Ultracold ions provide one of the most promising platforms for quantum computing and make it possible to reach record coherence times, the fidelity of preparation and readout operations, and single- ...and two-qubit operations. Encoding quantum information in an optical qubit based on the
→
quadrupole transition in the
171
Yb
+
ion at a wavelength of 435.5 nm, which has potential advantages over similar systems in the scaling of the number of qubits and their sensitivity to fluctuations of the magnetic field, is proposed and experimentally studied. The proposed optical qubit in ytterbium is compared to other most widespread types of ion qubits. Experimental results on the implementation of the Pauli-X single-qubit operation are given. The fidelity of the operation is 96% after correction to the error of preparation and readout and is limited by the temperature of the ion.
A scheme based on a laser cooling system has been proposed to detect the state of an optical qubit in the
171
Yb
+
ion. Analytical expressions have been derived for the readout fidelity including ...the dark photon counts and background. The parameters of the experiment have been numerically optimized to minimize the readout infidelity. The upper bound on the fidelity associated with a transient process at the beginning of the measurement procedure has been determined as 99.4%. The characteristic parameters of detection ensuring a sufficient proximity to the upper bound have been found.
Cadmium zinc telluride crystals were grown using the traveling heater method (THM) under microgravity conditions on board of Foton-M4 spacecraft, and a reference crystal was grown on Earth under ...gravity conditions. Structure, chemical and phase compositions of these crystals, their optical characteristics and microhardness were compared. It can be concluded that the THM growth in microgravity has a positive effect on CZT crystals, since they have more homogeneous composition and their structural perfection is improved as compared with the crystals grown under terrestrial conditions, which results in improvement of electric and optical characteristics.
•Traveling heater method was used to grow CZT crystals in microgravity.•As a result, CZT single crystals with homogeneous composition are obtained.•Growth in microgravity leads to increase in resistivity and IR transmission of CZT.
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•Three types of ore mineral assemblages were established at the Rogovik deposit.•T,X-parameters of two ore-forming stages were determined.•Formation of the Au, Ag, polymetallic ...mineralization was described by various models.
The T,X-parameters of the main ore-forming stages of the Rogovik epithermal gold-silver deposit (northeastern Russia) were determined using microthermometric techniques on fluid inclusion assemblages. On the basis of these data we carried out thermodynamic calculations that model the formation conditions of three types of ore mineral assemblages: gold-silver – at the early volcanic stage, silver-polymetallic and silver-gold-polymetallic – at the late volcanoplutonic stage. The silver-gold-polymetallic mineralization is located at the sites where silver-polymetallic and gold-silver zones overlap. The calculations were made using the “Selektor-C” software within a complex geochemical multicomponent system. Several scenarios of formation of gold-silver mineralization at an early volcanic stage were considered: 1) boiling of a hydrothermal solution; 2) interaction of residual aqueous solution with host rocks; 3) mixing of an ore-bearing gas phase with meteoric waters. For the late volcanoplutonic stage, we modeled formation of “silver mineralization” using an ore-forming solution genetically related to a deep-seated granite massif and its interaction with host rocks and gold-silver zones of early volcanic stage. These physicochemical models substantially improve our understanding of formation of the three types of mineral assemblages at the Rogovik deposit and can be applied to other epithermal deposits with similar mineralization styles.
In their previous work
1
, the authors presented a method of identifying the characteristics of a gaseous medium from measurements of the heat flux absorbed by the surface of a blunt body in a gas ...flow. The identification problem was stated in an extreme formulation: the sought-for transport properties of a gaseous medium were determined via minimization of the objective function of the estimated and measured heat fluxes absorbed by the surface of a solid body. For minimization of the objective function, the Nelder–Mead method was used in combination with random restarts; the results of testing the algorithm in a model experiment are given. This paper presents the technique of conduction of experiment to verify the method for identification of the gas flow parameters. Experimental results are given for two different gas flow sources.
In the paper, the spark plasma sintering (SPS) process for metal particles has been simulated based on experimental data and using the finite element method in the thermo-electro-mechanical ...formulation with taking into account the temperature influence on parameters of materials (nickel and copper). A comparison of obtained results with experimental data made it possible to create a computational model of the SPS process, the model being convenient to evaluate the influence of creep and plasticity parameters on the size of the interparticle neck forming in SPS. It was found that the creep effect significantly dominated over the plasticity influence on the process of forming the sintering neck at high temperatures. In this case, the variation of creep parameters in simulation also actively affects the formation of the neck.
A composition of the paste used in printing SOFC anodes is developed on the basis of nanosized nickel oxide and gadolinia-stabilized ceria with the aim of 3D inkjet printing followed by laser and ...thermal sintering. The parameters of the anode paste such as the size distribution of particles and the viscosity are determined. A SOFC anode sample is printed by means of a laboratory 3D printer equipped with a metering system for inkjet printing and also by a module for laser treatment. Experiments are carried out on printing three-dimensional test objects with the use of the developed ceramic paste. These samples are studied by a complex of physicochemical methods for determination of morphological and structural characteristics.
Abstract
The effect of different seeding rates, providing the density of 40, 60, and 80 thousand plants/ha, on the yield and its quality of the new sunflower hybrids of VNIIMK breeding (Immi, Arneb, ...Gorfild) was studied at the V.S. Pustovoit All-Russian Research Institute of Oil Crops (VNIIMK) (Krasnodar) in 2019-2020. The purpose of the research is to determine the effect of different seeding rates on the elements of plant productivity, yield, oil content of seeds, and oil yield of promising sunflower hybrids. The sunflower hybrid Arneb appeared to be the most stable in terms of productivity at different seeding rates. It has a high tolerance to its increase even under a water deficiency. Hybrids Immi and Gorfild are more susceptible to plant thickening. Their productivity is decreasing in unfavorable water conditions.
Within the program “Ecosystems of the Siberian Arctic Seas,” carried out by Shirshov Institute of Oceanology, Russian Academy of Sciences since 2007, studies of the water structure and spatial ...variability of the parameters of the carbonate system have been performed, and the intensity and direction of the carbon dioxide flux over the continental slope of the Laptev Sea and in the Vilkitsky Strait in September 2018 have been calculated. The presence of several main water masses that govern the water structure in the study area is shown. A strong spatial variability of the parameters of the carbonate system of seawater, determined by complexes of physical and chemical–biological processes, has been revealed. The intensity and direction of the carbon dioxide flux at the water–atmosphere boundary were calculated, which range from –12 to 4 mmol m
–2
day
–1
. It was revealed that the investigated area of the outer shelf and continental slope of the Laptev Sea is an emitter of carbon dioxide into the atmosphere as of September 2018. Conversely, the area of the Vilkitsky Strait, is a CO
2
sink zone.
Using the method of molecular beam epitaxy with the plasma activation of nitrogen, experimental AlN/GaN heterostructures (HSs) with an ultrathin AlN barrier are obtained
.
The layer resistance of the ...optimized structures is less than 230 Ω/□. The scattering processes that limit the mobility of a two-dimensional electron gas (2DEG) in undoped AlN/GaN HSs with an ultrathin AlN barrier are studied. It is shown that in the range of
n
s
characteristic for AlN/GaN HEMT HSs (
n
s
> 1 × 10
13
cm
–2
), a noticeable contribution to the scattering of charge carriers is made by the roughness of the heterointerface.
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