The Electron Density: a Fidelity Witness for Quantum Computation

Martin Rahm¹

¹ Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96, Gothenburg, Sweden.

*e-mail: martin.rahm@chalmers.se

This presentation is intended to offer new motivation for pursuing quantum crystallography and the ever more accurate experimental determination of electron densities. Quantum computation is a booming field worldwide, where expectations are high. However, no combination of quantum hardware and algorithms has yet demonstrated an advantage compared to conventional calculations. If or when such a time arrives, the verification of quantum computational results will become a real concern. We argue [1] that the electron density can serve as a robust, future-proof benchmark to validate the accuracy of quantum computation of chemistry and materials. A procedure for calculating molecular electron densities using quantum computation will be outlined, with quantum hardware data presented as a proof-of-concept alongside a discussion of quantum noise mitigation. Comparisons of topological features of derived densities against accurate ab initio results highlight a potential new utility of the Quantum Theory of Atoms in Molecules (QTAIM).

References

[1] Skogh et al., Chem. Sci. 2024, 15, 2257-2265