Experimental estimation of quantum discord for polarization qubit and the use of fidelity to assess quantum correlations

We address the experimental determination of entropic quantum discord for systems made of a pair of polarization qubits. We compare results from full and partial tomography and found that the two determinations are statistically compatible, with partial tomography leading to a smaller value of discord for depolarized states. Despite the fact that our states are well described, in terms of fidelity, by families of depolarized or phase-damped states, their entropic discord may be largely different from that predicted for these classes of states, such that no reliable estimation procedure beyond tomography may be effectively implemented. Our results, together with the lack of an analytic formula for the entropic discord of a generic two-qubit state, demonstrate that the estimation of quantum discord is an intrinsically noisy procedure. Besides, we question the use of fidelity as a figure of merit to assess quantum correlations

Statistical Estimation of Quantum Tomography Protocols Quality

A novel operational method for estimating the efficiency of quantum state tomography protocols is suggested. It is based on a-priori estimation of the quality of an arbitrary protocol by means of universal asymptotic fidelity distribution and condition number, which takes minimal value for better protocol. We prove the adequacy of the method both with numerical modeling and through the experimental realization of several practically important protocols of quantum state tomography

Experimental estimation of entanglement at the quantum limit

Entanglement is the central resource of quantum information processing and the precise characterization of entangled states is a crucial issue for the development of quantum technologies. This leads to the necessity of a precise, experimental feasible measure of entanglement. Nevertheless, such measurements are limited both from experimental uncertainties and intrinsic quantum bounds. Here we present an experiment where the amount of entanglement of a family of two-qubit mixed photon states is estimated with the ultimate precision allowed by quantum mechanics.Comment: 4 pages, 3 figure

TESTING OF MODELS OF EXPLOSION PROTECTION SYSTEM FOR HIGHVOLTAGE OIL-FILLED ELECTRICAL EQUIPMENT

Explosions of high voltage oil-filled electrical equipment (OFEE) lead to a significant material damage. These explosions occur under action of an arc discharge (AD) which arises after internal short circuit. Modernization of OFEE design and protection systems is the possible way to achieve significant reduction of potential explosion and substantial reduction of material losses. Examination of perspective explosion-proof OFEE designs and new explosion protection systems demands the effective test methods. In present work results of development and application of an arcless source of pulse pressure (ASPP) are described. In ASPP the testing impulse is produced by the jet of powder gases (JPG) which arises at the combustion of explosive materials. In this work results of experimental researches of AD in transformer oil (TO) at conditions typical for AD initial stage have been presented: current rise time was 3-5 ms, the maximum arc current was up to 30 kA, AD burning time was 3-20 ms. The energy released in AD amounted to 0.1 MJ. It was established, that electric field strength in AD column was about 0.2 kV/сm, gas producing factor in AD was 110 l/MJ, growth rate of pressure in TO was about 0.3 MPa/ms. These results allowed to create an ASPP with demanded parameters. Experiments proved that TO flow under action of AD and JPG are similar given that the same influence duration of the energy released in AD is equalled enthalpy of JPG at liquid inlet. In this work the transformer fracturing behavior after explosion has been analyzed; and the requirements for protection systems have been formulated. By means of ASPP the breadboard model tests of two well-known OFEE explosion protection methods were carried out. In the first method it is assumed that the protection is reached due to fast dump of pressure inside of OFEE case when special membranes are opened. In the second protection method it is offered to establish porous coverings on internal surfaces of OFEE cases. Experiments were carried out on OFEE model with the characteristic size of 1 m at action energy up to 1.5 MJ. It was shown, that these systems cannot protect the transformer body from significant damages. The dynamic protection system of transformer (DPS) has been described. The efficiency of this new system using ASPP has been verified in experiments with autotransformer of 25 MW. It was shown that DPS protects the transformer from considerable damages at least at dynamic impulse of about 3 MJ

The role of viruses, inflammation and myocardial macrophages in the development of idiopathic arrhythmia

We studied viral antigens, inflammation, and macrophages in the endomyocardial biopsies of patients with idiopathic arrhythmias. Immunohistological study was performed to identify the antigens of cardiotropic viruses and the types of lymphocytes and macrophages. We observed the presence of viral antigens in the myocardium of patients with and without histological criteria of myocarditis. Heart failure and ventricular arrhythmias were associated with small focal infiltration of the myocardium with macrophages. The presence of viral antigens in the myocardium was associated with fewer number of myocardial M2 macrophages. Severity of myocardial interstitial fibrosis correlated with small-focal infiltration of M2 macrophages

Thermal structure in the Venus middle cloud layer

Thermal structure measurements obtained by the two Vega balloons show the Venus atmosphere in the middle cloud layer to be near-adiabatic, on the whole; but discrete air masses are present that differ slightly from one another in potential temperature and entropy. The Vega 1 temperatures are 6.5 K warmer than measured by Vega 2 at given pressures. Measurements taken by the Vega 2 lander on descent through these levels agree with the Vega 2 balloon data

Meteorological Data Along the VEGA-1 and VEGA-2 Float Paths

During their flight through the Venus atmosphere the Vega 1 and Vega 2 balloon craft measured the pressure and temperature of the ambient medium, the vertical wind-velocity component (relative to the gondola), the cloud-layer backscatter coefficient, the mean illumination level, and the number and time of possible lightning flashes. In addition, the ground radio telescope network measured the balloon positions and drift velocities by the differential VLBI technique; these data are now being processed

Modernization of the Intake Tract of a Piston Engine by Using a Pipeline with a Square and Triangular Cross Section

Современные двигатели модернизируются каждый год. Совершенствование газодинамических трубопроводов перспективное направление улучшения двигателя внутреннего сгорания. Предлагаем применение треугольного и квадратного профиля сечения канала для уменьшения застойных зон. В ходе натурного эксперимента с использованием тепловизора мы заметили уменьшение застойных зон в цилиндре двигателя с треугольным каналом и ещё меньшее количество данных зон с квадратным профилем. Применение профилированных каналов значительно изменит структуру потока газа, создаст равномерное поле скоростей внутри цилиндра, увеличит наполнение газовой камеры.Modern engines are upgraded every year. Improvement of gas-dynamic pipelines is a promising direction for improving the internal combustion engine. We propose the use of triangular and square cross-section profiles of the channel to reduce stagnant zones. During a full-scale experiment using a thermal imager, we noticed a decrease in stagnant zones in the cylinder of an engine with a triangular channel and an even smaller number of these zones with a square profile. The use of profiled channels can significantly change the structure of the gas flow, create a uniform velocity field inside the cylinder, and increase the filling of the gas chamber.Работа выполнена при поддержке РНФ в рамках научного проекта №23-29-00022.Supported by grant from the Russian Science Foundation №23-29-00022