Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Parametric Resonances and Resonant Delocalization in Quasi-Phase Matched
  Photon-pair Generation and Quantum Frequency Conversion   The existing widely-accepted theory of photon-pair generation via spontaneous
down-conversion (SPDC) in nonlinear optical crystals and waveguides is
incomplete, as it fails to account for the important physical phenomenon of
parametric resonances. We demonstrate that exponential gain of classical fields
in the regime of parametric resonance corresponds to resonant delocalization in
the Glauber-Fock model of quantum SPDC. We propose a quantitative measure of
localisation of Floquet eigen-modes as an analogue of classical gain to
identify regimes of resonant delocalization. Using this method, we are able to
reconstruct the classical "Arnold tongues" map of domains of instabilities for
SPDC. We also predict novel regimes of resonant delocalization in the two-level
model describing quantum frequency conversion processes.

25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph