Abstract
We measure the electric-field-driven annihilation of nematic disclination pairs with strength ±1/2 in the 4−cyano−4′−n-pentylbiphenyl (5CB) liquid crystal. The use of a very weak azimuthal anchoring ensures a two-dimensional director field. The relaxation is governed by the formation of a π wall connecting the two opposite charge defects. The +1/2 disclinations move almost twice as fast as the −1/2 disclinations. The simple used geometry allows a quantitative comparison with numerical studies based on the hydrodynamics of the tensorial order parameter. The simulations show that in the π wall regime the symmetry breaking is due to the backflow and not to the elastic anisotropy.