Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gain-Driven Discrete Breathers in PT-Symmetric Nonlinear Metamaterials   We introduce a one dimensional parity-time (PT)-symmetric nonlinear magnetic
metamaterial consisted of split ring dimers having both gain and loss. When
nonlinearity is absent we find a transition between an exact to a broken
PT-phase; in the former the system features a two band gapped spectrum with
shape determined by the gain and loss coefficients as well as the inter-unit
coupling. In the presence of nonlinearity we show numerically that as a result
of the gain/dissipation matching a novel type of long-lived stable discrete
breathers can form below the lower branch of the band with no attenuation. In
these localized modes the energy is almost equally partitioned between two
adjacent split rings on the one with gain and the other one with loss.

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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int
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The categories of this paper are: math
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga