Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions

By means of a trial wave function, the multi‐D1 ansatz, extensive variational calculations with more than 10 000 parameters are carried out to study quantum phase transitions in the ground states of a two‐impurity system embedded in a common Ohmic bath of bosons. Quantum criticality in both the impu...

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Main Authors: Zhou, Nengji, Zhang, Yuyu, Lü, Zhiguo, Zhao, Yang
Other Authors: School of Materials Science & Engineering
Format: Article
Language:English
Published: 2020
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Online Access:https://hdl.handle.net/10356/137030
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1370302023-07-14T15:47:00Z Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions Zhou, Nengji Zhang, Yuyu Lü, Zhiguo Zhao, Yang School of Materials Science & Engineering Engineering::Materials Quantum Phase Transitions Spin–boson Model By means of a trial wave function, the multi‐D1 ansatz, extensive variational calculations with more than 10 000 parameters are carried out to study quantum phase transitions in the ground states of a two‐impurity system embedded in a common Ohmic bath of bosons. Quantum criticality in both the impurity system and the Ohmic bosonic bath is investigated with relevant transition points and critical exponents determined accurately. With the linear grid of the Ohmic spectral density, numerical calculations herein produce a much better description of the ground states with lower energies than other calculations employing a logarithmic grid with a discretization factor far greater than unity. This offers a possible resolution to the considerable controversy on the critical coupling in the literature. Moreover, the ground‐state phase transition is inferred to be of first order in the presence of strong antiferromagnetic spin–spin coupling, at variance with that in the ferromagnetic regime or in the absence of spin–spin coupling where the transition belongs to the Kosterlitz–Thouless universality class. Accepted version 2020-02-13T05:25:57Z 2020-02-13T05:25:57Z 2018 Journal Article Zhou, N., Zhang, Y., Lü, Z., & Zhao, Y. (2018). Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions. Annalen Der Physik, 530(10), 1800120-. doi:10.1002/andp.201800120 0003-3804 https://hdl.handle.net/10356/137030 10.1002/andp.201800120 2-s2.0-85053479242 10 530 en Annalen Der Physik This is the peer reviewed version of the following article: Zhou, N., Zhang, Y., Lü, Z., & Zhao, Y. (2018). Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions. Annalen Der Physik, 530(10), 1800120-. doi:10.1002/andp.201800120, which has been published in final form at https://doi.org/10.1002/andp.201800120. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Materials
Quantum Phase Transitions
Spin–boson Model
spellingShingle Engineering::Materials
Quantum Phase Transitions
Spin–boson Model
Zhou, Nengji
Zhang, Yuyu
Lü, Zhiguo
Zhao, Yang
Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions
description By means of a trial wave function, the multi‐D1 ansatz, extensive variational calculations with more than 10 000 parameters are carried out to study quantum phase transitions in the ground states of a two‐impurity system embedded in a common Ohmic bath of bosons. Quantum criticality in both the impurity system and the Ohmic bosonic bath is investigated with relevant transition points and critical exponents determined accurately. With the linear grid of the Ohmic spectral density, numerical calculations herein produce a much better description of the ground states with lower energies than other calculations employing a logarithmic grid with a discretization factor far greater than unity. This offers a possible resolution to the considerable controversy on the critical coupling in the literature. Moreover, the ground‐state phase transition is inferred to be of first order in the presence of strong antiferromagnetic spin–spin coupling, at variance with that in the ferromagnetic regime or in the absence of spin–spin coupling where the transition belongs to the Kosterlitz–Thouless universality class.
author2 School of Materials Science & Engineering
author_facet School of Materials Science & Engineering
Zhou, Nengji
Zhang, Yuyu
Lü, Zhiguo
Zhao, Yang
format Article
author Zhou, Nengji
Zhang, Yuyu
Lü, Zhiguo
Zhao, Yang
author_sort Zhou, Nengji
title Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions
title_short Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions
title_full Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions
title_fullStr Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions
title_full_unstemmed Variational study of the two‐impurity spin–boson model with a common Ohmic bath : ground‐state phase transitions
title_sort variational study of the two‐impurity spin–boson model with a common ohmic bath : ground‐state phase transitions
publishDate 2020
url https://hdl.handle.net/10356/137030
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