Entanglement of edge modes in (very) strongly correlated topological insulators

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Hauptverfasser: Ara, Nisa, Basu, Rudranil, Mathew, Emil, Raychowdhury, Indrakshi
Format: Preprint
Veröffentlicht: 2023
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author Ara, Nisa
Basu, Rudranil
Mathew, Emil
Raychowdhury, Indrakshi
author_facet Ara, Nisa
Basu, Rudranil
Mathew, Emil
Raychowdhury, Indrakshi
contents Identifying topological phases for a strongly correlated theory remains a non-trivial task, as defining order parameters, such as Berry phases, is not straightforward. Quantum information theory is capable of identifying topological phases for a theory that exhibits quantum phase transition with a suitable definition of order parameters that are related to different entanglement measures for the system. In this work, we study entanglement entropy for a bi-layer SSH model, both in the presence and absence of Hubbard interaction and at varying interaction strengths. For the free theory, edge entanglement acts as an order parameter, which is supported by analytic calculations and numerical (DMRG) studies. We calculate the symmetry-resolved entanglement and demonstrate the equipartition of entanglement for this model which itself acts as an order parameter when calculated for the edge modes. As the DMRG calculation allows one to go beyond the free theory, we study the entanglement structure of the edge modes in the presence of on-site Hubbard interaction for the same model. A sudden reduction of edge entanglement is obtained as interaction is switched on. The explanation for this lies in the change in the size of the degenerate subspaces in the presence and absence of interaction. We also study the signature of entanglement when the interaction strength becomes extremely strong and demonstrate that the edge entanglement remains protected. In this limit, the energy eigenstates essentially become a tensor product state, implying zero entanglement. However, a remnant entropy survives in the non-trivial topological phase which is exactly due to the entanglement of the edge modes.
format Preprint
id arxiv_https___arxiv_org_abs_2312_13598
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Entanglement of edge modes in (very) strongly correlated topological insulators
Ara, Nisa
Basu, Rudranil
Mathew, Emil
Raychowdhury, Indrakshi
Strongly Correlated Electrons
High Energy Physics - Theory
Quantum Physics
Identifying topological phases for a strongly correlated theory remains a non-trivial task, as defining order parameters, such as Berry phases, is not straightforward. Quantum information theory is capable of identifying topological phases for a theory that exhibits quantum phase transition with a suitable definition of order parameters that are related to different entanglement measures for the system. In this work, we study entanglement entropy for a bi-layer SSH model, both in the presence and absence of Hubbard interaction and at varying interaction strengths. For the free theory, edge entanglement acts as an order parameter, which is supported by analytic calculations and numerical (DMRG) studies. We calculate the symmetry-resolved entanglement and demonstrate the equipartition of entanglement for this model which itself acts as an order parameter when calculated for the edge modes. As the DMRG calculation allows one to go beyond the free theory, we study the entanglement structure of the edge modes in the presence of on-site Hubbard interaction for the same model. A sudden reduction of edge entanglement is obtained as interaction is switched on. The explanation for this lies in the change in the size of the degenerate subspaces in the presence and absence of interaction. We also study the signature of entanglement when the interaction strength becomes extremely strong and demonstrate that the edge entanglement remains protected. In this limit, the energy eigenstates essentially become a tensor product state, implying zero entanglement. However, a remnant entropy survives in the non-trivial topological phase which is exactly due to the entanglement of the edge modes.
title Entanglement of edge modes in (very) strongly correlated topological insulators
topic Strongly Correlated Electrons
High Energy Physics - Theory
Quantum Physics
url https://arxiv.org/abs/2312.13598