 \Big( M_{\sigma_0 {\boldsymbol{k}}_0, -\sigma_0{\boldsymbol{k}}_0 - {\boldsymbol{k}}_0}^{\uparrow, s(\sigma_0)} \delta_{{\boldsymbol{q}},\sigma_0 {\boldsymbol{k}}_0 + {\boldsymbol{k}}_0}  - M_{\sigma_0 {\boldsymbol{k}}_0,-\sigma_0{\boldsymbol{k}}_0 + {\boldsymbol{k}}_0}^{\downarrow, s(\sigma_0)} \delta_{{\boldsymbol{q}},\sigma_0 {\boldsymbol{k}}_0 - {\boldsymbol{k}}_0} \Big) v_{-{\boldsymbol{k}}_0}^{\ast} u_{{\boldsymbol{k}}_0}^{\ast}