Superconducting Junctions with Ferromagnetic, Antiferromagnetic or Charge-Density-Wave Interlayers

Spectra and spin structures of Andreev interface states and the Josephson current are investigated theoretically in junctions between clean superconductors (SC) with ordered interlayers. The Josephson current through the ferromagnet-insulator-ferromagnet interlayer can exhibit a nonmonotonic dependence on the misorientation angle. The characteristic behavior takes place if the pi state is the equilibrium state of the junction in the particular case of parallel magnetizations. We find a novel channel of quasiparticle reflection (Q reflection) from the simplest two-sublattice antiferromagnet (AF) on a bipartite lattice. As a combined effect of Andreev and Q reflections, Andreev states arise at the AF/SC interface. When the Q reflection dominates the specular one, Andreev bound states have almost zero energy on AF/ s-wave SC interfaces, whereas they lie near the edge of the continuous spectrum for AF/d-wave SC boundaries. For an s-wave SC/AF/s-wave SC junction, the bound states are found to split and carry the supercurrent. Our analytical results are based on a novel quasiclassical approach, which applies to interfaces involving itinerant antiferromagnets. Similar effects can take place on interfaces of superconductors with charge density wave materials (CDW), including the possible d-density wave state (DDW) of the cuprates.Comment: LT24 conference proceeding, 2 pages, 1 figur

Raising of the functioning efficiency of the automated information systems by planning the procedure of their improvement

Розглянуто принципи підвищення ефективності функціонування автоматизованих інформаційних систем на основі аналізу часу початку їх реінжинірингу, а також планування процедур удосконалення в цілому. Побудовано комплекс марковських і напівмарковських моделей для визначення показників надійності й продуктивності укрупнених кластерів автоматизованих інформаційних систем.Both, the principles of raising the efficiency of automated information systems functioning by analyzing the starting time of their re-engineering and improvement planning procedures in general are taken into consideration. The complex of the Markov and semi-Markov models to determine the reliability and productivity indices of enlarged clusters of automated information systems is built. To choose the depth (level) of penetration of reengineering procedures the quantitative and qualitative estimation is used. The depth of reengineering penetration is defined by the penetration coefficient correlated with the possible automation level of a certain system element in particular or the whole system in general. To determine the re-engineering starting time for the AIMS two approaches are used. The first one determines the best reengineering starting time by estimating the expenses increase on the system service. The second approach determines the average cycle time of the system on the basis of the semi-Markov model construction. The paper contains the numerical simulation of the distribution functions mean cycle time of dataset service for the Erlang distribution under the conditions defined mathematical expectation and variance for the time between failures, processing unit recovery time, set collection and dataset processing time Results obtained in our work limit the efficiency level of AIMS subsystems. For the systems with clear structural differentiation the estimation of the minimal acceptable level of the system performance indicator for each structural unit is done. As a result, the constraints ensemble was obtained. Thus, the obtained expressions for the structural components of AIMS can be used as limits of the effectiveness of these subsystems, when making decision on the whole system re-engineering. The novelty of this approach realization is the accounting of investments at the stage of the system functioning after the beginning of moral obsolescence and correlation of these expenses with the efficiency of the system ongoing improvement by estimation changes in the mean time of the system cycles. The total amount of efforts (financial, intellectual, creative) on continuous improvement determines the particular starting time and penetration depth of re-engineering procedures, which make possible to save due to the same factors providing the revolutionary change of the system modernization

Two experiments for the price of one? -- The role of the second oscillation maximum in long baseline neutrino experiments

We investigate the quantitative impact that data from the second oscillation maximum has on the performance of wide band beam neutrino oscillation experiments. We present results for the physics sensitivities to standard three flavor oscillation, as well as results for the sensitivity to non-standard interactions. The quantitative study is performed using an experimental setup similar to the Fermilab to DUSEL Long Baseline Neutrino Experiment (LBNE). We find that, with the single exception of sensitivity to the mass hierarchy, the second maximum plays only a marginal role due to the experimental difficulties to obtain a statistically significant and sufficiently background-free event sample at low energies. This conclusion is valid for both water Cherenkov and liquid argon detectors. Moreover, we confirm that non-standard neutrino interactions are very hard to distinguish experimentally from standard three-flavor effects and can lead to a considerable loss of sensitivity to \theta_{13}, the mass hierarchy and CP violation.Comment: RevTex 4.1, 23 pages, 10 figures; v2: Typos corrected, very minor clarifications; matches published version; v3: Fixed a typo in the first equation in sec. III

