2021/06/11 by Yordan S. Yordanov, C. H. W. Barnes, Yordanov, Yordan S. +4
Chemistry · Computer Science · Physics and Astronomy · #Algorithm #Benchmark (surveying) #Chemistry #Computer science #Controlled NOT gate #Excited state #FOS: Physical sciences #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Physics (quant-ph) #Quantum and electron transport phenomena #Quantum gate #Quantum mechanics #Qubit #Statistical physics #Theoretical computer science #quant-ph
paper · pdf · doi:10.48550/arxiv.2106.06296
published in arXiv (Cornell University) (Cornell University) · arXiv admin note: text overlap with arXiv:2011.10540
openalex publication_date 2021/06/11 · arxiv created 2021/10/18 · arxiv updated 2021/10/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Calculations of molecular spectral properties, like photodissociation rates and absorption bands, rely on knowledge of the excited state energies of the molecule of interest. Protocols based on the variational quantum eigensolver (VQE) are promising candidates to calculate such energies on emerging noisy intermediate scale quantum (NISQ) computers. The successful implementation of these protocols on NISQ computers, relies on ansätze that can accurately approximate the molecular states and that can be implemented by shallow quantum circuits. In this paper, we introduce the excited qubit-excitation-based adaptive (e-QEB-ADAPT)-VQE protocol to calculate molecular excited state energies. The e-QEB-ADAPT-VQE constructs efficient problem-tailored ansätze by iteratively appending evolutions of qubit excitation operators. The e-QEB-ADAPT-VQE is an adaptation of the QEB-ADAPT-VQE protocol, which is designed to be independent on the choice of an initial reference state. We perform classical numerical simulations for LiH and BeH2 to benchmark the performance of the e-QEB-ADAPT-VQE. We demonstrate that the e-QEB-ADAPT-VQE can construct highly accurate ansätze that require at least an order of magnitude fewer CNOTs than standard fixed UCC ansätze, such as the UCCSD and the GUCCSD.