Which options exist for NISQ-friendly linear response formulations?

Karl Michael Ziems, Erik Rosendahl Kjellgren*, Peter Reinholdt, Phillip Wagner Kastberg Jensen, Stephan P. A. Sauer, Jacob Kongsted, Sonia Coriani

*Corresponding author for this work

Research output: Working paperPreprintResearch

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Abstract

Linear response (LR) theory is a powerful tool in classic quantum chemistry crucial to understanding photo-induced processes in chemistry and biology. However, performing simulations for large systems and in the case of strong electron correlation remains challenging. Quantum computers are poised to facilitate the simulation of such systems, and recently, a quantum linear response formulation (qLR) was introduced. To apply qLR to near-term quantum computers beyond a minimal basis set, we here introduce a resource-efficient qLR theory using a truncated active-space version of the multi-configurational self-consistent field LR ansatz. Therein, we investigate eight different near-term qLR formalisms that utilize novel operator transformations that allow the qLR equations to be performed on near-term hardware. Simulating excited state potential energy curves and absorption spectra for various test cases, we identify two promising candidates dubbed ``proj LRSD'' and ``all-proj LRSD''.
Original languageEnglish
Publisherarxiv.org
Volume2312.13937
Number of pages50
DOIs
Publication statusPublished - 21 Dec 2023

Keywords

  • Faculty of Science
  • Quantum Computing
  • linear response theory
  • Excitation Energy
  • mult-iconfigurational self-consistent field

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