The Electron Density: A Fidelity Witness for Quantum Computation

09 October 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


There is currently no combination of quantum hardware and algorithms that can provide an advantage over conventional calculations of molecules or materials. However, if or when such a point is reached, new strategies will be needed to verify predictions made using quantum devices. We propose that the electron density, obtained through experimental or computational means, can serve as a robust benchmark for validating the accuracy of quantum computation of chemistry. An initial exploration into topological features of electron densities, facilitated by quantum computation, is presented here as a proof of concept. Additionally, we examine the effects of constraining and symmetrizing measured one-particle reduced density matrices on noise-driven errors in the electron density distribution. We emphasize the potential benefits and future need for high-quality electron densities derived from diffraction experiments for validating classically intractable quantum computations of materials.


Chemical bonding
error mitigation
quantum algorithms
electronic structure

Supplementary materials

Supporting Information
Details on calculations, quantum hardware, and noise model. 1-RDM data, molecular orbitals, electron density difference plots.


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