The dispersion relation of a dark soliton

The energy-velocity relation of a dark soliton is usually derived by its exact solution, which has been used to explain the kinetic motion of the dark soliton widely in many-body physical systems. We perform a variational method to re-derive the dispersion relation, with the consideration that the n...

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Main Authors: Ling-Zheng Meng, Ning Mao, Li-Chen Zhao
Format: Article
Language:English
Published: IOP Publishing 2023-01-01
Series:New Journal of Physics
Subjects:
Online Access:https://doi.org/10.1088/1367-2630/accb04
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author Ling-Zheng Meng
Ning Mao
Li-Chen Zhao
author_facet Ling-Zheng Meng
Ning Mao
Li-Chen Zhao
author_sort Ling-Zheng Meng
collection DOAJ
description The energy-velocity relation of a dark soliton is usually derived by its exact solution, which has been used to explain the kinetic motion of the dark soliton widely in many-body physical systems. We perform a variational method to re-derive the dispersion relation, with the consideration that the number of particles of the dark soliton could be conserved. The re-derived dispersion relation is completely different from that given by the exact dark soliton solution. The validity of these two dispersion relations is tested by observing the motion of the dark soliton when we drive impurity atoms that coupled with the soliton. The results suggest that the dispersion relation given by the exact solution usually works better than the one with particle number conservation. This motivates us to reveal that density waves (carrying particle transport) are generated during the acceleration process of a dark soliton, in addition to the previously known sound waves (only carrying energy transport). We further show that the density wave emissions of dark solitons can be inhibited by increasing the impurity atom number, which is trapped by the dark soliton through nonlinear coupling. The discussion is meaningful for investigating and understanding the kinetic motion of dark solitons in many different circumstances.
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spelling doaj.art-db85b6743dee4f9b8cbbf135d97258962023-08-09T14:12:41ZengIOP PublishingNew Journal of Physics1367-26302023-01-0125404301510.1088/1367-2630/accb04The dispersion relation of a dark solitonLing-Zheng Meng0https://orcid.org/0000-0001-6261-3601Ning Mao1Li-Chen Zhao2School of Physics, Northwest University , Xi’an 710127, People’s Republic of ChinaSchool of Physics, Northwest University , Xi’an 710127, People’s Republic of ChinaSchool of Physics, Northwest University , Xi’an 710127, People’s Republic of China; Peng Huanwu Center for Fundamental Theory , Xian 710127, People’s Republic of China; Shaanxi Key Laboratory for Theoretical Physics Frontiers , Xi’an 710127, People’s Republic of ChinaThe energy-velocity relation of a dark soliton is usually derived by its exact solution, which has been used to explain the kinetic motion of the dark soliton widely in many-body physical systems. We perform a variational method to re-derive the dispersion relation, with the consideration that the number of particles of the dark soliton could be conserved. The re-derived dispersion relation is completely different from that given by the exact dark soliton solution. The validity of these two dispersion relations is tested by observing the motion of the dark soliton when we drive impurity atoms that coupled with the soliton. The results suggest that the dispersion relation given by the exact solution usually works better than the one with particle number conservation. This motivates us to reveal that density waves (carrying particle transport) are generated during the acceleration process of a dark soliton, in addition to the previously known sound waves (only carrying energy transport). We further show that the density wave emissions of dark solitons can be inhibited by increasing the impurity atom number, which is trapped by the dark soliton through nonlinear coupling. The discussion is meaningful for investigating and understanding the kinetic motion of dark solitons in many different circumstances.https://doi.org/10.1088/1367-2630/accb04dark solitondispersion relationeffective masssound wave
spellingShingle Ling-Zheng Meng
Ning Mao
Li-Chen Zhao
The dispersion relation of a dark soliton
New Journal of Physics
dark soliton
dispersion relation
effective mass
sound wave
title The dispersion relation of a dark soliton
title_full The dispersion relation of a dark soliton
title_fullStr The dispersion relation of a dark soliton
title_full_unstemmed The dispersion relation of a dark soliton
title_short The dispersion relation of a dark soliton
title_sort dispersion relation of a dark soliton
topic dark soliton
dispersion relation
effective mass
sound wave
url https://doi.org/10.1088/1367-2630/accb04
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