Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fluctuations and Rheology in Active Bacterial Suspensions   We probe non-equilibrium properties of an active bacterial bath through
measurements of correlations of passive tracer particles and the response
function of a driven, optically trapped tracer. These measurements demonstrate
violation of the fluctuation-dissipation theorem and enable us to extract the
power spectrum of the active stress fluctuations. In some cases, we observe
$1/\sqrt{\omega}$ scaling in the noise spectrum which we show can be derived
from a theoretical model incorporating coupled stress, orientation, and
concentration fluctuations of the bacteria.

5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs