Coarsening dynamics in nematic liquid crystals

The dynamics of symmetry breaking phase transitions and the dynamics of defect tangles generated following the symmetry breaking are of interest in a number of fields of physics ranging from condensed matter physics to particle physics and cosmology. For the case when continuous symmetries are involved, as of yet, there has been little experimental work. Here we report on our studies of the dynamics of defects generated in a sudden quench of a uniaxial nematic liquid crystal from the isotropic phase to the nematic phase. The symmetry breaking is from O(3) to D_∞h. In this phase quench, stringlike defects belonging to the π₁ homotopy class, pointlike defects belonging to the π₂ homotopy class, and texture defects belonging to the π₃ homotopy class are created. Although the π₂ defect density scales as t^-1, nonscaling behavior is seen for π₂ defects.