 \label{I_Sigma_LT_0}\end{aligned}$$ $$\begin{aligned} &\Sigma^{(0)[(0)]}_{TT}(\textbf{q},\omega)=\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \  \ \ \ \ \ \ \ \ \ \ \ \ \  \nonumber \\&=\epsilon^0 q^0 