Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scheme for the implementation of a universal quantum cloning machine via
  cavity-assisted atomic collisions in cavity QED   We propose a scheme to implement the $1\to2$ universal quantum cloning
machine of Buzek et.al [Phys. Rev.A 54, 1844(1996)] in the context of cavity
QED. The scheme requires cavity-assisted collision processes between atoms,
which cross through nonresonant cavity fields in the vacuum states. The cavity
fields are only virtually excited to face the decoherence problem. That's why
the requirements on the cavity quality factor can be loosened.

28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph