Entanglement scaling and criticality of infinite-size quantum many-body systems in continuous space addressed by a tensor network approach

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Main Authors: Hong, Rui, Cui, Hao-Wei, Ji, An-Chun, Ran, Shi-Ju
Format: Preprint
Published: 2024
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author Hong, Rui
Cui, Hao-Wei
Ji, An-Chun
Ran, Shi-Ju
author_facet Hong, Rui
Cui, Hao-Wei
Ji, An-Chun
Ran, Shi-Ju
contents Simulating strongly-correlated quantum systems in continuous space belongs to the most challenging and long-concerned issues in quantum physics. This work investigates the quantum entanglement and criticality of the ground-state wave-functions of infinitely-many coupled quantum oscillators (iCQOs). The essential task involves solving a set of partial differential equations (Schrödinger equations in the canonical quantization picture) with infinitely-many variables, which currently lacks valid methods. By extending the imaginary-time evolution algorithm with translationally-invariant functional tensor network, we simulate the ground state of iCQOs with the presence of two- and three-body couplings. We determine the range of coupling strengths where there exists a real ground-state energy (dubbed as physical region). With two-body couplings, we reveal the logarithmic scaling law of entanglement entropy (EE) and the polynomial scaling law of correlation length against the virtual bond dimension $χ$ at the dividing point of physical and non-physical regions. These two scaling behaviors are signatures of criticality, according to the previous results in quantum lattice models, but were not reported in continuous-space quantum systems. The scaling coefficients result in a central charge $c=1$, indicating the presence of free boson conformal field theory (CFT). We further show that the presence of three-body couplings, for which there are no analytical or numerical results, breaks down the CFT description at the dividing point. Our work reveals the scaling behaviors of EE in continuous-space quantum many-body systems. These results provide strong numerical evidence supporting the efficiency of TN in representing continuous-space quantum wave-functions in the thermodynamic limit and offer an efficient approach to studying entanglement properties and criticality in continuous space.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23624
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Entanglement scaling and criticality of infinite-size quantum many-body systems in continuous space addressed by a tensor network approach
Hong, Rui
Cui, Hao-Wei
Ji, An-Chun
Ran, Shi-Ju
Quantum Physics
Strongly Correlated Electrons
Simulating strongly-correlated quantum systems in continuous space belongs to the most challenging and long-concerned issues in quantum physics. This work investigates the quantum entanglement and criticality of the ground-state wave-functions of infinitely-many coupled quantum oscillators (iCQOs). The essential task involves solving a set of partial differential equations (Schrödinger equations in the canonical quantization picture) with infinitely-many variables, which currently lacks valid methods. By extending the imaginary-time evolution algorithm with translationally-invariant functional tensor network, we simulate the ground state of iCQOs with the presence of two- and three-body couplings. We determine the range of coupling strengths where there exists a real ground-state energy (dubbed as physical region). With two-body couplings, we reveal the logarithmic scaling law of entanglement entropy (EE) and the polynomial scaling law of correlation length against the virtual bond dimension $χ$ at the dividing point of physical and non-physical regions. These two scaling behaviors are signatures of criticality, according to the previous results in quantum lattice models, but were not reported in continuous-space quantum systems. The scaling coefficients result in a central charge $c=1$, indicating the presence of free boson conformal field theory (CFT). We further show that the presence of three-body couplings, for which there are no analytical or numerical results, breaks down the CFT description at the dividing point. Our work reveals the scaling behaviors of EE in continuous-space quantum many-body systems. These results provide strong numerical evidence supporting the efficiency of TN in representing continuous-space quantum wave-functions in the thermodynamic limit and offer an efficient approach to studying entanglement properties and criticality in continuous space.
title Entanglement scaling and criticality of infinite-size quantum many-body systems in continuous space addressed by a tensor network approach
topic Quantum Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2410.23624