The decay of quantum correlations between quantum dot spin qubits and the characteristics of its magnetic field dependence

We address the question of the role of quantum correlations beyond entanglement in context of quantum magnetometry. To this end, we study the evolution of the quantum discord, measured by the rescaled discord, of two electron-spin qubits interacting with an environment of nuclear spins via the hyperfine interaction. We have found that depending on the initial state the evolution can or cannot display indifferentiability points in its time-evolution (due to the energy conservation law), as well as non-trivial dependence on inter-qubit phase. Furthermore, we show that for initial Bell states, quantum correlations display a strong magnetic-field sensitivity which can be utilized for decoherence-driven measurements of the external magnetic field. The potential discord-based measurement is sensitive to a wider range of magnetic field values than the entanglement-based measurement. In principle, entanglement is not a necessary resource for reliable decoherence-driven measurement, while the presence of quantum correlations beyond entanglement is.Comment: 9 pages, 6 figure

Sensor network infrastructure for intelligent building monitoring and management system

The aim of this study was to present that it is possible to design and implement an efficient and functional intel-ligent building management system based on free tools, own project and self-realization of sensor network sys-tem which may be a low cost alternative to commercial ones. The paper presents the designed system consisting of implemented devices on the basis of sensor network technology and own hardware project in a building manage-ment system. At the application level there was designed and implemented the building management system which allows communication between the sensors, data exchange between the sensors and the database as well as the system parameters visualization panel used for intelligent building monitoring

Performance Analysis of VPN Remote Access Tunnels

The purpose of the study is to analyze the efficiency of communication with the serverusing the methods of secure remote access, as well as checking and comparing the quality of servicesprovided by the server depending on the method of secure remote connection. The article focuses onVPN technology implemented in the latest Windows Server 2012 R2 operating system

OPTYMALIZACJA POŁOŻENIA KOLEKTORA SŁONECZNEGO

It is made the mathematic model of determining of the solar collector’s parameters, that allows to get its optimal values for any latitude at an any point of time. Also it is developed the computer model for determination of the daily influx of solar energy on the surface of the solar collector, which allows to determine its optimal position.Skonstruowano model matematyczny określenia parametrów kolektora słonecznego, który pozwala uzyskać ich optymalne wartości dla dowolnego położenia geograficznego w dowolnej chwili czasowej. Opracowano model komputerowy, za pomocą którego wyznacza się dzienne dostarczanie energii słonecznej w stosunku do powierzchni kolektora słonecznego, co pozwala wyznaczyć jego optymalne położenie

Operating system efficiency evaluation on the base of measurements analysis with the use of non-extensive statistics elements

The major goal of this article was to evaluate the efficiency of Linux operating systemusing statistical self-similarity and multifractal analysis. In order to collect the necessary data, thetools available in Linux such as vmstat, top and iostat were used. The measurement data collected withthose tools had to be converted into a format acceptable by applications which analyze statistical selfsimilarityand multifractal spectra. Measurements collected while using the MySQL database systemin a host operating system were therefore analyzed with the use of statistical self-similarity and allowedto determine the occurrence of long-range dependencies. Those dependencies were analyzed with theuse of adequately graduated diagrams. Multifractal analysis was conducted with the help of FracLabapplication. Two methods were applied to determine the multifractal spectra. The obtained spectrawere analyzed in order to establish the multifractal dependencies