Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lifetime of skyrmions in discrete systems with infinitesimal lattice
  constant   Topological protection of chiral magnetic structures is investigated by
taking a two-dimensional magnetic skyrmion as an example. The skyrmion lifetime
is calculated based on harmonic transition state theory for a discrete lattice
model using various values of the ratio of the lattice constant and the
skyrmion size. Parameters of the system corresponding to exchange, anisotropy
and Dzyaloshinsky-Moriya interaction are chosen in such a way as to keep the
energy and size of the skyrmion unchanged for small values of the lattice
constant, using scaling relations derived from continuous micromagnetic
description. The number of magnetic moments included in the calculations
reaches more than a million. The results indicate that in the limit of
infinitesimal lattice constant, the energy barrier for skyrmion collapse
approaches the Belavin-Polyakov lower bound of the energy of a topological
soliton in the $\sigma$-model, the entropy contribution to the pre-exponential
factor in the Arrhenius rate expression for collapse approaches a constant and
the skyrmion lifetime can, for large enough number of spins, correspond to
thermally stable skyrmion at room temperature even without magnetic
dipole-dipole interaction.

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The categories of this paper are: q-fin
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics