Bright solitons in quasi-one-dimensional dipolar condensates with spatially modulated interactions

摘要

We introduce a model for the condensate of dipolar atoms or molecules, in which the dipole-dipole interactionn(DDI) is periodically modulated in space due to a periodic change of the local orientation of the permanent dipoles,nimposed by the corresponding structure of an external field (the necessary field can be created, in particular,nby means of magnetic lattices, which are available to the experiment). The system represents a realization ofna nonlocal nonlinear lattice, which has a potential to support various spatial modes. By means of numericalnmethods and variational approximation (VA), we construct bright one-dimensional solitons in this system andnstudy their stability. In most cases, the VA provides good accuracy and correctly predicts the stability by meansnof the Vakhitov-Kolokolov criterion. It is found that the periodic modulation may destroy some solitons, whichnexist in the usual setting with unmodulated DDI and can create stable solitons in other cases, not verified in thenabsence of modulations. Unstable solitons typically transform into persistent localized breathers. The solitonsnare often mobile, with inelastic collisions between them leading to oscillating localized modes.