Orientational Correlations in Active and Passive Nematic Defects

We investigate the emergence of orientational order among + 1 / 2 disclinations in active nematic liquid crystals. Using a combination of theoretical and experimental methods, we show that + 1 / 2 disclinations have short-range antiferromagnetic alignment, as a consequence of the elastic torques originating from their polar structure. The presence of intermediate − 1 / 2 disclinations, however, turns this interaction from antialigning to aligning at scales that are smaller than the typical distance between like-sign defects. No long-range orientational order is observed. Strikingly, these effects are insensitive to material properties and qualitatively similar to what is found for defects in passive nematic liquid crystals.