Adaptive Variational Quantum Imaginary Time Evolution Approach for Ground State Preparation Gomes, Niladri Mukherjee, Anirban Zheng, Feng Iadecola, Thomas Wang, Cai-Zhuang Ho, Kai-Ming Orth, Peter Yao, Yong-Xin
dc.contributor.department Physics and Astronomy
dc.contributor.department Ames Laboratory 2022-04-25T22:28:41Z 2022-04-25T22:28:41Z 2021-10-29
dc.description.abstract An adaptive variational quantum imaginary time evolution (AVQITE) approach is introduced that yields efficient representations of ground states for interacting Hamiltonians on near-term quantum computers. It is based on McLachlan's variational principle applied to imaginary time evolution of variational wave functions. The variational parameters evolve deterministically according to equations of motions that minimize the difference to the exact imaginary time evolution, which is quantified by the McLachlan distance. Rather than working with a fixed variational ansatz, where the McLachlan distance is constrained by the quality of the ansatz, the AVQITE method iteratively expands the ansatz along the dynamical path to keep the McLachlan distance below a chosen threshold. This ensures the state is able to follow the quantum imaginary time evolution path in the system Hilbert space rather than in a restricted variational manifold set by a predefined fixed ansatz. AVQITE is used to prepare ground states of H4, H2O, and BeH2 molecules, where it yields compact variational ansätze and ground state energies within chemical accuracy. Polynomial scaling of circuit depth with system size is shown through a set of AVQITE calculations of quantum spin models. Finally, quantum Lanczos calculations are demonstrated alongside AVQITE without additional quantum resource costs.
dc.description.comments This is the published version of the following article: Gomes, Niladri, Anirban Mukherjee, Feng Zhang, Thomas Iadecola, Cai‐Zhuang Wang, Kai‐Ming Ho, Peter P. Orth, and Yong‐Xin Yao. "Adaptive variational quantum imaginary time evolution approach for ground state preparation." Advanced Quantum Technologies 4, no. 12 (2021): 2100114. DOI: 10.1002/qute.202100114. Copyright 2021 The Author(s). Attribution 4.0 International (CC BY 4.0). DOE Contract Number(s): AC02‐07CH11358. Posted with permission.
dc.identifier.other 1842214
dc.identifier.other 1828426
dc.language.iso en
dc.publisher Iowa State University Digital Repository, Ames IA (United States)
dc.relation.ispartofseries IS-J 10633
dc.relation.ispartofseries IS-J 10708
dc.source.uri *
dc.title Adaptive Variational Quantum Imaginary Time Evolution Approach for Ground State Preparation
dc.type Article
dspace.entity.type Publication
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relation.isOrgUnitOfPublication 25913818-6714-4be5-89a6-f70c8facdf7e
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