78 research outputs found
A grand-canonical approach to the disordered Bose gas
We study the problem of disordered interacting bosons within grand-canonical
thermodynamics and Bogoliubov theory. We compute the fractions of condensed and
non-condensed particles and corrections to the compressibility and the speed of
sound due to interaction and disorder. There are two small parameters, the
disorder strength compared to the chemical potential and the dilute-gas
parameter.Comment: 9 pages, 3 figure
Disorder and interference: localization phenomena
The specific problem we address in these lectures is the problem of transport
and localization in disordered systems, when interference is present, as
characteristic for waves, with a focus on realizations with ultracold atoms.Comment: Notes of a lecture delivered at the Les Houches School of Physics on
"Ultracold gases and quantum information" 2009 in Singapore. v3: corrected
mistakes, improved script for numerics, Chapter 9 in "Les Houches 2009 -
Session XCI: Ultracold Gases and Quantum Information" edited by C. Miniatura
et al. (Oxford University Press, 2011
Bogoliubov theory on the disordered lattice
Quantum fluctuations of Bose-Einstein condensates trapped in disordered
lattices are studied by inhomogeneous Bogoliubov theory. Weak-disorder
perturbation theory is applied to compute the elastic scattering rate as well
as the renormalized speed of sound in lattices of arbitrary dimensionality.
Furthermore, analytical results for the condensate depletion are presented,
which are in good agreement with numerical data.Comment: 10 pages, contributed to Lyon BEC 201
Anderson localization of Bogoliubov excitations on quasi-1D strips
Anderson localization of Bogoliubov excitations is studied for disordered
lattice Bose gases in planar quasi-one-dimensional geometries. The inverse
localization length is computed as function of energy by a numerical
transfer-matrix scheme, for strips of different widths. These results are
described accurately by analytical formulas based on a weak-disorder expansion
of backscattering mean free paths.Comment: 4 pages, 2 figure
- …