Linearized Field Equations and Extra Force in $f(R,{\mathbf{T}}^{(n)})$ Extended Gravity

Habib Abedi, Francesco Bajardi, Salvatore Capozziello

We consider an extended theory of gravity with Lagrangian $\mathcal{L}=f(R,{\mathbf{T}}^{(n)})$, with ${\mathbf{T}}^{(n)}$ being a $2n$-th order invariant made of contractions of the energ…