Vovk, R. V. Dobrovolskiy, O. V. Nazyrov, Z. F. Kotvitskaya, K. A. Chroneos, A.
Published in
Journal of Low Temperature Physics

We report the results of a study of the effect of structural relaxation on the basal-plane conductivity of heavily underdoped high-Tc\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begi...

Zamora-Zamora, R. Adame-Arana, O. Romero-Rochin, V.
Published in
Journal of Low Temperature Physics

We present a survey of macroscopic excitations of harmonically confined Bose–Einstein condensates (BEC), described by Gross–Pitaevskii (GP) equation, in search of routes to develop quantum turbulence. These excitations can all be created by phase-imprinting techniques on an otherwise equilibrium BEC. We analyze two crossed vortices, two parallel an...

Poluektov, Yu. M. Savchenko, V. M.
Published in
Journal of Low Temperature Physics

Magnetic transitions and Bose–Einstein condensation (BEC) are studied in a self-consistent field model, analogous to the model of a molecular field in the theory of ferromagnetism. It is shown that the present model is internally consistent and suitable for description at any value of a dimensionless parameter characterizing the system. Different p...

Maqbool, Muhammad Main, Kyle Ahmad, Iftikhar
Published in
Journal of Low Temperature Physics

Thin films of AlN doped with Titanium are deposited on Si(100) and Si(111) substrates and optical fibers at liquid nitrogen temperature by rf-magnetron sputtering. Thickness of the films is 400 nm on both silicon substrates and optical fibers. X-ray diffraction studies show that films deposited on both Si(100) and Si(111) substrate are amorphous, a...

Ivanov, Peter A.
Published in
Journal of Low Temperature Physics

We discuss analytical approximations to the ground-state phase diagram and the collective low-energy excitations of the cooperative Jahn–Teller model describing a strongly correlated spin-boson system on a lattice in various quantum optical systems. Based on the mean-field theory approach, we show that the system exhibits a quantum magnetic structu...

Bahrami, A. Tavares, P. E. S. Fritsch, A. R. Tonin, Y. R. Telles, G. D. Bagnato, V. S. Henn, E. A. L.
Published in
Journal of Low Temperature Physics

We investigate the momentum distribution of a Bose–Einstein condensate (BEC) under the effect of an external small oscillatory perturbation. The condensate is perturbed, and we let it evolve in-trap after which we perform standard time-of-flight absorption imaging. The momentum distribution is extracted and analyzed as a function of the in-trap fre...

Fetter, Alexander L.
Published in
Journal of Low Temperature Physics

Vortices in a one-component dilute atomic ultracold Bose–Einstein condensate (BEC) usually arise as a response to externally driven rotation. Apart from a few special situations, these vortices are singly quantized with unit circulation (Fetter, Rev Mod Phys 81, 647–691, 2009). Recently, the NIST group has constructed a two-component BEC with a spi...

Hou, Long Yang, Weiming Liu, Haishun Huo, Juntao Jiao, Yang Liu, Qingling
Published in
Journal of Low Temperature Physics

Low temperature specific heats of Fe50\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{50}$$\end{document}Co50\documentclass[12pt]{minimal} \usepackage{amsmath} \usepa...

Kandemir, B. S. Aydin, Emine
Published in
Journal of Low Temperature Physics

We calculate the phonon spectra of chiral single-walled carbon nanotubes and graphene within a mass and spring model which includes up to third neighbour interactions together with a radial bond-bending interaction. Firstly, the classical Hamiltonian for lattice vibrations of chiral single-walled carbon nanotubes is derived and then it is quantized...

Yukalov, V. I. Novikov, A. N. Bagnato, V. S.
Published in
Journal of Low Temperature Physics

A trapped Bose–Einstein condensate, being strongly perturbed, exhibits several spatial structures. First, there appear quantum vortices. Increasing the amount of the injected energy leads to the formation of vortex tangles representing quantum vortex turbulence. Continuing energy injection makes the system so strongly perturbed that vortices become...