Microswimmers Unveil Novel Dynamical Phase in Active Nematics

Active nematics has shown interesting dynamical and steady state properties: large-scale dynamic structures and collective flows, multi-spatial temporal dynamics etc. for pure active nematics. Whereas it also exhibits interesting dynamical and steady state features in the presence of external agents. Here, we focus on the properties of active nematics when the foreign agents are polar in nature. The example of such systems can be visualised as a collection of active apolar cells, where microswimmers are present as impurities. In this work we performed an extensive numerical study and showed that by varying the motility of microswimmers the background active nematics show an attractive dynamical state. Where the system evolves to a new dynamical rotating phase with the presence of vortices on the macroscopic scales, this phase appears at the cost of globally ordered active nematics. The motility of the microswmmers is responsible for such phase and this phase appears for intermediate range of motility, where microswimmers start to develop local clusters and coherent motion. Whereas the vortex state weakens when clustering of microswimmer increases for large motility. Hence our study provides a new interesting dynamical phase in active nematics, which can be completely tuned by controlling the motility of microswimmers and can be used for differentiating a variety of pathogens in apolar cells.