Publications by the Laboratory of Theoretical Physics

Matter sound waves in two-component BoseEinstein condensates, B. B. Baizakov, F. Kh. Abdullaev, B. A. Malomed, and M. Salerno, J. Phys. B: At. Mol. Opt. Phys. 42, 175302 (2009).    [PDF-file  (1.92 MB)] Abstract: The existence of bright solitons in the model of the Tonks–Girardeau (TG) gas with dipole–dipole (DD) interactions is reported. The governing equation is taken as the quintic nonlinear SchrЁodinger equation (NLSE) with the nonlocal cubic term accounting for the DD attraction. In different regions of the parameter space (the dipole moment and atom number), matter-wave solitons feature flat-top or compacton-like shapes. For the flat-top states, the NLSE with the local cubic-quintic (CQ) nonlinearity is shown to be a good approximation. Specific dynamical effects are studied assuming that the strength of the DD interactions is ramped up or drops to zero. Generation of dark-soliton pairs in the gas shrinking under the action of the intensifying DD attraction is observed. Dark solitons exhibit particle-like collision behaviour. Peculiarities of dipole solitons in the TG gas are highlighted by comparison with the NLSE including the local CQ terms. Collisions between the bright solitons are also studied. In many cases, the collisions result in the merger of the solitons into a breather, due to a strong attraction between them. The papers have Copyright © by the corresponding publishers. The papers may be downloaded for personal use only. Any other use requires prior permission of the author and the publisher.