Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of Photon Subtraction for Two-Mode Entangled Light Beams   Photon subtraction is useful to produce nonclassical states of light
addressed to applications in photonic quantum technologies. After a very
accelerated development, this technique makes possible obtaining either single
photons or optical cats on demand. However, it lacks theoretical formulation
enabling precise predictions for the produced fields. Based on the
representation generated by the two-mode $SU(2)$ coherent states, we introduce
a model of entangled light beams leading to the subtraction of photons in one
of the modes, conditioned to the detection of any photon in the other mode. We
show that photon subtraction does not produce nonclassical fields from
classical fields. It is also derived a compact expression for the output field
from which the calculation of conditional probabilities is straightforward for
any input state. Examples include the analysis of squeezed-vacuum and
odd-squeezed states. We also show that injecting optical cats into a beam
splitter gives rise to entangled states in the Bell representation.

6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin