ffsim.apply_num_op_prod_interaction¶

ffsim.apply_num_op_prod_interaction(vec, theta, target_orbs, norb, nelec, *, copy=True)[source]¶

Apply interaction gate for product of number operators.

The gate is

\[\text{NP}(\theta, (S_\alpha, S_\beta)) = \exp\left(i \theta \prod_{p \in S_\alpha} a^\dagger_{p\alpha} a_{p\alpha} \prod_{p \in S_\beta} a^\dagger_{p\beta} a_{p\beta} \right)\]

Parameters:

vec (ndarray) – The state vector to be transformed.
theta (float) – The rotation angle.
target_orbs (tuple[Sequence[int], Sequence[int]]) – A pair of lists of integers giving the orbitals on which to apply the interaction. The first list specifies the alpha orbitals and the second list specifies the beta orbitals.
norb (int) – The number of spatial orbitals.
nelec (tuple[int, int]) – The number of alpha and beta electrons.
copy (bool) –
Whether to copy the vector before operating on it.
- If copy=True then this function always returns a newly allocated vector and the original vector is left untouched.
- If copy=False then this function may still return a newly allocated vector, but the original vector may have its data overwritten. It is also possible that the original vector is returned, modified in-place.