Excitation spectrum in two-dimensional superfluid ⁴He
In this work we perform an ab-initio study of an ideal two-dimensional sample of ⁴He atoms, a model for ⁴He films adsorbed on several kinds of substrates. Starting from a realistic hamiltonian we face the microscopic study of the excitation phonon–roton spectrum of the system at zero temperature...
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| Опубліковано в: : | Физика низких температур |
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| Дата: | 2013 |
| Автори: | , , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2013
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| Онлайн доступ: | https://nasplib.isofts.kiev.ua/handle/123456789/118751 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Excitation spectrum in two-dimensional superfluid ⁴He / F. Arrigoni, E. Vitali, D.E. Galli, L. Reatto// Физика низких температур. — 2013. — Т. 39, № 9. — С. 1021–1030. — Бібліогр.: 37 назв. — англ. |
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Arrigoni, F. Vitali, E. Galli, D.E. Reatto, L. 2017-05-31T06:31:49Z 2017-05-31T06:31:49Z 2013 Excitation spectrum in two-dimensional superfluid ⁴He / F. Arrigoni, E. Vitali, D.E. Galli, L. Reatto// Физика низких температур. — 2013. — Т. 39, № 9. — С. 1021–1030. — Бібліогр.: 37 назв. — англ. 0132-6414 PACS: 67.25.bh,67.25.dt https://nasplib.isofts.kiev.ua/handle/123456789/118751 In this work we perform an ab-initio study of an ideal two-dimensional sample of ⁴He atoms, a model for ⁴He films adsorbed on several kinds of substrates. Starting from a realistic hamiltonian we face the microscopic study of the excitation phonon–roton spectrum of the system at zero temperature. Our approach relies on path integral ground state Monte Carlo projection methods, allowing to evaluate exactly the dynamical density correlation functions in imaginary time, and this gives access to the dynamical structure factor of the system S(q, ), containing information about the excitation spectrum E(q), resulting in sharp peaks in S(q, ). The actual evaluation of S(q, ) requires the inversion of the Laplace transform in ill-posed conditions, which we face via the genetic inversion via falsification of theories technique. We explore the full density range from the region of spinodal decomposition to the freezing density, i.e., 0.0321 Å⁻² – 0.0658 Å⁻². In particular we follow the density dependence of the excitation spectrum, focusing on the low-wave vector behavior of E(q), the roton dispersion, the strength of single quasiparticle peak, Z(q), and the static density response function, (q). As the density increases, the dispersion E(q) at low-wave vector changes from a superlinear (anomalous dispersion) trend to a sublinear (normal dispersion) one, anticipating the crystallization of the system; at the same time the maxon–roton structure, which is barely visible at low density, becomes well developed at high densities and the roton wave vector has a strong density dependence. Connection is made with recent inelastic neutron scattering results from highly ordered silica nanopores partially filled with ⁴He. en Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України Физика низких температур Сверхтекучесть в низкоразмерных системах и в условиях ограниченной геометрии Excitation spectrum in two-dimensional superfluid ⁴He Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Excitation spectrum in two-dimensional superfluid ⁴He |
| spellingShingle |
Excitation spectrum in two-dimensional superfluid ⁴He Arrigoni, F. Vitali, E. Galli, D.E. Reatto, L. Сверхтекучесть в низкоразмерных системах и в условиях ограниченной геометрии |
| title_short |
Excitation spectrum in two-dimensional superfluid ⁴He |
| title_full |
Excitation spectrum in two-dimensional superfluid ⁴He |
| title_fullStr |
Excitation spectrum in two-dimensional superfluid ⁴He |
| title_full_unstemmed |
Excitation spectrum in two-dimensional superfluid ⁴He |
| title_sort |
excitation spectrum in two-dimensional superfluid ⁴he |
| author |
Arrigoni, F. Vitali, E. Galli, D.E. Reatto, L. |
| author_facet |
Arrigoni, F. Vitali, E. Galli, D.E. Reatto, L. |
| topic |
Сверхтекучесть в низкоразмерных системах и в условиях ограниченной геометрии |
| topic_facet |
Сверхтекучесть в низкоразмерных системах и в условиях ограниченной геометрии |
| publishDate |
2013 |
| language |
English |
| container_title |
Физика низких температур |
| publisher |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
| format |
Article |
| description |
In this work we perform an ab-initio study of an ideal two-dimensional sample of
⁴He atoms, a model for
⁴He
films adsorbed on several kinds of substrates. Starting from a realistic hamiltonian we face the microscopic study
of the excitation phonon–roton spectrum of the system at zero temperature. Our approach relies on path integral
ground state Monte Carlo projection methods, allowing to evaluate exactly the dynamical density correlation
functions in imaginary time, and this gives access to the dynamical structure factor of the system S(q, ), containing
information about the excitation spectrum E(q), resulting in sharp peaks in S(q, ). The actual evaluation of
S(q, ) requires the inversion of the Laplace transform in ill-posed conditions, which we face via the genetic inversion
via falsification of theories technique. We explore the full density range from the region of spinodal decomposition
to the freezing density, i.e., 0.0321 Å⁻²
– 0.0658 Å⁻². In particular we follow the density dependence
of the excitation spectrum, focusing on the low-wave vector behavior of E(q), the roton dispersion, the strength
of single quasiparticle peak, Z(q), and the static density response function, (q). As the density increases, the
dispersion E(q) at low-wave vector changes from a superlinear (anomalous dispersion) trend to a sublinear (normal
dispersion) one, anticipating the crystallization of the system; at the same time the maxon–roton structure,
which is barely visible at low density, becomes well developed at high densities and the roton wave vector has a
strong density dependence. Connection is made with recent inelastic neutron scattering results from highly ordered
silica nanopores partially filled with
⁴He.
|
| issn |
0132-6414 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/118751 |
| citation_txt |
Excitation spectrum in two-dimensional superfluid ⁴He / F. Arrigoni, E. Vitali, D.E. Galli, L. Reatto// Физика низких температур. — 2013. — Т. 39, № 9. — С. 1021–1030. — Бібліогр.: 37 назв. — англ. |
| work_keys_str_mv |
AT arrigonif excitationspectrumintwodimensionalsuperfluid4he AT vitalie excitationspectrumintwodimensionalsuperfluid4he AT gallide excitationspectrumintwodimensionalsuperfluid4he AT reattol excitationspectrumintwodimensionalsuperfluid4he |
| first_indexed |
2025-12-07T18:56:29Z |
| last_indexed |
2025-12-07T18:56:29Z |
| _version_ |
1850876928858259456 |