Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Living Liquid Crystals   Collective motion of self-propelled organisms or synthetic particles often
termed active fluid has attracted enormous attention in broad scientific
community because of it fundamentally non-equilibrium nature. Energy input and
interactions among the moving units and the medium lead to complex dynamics.
Here we introduce a new class of active matter, living liquid crystals (LLCs)
that combine living swimming bacteria with a lyotropic liquid crystal. The
physical properties of LLCs can be controlled by the amount of oxygen available
to bacteria, by concentration of ingredients, or by temperature. Our studies
reveal a wealth of new intriguing dynamic phenomena, caused by the coupling
between the activity-triggered flow and long-range orientational order of the
medium. Among these are (a) non-linear trajectories of bacterial motion guided
by non-uniform director, (b) local melting of the liquid crystal caused by the
bacteria-produced shear flows, (c) activity-triggered transition from a
non-flowing uniform state into a flowing one-dimensional periodic pattern and
its evolution into a turbulent array of topological defects, (d)
birefringence-enabled visualization of microflow generated by the
nanometers-thick bacterial flagella. Unlike their isotropic counterpart, the
LLCs show collective dynamic effects at very low volume fraction of bacteria,
on the order of 0.2%. Our work suggests an unorthodox design concept to control
and manipulate the dynamic behavior of soft active matter and opens the door
for potential biosensing and biomedical applications.

8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn