Drag force in bimodal cubic-quintic nonlinear Schr\"odinger equation
  We consider a system of two cubic-quintic non-linear Schr\"odinger equations in two dimensions, coupled by repulsive cubic terms. We analyse situations in which a probe lump of one of the modes is surrounded by a fluid of the other one and analyse their interaction. We find a realization of D'Alembert's paradox for small velocities and non-trivial drag forces for larger ones. We present numerical analysis including the search of static and traveling form-preserving solutions along with simulations of the dynamical evolution in some representative examples. 
David Feijoo, Ismael Ord\'o\~nez, \'Angel Paredes, and Humberto   Michinel
cond-mat.quant-gas physics.optics