  For variational algorithms on the near term quantum computing hardware, it is
highly desirable to use very accurate ansatze with low implementation cost.
Recent studies have shown that the antisymmetrized geminal power (AGP)
wavefunction can be an excellent starting point for ansatze describing systems
with strong pairing correlations, as those occurring in superconductors. In
this work, we show how AGP can be efficiently implemented on a quantum computer
with circuit depth, number of CNOTs, and number of measurements being linear in
system size. Using AGP as the initial reference, we propose and implement a
unitary correlator on AGP and benchmark it on the ground state of the pairing
Hamiltonian. The results show highly accurate ground state energies in all
correlation regimes of this model Hamiltonian.
