Partially incoherent gap solitons in Bose-Einstein condensates

Abstract

We construct families of incoherent matter-wave solitons in a repulsive degenerate Bose gas trapped in an optical lattice (OL), i.e., gap solitons, and investigate their stability at zero and finite temperature, using the Hartree-Fock-Bogoliubov equations. The gap solitons are composed of a coherent condensate, and normal and anomalous densities of incoherent vapor co-trapped with the condensate. Both intragap and intergap solitons are constructed, with chemical potentials of the components falling in one or different bandgaps in the OL-induced spectrum. Solitons change gradually with temperature. Families of intragap solitons are completely stable (both in direct simulations, and in terms of eigenvalues of perturbation modes), while the intergap family may have a very small unstable eigenvalue (nevertheless, they feature no instability in direct simulations). Stable higher-order (multi-humped) solitons, and bound complexes of fundamental solitons are found too.

8 pages, 9 figures. Physical Review A, in press

References in corpus (6)

• Formation of bright matter-wave solitons during the collapse of Bose-Einstein condensates
• Bifurcations and stability of gap solitons in periodic potentials
• Deviation from one-dimensionality in stationary properties and collisional dynamics of matter-wave solitons
• Multi-gap discrete vector solitons
• Friction and diffusion of matter-wave bright solitons
• Beyond Mean-Field Theory for Attractive Bosons under Transverse Harmonic Confinement

Cited by in corpus (1)

• Competition between attractive and repulsive interactions in two-component Bose-Einstein condensates trapped in an optical lattice