Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Broadband sensitivity improvement via coherent quantum feedback with PT
  symmetry   A conventional resonant detector is often subject to a trade-off between
bandwidth and peak sensitivity that can be traced back to quantum Cramer-Rao
Bound. Anomalous dispersion has been shown to improve it by signal
amplification and is thus more robust against decoherence, while it leads to
instabilities. We propose a stable quantum amplifier applicable to linear
systems operating at the fundamental detection limits, enabled by two-mode
non-degenerate parametric amplification. At threshold, one mode of the
amplifier forms a PT-symmetric system of original detector mode. Sensitivity
improvements are shown for laser-interferometric gravitational-wave detectors
and microwave cavity axion detectors.

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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: nlin
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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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: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat