qiskit_addon_sqd.fermion.rotate_integrals

rotate_integrals(hcore, eri, k_flat)

Perform a similarity transform on the integrals.

The transformation is described as:

\[\hat{\widetilde{H}} = \hat{U^{\dagger}}(k)\hat{H}\hat{U}(k)\]

For more information on how \(\hat{U}\) and \(\hat{U^{\dagger}}\) are generated from k_flat and applied to the one- and two-body integrals, refer to Sec. II A 4.

Parameters:

• hcore (ndarray) – Core Hamiltonian matrix representing single-electron integrals

• eri (ndarray) – Electronic repulsion integrals representing two-electron integrals

• k_flat (ndarray) –

  1D array defining the orbital transform. Refer to Sec. II A 4 for more information on how these values are used to generate the transform operator.

Returns:

• The rotated core Hamiltonian matrix

• The rotated ERI matrix

Return type:

tuple[ndarray, ndarray]