Publication in IOP Quantum Science and Technology: “Solving an industrially relevant quantum chemistry problem on quantum hardware”
Today, IOP Quantum Science and Technology has published our work which had appeared earlier as a pre-print. This project was jointly realized by Ludwig Nützel, Alexander Gresch, Lukas Hehn, Lucas Marti, Robert Freund, Alex Steiner, Christian D. Marciniak, Timo Eckstein, Nina Stockinger, Stefan Wolf, Thomas Monz, Michael Kühn, and Michael J. Hartmann.
In this work, we provide the first end-to-end workflow to determine the ground state energies, and subsequently the chemically interesting Gibbs free energies, of industrially relevant molecules using results obtained from actual quantum hardware. To this end, we train a variational quantum circuit and use efficient measurement and post-processing techniques to evaluate the ground state energies of two different spin states of the Fe(III)-NTA complex. Importantly, we optimize the variational parameters by evaluating the cost function on a real quantum processor, as opposed to the widespread way of pre-optimizing variational parameters classically. The estimated energies lie within chemical accuracy of the exact ground state energies of the corresponding active space Hamiltonians, showcasing a potential application for quantum processors in quantum chemistry.