Solving the difference initial-boundary value problems by the operator exponential method

We suggest a modification of the operator exponential method for the numerical solving the difference linear initial boundary value problems. The scheme is based on the representation of the difference operator for given boundary conditions as the perturbation of the same operator for periodic ones. We analyze the error, stability and efficiency of the scheme for a model example of the one-dimensional operator of second difference

Localization of superconductivity in superconductor-electromagnet hybrids

We investigate the nucleation of superconductivity in a superconducting Al strip under the influence of the magnetic field generated by a current-carrying Nb wire, perpendicularly oriented and located underneath the strip. The inhomogeneous magnetic field, induced by the Nb wire, produces a spatial modulation of the critical temperature T_c, leading to a controllable localization of the superconducting order parameter (OP) wave function. We demonstrate that close to the phase boundary T_c(B_ext) the localized OP solution can be displaced reversibly by either applying an external perpendicular magnetic field B_ext or by changing the amplitude of the inhomogeneous field.Comment: 10 pages, 6 figure

Mesoscopic cross-film cryotrons: Vortex trapping and dc-Josephson-like oscillations of the critical current

We investigate theoretically and experimentally the transport properties of a plain Al superconducting strip in the presence of a single straight current-carrying wire, oriented perpendicular to the superconducting strip. It is well known that the critical current of the superconducting strip, Ic, in such cryotron--like system can be tuned by changing the current in the control wire, Iw. We demonstrated that the discrete change in the number of the pinned vortices/antivortices inside the narrow and long strip nearby the current-carrying wire results in a peculiar oscillatory dependence of Ic on Iw.Comment: 8 pages, 8 figure

Water data analysis: data reduction from beam and ITC info

After recalling the motivation for the analysis of water data, the first stage of data reduction is discussed. This data reduction is based on the selection of protons using beam detector data and ITC information. The resolution of the interaction time in the target which serves as reference for time-of-flight measurement of secondaries, is determined with stable beam optics to be 77 ps, otherwise 106 ps. Cuts, their selection efficiency, event numbers, purity of the data sample after cuts, and some ITC characteristics are presented

Роль кристонных источников сдвига в формировании полос Чернова-Людерса

Shear bands often appear during plastic deformation. The Chernov-Luders band is an example of a complex multiscale heterogeneous structure containing shear bands. The article is devoted to the analysis of a part of the experimental data on the formation (under tension) of Chernov-Luders band in textured polycrystalline steel samples with fine grain, pre-deformed by rolling. The main attention is focused on the criston mechanism of formation of the observed texture components. The essence of the criston approach, associated with the contact interaction of dislocations at the intersection of slip planes, is briefly described. Information on the observed types of texture is given and a sufficiently detailed analysis of the reconstruction of the mechanism of the appearance of several texture components is carried out taking into account the interaction of the main dislocation slip systems for a body-centered cubic (bcc) lattice. It is shown that some of the real shear directions correspond to the interaction of more than two dislocation slip systems, that is, in fact, there are criston-cristons combinations. A summary table of the results of the analysis of the "composition" of cristons for all texture components is presented, reflecting the fractional contribution of dislocations belonging to interacting slip systems. The analysis has shown that practically all systems of standard slip along the planes of the {110}, {112}, {123} families play an active role in the formation of cristons and, accordingly, the observed texture. Brief summary comments are provided. In particular, it was noted that, with a sequential criston approach, the issue of non-Schmidian slip variants can be eliminated. The important role of texturing is also noted for the ordering of the intergranular medium and the appearance of macroconcentrators in groups of contacting grains, which, as experience shows, are important in the formation of Chernov-Luders band. © 2021 Izdatel'stvo Meditsina. All rights reserved.This work was supported by the Ministry of Science and Higher Education of the Russian Federation (state task No 075-00243-20-01, FEUZ-2020-0013)

S 2p photoabsorption of the SF5CF3 molecule: Experiment, theory and comparison with SF6

The S 2p core excitation spectrum of the SF5CF3 molecule has been measured in the total ion yield mode. It resembles a lot the analogous spectrum of SF6, also recorded in this study, displaying intense transitions to the empty molecular orbitals both below and above the S 2p ionization potential (IP) and weak transitions to the Rydberg orbitals. The S 2p photoabsorption spectra of SF6 and SF5CF3 have been calculated using time-dependent density functional theory, whereby the spin–orbit coupling was included for the transitions below the S 2p IP. The agreement between experiment and theory is good for both molecules, which allows us to assign the main S 2p absorption features in SF5CF3

Revisiting the 'LSND anomaly' II: critique of the data analysis

This paper, together with a preceding paper, questions the so-called 'LSND anomaly': a 3.8 sigma excess of antielectronneutrino interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the antimuonneutrino to antielectronneutrino oscillation in the \Deltam2 range from 0.2 eV2 to 2 eV2. Such a \Deltam2 range is incompatible with the widely accepted model of oscillations between three light neutrino species and would require the existence of at least one light 'sterile' neutrino. In a preceding paper, it was concluded that the estimates of standard backgrounds must be significantly increased. In this paper, the LSND Collaboration's estimate of the number of antielectronneutrino interactions followed by neutron capture, and of its error, is questioned. The overall conclusion is that the significance of the 'LSND anomaly' is not larger than 2.3 sigma.Comment: 30 pages, 16 figures, 6 table