QUBO–SAMPLING–DRIVEN SELECTED CONFIGURATION INTERACTION
Abstract
Accurate solutions to the electronic Schrödinger equation remain a central challenge in quantum chemistry due to the exponential growth of the many-electron Hilbert space. Selected configuration interaction (SCI) methods mitigate this challenge by restricting the wavefunction expansion to a subset of important determinants, but their efficiency is limited by the quality/cost of determinant selection and Hamiltonian diagonalization. In this work, we propose QUBO-SCI, a novel approach that reformulates the selection step in SCI as a quadratic unconstrained binary optimization (QUBO) problem. This formulation enables the sampling of low-energy electronic configurations as bitstrings using both quantum-inspired approaches and quantum annealing hardware. The sampled configurations are then incorporated into an iterative SCI framework using a perturbative importance criterion. We demonstrate the method on small benchmark systems, including H 2 , C 2 , H 2 O, and N 2 , showing that QUBO-SCI achieves near-FCI accuracy with a significantly reduced number of determinants. The results highlight the potential of annealing-based sampling as an efficient alternative to both conventional determinant selection strategies and circuit-based quantum SCI approaches in electronic structure calculations.
Related
- Selected Coupled Cluster Guided by Selected Configuration Interaction
- A Divide-and-Conquer Quantum-Selected Configuration Interaction for Evaluating π-π Stacking Interaction Energies in the Benzene Dimer
- Rotated-Frame Determinant Discovery for Ground- and Excited-State Quantum Selected Configuration Interaction
- Circuit growth and subspace read-out in quantum-selected configuration interaction: Separating the Hartree-Fock determinant
- QSCI-CMP: Quantum-Selected Configuration Interaction with Chemically Motivated Preselection
BibTeX
@misc{rocha2026qubosamplingdriven,
title = {{QUBO–SAMPLING–DRIVEN SELECTED CONFIGURATION INTERACTION}},
author = {Carlos M. R. Rocha},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008372/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008372/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - QUBO–SAMPLING–DRIVEN SELECTED CONFIGURATION INTERACTION
AU - Carlos M. R. Rocha
PY - 2026
DA - 2026/09/06
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008372/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008372/v1
AB - Accurate solutions to the electronic Schrödinger equation remain a central challenge in quantum chemistry due to the exponential growth of the many-electron Hilbert space. Selected configuration interaction (SCI) methods mitigate this challenge by restricting the wavefunction expansion to a subset of important determinants, but their efficiency is limited by the quality/cost of determinant selection and Hamiltonian diagonalization. In this work, we propose QUBO-SCI, a novel approach that reformulates the selection step in SCI as a quadratic unconstrained binary optimization (QUBO) problem. This formulation enables the sampling of low-energy electronic configurations as bitstrings using both quantum-inspired approaches and quantum annealing hardware. The sampled configurations are then incorporated into an iterative SCI framework using a perturbative importance criterion. We demonstrate the method on small benchmark systems, including H 2 , C 2 , H 2 O, and N 2 , showing that QUBO-SCI achieves near-FCI accuracy with a significantly reduced number of determinants. The results highlight the potential of annealing-based sampling as an efficient alternative to both conventional determinant selection strategies and circuit-based quantum SCI approaches in electronic structure calculations.
ER -