Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Casimir interaction of rod-like particles in a two-dimensional critical
  system   We consider the fluctuation-induced interaction of two thin, rod-like
particles or "needles" immersed in a two-dimensional critical fluid of Ising
symmetry right at the critical point. Conformally mapping the plane containing
the needles onto a simpler geometry in which the stress tensor is known, we
analyze the force and torque between needles of arbitrary length, separation,
and orientation. For infinite and semi-infinite needles we utilize the mapping
of the plane bounded by the needles onto the half plane, and for two needles of
finite length the mapping onto an annulus. For semi-infinite and infinite
needles the force is expressed in terms of elementary functions, and we also
obtain analytical results for the force and torque between needles of finite
length with separation much greater than their length. Evaluating formulas in
our approach numerically for several needle geometries and surface universality
classes, we study the full crossover from small to large values of the
separation to length ratio. In these two limits the numerical results agree
with results for infinitely long needles and with predictions of the
small-particle operator expansion, respectively.

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The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex