Operator Learning for Schrödinger Equation: Unitarity, Error Bounds, and Time Generalization

Fuente: arXiv
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Autores principales: Patel, Yash, Subedi, Unique, Tewari, Ambuj
Formato: Preprint
Publicado: 2025
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author Patel, Yash
Subedi, Unique
Tewari, Ambuj
author_facet Patel, Yash
Subedi, Unique
Tewari, Ambuj
contents We consider the problem of learning the evolution operator for the time-dependent Schrödinger equation, where the Hamiltonian may vary with time. Existing neural network-based surrogates often ignore fundamental properties of the Schrödinger equation, such as linearity and unitarity, and lack theoretical guarantees on prediction error or time generalization. To address this, we introduce a linear estimator for the evolution operator that preserves a weak form of unitarity. We establish both upper bounds and lower bounds on the prediction error of the proposed estimator that hold uniformly over classes of sufficiently smooth initial wave functions. Additionally, we derive time generalization bounds that quantify how the estimator extrapolates beyond the time points seen during training. Experiments across real-world Hamiltonians -- including hydrogen atoms, ion traps for qubit design, and optical lattices -- show that our estimator achieves relative errors up to two orders of magnitude smaller than state-of-the-art methods such as the Fourier Neural Operator and DeepONet.
format Preprint
id arxiv_https___arxiv_org_abs_2505_18288
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Operator Learning for Schrödinger Equation: Unitarity, Error Bounds, and Time Generalization
Patel, Yash
Subedi, Unique
Tewari, Ambuj
Machine Learning
We consider the problem of learning the evolution operator for the time-dependent Schrödinger equation, where the Hamiltonian may vary with time. Existing neural network-based surrogates often ignore fundamental properties of the Schrödinger equation, such as linearity and unitarity, and lack theoretical guarantees on prediction error or time generalization. To address this, we introduce a linear estimator for the evolution operator that preserves a weak form of unitarity. We establish both upper bounds and lower bounds on the prediction error of the proposed estimator that hold uniformly over classes of sufficiently smooth initial wave functions. Additionally, we derive time generalization bounds that quantify how the estimator extrapolates beyond the time points seen during training. Experiments across real-world Hamiltonians -- including hydrogen atoms, ion traps for qubit design, and optical lattices -- show that our estimator achieves relative errors up to two orders of magnitude smaller than state-of-the-art methods such as the Fourier Neural Operator and DeepONet.
title Operator Learning for Schrödinger Equation: Unitarity, Error Bounds, and Time Generalization
topic Machine Learning
url https://arxiv.org/abs/2505.18288