Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Characterisations of Classical and Non-classical states of Quantised
  Radiation   A new operator based condition for distinguishing classical from
non-classical states of quantised radiation is developed. It exploits the fact
that the normal ordering rule of correspondence to go from classical to quantum
dynamical variables does not in general maintain positivity. It is shown that
the approach naturally leads to distinguishing several layers of increasing
nonclassicality, with more layers as the number of modes increases. A
generalisation of the notion of subpoissonian statistics for two-mode radiation
fields is achieved by analysing completely all correlations and fluctuations in
quadratic combinations of mode annihilation and creation operators conserving
the total photon number. This generalisation is nontrivial and intrinsically
two-mode as it goes beyond all possible single mode projections of the two-mode
field. The nonclassicality of pair coherent states, squeezed vacuum and
squeezed thermal states is analysed and contrasted with one another, comparing
the generalised subpoissonian statistics with extant signatures of nonclassical
behaviour.

28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph