tequila.quantumchemistry.QuantumChemistryPsi4.compute_rdms

QuantumChemistryPsi4.compute_rdms(U: tequila.circuit.circuit.QCircuit = None, variables: tequila.objective.objective.Variables = None, spin_free: bool = True, get_rdm1: bool = True, get_rdm2: bool = True, psi4_method: str = None, psi4_options: dict = {})[source]

Same functionality as qc_base.compute_rdms (look there for more information), plus the additional option to compute 1- and 2-RDM using psi4 by the keyword psi4_rdms

Parameters

  • U – Quantum Circuit to achieve the desired state \(\psi = U |0\rangle\), optional if psi4_rdms is set to True

  • variables – If U is parametrized, then need to hand over a set of fixed variables

  • spin_free – Set whether matrices should be spin-free (summation over spin) or defined by spin-orbitals

  • get_rdm1 – Set whether either one or both rdm1, rdm2 should be computed. If both are needed at some point, it is recommended to compute them at once. Note that whatever is specified in psi4_options has priority.

  • get_rdm2 – Set whether either one or both rdm1, rdm2 should be computed. If both are needed at some point, it is recommended to compute them at once. Note that whatever is specified in psi4_options has priority.

  • psi4_method – Method to be run, currently only methods returning a CIWavefuntion are supported (e.g. “detci” + ex_level in options, or “fci”, “cisdt”, “casscf”, but NOT “cisd”)

  • psi4_options – Options to be handed over to psi4, containing e.g. excitation level of “detci”-method. If “detci__opdm” for 1-RDM and “detci__tpdm” for 2-RDM are not included, the keywords get_rdm1, get_rdm2 are used (if both are specified, prioritizing psi4_options).