Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chiral Soliton Lattice and Charged Pion Condensation in Strong Magnetic
  Fields   The Chiral Soliton Lattice (CSL) is a state with a periodic array of
topological solitons that spontaneously breaks parity and translational
symmetries. Such a state is known to appear in chiral magnets. We show that CSL
also appears as a ground state of quantum chromodynamics at nonzero chemical
potential in a magnetic field. By analyzing the fluctuations of the CSL, we
furthermore demonstrate that in strong but achievable magnetic fields, charged
pions undergo Bose-Einstein condensation. Our results, based on a systematic
low-energy effective theory, are model-independent and fully analytic.

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The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
1
The categories of this paper are: cs
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
5
The categories of this paper are: gr-qc