We investigate the stability of an attractive Bose-Einstein condensate in a one-dimensional lattice in the presence of radial confinement. We find that the system is dynamically unstable for low quasimomenta and becomes stable near the band edge, in a specular fashion with respect to the repulsive case. For low interactions the instability occurs via long-wavelength excitations that produce an oscillating density pattern in both real and momentum space instead of spoiling the condensate coherence. This behavior is illustrated by simulations for the expansion of the condensate in a moving lattice.
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 16 Oct 2007|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physics and Astronomy(all)