Toward Resilient Many-Body Formulations under Incomplete Correlation Models: A Dual-Space Variational Formulation
Abstract
Quantum simulations of correlated many-body systems will inevitably operate with imperfect information: the prepared states may arise from incomplete or approximate ansatze, while their measured Hamiltonian and overlap matrix elements are additionally affected by hardware and statistical noise. Robust quantum algorithms will be those that can improve upon reliable lower-level descriptions in spite of these imperfections. We introduce a dual-space nonorthogonal configuration-interaction (DS-NOCI) framework built around this principle. Rather than replacing a classically accessible NOCI reference manifold with correlated quantum states, DS-NOCI retains both spaces and couples them variationally. The reference sector provides a stable many-body backbone, while the quantum states contribute whatever additional correlation directions they contain. With exact matrix elements, the enlarged dual space gives a ground-state energy no higher than either the reference-only NOCI or correlated-only quantum-NOCI spaces, ensuring that an incomplete correlation model cannot degrade the underlying variational description. The additional reference--correlated matrix elements require only one correlated state preparation and are therefore less demanding than the correlated--correlated block already required by quantum variant of NOCI. Molecular benchmarks further show enhanced resilience to imperfect amplitudes and noisy matrix elements. DS-NOCI thus provides a general strategy for building quantum many-body formulations that remain useful when both correlation models and quantum computations are necessarily incomplete and noisy.
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BibTeX
@misc{abraham2026toward,
title = {{Toward Resilient Many-Body Formulations under Incomplete Correlation Models: A Dual-Space Variational Formulation}},
author = {Vibin Abraham and Bhumika Jayee and Bo Peng and Nicholas P. Bauman and Karol Kowalski},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.04387},
eprint = {2609.04387},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.04387},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Toward Resilient Many-Body Formulations under Incomplete Correlation Models: A Dual-Space Variational Formulation
AU - Vibin Abraham
AU - Bhumika Jayee
AU - Bo Peng
AU - Nicholas P. Bauman
AU - Karol Kowalski
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.04387
UR - https://arxiv.org/abs/2609.04387
AB - Quantum simulations of correlated many-body systems will inevitably operate with imperfect information: the prepared states may arise from incomplete or approximate ansatze, while their measured Hamiltonian and overlap matrix elements are additionally affected by hardware and statistical noise. Robust quantum algorithms will be those that can improve upon reliable lower-level descriptions in spite of these imperfections. We introduce a dual-space nonorthogonal configuration-interaction (DS-NOCI) framework built around this principle. Rather than replacing a classically accessible NOCI reference manifold with correlated quantum states, DS-NOCI retains both spaces and couples them variationally. The reference sector provides a stable many-body backbone, while the quantum states contribute whatever additional correlation directions they contain. With exact matrix elements, the enlarged dual space gives a ground-state energy no higher than either the reference-only NOCI or correlated-only quantum-NOCI spaces, ensuring that an incomplete correlation model cannot degrade the underlying variational description. The additional reference--correlated matrix elements require only one correlated state preparation and are therefore less demanding than the correlated--correlated block already required by quantum variant of NOCI. Molecular benchmarks further show enhanced resilience to imperfect amplitudes and noisy matrix elements. DS-NOCI thus provides a general strategy for building quantum many-body formulations that remain useful when both correlation models and quantum computations are necessarily incomplete and noisy.
ER -