Abstract
We examine bosons hopping on a one-dimensional lattice in the presence of a random potential at zero temperature. Bogoliubov excitations of the Bose-Einstein condensate formed under such conditions are localized, with the localization length diverging at low frequency as . We show that the well-known result applies only for sufficiently weak random potential. As the random potential is increased beyond a certain strength, starts decreasing. At a critical strength of the potential, when the system of bosons is at the transition from a superfluid to an insulator, . This result is relevant for understanding the behavior of the atomic Bose-Einstein condensates in the presence of random potential, and of the disordered Josephson junction arrays.
- Received 30 June 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.170407
©2008 American Physical Society