On the Spectra of Real and Complex Lamé Operators

We study Lamé operators of the form
 L=−d²/dx²+m(m+1)ω²℘(ωx+z₀),
 with m∈N and ω a half-period of ℘(z). For rectangular period lattices, we can choose ω and z0 such that the potential is real, periodic and regular. It is known after Ince that the spectrum of the corresponding Lamé...

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Veröffentlicht in:Symmetry, Integrability and Geometry: Methods and Applications
Datum:2017
Hauptverfasser: Haese-Hill, W.A., Hallnäs, M.A., Veselov, A.P.
Format: Artikel
Sprache:Englisch
Veröffentlicht: Інститут математики НАН України 2017
Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/148577
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Zitieren:On the Spectra of Real and Complex Lamé Operators
 / W.A. Haese-Hill, M.A. Hallnäs, A.P. Veselov // Symmetry, Integrability and Geometry: Methods and Applications. — 2017. — Т. 13. — Бібліогр.: 32 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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author Haese-Hill, W.A.
Hallnäs, M.A.
Veselov, A.P.
author_facet Haese-Hill, W.A.
Hallnäs, M.A.
Veselov, A.P.
citation_txt On the Spectra of Real and Complex Lamé Operators
 / W.A. Haese-Hill, M.A. Hallnäs, A.P. Veselov // Symmetry, Integrability and Geometry: Methods and Applications. — 2017. — Т. 13. — Бібліогр.: 32 назв. — англ.
collection DSpace DC
container_title Symmetry, Integrability and Geometry: Methods and Applications
description We study Lamé operators of the form
 L=−d²/dx²+m(m+1)ω²℘(ωx+z₀),
 with m∈N and ω a half-period of ℘(z). For rectangular period lattices, we can choose ω and z0 such that the potential is real, periodic and regular. It is known after Ince that the spectrum of the corresponding Lamé operator has a band structure with not more than m gaps. In the first part of the paper, we prove that the opened gaps are precisely the first m ones. In the second part, we study the Lamé spectrum for a generic period lattice when the potential is complex-valued. We concentrate on the m=1 case, when the spectrum consists of two regular analytic arcs, one of which extends to infinity, and briefly discuss the m=2 case, paying particular attention to the rhombic lattices.
first_indexed 2025-12-07T17:49:29Z
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institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
issn 1815-0659
language English
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publishDate 2017
publisher Інститут математики НАН України
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spelling Haese-Hill, W.A.
Hallnäs, M.A.
Veselov, A.P.
2019-02-18T16:10:46Z
2019-02-18T16:10:46Z
2017
On the Spectra of Real and Complex Lamé Operators
 / W.A. Haese-Hill, M.A. Hallnäs, A.P. Veselov // Symmetry, Integrability and Geometry: Methods and Applications. — 2017. — Т. 13. — Бібліогр.: 32 назв. — англ.
1815-0659
2010 Mathematics Subject Classification: 34L40; 47A10; 33E10
DOI:10.3842/SIGMA.2017.049
https://nasplib.isofts.kiev.ua/handle/123456789/148577
We study Lamé operators of the form
 L=−d²/dx²+m(m+1)ω²℘(ωx+z₀),
 with m∈N and ω a half-period of ℘(z). For rectangular period lattices, we can choose ω and z0 such that the potential is real, periodic and regular. It is known after Ince that the spectrum of the corresponding Lamé operator has a band structure with not more than m gaps. In the first part of the paper, we prove that the opened gaps are precisely the first m ones. In the second part, we study the Lamé spectrum for a generic period lattice when the potential is complex-valued. We concentrate on the m=1 case, when the spectrum consists of two regular analytic arcs, one of which extends to infinity, and briefly discuss the m=2 case, paying particular attention to the rhombic lattices.
We are grateful to Jenya Ferapontov, John Gibbons and Anton Zabrodin for very useful and
 encouraging discussions, and especially to Boris Dubrovin, who many years ago asked one of
 us (APV) about the position of open gaps in the spectra of Lam´e operators. We would like
 to thank Professor Gesztesy for his interest in our work and for pointing out further relevant
 references, including [1] and [9]. The work of WAH was partially supported by the Department
 of Mathematical Sciences at Loughborough University as part of his PhD studies.
en
Інститут математики НАН України
Symmetry, Integrability and Geometry: Methods and Applications
On the Spectra of Real and Complex Lamé Operators
Article
published earlier
spellingShingle On the Spectra of Real and Complex Lamé Operators
Haese-Hill, W.A.
Hallnäs, M.A.
Veselov, A.P.
title On the Spectra of Real and Complex Lamé Operators
title_full On the Spectra of Real and Complex Lamé Operators
title_fullStr On the Spectra of Real and Complex Lamé Operators
title_full_unstemmed On the Spectra of Real and Complex Lamé Operators
title_short On the Spectra of Real and Complex Lamé Operators
title_sort on the spectra of real and complex lamé operators
url https://nasplib.isofts.kiev.ua/handle/123456789/148577
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AT veselovap onthespectraofrealandcomplexlameoperators