openfermion.hamiltonians.sz_operator

Return the sz operator.

openfermion.hamiltonians.sz_operator(
    n_spatial_orbitals: int
) -> openfermion.ops.FermionOperator
$$ \begin{align} S^{z} = \frac{1}{2}\sum_{i = 1}^{n}(n_{i, \alpha} - n_{i, \beta}) \end{align} $$

n_spatial_orbitals number of spatial orbitals (n_qubits // 2).

operator (FermionOperator): corresponding to the sz operator over n_spatial_orbitals.

Note:

The indexing convention used is that even indices correspond to spin-up (alpha) modes and odd indices correspond to spin-down (beta) modes.