11,332 research outputs found
Scale-free trees: the skeletons of complex networks
We investigate the properties of the spanning trees of various real-world and
model networks. The spanning tree representing the communication kernel of the
original network is determined by maximizing total weight of edges, whose
weights are given by the edge betweenness centralities. We find that a
scale-free tree and shortcuts organize a complex network. The spanning tree
shows robust betweenness centrality distribution that was observed in
scale-free tree models. It turns out that the shortcut distribution
characterizes the properties of original network, such as the clustering
coefficient and the classification of networks by the betweenness centrality
distribution
Bound entangled states with nonzero distillable key rate
In this paper, we present sufficient conditions for states to have positive
distillable key rate. Exploiting the conditions, we show that the bound
entangled states given by Horodecki et al. [Phys. Rev. Lett. 94, 160502 (2005),
quant-ph/0506203] have nonzero distillable key rate, and finally exhibit a new
class of bound entangled states with positive distillable key rate, but with
negative Devetak-Winter lower bound of distillable key rate for the ccq states
of their privacy squeezed versions.Comment: 7 pages, 1 figure, typos corrected, accepted for publication in PR
Inhomogeneous substructures hidden in random networks
We study the structure of the load-based spanning tree (LST) that carries the
maximum weight of the Erdos-Renyi (ER) random network. The weight of an edge is
given by the edge-betweenness centrality, the effective number of shortest
paths through the edge. We find that the LSTs present very inhomogeneous
structures in contrast to the homogeneous structures of the original networks.
Moreover, it turns out that the structure of the LST changes dramatically as
the edge density of an ER network increases, from scale free with a cutoff,
scale free, to a starlike topology. These would not be possible if the weights
are randomly distributed, which implies that topology of the shortest path is
correlated in spite of the homogeneous topology of the random network.Comment: 4 pages, 4 figure
Mirage cosmology with an unstable probe D3-brane
We consider the mirage cosmology by an unstable probe brane whose action is
represented by BDI action with tachyon. We study how the presence of tachyon
affects the evolution of the brane inflation. At the early stage of the brane
inflation, the tachyon kinetic term can play an important role in curing the
superluminal expansion in mirage cosmology.Comment: 11 pages, improved presentation with some clarifications, typos
corrected, references adde
Analysis of Pay Inequality and its Impacts on Growth and Performance in the Korean Manufacturing Industry
This paper examines the relationship between pay inequality, economic growth, and performance in Korea. Pay inequality is estimated by using Theil's index to identify the factors determining the level of pay inequality, and establish its relationship with economic growth and performance. For the empirical results we use panel data on the Korean manufacturing sector for the period 1993 to 2003. It appears that a large portion of rising pay inequality can be attributed to rising relative pay among the small-sized firms, outside the capital city area and in the ICT sectors which were affected by the economic structural reform since 1997. The findings support the hypothesis of an "augmented" Kuznets Curve, according to which certain developed countries are found on an upward-sloping addendum to the original formulation of Kuznets.pay inequality, financial crisis, Kuznets Curve, economic growth, performance
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