Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: L\'evy Fluctuations and Tracer Diffusion in Dilute Suspensions of Algae
  and Bacteria   Swimming microorganisms rely on effective mixing strategies to achieve
efficient nutrient influx. Recent experiments, probing the mixing capability of
unicellular biflagellates, revealed that passive tracer particles exhibit
anomalous non-Gaussian diffusion when immersed in a dilute suspension of
self-motile Chlamydomonas reinhardtii algae. Qualitatively, this observation
can be explained by the fact that the algae induce a fluid flow that may
occasionally accelerate the colloidal tracers to relatively large velocities. A
satisfactory quantitative theory of enhanced mixing in dilute active
suspensions, however, is lacking at present. In particular, it is unclear how
non-Gaussian signatures in the tracers' position distribution are linked to the
self-propulsion mechanism of a microorganism. Here, we develop a systematic
theoretical description of anomalous tracer diffusion in active suspensions,
based on a simplified tracer-swimmer interaction model that captures the
typical distance scaling of a microswimmer's flow field. We show that the
experimentally observed non-Gaussian tails are generic and arise due to a
combination of truncated L\'evy statistics for the velocity field and
algebraically decaying time correlations in the fluid. Our analytical
considerations are illustrated through extensive simulations, implemented on
graphics processing units to achieve the large sample sizes required for
analyzing the tails of the tracer distributions.

1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph