qat.fermion.chemistry.ucc.construct_ucc_ansatz

qat.fermion.chemistry.ucc.construct_ucc_ansatz(cluster_ops: List[SpinHamiltonian], ket_hf: int, n_steps: int = 1) Program

Builds the parametric state preparation circuit implementing the provided cluster operator.

The returned function maps \(\vec{\theta}\) to a QRoutine describing \(Q\) such as:

\[Q \vert \vec{0} \rangle = \vert \mathrm{UCC} (\vec{\theta}) \rangle = e^{T(\vec{\theta})} \vert \mathrm{HF}\rangle\]
Parameters
  • cluster_ops (List[SpinHamiltonian]) – The cluster operators iT (note the i factor).

  • ket_hf (int) – The Hartree-Fock state in integer representation.

  • n_steps (int) – Number of trotter steps.

Returns

The parametric program implementing the UCCSD method.

Return type

Program