openfermion.linalg.jw_sz_indices

Return the indices of basis vectors with fixed Sz under JW encoding.

openfermion.linalg.jw_sz_indices(
    sz_value,
    n_qubits,
    n_electrons=None,
    up_index=openfermion.utils.up_index,
    down_index=openfermion.utils.down_index
)

The returned indices label computational basis vectors which lie within the corresponding eigenspace of the Sz operator,

\[ \begin{align} S^{z} = \frac{1}{2}\sum_{i = 1}^{n}(n_{i, \alpha} - n_{i, \beta}) \end{align} \]

sz_value float

Desired Sz value. Should be an integer or half-integer.

n_qubits int

Number of qubits defining the total state

n_electrons int, optional

Number of particles to restrict the operator to, if such a restriction is desired

up_index Callable, optional

Function that maps a spatial index to the index of the corresponding up site

down_index Callable, optional

Function that maps a spatial index to the index of the corresponding down site

indices list

The list of indices