1,504 research outputs found
Error of an arbitrary single-mode Gaussian transformation on a weighted cluster state using a cubic phase gate
In this paper, we propose two strategies for decreasing the error of
arbitrary single-mode Gaussian transformations implemented using one-way
quantum computation on a four-node linear cluster state. We show that it is
possible to minimize the error of the arbitrary single-mode Gaussian
transformation by a proper choice of the weight coefficients of the cluster
state. We modify the computation scheme by adding a non-Gaussian state obtained
using a cubic phase gate as one of the nodes of the cluster. This further
decreases the computation error. We evaluate the efficiencies of the proposed
optimization schemes comparing the probabilities of the error correction of the
quantum computations with and without optimizations. We have shown that for
some transformations, the error probability can be reduced by up to 900 times.Comment: 14 pages, 8 figure
Guided random walk calculation of energies and <\sq {r^2} > values of the state of H_2 in a magnetic field
Energies and spatial observables for the state of the hydrogen
molecule in magnetic fields parallel to the proton-proton axis are calculated
with a guided random walk Feynman-Kac algorithm. We demonstrate that the
accuracy of the results and the simplicity of the method may prove it a viable
alternative to large basis set expansions for small molecules in applied
fields.Comment: 10 pages, no figure
Atomic, electronic and magnetic structure of graphene/iron and nickel interfaces: theory and experiment
First-principles calculations of the effect of carbon coverage on the atomic,
electronic and magnetic structure of nickel and iron substrates demonstrate
insignificant changes in the interatomic distances and magnetic moments on the
atoms of the metallic substrates. The coverage of the iron surface by mono- and
few-layer graphene induces significant changes in the orbital occupancies and
exchange interactions between the layers in contrast to the case of a nickel
substrate for which changes in the orbital ordering and exchange interactions
are much smaller. Experimental measurements demonstrate the presence of
ferromagnetic fcc-iron in Fe@C nanoparticles and the superparamagnetic behavior
of Ni@C nanoparticles.Comment: 19 pages, 7 figures, accepted to RSC Advance
Einfluß der Zusammensetzung auf die Strahlenversprödung von Eisenlegierungen
The radiation embrittlement of the reactor pressure vessel is highly safety-relevant for VVER-type pressure vessels. The sensitivity against radiation embrittlement depends on the chemical composition of the pressure vessel steel. Using an irradiation experiment at surveillance positions in two Russian VVER 440-type reactors the effects of copper, phosphorus and nickel on the radiation embrittlement should be investigated. For that, eight mock-up alloys were selected. Their chemical composition varied between 0.015 and 0.42 % Cu, 0.002 and 0.039 % P, 0.01 and 1.98 % Ni, 0.09 and 0.37 % Si, and 0.35 and 0.49 % Mn. Charpy-V impact tests and tensile tests were performed with specimens machined from these alloys. The specimens were tested in the as-received state, in the irradiated state (fluence: 1x1019 and 8x1019 /cm2 [E>0.5 MeV]) an in the post-irradiation annealed state. In the as-received state, the alloys have a ferritic microstructure. Apart from Cu, the alloyed elements are solved in the matrix. Irradiation produces strong hardening and embrittlement. The effect increases with the Cu and P content. Ni causes an additional embrittlement. It is independent on the Ni concentration within the range of 1.1 to 2 % Ni and results in a shift of the ductile-brittle transition temperature of about 120 °C after a fluence of 1x1019 /cm2 by a flux of 4x1011 /cm2s. The shift does not depend on the Cu or P content. Furthermore the upper shelf energy is especially reduced by the Ni-rich alloys. For very low content of Cu and P these relations are not valid. The irradiation effect can be eliminated by annealing at 475 °C /100 h. For high content of Cu or P the recovery is incomplete, it remains a residue of 20 to 25 % of the irradiation effect. Ni has no influence on the recovery. Comparing the results of this study with the ones of the surveillance programmes of the VVER 440-type reactors, the alloys with low Ni content show the same irradiation behaviour as the weld metal. For the Ni rich alloys such well-walidated references are missing. The experiment is part of an extended research programme. It supposed to continue in order to gain information about the synergistic effects of these elements
Excitonic instability and electric-field-induced phase transition towards a two dimensional exciton condensate
We present an InAs-GaSb-based system in which the electric-field tunability
of its 2D energy gap implies a transition towards a thermodynamically stable
excitonic condensed phase. Detailed calculations show a 3 meV BCS-like gap
appearing in a second-order phase transition with electric field. We find this
transition to be very sharp, solely due to exchange interaction, and so, the
