Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unbounded quantum Fisher information in two-path interferometry with
  finite photon number   The minimum error of unbiased parameter estimation is quantified by the
quantum Fisher information in accordance to the Cram\'{e}r-Rao bound. We
indicate that only superposed NOON states by simultaneous measurements can
achieve the maximum quantum Fisher information with form $<\hat{N}^{2}>$ for a
given photon number distribution by a POVM in linear two-path interferometer
phase measurement. We present a series of specified superposed states with
infinite quantum Fisher information but with finite average photon numbers. The
advantage of this unbounded quantum Fisher information will be beneficial to
many applications in quantum technology.

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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph