Energy conditions in $F(T,\Theta)$ gravity and compatibility with a stable de Sitter solution

Understand

We study a new type of the modified teleparallel gravity of the form $F(T,\,\Theta)$ in which $T$, the torsion scalar, is coupled with $\Theta$, the trace of the stress-energy tensor.

• In a perturbational approach, we study the stability of the solutions and as a special case we find a condition for stability of the de Sitter phase.
• Then we adopt a suitable form for $F(T,\Theta)$ that realizes a stable de Sitter solution so that the stability condition creates a specific constraint on the parametric space of the model.
• Finally, the energy conditions in the framework of $F(T,\Theta)$ gravity is investigated.