Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum key distribution using superposition of the vacuum and single
  photon states   B92-type and BB84-type quantum cryptography schemes using superposed states
of the vacuum and single particle states which are robust against PNS attacks
are studied. The number of securely transferred classical bits per particle
(not per qubit) sent in these schemes is calculated and found to have upper
bounds. Possible experimental realizations using the cavity QED or linear
optics are suggested.

21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con