Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stability of Half-Quantum Vortices in Equal-Spin Pairing States of
  $^3$He   Recent experiments on superfluid $^3$He in globally anisotropic aerogels have
shown realization of the polar superfluid phase and of the half-quantum
vortices (HQVs) in this phase upon rotation. To clarify why the HQVs, which had
not been detected clearly in the A phase of the bulk liquid, have been realized
in the polar phase, we theoretically examine the relative stability of a
HQV-pair against a single phase vortex in both the bulk A-phase and the polar
phase in an aerogel. By taking care of important roles of a higher order
gradient term, which assists the stability of HQVs but has never been
incorporated so far in the Ginzburg-Landau (GL) approach, we find that several
consequences, including the extension of the polar phase at lower pressures in
the phase diagram, facilitate realization of the HQVs there in contrast to the
case of the A phase in a slab geometry.

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The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio
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The categories of this paper are: nlin