Preferred Basis in Coupled Electron-Nuclear Dynamics

Fuente: arXiv
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Autor principal: Bang, Junhyeok
Formato: Preprint
Publicado: 2025
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author Bang, Junhyeok
author_facet Bang, Junhyeok
contents Beyond the adiabatic regime, our understanding of quantum dynamics in coupled systems remains limited, and the choice of representation continues to obscure physical interpretation and simulation accuracy. Here we propose a natural and efficient basis for electron nuclear dynamics by drawing on the concepts of pointer and preferred states from decoherence theory, adapted to systems where electrons and nuclei interact strongly. Within this framework, we show that 1) the independent dynamics exploited by mixed quantum classical (MQC) methods is best understood as a manifestation of entanglement viewed in a preferred basis, rather than a consequence of decoherence, and 2) the adiabatic Born Oppenheimer states satisfy the conditions of an approximate preferred basis. This perspective reconciles widely used approximations with a more fundamental structure of the theory and provides a systematic route to more reliable MQC strategies. In effect, we revisit MQC methods through the lens of preferred states, clarifying when they succeed and how they can be improved.
format Preprint
id arxiv_https___arxiv_org_abs_2511_04559
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Preferred Basis in Coupled Electron-Nuclear Dynamics
Bang, Junhyeok
Quantum Physics
Chemical Physics
Beyond the adiabatic regime, our understanding of quantum dynamics in coupled systems remains limited, and the choice of representation continues to obscure physical interpretation and simulation accuracy. Here we propose a natural and efficient basis for electron nuclear dynamics by drawing on the concepts of pointer and preferred states from decoherence theory, adapted to systems where electrons and nuclei interact strongly. Within this framework, we show that 1) the independent dynamics exploited by mixed quantum classical (MQC) methods is best understood as a manifestation of entanglement viewed in a preferred basis, rather than a consequence of decoherence, and 2) the adiabatic Born Oppenheimer states satisfy the conditions of an approximate preferred basis. This perspective reconciles widely used approximations with a more fundamental structure of the theory and provides a systematic route to more reliable MQC strategies. In effect, we revisit MQC methods through the lens of preferred states, clarifying when they succeed and how they can be improved.
title Preferred Basis in Coupled Electron-Nuclear Dynamics
topic Quantum Physics
Chemical Physics
url https://arxiv.org/abs/2511.04559