https://doi.org/10.1140/epjb/e2009-00055-1
Ultracold bosons with 3-body attractive interactions in an optical lattice
1
International School for Advanced Studies, Via Beirut 2/4, Trieste, 34014, Italy
2
Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Italy
3
Department of Physical Electronics, School of Electrical Engineering,
Faculty of Engineering, Tel Aviv University, Tel Aviv, 69978, Israel
4
Abdus Salam International Centre of Theoretical Physics, Strada Costiera 11, Trieste, 34014, Italy
Corresponding author: a fersino@sissa.it
Received:
31
July
2008
Revised:
21
December
2008
Published online:
18
February
2009
We study the effect of an optical lattice (OL) on the ground-state properties of one-dimensional ultracold bosons with three-body attractive interactions and two-body repulsive interactions, which are described by a cubic-quintic Gross-Pitaevskii equation with a periodic potential. Without the optical lattice and with a vanishing two-body interaction term, normalizable soliton solutions of the Townes type are possible only at a critical value of the interaction strength, at which an infinite degeneracy of the ground state occurs; a repulsive two-body interaction makes such localized solutions unstable. We show that the OL opens a stability window around the critical point when the strength of the periodic potential is above a critical threshold. We also consider the effect of an external parabolic trap, studying how the stability properties depend on the matching between minima of the periodic potential and the minimum of the parabolic trap.
PACS: 03.75.-b – Matter waves / 67.85.-d – Ultracold gases, trapped gases
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009