Role of boundary conditions in the annihilation of nematic point defects

Abstract

We describe the effect of boundary conditions on the motion of point defects in a nematic liquid crystal confined within a capillary tube. In particular, we show how even a small tilt of the director on the lateral boundary could considerably affect the dynamics of defects. In our model the hydrodynamic flow induced by the director rotation, often called the backflow, is systematically neglected. We also suggest describing the backflow by introducing phenomenologically an effective rotational viscosity depending on the distance between the defects