ffsim.slater_determinant

ffsim.slater_determinant(norb, occupied_orbitals, orbital_rotation=None)[source]

Return a Slater determinant.

A Slater determinant is a state of the form

\[\mathcal{U} \lvert x \rangle,\]

where \(\mathcal{U}\) is an orbital rotation and \(\lvert x \rangle\) is an electronic configuration.

Parameters:

  • norb (int) – The number of spatial orbitals.

  • occupied_orbitals (Sequence[int] | tuple[Sequence[int], Sequence[int]]) – The occupied orbitals in the electronic configuration. This is either a list of integers specifying spinless orbitals, or a pair of lists, where the first list specifies the spin alpha orbitals and the second list specifies the spin beta orbitals.

  • orbital_rotation (ndarray | tuple[ndarray | None, ndarray | None] | None) – The optional orbital rotation. You can pass either a single Numpy array specifying the orbital rotation to apply to both spin sectors, or you can pass a pair of Numpy arrays specifying independent orbital rotations for spin alpha and spin beta. If passing a pair, you can use None for one of the values in the pair to indicate that no operation should be applied to that spin sector.

Return type:

ndarray

Returns:

The Slater determinant as a state vector.