Simple protocol for secure decoy-state quantum key distribution with a loosely controlled source

The method of decoy-state quantum key distribution (QKD) requests different intensities of light pulses. Existing theory has assumed exact control of intensities. Here we propose a simple protocol which is secure and efficient even there are errors in intensity control. In our protocol, decoy pulses and signal pulses are generated from the same father pulses with a two-value attenuation. Given the upper bound of fluctuation of the father pulses, our protocol is secure provided that the two-value attenuation is done exactly. We propose to use unbalanced beam-splitters for a stable attenuation. Given that the intensity error is bounded by $\pm5$, with the same key rate, our method can achieve a secure distance only 1 km shorter than that of an ideal protocol with exactly controlled source

Model Rute dan Peta Interaktif Posyandu di Kota Semarang Menggunakan Geolocation dan Haversine Berbasis Mobile Android

Users of mobile phones with android operating system is increasing from year to year as more affordable. Thisgives the potential use of mobile phones as a means of disseminating information. As the capital of Central Java,Semarang has a variety of health care facilities which include Posyandu is always used by the surroundingcommunity. However, not all locations Posyandu known by the public because they lack information about thelocation. It is necessary for the navigation application Posyandu in Semarang. The purpose of this research ishow to design the application model and the location of Posyandu in real time with the geolocation methods andformulas Haversine. The method used is the Systems Development Life Cycle. System analysis model using UseCase Diagrams, Activity Diagrams, Sequence Diagrams and Class Diagrams. Results of this research is theapplication of navigation map based on Android mobile can provide information about the existence of thelocation, route and distance Posyandu. Results of this application is important for people who need drivingdirections Posyandu location. With this application is expected the results will help the public to obtaininformation and the location of the neighborhood health center (posyandu) in the city of Semarang can be met

General theory of decoy-state quantum cryptography with source errors

The existing theory of decoy-state quantum cryptography assumes the exact control of each states from Alice's source. Such exact control is impossible in practice. We develop the theory of decoy-state method so that it is unconditionally secure even there are state errors of sources, if the range of a few parameters in the states are known. This theory simplifies the practical implementation of the decoy-state quantum key distribution because the unconditional security can be achieved with a slightly shortened final key, even though the small errors of pulses are not corrected.Comment: Our results can be used securely for any source of diagonal states, including the Plug-&-Play protocol with whatever error pattern, if we know the ranges of errors of a few parameter

Experimental Quantum Teleportation and Multi-Photon Entanglement via Interfering Narrowband Photon Sources

In this letter, we report a realization of synchronization-free quantum teleportation and narrowband three-photon entanglement through interfering narrowband photon sources. Since both the single-photon and the entangled photon pair utilized are completely autonomous, it removes the requirement of high demanding synchronization technique in long-distance quantum communication with pulsed spontaneous parametric down-conversion sources. The frequency linewidth of the three-photon entanglement realized is on the order of several MHz, which matches the requirement of atomic ensemble based quantum memories. Such a narrowband multi-photon source will have applications in some advanced quantum communication protocols and linear optical quantum computation

Impact of quadrupole deformation on intermediate-energy heavy-ion collisions

This study employs the isospin-dependent Boltzmann-Uehling-Uhlenbeck model to simulate intermediate-energy heavy-ion collisions between prolate nuclei $^{24}$Mg. The emphasis is on investigating the influence of centrality and orientation in several collision scenarios. The final-state particle multiplicities and anisotropic flows are primarily determined by the eccentricity and the area of the initial overlap. This not only provides feedback on the collision systems, but also, to some extent, provides a means to explore the fine structure inside deformed nuclei. Additionally, non-polarized collisions have been further discussed. These results contribute to the understanding of the geometric effects in nuclear reactions, and aid in the exploration of other information on reaction systems, such as the equation of state and nuclear high-momentum tail