Temat: 67.90.+z - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Low Energy Excitation Spectra of Trapped Bose Condensates
Autorzy:: You, L.
Hoston, W.
Lewenstein, M.
Marinescu, M.
Powiązania:: https://bibliotekanauki.pl/articles/1968542.pdf
Data publikacji:: 1998-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 03.75.Fi
67.90.+z
Opis:: We discuss our numerical studies of the low energy excitations of trapped Bose condensates using a Bogoliubov-Hartree treatment. In the zero temperature limit, the lowest few excitation frequencies calculated within the Bogoliubov approximation agree well with the experimental data. Finite temperature results obtained using the Popov approximation display qualitative differences from the experimental data close to the critical temperature region. Details of our numerical approach are presented and comparison with other results is discussed.
Źródło:: Acta Physica Polonica A; 1998, 93, 1; 211-235
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Phase Transitions of Bosons in Optical Lattices with a Mixture of Single and Pair Hoppings
Autorzy:: Travin, V.
Kopeć, T.
Powiązania:: https://bibliotekanauki.pl/articles/1398644.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 67.10.Fj
67.85.Hj
67.90.+z
Opis:: We considered Bose condensate in optical lattice with mixture of single and pair hoppings for arbitrary temperatures. In order to calculate free energy of the system and determine phase transition lines between disordered and ordered phases, the Laplace transform method has been applied. We identified several possible scenarios for phase diagrams with phase transitions of the second kind. The results have been obtained from both analytical and numerical methods of calculation. Finally, we obtained thermal insensitivity of the system for big values of reduced pair hopping and (or) reduced chemical potential.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 625-628
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Trapped Bose-einstein Condensates at Finite Temperature: a Two-gas Model
Autorzy:: Dodd, R. J.
Burnett, K.
Edwards, M.
Clark, Ch. W.
Powiązania:: https://bibliotekanauki.pl/articles/1968506.pdf
Data publikacji:: 1998-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 03.75.Fi
67.40.Db
67.90.+z
Opis:: A simple picture describes the results of recent treatments of partially-condensed, dilute, trapped Bose gases at temperature T>0. The condensate wave function is nearly identical to that of a T=0 condensate with the same number of condensate atoms, N$\text{}_{0}$. The cloud of non-condensed atoms is described by the statistical mechanics of an ideal Bose gas in the combined potentials of the magnetic trap and the cloud-condensate interaction. We provide a physical motivation for this result, show how it emerges in the Hartree-Fock-Bogoliubov-Popov approximation, and explore some of its implications for future experiments.
Źródło:: Acta Physica Polonica A; 1998, 93, 1; 45-53
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Characterization of Nitride Thin Films Using SEM and EDX
Autorzy:: Mammeri, F.
Chekour, L.
Rouag, N.
Powiązania:: https://bibliotekanauki.pl/articles/1399799.pdf
Data publikacji:: 2013-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 67.25.dp
68.55.J-
81.15.-z
68.37.Hk
68.90.+g
Opis:: The chromium nitride thin films have became more and more popular in the last years because of their very good physical, chemical and mechanical properties. The present study relates to thermal stability of hard thin films of chromium nitride CrN, carried out physical vapour deposition. We studied the influence of the annealing temperature on the morphology of CrN films, deposited on silicon substrate using magnetron sputtering. The characterizations are examined using scanning electron microscope equipped with energy dispersive X-ray spectroscopy. Annealing treatments in $N_2$ at 600-1000C for 1 h are performed on CrN coating samples for 530 nm thickness. At low temperature, the results show a thermal stability of these coatings. The $Cr_2O_3$ phase is completely replaced by the CrN phase at temperature above 1000°C. The results given by scanning electron microscopy-energy dispersive X-ray spectroscopy and X-ray diffraction are compared.
Źródło:: Acta Physica Polonica A; 2013, 123, 2; 294-295
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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