Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kink State in a Stack of Intrinsic Josephson Junctions in Layered
  High-$T_c$ Superconductors and Terahertz Radiation   A new family of dynamic states are found in a stack of inductively coupled
intrinsic Josephson junctions in the absence of an external magnetic field. In
this state, $(2m_l+1)\pi$ phase kinks with integers $m_l$'s stack along the c
axis and lock neighboring junction together. Large dc power is pumped into
plasma oscillation via kinks at the cavity resonance. The plasma oscillation is
uniform along the c axis with the frequency satisfying the ac Josephson
relation. Thus this state supports strong terahertz radiation and seems to be
compatible with the recent experimental observations.

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The categories of this paper are: cs
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ph
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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: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: q-alg