Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Collective Spin Modes in Superconducting Double Layers   We investigate a double layer system with tight-binding hopping, intra-layer
and inter-layer interactions, as well as a Josephson like coupling. We find
that an antiferromagnetic spin polarization induces additional spin-triplet
pairing (with $S_z =0$) to the singlet order parameter. This causes an undamped
collective mode in the superconducting state below the particle-hole threshold,
which is interpreted as a Goldstone excitation.

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The categories of this paper are: math-ph
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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: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
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The categories of this paper are: chao-dyn