Hartree-Fock on a superconducting qubit quantum computer

The simulation of fermionic systems is among the most anticipated
applications of quantum computing. Here, we performed several quantum
simulations of chemistry with up to one dozen qubits, including modeling
the isomerization mechanism of diazene. We also demonstrated
error-mitigation strategies based on N-representability which dramatically
improve the effective fidelity of our experiments. Our parameterized
ansatz circuits realized the Givens rotation approach to
non-interacting fermion evolution, which we variationally
optimized to prepare the Hartree-Fock wavefunction. This ubiquitous
algorithmic primitive is classically tractable to simulate, yet still
generates highly entangled states over the computational basis, which
allowed us to assess the performance of our hardware and establish a
foundation for scaling up correlated quantum chemistry simulations.