Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Collective behavior of penetrable self-propelled rods in two dimensions   Collective behavior of self-propelled particles is observed on a microscale
for swimmers such as sperm and bacteria as well as for protein filaments in
motility assays. The properties of such systems depend both on their
dimensionality and the interactions between their particles. We introduce a
model for self-propelled rods in two dimensions that interact via a
separation-shifted Lennard-Jones potential. Due to the finite potential
barrier, the rods are able to cross. This model allows us to efficiently
simulate systems of self-propelled rods that effectively move in two dimensions
but can occasionally escape to the third dimension in order to pass each other.
Our quasi-two-dimensional self-propelled particles describe a class of active
systems that encompasses microswimmers close to a wall and filaments propelled
on a substrate. Using Monte Carlo simulations, we first determine the
isotropic-nematic transition for passive rods. Using Brownian dynamics
simulations, we characterize cluster formation of self-propelled rods as a
function of propulsion strength, noise, and energy barrier. Contrary to rods
with an infinite potential barrier, an increase of the propulsion strength does
not only favor alignment but also effectively decreases the potential barrier
that prevents crossing of rods. We thus find a clustering window with a maximum
cluster size at medium propulsion strengths.

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The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: supr-con