Scaling of entanglement entropy at quantum critical points in random spin chains

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Hauptverfasser: Kumar, Prashant, Bhatt, R. N.
Format: Preprint
Veröffentlicht: 2023
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author Kumar, Prashant
Bhatt, R. N.
author_facet Kumar, Prashant
Bhatt, R. N.
contents We study the scaling properties of the entanglement entropy (EE) near quantum critical points in interacting random antiferromagnetic (AF) spin chains. Using density-matrix renormalization group, we compute the half-chain EE near the topological phase transition between Haldane and Random Singlet phases in a disordered spin-1 chain. It is found to diverge logarithmically in system size with an effective central charge $c_{\rm eff} = 1.17(4)$ at the quantum critical point (QCP). Moreover, a scaling analysis of EE yields the correlation length exponent $ν=2.28(5)$. Our unbiased calculation establishes that the QCP is in the universality class of the infinite-randomness fixed point predicted by previous studies based on strong disorder renormalization group technique. However, in the disordered spin-1/2 Majumdar-Ghosh chain, where a valence bond solid phase is unstable to disorder, the crossover length exponent obtained from a scaling analysis of EE disagrees with the expectation based on Imry-Ma argument. We provide a possible explanation.
format Preprint
id arxiv_https___arxiv_org_abs_2307_00062
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Scaling of entanglement entropy at quantum critical points in random spin chains
Kumar, Prashant
Bhatt, R. N.
Disordered Systems and Neural Networks
Strongly Correlated Electrons
We study the scaling properties of the entanglement entropy (EE) near quantum critical points in interacting random antiferromagnetic (AF) spin chains. Using density-matrix renormalization group, we compute the half-chain EE near the topological phase transition between Haldane and Random Singlet phases in a disordered spin-1 chain. It is found to diverge logarithmically in system size with an effective central charge $c_{\rm eff} = 1.17(4)$ at the quantum critical point (QCP). Moreover, a scaling analysis of EE yields the correlation length exponent $ν=2.28(5)$. Our unbiased calculation establishes that the QCP is in the universality class of the infinite-randomness fixed point predicted by previous studies based on strong disorder renormalization group technique. However, in the disordered spin-1/2 Majumdar-Ghosh chain, where a valence bond solid phase is unstable to disorder, the crossover length exponent obtained from a scaling analysis of EE disagrees with the expectation based on Imry-Ma argument. We provide a possible explanation.
title Scaling of entanglement entropy at quantum critical points in random spin chains
topic Disordered Systems and Neural Networks
Strongly Correlated Electrons
url https://arxiv.org/abs/2307.00062