Quantum-classical hybrid algorithm using an error-mitigating $N$-representability condition to compute the Mott metal-insulator transition

Journal Article · 28 August 2019 · Physical Review A

DOI: https://doi.org/10.1103/PhysRevA.100.022517 · OSTI ID:1559291

Smart, Scott E. ^[1]; Mazziotti, David A. ^[1]

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1. Chicago State Univ., IL (United States)

Quantum algorithms for molecular electronic structure have been developed with lower computational scaling than their classical counterparts, but emerging quantum hardware is far from being capable of the coherence, connectivity, and gate errors required for their experimental realization. Here we propose a class of quantumclassical hybrid algorithms that computes the energy from a two-electron reduced density matrix (2-RDM). The 2-RDM is constrained by $$N$$-representability conditions, constraints for representing an $$N$$-electron wave function, which mitigate noise from the quantum circuit. We compute the strongly correlated dissociation of doublet H₃ into three hydrogen atoms. The hybrid quantum-classical computer matches the energies from full configuration interaction to 0.1 kcal/mol, one-tenth of “chemical accuracy,” even in the strongly correlated limit of dissociation. Furthermore, the spatial locality of the computed one-electron RDM reveals that the quantum computer accurately predicts the Mott metal-insulator transition.

• Research Organization: Chicago State Univ., IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
• Grant/Contract Number: SC0019215
• OSTI ID: 1559291
• Alternate ID(s): OSTI ID: 1559080
• Journal Information: Physical Review A, Vol. 100, Issue 2; ISSN 2469-9926
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English