Quantum-Centric Geometry Optimization with Wave-Function-Based Embedding

Abstract:The EWF-(FCI,SQD) method, a wave-function-based embedding approach combining full configuration interaction (FCI) and sample-based quantum diagonalization (SQD), is a promising new tool for the simulation of molecular systems. However, applications of EWF-(FCI,SQD) have so far been limited to single-point calculations, whereas the study of complex chemical processes requires the ability to explore potential energy surfaces. In this work, we demonstrate geometry optimization with EWF-(FCI,SQD), scaling our simulations to molecules as large as menthone and benzidine within the STO-3G basis set. Without fragmentation, these systems comprise 73 and 82 molecular orbitals respectively, presenting an intractable Hilbert space for conventional exact or high-level subspace solvers and establishing a clear necessity for fragmentation-based methodologies. The underlying fragment SQD simulations in the EWF-(FCI,SQD) geometry optimizations use up to 70 qubits. The resulting geometries show exceptional accuracy relative to the classical reference, with deviations below 4 picometers.

Quantum Physics (quant-ph); Chemical Physics (physics.chem-ph)

arXiv:2607.16410 [quant-ph]

(or arXiv:2607.16410v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2607.16410 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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