  Swimming bacteria in passive nematics in the form of lyotropic liquid
crystals are defined as a new class of active matter known as living liquid
crystals in recent studies. It has also been shown that liquid crystal
solutions are promising candidates for trapping and detecting bacteria. We ask
the question, can a similar class of matter be designed for background nematics
which are also active? Hence, we developed a minimal model for the mixture of
polar particles in active nematics. It is found that the active nematics in
such a mixture are highly sensitive to the presence of polar particles, and
show the formation of large scale higher order structures for a relatively low
polar particle density. Upon increasing the density of polar particles,
different phases of active nematics are found and it is observed that the
system shows two phase transitions. The first phase transition is a first order
transition from quasi-long ranged ordered active nematics to disordered active
nematics with larger scale structures. On further increasing density of polar
particles, the system transitions to a third phase, where polar particles form
large, mutually aligned clusters. These clusters sweep the whole system and
enforce local order in the nematics. The current study can be helpful for
detecting the presence of very low densities of polar swimmers in active
nematics and can be used to design and control different structures in active
nematics.
