openfermion.circuits.uccsd_singlet_generator

Create a singlet UCCSD generator for a system with n_electrons

openfermion.circuits.uccsd_singlet_generator(
    packed_amplitudes, n_qubits, n_electrons, anti_hermitian=True
)

This function generates a FermionOperator for a UCCSD generator designed to act on a single reference state consisting of n_qubits spin orbitals and n_electrons electrons, that is a spin singlet operator, meaning it conserves spin.

packed_amplitudes list

List storing the unique single and double excitation amplitudes for a singlet UCCSD operator. The ordering lists unique single excitations before double excitations.

n_qubits int

Number of spin-orbitals used to represent the system, which also corresponds to number of qubits in a non-compact map.

n_electrons int

Number of electrons in the physical system.

anti_hermitian Bool

Flag to generate only normal CCSD operator rather than unitary variant, primarily for testing

generator FermionOperator

Generator of the UCCSD operator that builds the UCCSD wavefunction.