100 research outputs found

    The Photodetection Process under the Conditions of an Imperfect Measurement Device

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    The process of cavity mode quantum state photodetection subject to a nonideal measurement device is under consideration. A set of nonorthogonal probabilistic operator valued measures (POVMs) describing the photodetection process is suggested. The superoperators of conditional system evolution and their Kraus representations are obtained. Developed formalism is used to the quantum state reconstruction problem. We recalculate the probabilities of hypotheses about the initial state of cavity quantum mode in the case of unknown superposition of vacuum and single photon states.Comment: 2 figures, 8 pages, reported at XI International Workshop on Quantum Optics, Volgograd, Russi

    Optical bistability in nonlinear system with two loops of feedback

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    A model of nonlinear optical system surrounded by two loops of feedback is investigated. The cell with the vapor of rubidium - type atoms is taken in the capacity of nonlinear element. Two modes of near-resonant electromagnetic field interacting with the cell are involved in the feedback. Two-dimensional optical bistability domain in location of input field intensities is obtained and dependence of its form and magnitude from the system parameters (photon detunings, feedback factor etc.) is investigated. "Input - output" relations corresponding to different trajectories in the bistability domain are obtained. Cross-hysteresis is studied.Comment: 7 pages, 14 figures, conference ICONO/LAT 2010, Kazan, Russi

    Reduced conditional dynamic of quantum system under indirect quantum measurement

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    In this report, we study the reduced conditional dynamics of a quantum system in the case of indirect quantum measurement. The detectors microscopic part (pointer) interacts with the measured system (target) and the environment, which results in a nonunitary interaction between target and pointer. The quantum state evolution conditioned by the measurement result is under investigation. Particularly, we are interested in explicit analytical expressions for the conditional evolution superoperators and basic information characteristics of this measurement process, which is applied to the cavity mode photodetection problem.Comment: 14 pages, 8 figures, Central European Workshop on Quantum Optics 2013, Stockholm, Swede

    An indirect measurement protocol of intracavity mode quadratures dispersion in Dynamical Casimir Effect

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    This work deals with the problem of photon detection generated from the mirror-induced Dynamical Casimir Effect. Particularly we are interested in measurement of those statistical characteristics of a generated intracavity field which may confirm its nonthermal properties. Here an indirect protocol for quadrature dispersion measurement is presented.Comment: 9 pages, 2 figures, Central European Workshop on Quantum Optics 2015, Bruxels, Belgiu

    “Ural-20R” combines loading drives evaluation in two-stage development of the face

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    The technological features of the use of high-performance Ural-20R combines in the conditions of potash mines in Russia are described. It is shown that when the capacity of the worked potash seams is over 4 m, a two-layer ore extraction is used. The formation of cutting process, implemented by the second course of the combine in the treatment chamber, is carried out by an incomplete section of the executive bodies. The standard control system, display and protection of the Ural-20R combine does not allow monitoring and reliable estimation of the magnitude of dynamic components on the drives of the mining machine loads, as well as tracking the feed rate of the combine to the face. The regulation of the operating parameters and the assessment of the degree of loading of the drives of the excavating machine in real time are assigned to the operator. The fundamentals of the experimental research methodology for assessing the loading of drives of Ural-20R combines with the destruction of the potash mass by an incomplete section of the executive bodies are described. The device and the operating procedure of the “Vatur” software-recording complex, which measures, records and records the electrical parameters of the drive motors of a mining machine, is described. The process studies results of forming loads on drive elements of Ural-20R combines when mining a face with an incomplete section of executive bodies are presented. It is proved that the work of combine harvesters on the undercut of the formation with a high feed rate is accompanied by significant dynamic loads on the drives of planetary organs and an overload of the drives of the Berm organs, which leads to an accelerated consumption of the resource and emergency failures of the gearboxes and motors of the extraction machine

    Fourier domain optical coherence tomography system with balance detection

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    A Fourier domain optical coherence tomography system with two spectrometers in balance detection is assembled using each an InGaAs linear camera. Conditions and adjustments of spectrometer parameters are presented to ensure anti-phase channeled spectrum modulation across the two cameras for a majority of wavelengths within the optical source spectrum. By blocking the signal to one of the spectrometers, the setup was used to compare the conditions of operation of a single camera with that of a balanced configuration. Using multiple layer samples, balanced detection technique is compared with techniques applied to conventional single camera setups, based on sequential deduction of averaged spectra collected with different on/off settings for the sample or reference beams. In terms of reducing the autocorrelation terms and fixed pattern noise, it is concluded that balance detection performs better than single camera techniques, is more tolerant to movement, exhibits longer term stability and can operate dynamically in real time. The cameras used exhibit larger saturation power than the power threshold where excess photon noise exceeds shot noise. Therefore, conditions to adjust the two cameras to reduce the noise when used in a balanced configuration are presented. It is shown that balance detection can reduce the noise in real time operation, in comparison with single camera configurations. However, simple deduction of an average spectrum in single camera configurations delivers less noise than the balance detection

    Revision of the total nitrogen and phosphorus content in a cattle manure-based organic fertiliser in North-West Russia

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    This study aimed to verify the applicability of a mass balance method for estimating nitrogen (N) and phosphorus (P) content in the solid organic fertiliser produced from cattle manure in North-West Russia. The study compared the relevant established norms in Russia, the data calculated by the mass balance method, and the average experimental data on N and P content in cattle manure (ex-housing) and the organic fertilizer ready to use from the selected cattle-breeding complex with 1250 heads and a manure output of 70 t day-1. Three animal categories were considered. The difference between the calculated and experimental data was 10% maximum but the experimental data and the established norms differed by above 15%. This proves the demand to revise the norms in the Russian regulatory documents to improve the accuracy of fertiliser application rates and the estimation of agricultural land required. Even an increase of 10% in the nutrient content of the organic fertiliser results in an increase in the required agricultural land from 451 to 526 ha for spreading the organic fertiliser from the 1250 heads of cattle at the selected farm
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