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Main Authors: Bao, Shuai-Tin., Wu, Dian, Zhang, Pan, Wang, Ling
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.20065
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author Bao, Shuai-Tin.
Wu, Dian
Zhang, Pan
Wang, Ling
author_facet Bao, Shuai-Tin.
Wu, Dian
Zhang, Pan
Wang, Ling
contents The exploration of neural network quantum states has become widespread in the studies of complicated quantum many-body systems. However, achieving high precision remains challenging due to the exponential growth of Hilbert space size and the intricate sign structures. Utilizing symmetries of the physical system, we propose a method to evaluate and sample the variational ansatz within a symmetric subspace. This approach isolates different symmetry sectors, reducing the relevant Hilbert space size by a factor approximately proportional to the size of the symmetry group. It is inspired by exact diagonalization techniques and the work of Choo et al. in Phys. Rev. Lett. 121, 167204 (2018). We validate our method using the frustrated spin-1/2 $J_1$-$J_2$ antiferromagnetic Heisenberg chain and compare its performance to the case without symmetrization. The results indicate that our symmetric subspace approach achieves a substantial improvement over the full Hilbert space on optimizing the ansatz, reducing the energy error by orders of magnitude. We also compare the results on degenerate eigenstates with different quantum numbers, highlighting the advantage of operating within a smaller Hilbert subspace.
format Preprint
id arxiv_https___arxiv_org_abs_2407_20065
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Learning eigenstates of quantum many-body Hamiltonians within the symmetric subspaces using neural network quantum states
Bao, Shuai-Tin.
Wu, Dian
Zhang, Pan
Wang, Ling
Strongly Correlated Electrons
The exploration of neural network quantum states has become widespread in the studies of complicated quantum many-body systems. However, achieving high precision remains challenging due to the exponential growth of Hilbert space size and the intricate sign structures. Utilizing symmetries of the physical system, we propose a method to evaluate and sample the variational ansatz within a symmetric subspace. This approach isolates different symmetry sectors, reducing the relevant Hilbert space size by a factor approximately proportional to the size of the symmetry group. It is inspired by exact diagonalization techniques and the work of Choo et al. in Phys. Rev. Lett. 121, 167204 (2018). We validate our method using the frustrated spin-1/2 $J_1$-$J_2$ antiferromagnetic Heisenberg chain and compare its performance to the case without symmetrization. The results indicate that our symmetric subspace approach achieves a substantial improvement over the full Hilbert space on optimizing the ansatz, reducing the energy error by orders of magnitude. We also compare the results on degenerate eigenstates with different quantum numbers, highlighting the advantage of operating within a smaller Hilbert subspace.
title Learning eigenstates of quantum many-body Hamiltonians within the symmetric subspaces using neural network quantum states
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2407.20065