Physical Review A
Dynamics of two-dimensional dark quasisolitons in a smoothly inhomogeneous Bose-Einstein condensate
Lev A. Smirnov, V. A. Mironov
Abstract
We develop an asymptotic theory describing the dynamics of two-dimensional dark quasisolitons in a smoothly inhomogeneous Bose-Einstein condensate (BEC) with repulsive interaction between atoms. It is shown that the trajectories of such quasisolitons coincide with the geometric-optical rays in an equivalent isotropic medium characterized by the effective refractive index dependent on both the density of the undisturbed condensate and the energy of the structures. An expression for this effective refractive index is found and specific features of the refraction of quasisolitons with different initial energies by the condensate inhomogeneities are studied. The obtained results are confirmed by direct numerical simulation using the Gross-Pitaevskii (GP) equation.