Abstract
We investigate the propagation of density-wave packets in a Bose-Hubbard model using the adaptive time-dependent density-matrix renormalization group method. We discuss the decay of the amplitude with time and the dependence of the velocity on density, interaction strength, and the height of the perturbation in a numerically exact way, covering arbitrary interactions and amplitudes of the perturbation. In addition, we investigate the effect of self-steepening due to the amplitude dependence of the velocity and discuss the possibilities for an experimental detection of the moving wave packet in time-of-flight pictures. By comparing the sound velocity to theoretical predictions, we determine the limits of a Gross-Pitaevskii- or Bogoliubov-type description and the regime where repulsive one-dimensional Bose gases exhibit fermionic behavior.
1 More- Received 16 November 2004
DOI:https://doi.org/10.1103/PhysRevA.71.053606
©2005 American Physical Society