Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strong Coupling of a Spin Ensemble to a Superconducting Resonator   We report the realization of a quantum circuit in which an ensemble of
electronic spins is coupled to a frequency tunable superconducting resonator.
The spins are Nitrogen-Vacancy centers in a diamond crystal. The achievement of
strong coupling is manifested by the appearance of a vacuum Rabi splitting in
the transmission spectrum of the resonator when its frequency is tuned through
the NV center electron spin resonance.

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The categories of this paper are: physics
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: q-bio
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The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin
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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: acc-phys