Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Period-doubling-bifurcation readout for a Josephson qubit   We propose a threshold detector with an operation principle, based on a
parametric period-doubling bifurcation in an externally pumped nonlinear
resonance circuit. The ac-driven resonance circuit includes a dc-current-biased
Josephson junction ensuring parametric frequency conversion (period-doubling
bifurcation) due to its quadratic nonlinearity. A sharp onset of oscillations
at the half-frequency of the drive allows for detection of small variations of
an effective inductance and, therefore, the read-out of the quantum state of a
coupled Josephson qubit. The bifurcation characteristics of this circuit are
compared with those of the conventional Josephson bifurcation amplifier, and
its possible advantages are discussed.

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The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph