quantax.operator.S_z# quantax.operator.S_z(*index) → Operator# \(S^z\) operator \[\begin{split}S^z = \begin{pmatrix} 1/2 & 0 \\ 0 & -1/2 \end{pmatrix}\end{split}\] Parameters: index – Site to act on, as a flat index or lattice coordinates; see the module docstring for the convention.