Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Planck Spectroscopy and the Quantum Noise of Microwave Beam Splitters   We use a correlation function analysis of the field quadratures to
characterize both the black body radiation emitted by a 50 Ohm load resistor
and the quantum properties of two types of beam splitters in the microwave
regime. To this end, we first study vacuum fluctuations as a function of
frequency in a Planck spectroscopy experiment and then measure the covariance
matrix of weak thermal states. Our results provide direct experimental evidence
that vacuum fluctuations represent the fundamental minimum quantum noise added
by a beam splitter to any given input signal.

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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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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: gr-qc
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
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The categories of this paper are: stat