2 research outputs found
Anderson localization of a Bose-Einstein condensate in a 3D random potential
We study the effect of Anderson localization on the expansion of a
Bose-Einstein condensate, released from a harmonic trap, in a 3D random
potential. We use scaling arguments and the self-consistent theory of
localization to show that the long-time behavior of the condensate density is
controlled by a single parameter equal to the ratio of the mobility edge and
the chemical potential of the condensate. We find that the two critical
exponents of the localization transition determine the evolution of the
condensate density in time and space.Comment: 4 pages, 2 figure
Disorder-induced trapping versus Anderson localization in Bose-Einstein condensates expanding in disordered potentials
We theoretically investigate the localization of an expanding Bose-Einstein
condensate with repulsive atom-atom interactions in a disordered potential. We
focus on the regime where the initial inter-atomic interactions dominate over
the kinetic energy and the disorder. At equilibrium in a trapping potential and
for small disorder, the condensate shows a Thomas-Fermi shape modified by the
disorder. When the condensate is released from the trap, a strong suppression
of the expansion is obtained in contrast to the situation in a periodic
potential with similar characteristics. This effect crucially depends on both
the momentum distribution of the expanding BEC and the strength of the
disorder. For strong disorder, the suppression of the expansion results from
the fragmentation of the core of the condensate and from classical reflections
from large modulations of the disordered potential in the tails of the
condensate. We identify the corresponding disorder-induced trapping scenario
for which large atom-atom interactions and strong reflections from single
modulations of the disordered potential play central roles. For weak disorder,
the suppression of the expansion signals the onset of Anderson localization,
which is due to multiple scattering from the modulations of the disordered
potential. We compute analytically the localized density profile of the
condensate and show that the localization crucially depends on the correlation
function of the disorder. In particular, for speckle potentials the long-range
correlations induce an effective mobility edge in 1D finite systems. Numerical
calculations performed in the mean-field approximation support our analysis for
both strong and weak disorder.Comment: New Journal of Physics; focus issue "Quantum Correlations in Tailored
Matter - Common perspectives of mesoscopic systems and quantum gases"; 30
pages, 10 figure