Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hamiltonian models of multiphoton processes and four--photon squeezed
  states via nonlinear canonical transformations   We introduce nonlinear canonical transformations that yield effective
Hamiltonians of multiphoton down conversion processes, and we define the
associated non-Gaussian multiphoton squeezed states as the coherent states of
the multiphoton Hamiltonians. We study in detail the four-photon processes and
the associated non-Gaussian four-photon squeezed states. The realization of
squeezing, the behavior of the field statistics, and the structure of the phase
space distributions show that these states realize a natural four-photon
generalization of the two-photon squeezed states.

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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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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: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an