Binary matterwave compactons induced by interspecies scattering length modulations
Abstract
Binary mixtures of quasi onedimensional BoseEinstein condensates (BECs) trapped in deep optical lattices (OLs) in the presence of periodic time modulations of the interspecies scattering length are investigated. We adopt a mean field description and use the tightbinding approximation and averaging method to derive averaged model equations in the form of two coupled discrete nonlinear Schrödinger equations (DNLSEs) with tunneling constants that nonlinearly depend on interspecies coupling. We show that for strong and rapid modulations of the interspecies scattering length, the averaged system admits exact compacton solutions, e.g. solutions that have no tails and are fully localized on a compact which is achieved when the densities at the compact edges are in correspondence with zeros of the Bessel function (zero tunneling condition). Deviations from exact conditions give rise to the formation of quasicompactons, e.g. nonexact excitations which look like compactons for any practical purpose, for which the zero tunneling condition is achieved dynamically thanks to an effective nonlinear dispersive coupling induced by scattering length modulation. The stability properties of compactons and quasicompactons are investigated by linear analysis and numerical integrations of the averaged system, respectively, and the results are compared with those of the original time dependent driven system. In particular, the occurrence of delocalizing transitions with the existence of thresholds in the mean interspecies scattering length is explicitly demonstrated. Under proper management conditions, stationary compactons and quasicompactons are quite stable and robust excitations that can survive on a very long time scale. A parameter design and a possible experimental setting for the observation of these excitations are briefly discussed.
 Publication:

Journal of Physics B Atomic Molecular Physics
 Pub Date:
 August 2017
 DOI:
 10.1088/13616455/aa7dd5
 arXiv:
 arXiv:1801.00135
 Bibcode:
 2017JPhB...50p5301A
 Keywords:

 Condensed Matter  Quantum Gases
 EPrint:
 20 pages, 10 figures