Improved Ground State Estimation in Quantum Field Theories via Normalising Flow-Assisted Neural Quantum States

Fuente: arXiv
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Autores principales: Ngairangbam, Vishal S., Spannowsky, Michael, Sypchenko, Timur
Formato: Preprint
Publicado: 2025
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author Ngairangbam, Vishal S.
Spannowsky, Michael
Sypchenko, Timur
author_facet Ngairangbam, Vishal S.
Spannowsky, Michael
Sypchenko, Timur
contents We propose a hybrid variational framework that enhances Neural Quantum States (NQS) with a Normalising Flow-based sampler to improve the expressivity and trainability of quantum many-body wavefunctions. Our approach decouples the sampling task from the variational ansatz by learning a continuous flow model that targets a discretised, amplitude-supported subspace of the Hilbert space. This overcomes limitations of Markov Chain Monte Carlo (MCMC) and autoregressive methods, especially in regimes with long-range correlations and volume-law entanglement. Applied to the transverse-field Ising model with both short- and long-range interactions, our method achieves comparable ground state energy errors with state-of-the-art matrix product states and lower energies than autoregressive NQS. For systems up to 50 spins, we demonstrate high accuracy and robust convergence across a wide range of coupling strengths, including regimes where competing methods fail. Our results showcase the utility of flow-assisted sampling as a scalable tool for quantum simulation and offer a new approach toward learning expressive quantum states in high-dimensional Hilbert spaces.
format Preprint
id arxiv_https___arxiv_org_abs_2506_12128
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Improved Ground State Estimation in Quantum Field Theories via Normalising Flow-Assisted Neural Quantum States
Ngairangbam, Vishal S.
Spannowsky, Michael
Sypchenko, Timur
Quantum Physics
Machine Learning
High Energy Physics - Lattice
High Energy Physics - Phenomenology
We propose a hybrid variational framework that enhances Neural Quantum States (NQS) with a Normalising Flow-based sampler to improve the expressivity and trainability of quantum many-body wavefunctions. Our approach decouples the sampling task from the variational ansatz by learning a continuous flow model that targets a discretised, amplitude-supported subspace of the Hilbert space. This overcomes limitations of Markov Chain Monte Carlo (MCMC) and autoregressive methods, especially in regimes with long-range correlations and volume-law entanglement. Applied to the transverse-field Ising model with both short- and long-range interactions, our method achieves comparable ground state energy errors with state-of-the-art matrix product states and lower energies than autoregressive NQS. For systems up to 50 spins, we demonstrate high accuracy and robust convergence across a wide range of coupling strengths, including regimes where competing methods fail. Our results showcase the utility of flow-assisted sampling as a scalable tool for quantum simulation and offer a new approach toward learning expressive quantum states in high-dimensional Hilbert spaces.
title Improved Ground State Estimation in Quantum Field Theories via Normalising Flow-Assisted Neural Quantum States
topic Quantum Physics
Machine Learning
High Energy Physics - Lattice
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2506.12128