Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Passive decoy state quantum key distribution with practical light
  sources   Decoy states have been proven to be a very useful method for significantly
enhancing the performance of quantum key distribution systems with practical
light sources. While active modulation of the intensity of the laser pulses is
an effective way of preparing decoy states in principle, in practice passive
preparation might be desirable in some scenarios. Typical passive schemes
involve parametric down-conversion. More recently, it has been shown that phase
randomized weak coherent pulses (WCP) can also be used for the same purpose [M.
Curty {\it et al.}, Opt. Lett. {\bf 34}, 3238 (2009).] This proposal requires
only linear optics together with a simple threshold photon detector, which
shows the practical feasibility of the method. Most importantly, the resulting
secret key rate is comparable to the one delivered by an active decoy state
setup with an infinite number of decoy settings. In this paper we extend these
results, now showing specifically the analysis for other practical scenarios
with different light sources and photo-detectors. In particular, we consider
sources emitting thermal states, phase randomized WCP, and strong coherent
light in combination with several types of photo-detectors, like, for instance,
threshold photon detectors, photon number resolving detectors, and classical
photo-detectors. Our analysis includes as well the effect that detection
inefficiencies and noise in the form of dark counts shown by current threshold
detectors might have on the final secret ket rate. Moreover, we provide
estimations on the effects that statistical fluctuations due to a finite data
size can have in practical implementations.

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The categories of this paper are: hep-ph
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int