Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetostatic interaction in oriented assembly of elongated
  nanoparticles   The elements of the magneto-dipole (MD) interaction matrix are calculated for
a pair of oriented spheroidal magnetic nanoparticles with a semiaxes ratio a/b
= 1.25, 1.5, 2.0 and 3.0 as a function of the distance between the particle
centers. It is shown that the spherical approximation for MD interaction matrix
is incorrect already at aspect ratios a/b > 1.25, if the distance R between the
particle centers is of the order of particle sizes. However, for moderate
particle aspect ratios, a/b < 1.5, the first order correction to spherical
approximation with respect to a corresponding small parameter is shown to be in
a good agreement with numerical data. Using exact MD interaction matrix, the
quasi-static hysteresis loops of dilute assemblies of oriented clusters of
spheroidal nanoparticles with different filling densities are calculated,
depending on the direction of the external magnetic field with respect to the
particle orientation axis.

9
The categories of this paper are: nlin
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph