  ( b_0 | \vphantom{\sum} B_{s_{0}}^{[0]r_0} \cdot \ldots \cdot B_{s_{L}}^{[L]r_L} | b_L)\;  (c_{0}^{\dagger})^{s_0} \ldots (c_{L}^{\dagger})^{s_L} |\Omega\rangle \langle \Omega |  \,c_{L}^{r_L} \ldots c_{0}^{r_0}