Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Circling particles and drafting in optical vortices   Particles suspended in a viscous fluid circle in optical vortices generated
by holographic optical-tweezer techniques [Curtis J E and Grier D G 2003 Phys.
Rev. Lett. 90 133901]. We model this system and show that hydrodynamic
interactions between the circling particles determine their collective motion.
We perform a linear-stability analysis to investigate the stability of regular
particle clusters and illustrate the limit cycle to which the unstable modes
converge. We clarify that drafting of particle doublets is essential for the
understanding of the limit cycle.

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The categories of this paper are: chem-ph
2
The categories of this paper are: math
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc