Bridging physical intuition and hardware efficiency for correlated electronic states: the local unitary cluster Jastrow ansatz for electronic structure

17 April 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


A prominent goal in quantum chemistry is to solve the molecular electronic structure problem for the ground state energy with high accuracy. While classical quantum chemistry is a relatively mature field, the accurate and scalable prediction of strongly correlated states found, e.g., in bond breaking and polynuclear transition metal compounds remains an open problem. Within the context of a variational quantum eigensolver, we propose a new family of ansatzes which provides a more physically appropriate description of strongly correlated electrons than unitary coupled cluster with singles and doubles excitations, with vastly reduced quantum resource requirements. Specifically, we present a set of local approximations to the unitary cluster Jastrow wavefunction motivated by Hubbard physics. The resulting ansatz removes the need for SWAP gates and can be tailored to arbitrary qubit topologies (e.g., square, hex, heavy-hex). Our ansatz is well-suited to take advantage of continuous sets of quantum gates recently realized on superconducting devices with tunable couplers, while retaining a unique level of physical transparency and interpretability. As the capabilities of quantum computing devices continue to progress, we expect that the local cluster Jastrow ansatz to be a natural choice to encode both statically and dynamically correlated electronic wavefunctions.


Strong correlation
Electronic structure theory
Hubbard Model
Quantum computing

Supplementary materials

Supplemental Material
I. Unitary coupled cluster calculations, II. Dissociation of ethene, III. Additional LUCJ calculations, IV. Computational details for classical simulation of the LUCJ ansatz


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.