure is a more complicated constraint equation. However, it allows the dynamical system to be formulated in fewer dimensions than using other approaches. We focus on a recent model of interest, the power-exponential model, and generalize the fluid content of the model.

Automated summary

Modified gravity theories describe homogeneous and isotropic cosmological models through field equations. These equations can be transformed into autonomous differential equation systems due to their dependence on a well-chosen time variable. This allows for a reliable study of the equations using a dynamical systems approach. Through a model-independent set of variables, all f(Q) modified gravity models can be analyzed. The drawback is a more complicated constraint equation, but it reduces the dimensions of the dynamical system compared to other methods. We focus on the power-exponential model and generalize its fluid content.