Gauging the variational optimization of projected entangled-pair states

Fuente: arXiv
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Autores principales: Tang, Wei, Vanderstraeten, Laurens, Haegeman, Jutho
Formato: Preprint
Publicado: 2025
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author Tang, Wei
Vanderstraeten, Laurens
Haegeman, Jutho
author_facet Tang, Wei
Vanderstraeten, Laurens
Haegeman, Jutho
contents Projected entangled-pair states (PEPS) constitute a powerful variational ansatz for capturing ground state physics of two-dimensional quantum systems. However, accurately computing and minimizing the energy expectation value remains challenging, in part because the impact of the gauge degrees of freedom that are present in the tensor network representation is poorly understood. We analyze the role of gauge transformations for the case of a U(1)-symmetric PEPS with point group symmetry, thereby reducing the gauge degrees of freedom to a single class. We show how gradient-based optimization strategies exploit the gauge freedom, causing the tensor network contraction to become increasingly inaccurate and to produce artificially low variational energies. Furthermore, we develop a gauge-fixed optimization strategy that largely suppresses this effect, resulting in a more robust optimization. Our study underscores the need for gauge-aware optimization strategies to guarantee reliability of variational PEPS in general settings.
format Preprint
id arxiv_https___arxiv_org_abs_2508_10822
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Gauging the variational optimization of projected entangled-pair states
Tang, Wei
Vanderstraeten, Laurens
Haegeman, Jutho
Strongly Correlated Electrons
Quantum Physics
Projected entangled-pair states (PEPS) constitute a powerful variational ansatz for capturing ground state physics of two-dimensional quantum systems. However, accurately computing and minimizing the energy expectation value remains challenging, in part because the impact of the gauge degrees of freedom that are present in the tensor network representation is poorly understood. We analyze the role of gauge transformations for the case of a U(1)-symmetric PEPS with point group symmetry, thereby reducing the gauge degrees of freedom to a single class. We show how gradient-based optimization strategies exploit the gauge freedom, causing the tensor network contraction to become increasingly inaccurate and to produce artificially low variational energies. Furthermore, we develop a gauge-fixed optimization strategy that largely suppresses this effect, resulting in a more robust optimization. Our study underscores the need for gauge-aware optimization strategies to guarantee reliability of variational PEPS in general settings.
title Gauging the variational optimization of projected entangled-pair states
topic Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2508.10822