48 research outputs found

    Spin-polarized Andreev tunneling through the Rashba chain

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    We demonstrate that the selective equal spin Andreev reflection (SESAR) spectroscopy can be used in STM experiments to distinguish the zero-energy Majorana quasiparticles from the ordinary fermionic states of the Rashba chain. Such technique, designed for probing the p-wave superconductivity, could be applied to the intersite pairing of equal-spin electrons in the chain of magnetic Fe atoms deposited on the superconducting Pb substrate. Our calculations of the effective pairing amplitude for individual spin components imply the magnetically polarized Andreev conductance, which can be used to `filter' the Majorana quasiparticles from the ordinary in-gap states, although the pure spin current (i.e., perfect polarization) is impossible.Comment: 8 pages, 6 figure

    Transport properties of nanosystems with conventional and unconventional charge density waves

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    We report a systematic study of transport properties of nanosytems with charge density waves. We demonstrate, how the presence of density waves modifies the current-voltage characteristics. On the other hand hand, we show that the density waves themselves are strongly affected by the applied voltage. This self-consistent problem is solved within the formalism of the nonequilibrium Green functions. The conventional charge density waves occur only for specific, periodically distributed ranges of the voltage. Apart from the low voltage regime, they are incommensurate and the corresponding wave vectors decrease discontinuously when the voltage increases.Comment: 7 pages, 7 figures, revte

    Spontaneous currents in a bosonic ring

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    Nonequilibrium dynamics of noninteracting bosons in a one-dimensional ring-shaped lattice is studied by means of the Kinetic Monte Carlo method. The system is approximated by the classical XY model (the kinetic term is neglected) and then the simulations are performed for the planar classical spins. We study the dynamics that follows a finite-time quench to zero temperature. If the quench is slow enough the system can equilibrate and finally reaches the ground state with uniform spin alignment. However, we show that if the quench is faster than the relaxation rate, the system can get locked in a current-carrying metastable state characterized by a nonzero winding number. We analyze how the zero-temperature state depends on the quench rate.Comment: 6 pages, 3 figure

    What effect might the No Child Left Behind Act have on administrators\u27 and teachers\u27 decisions to promote or retain the low achieving student in the elementary grades?

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    This study attempts to determine how this Act impacts professional educators in their decisions regarding promotion or retention of the low achieving student. Regular Educators in the West Deptford School District were asked to participate to show whether NCLB impacts the professional educators within this district when deciding whether to promote or retain the low achieving student. A Likert survey was designed and\u27distributed to 51 professional educators within the district. Of the educators asked, 21 responded. The survey results were graphed and analyzed. The scores of the West Deptford School District participants were compared to a hypothetical school district of professional experts. Comparison of the groups measured by the results of this survey showed a significant difference existed between the experts and educators resulting in the rejection of the Null Hypothesis which states that there is no significant difference between professional educators and experts decisions to promote or retain the low achieving student when factoring in the No Child Left Behind Act

    Pattern formation in mixtures of ultracold atoms in optical lattices

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    Regular pattern formation is ubiquitous in nature; it occurs in biological, physical, and materials science systems. Here we propose a set of experiments with ultracold atoms that show how to examine different types of pattern formation. In particular, we show how one can see the analog of labyrinthine patterns (so-called quantum emulsions) in mixtures of light and heavy atoms (that tend to phase separate) by tuning the trap potential and we show how complex geometrically ordered patterns emerge (when the mixtures do not phase separate), which could be employed for low-temperature thermometry. The complex physical mechanisms for the pattern formation at zero temperature are understood within a theoretical analysis called the local density approximation.Comment: 5 pages, 4 figures, typeset in ReVTe
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