Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice

Topological physics in optical lattices have attracted much attention in recent years. The nonlinear effects on such optical systems remain well-explored and a large amount of progress has been achieved. In this paper, under the mean-field approximation for a nonlinearly optical coupled boson–hexago...

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Main Authors: Fude Li, Kang Xue, Xuexi Yi
Format: Article
Language:English
Published: MDPI AG 2021-10-01
Series:Entropy
Subjects:
Online Access:https://www.mdpi.com/1099-4300/23/11/1404
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author Fude Li
Kang Xue
Xuexi Yi
author_facet Fude Li
Kang Xue
Xuexi Yi
author_sort Fude Li
collection DOAJ
description Topological physics in optical lattices have attracted much attention in recent years. The nonlinear effects on such optical systems remain well-explored and a large amount of progress has been achieved. In this paper, under the mean-field approximation for a nonlinearly optical coupled boson–hexagonal lattice system, we calculate the nonlinear Dirac cone and discuss its dependence on the parameters of the system. Due to the special structure of the cone, the Berry phase (two-dimensional Zak phase) acquired around these Dirac cones is quantized, and the critical value can be modulated by interactions between different lattices sites. We numerically calculate the overall Aharonov-Bohm (AB) phase and find that it is also quantized, which provides a possible topological number by which we can characterize the quantum phases. Furthermore, we find that topological phase transition occurs when the band gap closes at the nonlinear Dirac points. This is different from linear systems, in which the transition happens when the band gap closes and reopens at the Dirac points.
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spelling doaj.art-52eaee0d818f41eb9808f30126e9fe2a2023-11-22T23:14:29ZengMDPI AGEntropy1099-43002021-10-012311140410.3390/e23111404Nonlinear Topological Effects in Optical Coupled Hexagonal LatticeFude Li0Kang Xue1Xuexi Yi2Center for Quantum Sciences and School of Physics, Northeast Normal University, Renmin Street 5268, Changchun 130024, ChinaCenter for Quantum Sciences and School of Physics, Northeast Normal University, Renmin Street 5268, Changchun 130024, ChinaCenter for Quantum Sciences and School of Physics, Northeast Normal University, Renmin Street 5268, Changchun 130024, ChinaTopological physics in optical lattices have attracted much attention in recent years. The nonlinear effects on such optical systems remain well-explored and a large amount of progress has been achieved. In this paper, under the mean-field approximation for a nonlinearly optical coupled boson–hexagonal lattice system, we calculate the nonlinear Dirac cone and discuss its dependence on the parameters of the system. Due to the special structure of the cone, the Berry phase (two-dimensional Zak phase) acquired around these Dirac cones is quantized, and the critical value can be modulated by interactions between different lattices sites. We numerically calculate the overall Aharonov-Bohm (AB) phase and find that it is also quantized, which provides a possible topological number by which we can characterize the quantum phases. Furthermore, we find that topological phase transition occurs when the band gap closes at the nonlinear Dirac points. This is different from linear systems, in which the transition happens when the band gap closes and reopens at the Dirac points.https://www.mdpi.com/1099-4300/23/11/1404nonlinear energy bandnonlinear Berry phasetopological phase transition
spellingShingle Fude Li
Kang Xue
Xuexi Yi
Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice
Entropy
nonlinear energy band
nonlinear Berry phase
topological phase transition
title Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice
title_full Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice
title_fullStr Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice
title_full_unstemmed Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice
title_short Nonlinear Topological Effects in Optical Coupled Hexagonal Lattice
title_sort nonlinear topological effects in optical coupled hexagonal lattice
topic nonlinear energy band
nonlinear Berry phase
topological phase transition
url https://www.mdpi.com/1099-4300/23/11/1404
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AT kangxue nonlineartopologicaleffectsinopticalcoupledhexagonallattice
AT xuexiyi nonlineartopologicaleffectsinopticalcoupledhexagonallattice