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DOE OSTI · 2447968

Excited-state downfolding using ground-state formalisms

Bauman, Nicholas P.
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Abstract

Downfolding coupled cluster (CC) techniques are powerful tools for reducing the dimensionality of many-body quantum problems. This work investigates how ground-state downfolding formalisms can target excited states using non-Aufbau reference determinants, paving the way for applications of quantum computing in excited-state chemistry. This study focuses on doubly excited states for which canonical equation-of-motion CC approaches struggle to describe unless one includes higher-than-double excitations. The downfolding technique results in state-specific effective Hamiltonians that, when diagonalized in their respective active spaces, provide ground- and excited-state total energies (and therefore excitation energies) comparable to high-level CC methods. The performance of this procedure is examined with doubly excited states of H 2 , Methylene, Formaldehyde, and Nitroxyl.

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICSdimensionality reductiondownfoldingeffective Hamiltonianquantum computingunitary coupled cluster

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Bauman, Nicholas P.. 2024-05-15. Excited-state downfolding using ground-state formalisms. https://doi.org/10.1088/2516-1075%2Fad46b6

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