exciton binding energy is greatly renormalized even at small condensate
densities. This density gradually increases with external field, thus enabling
the direct probe of the Bose-Einstein to BCS crossover.Comment: LaTex, 11 pages, 3 ps figures, To appear in PR
Kostroma cattle breed in the new century: the state and the prospects (review)
The article reflects the current state and the prospects of the Kostroma cattle breed development. The creation and improvement of the breed anticipated the formation and further breed development in the domestic and world zoo technical science. In recent years, the number of Kostroma cattle breed has been unreasonably reducing despite its economic valuable traits. At the same time in the Kostroma region there are prospects for preserving the valuable gene pool of one of the best domestic dairy and meat cattle breeds. As a result of directed selection and breeding work with the use of Brown Swiss bulls, a stud milk breed "Karavaevsky KK-1" has been developed. At present cow-champions of the Kostroma breed give up to 12,000 kg of milk per lactation. The milk of the Kostroma breed cows has a high content of protein and fat. The animals of Kostroma breed have good meat qualities, high resistance to a number of diseases, strong ungulate horn, easy adaptability to intensive technologies, good fertility and high productive longevity. To save the Kostroma breed it is important to put on 8-10 bulls of 8 planned lines and related groups for the validation and accumulation of sperm every year. The restoration of previously created lines with high genetic potential should be foreseen. It is necessary to identify and actively use the stud bulls bred in their own breeding farms; to conduct a linear assessment of bulls and daughter heifers by body type for more competent selection. In addition to the generally accepted forms and methods of selection, it is necessary to continue immunogenetic control of the authenticity of the origin of breeding animals and introduce modern methods of DNA technology to assess the breeding and productive qualities of cattle, which will reveal valuable genetic complexes in the best breeding animals and thus 1.5-2 times accelerate the selection processes.Conflict of interest: the authors stated that there was no conflict of interest
Particle-in-cell simulations of rf breakdown
Breakdown voltages of a capacitively coupled radio frequency argon discharge
at 27 MHz are studied. We use a one-dimensional electrostatic PIC code to
investigate the effect of changing the secondary emission properties of the
electrodes on the breakdown voltage, particularly at low pd values. Simulation
results are compared with the available experimental results and a satisfactory
agreement is found.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
Comparison of phenotypic properties of innate lymphoid cells at various stages of rheumatoid arthritis
Autoimmune diseases currently take a leading place in terms of frequency of occurrence in the population, among which 1 percent is occupied by rheumatoid arthritis (RA). Remission in this type of disease is extremely rare and requires constant use of pharmacotherapy. Studying the pathogenesis of RA is necessary to study to search for new drug targets. It is known that T helpers 1 (Th) and Th17 are involved in the development of RA. However, some researchers suggest that ILCs play a role in the development of RA. ILCs are “innate analogues” of Th, due to the fact that this subpopulation synthesizes the same cytokines. ILC1 is innate analogs of Th1, ILC2-Th2, ILC3-Th17. ILCs are tissue-resident innate lymphoid cells that have functional diversity and regulate the direction of the immune response through the production of cytokines.We used peripheral blood mononuclear cells (PBMCs) from patients (n = 19) and conditionally healthy donors (n = 10) as material. The group of patients was divided biologic disease-modifying anti-rheumatic drugs (bDMARDs) and Metotrexate (MTX) and of stage of RA (early and very early arthritis, advanced and late). PBMCs were stained with monoclonal antibodies. ILCs were identified as Lin-CD127+, CD294+ILCs (ILC2) were measured in the general population, CD117-CD294-ILCs were identified as ILC1, and CD117+CD294-ILCs were identified as ILC3.We obtained the following results: ILC1 was significantly reduced in patients treated with MTX comparison with patients on bDMARDs and healthy donors. However, patients on MTX with advanced RA had low levels of ILC2 and ILC3 compared to patients on bDMARDs. ILC2 significantly increased in patients with early stages of RA comparison with patients with advanced RA. However, ILC1 was significantly reduced in patients treated with MTX, and ILC3 increased significantly in patients treated with MTX comparison with bDMARDs. Expression of PD1 on ILC1 was increased compared to patients treated with bDMARDs. However, ILC3 patients with advanced stages on MTX had increased expression of PD1 comparison with patients taking bDMARDs. The ILC3 of donors was significantly increased comparison with patients on bDMARDs
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