Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region

The properties of the translationally invariant polaron functional have been investigated in the strong- and extremely-strong-coupling regimes. It has been shown that the Gross–Tulub polaron functional obtained earlier using field-theoretic methods was derived only for the region α ≤ 10, where α is...

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Veröffentlicht in:Semiconductor Physics Quantum Electronics & Optoelectronics
Datum:2017
1. Verfasser: Kashirina, N.I.
Format: Artikel
Sprache:Englisch
Veröffentlicht: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2017
Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/214998
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Zitieren:Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region / N.I. Kashirina // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2017. — Т. 20, № 4. — С. 430-436. — Бібліогр.: 21 назв. — англ.

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author Kashirina, N.I.
author_facet Kashirina, N.I.
citation_txt Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region / N.I. Kashirina // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2017. — Т. 20, № 4. — С. 430-436. — Бібліогр.: 21 назв. — англ.
collection DSpace DC
container_title Semiconductor Physics Quantum Electronics & Optoelectronics
description The properties of the translationally invariant polaron functional have been investigated in the strong- and extremely-strong-coupling regimes. It has been shown that the Gross–Tulub polaron functional obtained earlier using field-theoretic methods was derived only for the region α ≤ 10, where α is the Fröhlich constant of the electron-phonon coupling. Various representations of exact and approximate polaron functionals have been considered. Asymptotic dependences of the polaron energy have been obtained using a functional extending the Gross–Tulub functional to the region of extremely strong coupling. The asymptotic dependence of polaron energies for an extremely strong coupling is Ep ≈ −0.31683α⁴/ ³ (for the one-parameter variational function fₖ), and Ep ≈ −0.31767α⁴/ ³ (for a two-parameter function f′ₖ ). It has been shown that the virial theorem 1:3:4 holds for the two-parameter function f′ₖ. Minimization of the approximate functional obtained by expanding the exact Gross–Tulub functional in a series on 1/α leads to a quadratic dependence of the polaron energy. This approximation is justified for α ≈ 7.5...8 . For a two-parameter function f′ₖ, the corresponding dependence has the form Ep ≈ −0.125α². However, the use of approximate functionals, in contrast to the strict variational procedure, when the exact polaron functional varies, does not guarantee obtaining the upper limit for the polaron energy.
first_indexed 2026-03-21T04:33:54Z
format Article
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id nasplib_isofts_kiev_ua-123456789-214998
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
issn 1560-8034
language English
last_indexed 2026-03-21T04:33:54Z
publishDate 2017
publisher Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
record_format dspace
spelling Kashirina, N.I.
2026-03-06T09:54:43Z
2017
Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region / N.I. Kashirina // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2017. — Т. 20, № 4. — С. 430-436. — Бібліогр.: 21 назв. — англ.
1560-8034
PACS: 71.38, 71.38.-k, 74.20.-z, 74.72-h
https://nasplib.isofts.kiev.ua/handle/123456789/214998
https://doi.org/10.15407/spqeo20.04.430
The properties of the translationally invariant polaron functional have been investigated in the strong- and extremely-strong-coupling regimes. It has been shown that the Gross–Tulub polaron functional obtained earlier using field-theoretic methods was derived only for the region α ≤ 10, where α is the Fröhlich constant of the electron-phonon coupling. Various representations of exact and approximate polaron functionals have been considered. Asymptotic dependences of the polaron energy have been obtained using a functional extending the Gross–Tulub functional to the region of extremely strong coupling. The asymptotic dependence of polaron energies for an extremely strong coupling is Ep ≈ −0.31683α⁴/ ³ (for the one-parameter variational function fₖ), and Ep ≈ −0.31767α⁴/ ³ (for a two-parameter function f′ₖ ). It has been shown that the virial theorem 1:3:4 holds for the two-parameter function f′ₖ. Minimization of the approximate functional obtained by expanding the exact Gross–Tulub functional in a series on 1/α leads to a quadratic dependence of the polaron energy. This approximation is justified for α ≈ 7.5...8 . For a two-parameter function f′ₖ, the corresponding dependence has the form Ep ≈ −0.125α². However, the use of approximate functionals, in contrast to the strict variational procedure, when the exact polaron functional varies, does not guarantee obtaining the upper limit for the polaron energy.
en
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
Semiconductor Physics Quantum Electronics & Optoelectronics
Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region
Article
published earlier
spellingShingle Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region
Kashirina, N.I.
title Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region
title_full Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region
title_fullStr Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region
title_full_unstemmed Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region
title_short Asymptotic dependence of Gross–Tulub polaron ground-state energy in the strong coupling region
title_sort asymptotic dependence of gross–tulub polaron ground-state energy in the strong coupling region
url https://nasplib.isofts.kiev.ua/handle/123456789/214998
work_keys_str_mv AT kashirinani asymptoticdependenceofgrosstulubpolarongroundstateenergyinthestrongcouplingregion