1,065 research outputs found
Quantum Communication Network Utilizing Quadripartite Entangled States of Optical Field
We propose two types of quantum dense coding communication networks with
optical continuous variables, in which a quadripartite entangled state of the
optical field with totally three-party correlations of quadrature amplitudes is
utilized. In the networks, the exchange of information between any two
participants can be manipulated by one or two of the remaining participants.
The channel capacities for a variety of communication protocols are numerically
calculated. Due to the fact that the quadripartite entangled states applied in
the communication systems have been successfully prepared already in the
laboratory, the proposed schemes are experimentally accessible at present
Neutrino emission from dark matter annihilation/decay in light of cosmic and data
A self-consistent global fitting method based on the Markov Chain Monte Carlo
technique to study the dark matter (DM) property associated with the cosmic ray
electron/positron excesses was developed in our previous work. In this work we
further improve the previous study to include the hadronic branching ratio of
DM annihilation/decay. The PAMELA data are employed to constrain
the hadronic branching ratio. We find that the 95% () upper limits of
the quark branching ratio allowed by the PAMELA data is for DM annihilation and for DM decay respectively. This
result shows that the DM coupling to pure leptons is indeed favored by the
current data. Based on the global fitting results, we further study the
neutrino emission from DM in the Galactic center. Our predicted neutrino flux
is some smaller than previous works since the constraint from -rays is
involved. However, it is still capable to be detected by the forth-coming
neutrino detector such as IceCube. The improved points of the present study
compared with previous works include: 1) the DM parameters, both the particle
physical ones and astrophysical ones, are derived in a global fitting way, 2)
constraints from various species of data sets, including -rays and
antiprotons are included, and 3) the expectation of neutrino emission is fully
self-consistent.Comment: 13 pages, 2 figures, 1 table; Published in IJMPA 201
Experimental realization of three-color entanglement at optical fiber communication and atomic storage wavelengths
Multi-color entangled states of light including low-loss optical fiber
transmission and atomic resonance frequencies are essential resources for
future quantum information network. We present the experimental achievement on
the three-color entanglement generation at 852 nm, 1550 nm and 1440 nm
wavelengths for optical continuous variables. The entanglement generation
system consists of two cascaded non-degenerated optical parametric oscillators
(NOPOs). The flexible selectivity of nonlinear crystals in the two NOPOs and
the tunable property of NOPO provide large freedom for the frequency selection
of three entangled optical beams, so the present system is possible to be
developed as practical devices used for quantum information networks with
atomic storage units and long fiber transmission lines.Comment: 4pages, 4 figure
Genetic Analysis Workshop 13: Simulated longitudinal data on families for a system of oligogenic traits
The Genetic Analysis Workshop 13 simulated data aimed to mimic the major features of the real Framingham Heart Study data that formed Problem 1, but under a known inheritance model and with 100 replicates, so as to allow evaluation of the statistical properties of various methods. The pedigrees used were the 330 real pedigree structures (comprising 4692 individuals) with some minor changes to protect confidentiality. Fifty trait genes and 399 microsatellite markers were simulated by gene dropping on 22 autosomal chromosomes. Assuming random ascertainment of families, a system of eight longitudinal quantitative traits (designed to be similar to those in the real data) was generated with a wide range of heritabilities, including some pleiotropic and interactive effects. Genes could affect either the baseline level or the rate of change of the phenotype. Hypertension diagnosis and treatment were simulated with treatment availability, compliance, and efficacy depending on calendar year. Nongenetic traits of smoking and alcohol were generated as covariates for other traits. Death was simulated as a hazard rate depending upon age, sex, smoking, cholesterol, and systolic blood pressure. After the complete data were simulated, missing data indicators were generated based on logistic models fitted to the real data, involving the subject's history of previous missing values, together with that of their spouses, parents, siblings, and offspring, as well as marital status, only-child indicators, current value at certain simulated traits, and the data collection pattern on the cohort into which each subject was ascertained
Frequency Conversion of Entangled State
The quantum characteristics of sum-frequency process in an optical cavity
with an input signal optical beam, which is a half of entangled optical beams,
are analyzed. The calculated results show that the quantum properties of the
signal beam can be maintained after its frequency is conversed during the
intracavity nonlinear optical interaction. The frequency-conversed output
signal beam is still in an entangled state with the retained other half of
initial entangled beams. The resultant quantum correlation spectra and the
parametric dependences of the correlations on the initial squeezing factor, the
optical losses and the pump power of the sum-frequency cavity are calculated.
The proposed system for the frequency conversion of entangled state can be used
in quantum communication network and the calculated results can provide direct
references for the design of experimental systems.Comment: Accepted by Phys. Rev.
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