Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of Two-Photon Absorption with Broadband Bright Squeezed Vacuum:
  Part 1 Quantum Model   We present an analytical quantum theoretic model for molecular two-photon
absorption (TPA) of broadband, spectrally multi-mode squeezed vacuum with pulse
duration much greater than the coherence time, including low-gain (isolated
entangled photon pairs or EPP) and high-gain (bright squeezed vacuum or BSV)
regimes. We treat only cases where the exciting light is spatially single-mode
and is nonresonant with all intermediate molecular states. In the case of high
gain, we find that if the linewidth of the final molecular state is much
narrower than the bandwidth of the exciting light, bright squeezed vacuum is
found to be equally (but no more) effective in driving TPA as is a
quasi-monochromatic coherent-state (classical) pulse of the same temporal
shape, duration and mean photon number. Therefore, the sought-for advantage of
observing TPA at extremely low optical flux is not provided by broadband bright
squeezed vacuum. In the opposite case that the final-state linewidth is much
broader than the bandwidth of the BSV exciting light, we show that the TPA rate
is proportional to the second-order intensity autocorrelation function at zero
time delay g^(2)(0), as expected. And we find that for g^(2)(0) to reach the
idealized form g^(2)(0) = 3 + 1/n, with n, being the mean number of photons per
temporal mode, it is required to compensate the dispersion inherent in the
nonlinear-optical crystal used to generate the BSV. Part 2 of this two-paper
series considers the same questions in the context of a classical model of
squeezed light and also extends the analysis to the case of sum-frequency
generation.

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The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: cond-mat
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: physics