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Chemically motivated simulation problems are efficiently solvable on a quantum computer

Philipp Schleich, Lasse Bjørn Kristensen, Jorge A. Campos-Gonzalez-Angulo, Abdulrahman Aldossary, Davide Avagliano, Mohsen Bagherimehrab, Christoph Gorgulla, Joe Fitzsimons, Alán Aspuru‐Guzik

Published Nov 27, 2025• 2 citations
Publisher

Abstract

Preparing molecular states for chemical simulations by circumventing the need for ground-state preparation through scattering constituents.
DOI
10.1039/d5dd00377f

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We show that optimal control of the electron dynamics is able to prepare molecular ground states, within chemical accuracy, with evolution times approaching the bounds imposed by quantum mechanics. We propose a specific parameterization of the molecular evolution only in terms of interaction already present in the molecular Hamiltonian. Thus, the proposed method solely utilizes quantum simulation routines, retaining their favorable scalings. Due to the intimate relationships between variational quantum algorithms and optimal control, we compare, when possible, our results with state-of-the-art methods in the literature. We found that the number of parameters needed to reach chemical accuracy and algorithmic scaling is in line with compact adaptive strategies to build variational Ansätze. The algorithm, which is also suitable for quantum simulators, is implemented by emulating a digital quantum processor (up to 16 qubits) and tested on different molecules and geometries spanning different degrees of electron correlation.