Orientational capillary pressure on a nematic point defect

The analysis of some experimental data for the coalescence of two point defects in a capillary tube filled with a lyotropic liquid crystal shows that before the very interaction starts, defects move under the effect of a constant force. We suggest that this effect could be due to a capillary pressure and show how it can be justified by only assuming that there is a slight misalignment from the homeotropic anchoring on the boundary. These predictions are in good agreement with the data and open the way to further experiments.