3,959 research outputs found
Effects of depolarizing quantum channels on BB84 and SARG04 quantum cryptography protocols
We report experimental studies on the effect of the depolarizing quantum
channel on weak-pulse BB84 and SARG04 quantum cryptography. The experimental
results show that, in real world conditions in which channel depolarization
cannot be ignored, BB84 should perform better than SARG04.Comment: 4 pages, 4 figure
Study of the Top-quark Pair Production in Association with a Bottom-quark Pair from Fast Simulations at the LHC
A large number of top quarks will be produced at the Large Hadron Collider
(LHC) for Run II period. This will allow us to measure the rare processes from
the top sector in great details. We present the study of the top-quark pair
production in association with a bottom-quark pair (ttbb) from fast simulations
for the Compact Muon Solenoid (CMS) experiment. The differential distributions
of ttbb are compared with the top-quark pair production with two additional
jets (ttjj) and with the production in association with the Higgs (ttH), where
the Higgs decays to a bottom-quark pair. The significances of ttbb process in
the dileptonic and semileptonic decay mode are calculated with the data
corresponding to an integrated luminosity of 10 fb-1, which is foreseen to be
collected in the early Run II period. This study will be an important input in
searching for new physics beyond the standard model as well as in searching for
ttH process where the Yukawa coupling with the top quark can be directly
measured.Comment: 12 pages, 12 figure
Clustering of Nodes in Layered-Tree Topology for Wireless Sensor Networks
Wireless sensor network is composed of a large number of sensor nodes of limited energy resource. The node clustering approach can improve the scalability and lifetime of wireless sensor network. In this paper we propose a novel node clustering protocol based on layered-tree topology for self-organizing distributed wireless sensor networks. It decides optimal number of clusters by employing a new approach for setting threshold value, including the probability of optimum number of cluster-heads and residual energy of the nodes. We also introduce a new scheme for layered-tree construction in each cluster. As a result, the proposed scheme can significantly improve the energy efficiency of the network and increase its lifetime. Computer simulation shows that the proposed scheme effectively reduces and balances the energy consumption of the nodes, and thus significantly extends the network lifetime compared to the existing schemes
Abrupt metal-insulator transition observed in VO2 thin films induced by a switching voltage pulse
An abrupt metal-insulator transition (MIT) was observed in VO2 thin films
during the application of a switching voltage pulse to two-terminal devices.
Any switching pulse over a threshold voltage for the MIT of 7.1 V enabled the
device material to transform efficiently from an insulator to a metal. The
characteristics of the transformation were analyzed by considering both the
delay time and rise time of the measured current response. The extrapolated
switching time of the MIT decreased down to 9 ns as the external load
resistance decreased to zero. Observation of the intrinsic switching time of
the MIT in the correlated oxide films is impossible because of the
inhomogeneity of the material; both the metallic state and an insulating state
co-exist in the measurement volume. This indicates that the intrinsic switching
time is in the order of less than a nanosecond. The high switching speed might
arise from a strong correlation effect (Coulomb repulsion) between the
electrons in the material.Comment: 5 pages, 5 figure
Terrace solutions for non-Lipschitz multistable nonlinearities
Traveling wave solutions of reaction-diffusion equations are well-studied for
Lipschitz continuous monostable and bistable reaction functions. These special
solutions play a key role in mathematical biology and in particular in the
study of ecological invasions. However, if there are more than two stable
steady states, the invasion phenomenon may become more intricate and involve
intermediate steps, which leads one to consider not a single but a collection
of traveling waves with ordered speeds. In this paper we show that, if the
reaction function is discontinuous at the stable steady states, then such a
collection of traveling waves exists and even provides a special solution which
we call a terrace solution. More precisely, we will address both the existence
and uniqueness of the terrace solution
Performance Tests for Wireless Real-Time Localization Systems to Improve Mobile Robot Navigation in Various Indoor Environments
- …