Characterization of the vortex-pair interaction law and nonlinear mobility effects

R. Barboza, T. Sauma, U. Bortolozzo, G. Assanto, M.G. Clerc and S. Residori

New J. Phys. 15 (1), 013028 (2013)


Employing nematic liquid crystals in a homeotropic cell with a photosensitive wall, dissipative vortex pairs are selectively induced by external illumination and the interaction law is characterized for pairs of opposite topological charges. Contrary to the phenomenological fit with a force inversely proportional to the distance, the data provide evidence that nonlinear mobility effects must be taken into account. The observations lead to a reconciliation of experiments with theory.