Migratory Patterns in IRs: CONTENTdm, Digital Commons and Flying the Coop

What is the importance of institutional history and special collections in a digital environment? Should these pieces of history have their own digital platform or be merged with the institutional repository? What role do repositories play in the institutional environment? What impact do digital historical collections have on the stakeholder contingent as well as the global community? The speakers will discuss the rationale behind migrating collections from CONTENTdm to institutional repositories (all using bepress’s Digital Commons platform). Reasons range from subscription costs to file format concerns to increased search optimization. The migratory act will be covered in terms of method used (Excel spreadsheets, bepress add-on service, and manual) along with suggestions and lessons learned. Comparisons in usage statistics between CONTENTdm and Digital Commons demonstrating increased access to collections will also be discussed. Ultimately, the speakers hope to engage in a dialogue on the initial questions of this abstract

Interface-induced d-wave pairing

We discuss a scenario for interface-induced superconductivity involving pairing by dipolar excitations proximate to a two-dimensional electron system controlled by a transverse electric field. If the interface consists of transition metal oxide materials, the repulsive on-site Coulomb interaction is typically strong and a superconducting state is formed via exchange of non-local dipolar excitations in the d-wave channel. Perspectives to enhance the superconducting transition temperature are discussed.Comment: 4 pages, 3 figure

Phosphorus-31 NMR of the Intact Crystalline Lens: I. The Living Lens Spectrum. II. The Spectroscopic Effects of Deuterium Oxide Incubation

Spectra of intact bovine and canine crystalline lenses in vitro at 37°C were generated using phosphorus-31 nuclear magnetic resonance (NMR). Lens incubation in a pure D2O buffer results in a progressive narrowing of the tissue P-31 NMR signals

Twist Defect in Chiral Photonic Structures

We demonstrate that twisting one part of a chiral photonic structure about its helical axis produces a single circularly polarized localized mode that gives rise to an anomalous crossover in propagation. Up to a crossover thickness, this defect results in a peak in transmission and exponential scaling of the linewidth for a circularly polarized wave with the same handedness as structure. Above the crossover, however, the linewidth saturates and the defect mode can be excited only by the oppositely polarized wave, resulting in a peak in reflection instead of transmission.Comment: 12 page

Two-dimensional electron liquid state at LaAlO3-SrTiO3 interfaces

Using tunneling spectroscopy we have measured the spectral density of states of the mobile, two-dimensional electron system generated at the LaAlO3-SrTiO3 interface. As shown by the density of states the interface electron system differs qualitatively, first, from the electron systems of the materials defining the interface and, second, from the two-dimensional electron gases formed at interfaces between conventional semiconductors

Towards common file formats and data standards for seafloor geodesy - Community Whitepaper for UNAVCO’s “Future Directions for Seafloor Geodesy” Committee, September 2020 (revision of July 13, 2021)

Seafloor geodesy experiments have been expanding considerably in recent years. More and more research teamsaround the globe are conducting projects to monitor the tectonic or volcanic deformation of the seafloor. Theseexperiments are commonly based on limited-duration experiments, but increasingly, permanent observatories arealso being installed. This dynamic development is very encouraging for the establishment of a strong community which arguably willlead to the emergence of a worldwide scientific and technical synergy. However, data andknowledge transferbetween the different groups working on similar topics are still limited at the present time. This can be partlyexplained by the fact that the instruments, infrastructure, and processing software developed are custom-made andthus various file formats are used, although the fundamental observables are most of the time identical. One wayto overcome this limitation is to set up exchange standards in the form of standardized file formats. These fileswould gather and store all the physical quantities observed and will prove useful for the processing simplificationand, in the end, the extraction of the geodetic signal sought. Furthermore, uniformized formats would allow muchmore easily the comparison of software and processing methods between research groups, whether during tests oroperational measurement campaigns. Standardized data will eventually provide a base for the activities of potentialfuture national or international observation services. They would also make it possible to envisage the datadissemination similar to geodetic data recorded on land

Coronal heating distribution due to low-frequency wave-driven turbulence

The heating of the lower solar corona is examined using numerical simulations and theoretical models of magnetohydrodynamic turbulence in open magnetic regions. A turbulent energy cascade to small length scales perpendicular to the mean magnetic field can be sustained by driving with low-frequency Alfven waves reflected from mean density and magnetic field gradients. This mechanism deposits energy efficiently in the lower corona, and we show that the spatial distribution of the heating is determined by the mean density through the Alfven speed profile. This provides a robust heating mechanism that can explain observed high coronal temperatures and accounts for the significant heating (per unit volume) distribution below two solar radius needed in models of the origin of the solar wind. The obtained heating per unit mass on the other hand is much more extended indicating that the heating on a per particle basis persists throughout all the lower coronal region considered here.Comment: 19 pages, 5 figures. Accepted for publication in Ap