Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Passive and active colloidal chemotaxis in a microfluidic channel:
  mesoscopic and stochastic models   Chemotaxis is the response of a particle to a gradient in the chemical
composition of the environment. While it was originally observed for biological
organisms, it is of great interest in the context of synthetic active particles
such as nanomotors. Experimental demonstration of chemotaxis for
chemically-powered colloidal nanomotor was reported in the literature in the
context of chemo-attraction in a still fluid or in a microfluidic channel where
the gradient is sustained by a specific inlet geometry. In this work, we use
mesoscopic particle-based simulations of the colloid and solvent to demonstrate
chemotaxis in a microfluidic channel. On the basis of this particle-based
model, we evaluate the chemical concentration profiles in the presence of
passive or chemically active colloids, compute the chemotactic force acting
upon them and propose a stochastic model that rationalises our findings on
colloidal chemotaxis. Our model is also able to explain the results of an
earlier simulation work that uses a simpler geometry and to extend its
interpretation.

18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat