Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Practical long-distance quantum key distribution through concatenated
  entanglement swapping with parametric down-conversion sources   We develop a theory for long-distance quantum key distribution based on
concatenated entanglement swapping using parametric down-conversion sources and
show numerical results of our model. The model incorporates practical resources
including multi-pair sources, inefficient detectors with dark counts and lossy
channels. We calculate the maximum secret key-generation ratefor up to three
entanglement swapping stations by optimizing over resource parameters, and our
numerical simulation shows that the range of quantum key distribution can in
principle be markedly increased but at the expense of an atrociously unfeasible
secret key-generation rate; however, the upper bound of our key rates closely
approach the Takeoka-Guha-Wilde upper bound. Our analysis demonstrates the need
for new technology such as quantum memory to synchronize photons and our
methods should serve as a valuable component for accurately modelling
quantum-memory-based long-distance quantum key distribution.

1
The categories of this paper are: cs
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin