121,797 research outputs found

    Guiding-center Hall viscosity and intrinsic dipole moment along edges of incompressible fractional quantum Hall fluids

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    The discontinuity of guiding-center Hall viscosity (a bulk property) at edges of incompressible quantum Hall fluids is associated with the presence of an intrinsic electric dipole moment on the edge. If there is a gradient of drift velocity due to a non-uniform electric field, the discontinuity in the induced stress is exactly balanced by the electric force on the dipole. The total Hall viscosity has two distinct contributions: a "trivial" contribution associated with the geometry of the Landau orbits, and a non-trivial contribution associated with guiding-center correlations. We describe a relation between the guiding-center edge-dipole moment and "momentum polarization", which relates the guiding-center part of the bulk Hall viscosity to the "orbital entanglement spectrum(OES)". We observe that using the computationally-more-onerous "real-space entanglement spectrum (RES)" just adds the trivial Landau-orbit contribution to the guiding-center part. This shows that all the non-trivial information is completely contained in the OES, which also exposes a fundamental topological quantity γ\gamma = c~−ν\tilde c-\nu, the difference between the "chiral stress-energy anomaly" (or signed conformal anomaly) and the chiral charge anomaly. This quantity characterizes correlated fractional quantum Hall fluids, and vanishes in uncorrelated integer quantum Hall fluids

    Comments on "Entropy of 2D Black Holes from Counting Microstates"

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    In a recent letter, Cadoni and Mignemi proposed a formulation for the statistical computation of the 2D black holes entropy. We present a criticism about their formulation.Comment: 5 pages, Latex, no figure

    Anomalous Pressure Dependence of Kadowaki-Woods ratio and Crystal Field Effects in Mixed-valence YbInCu4

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    The mixed-valence (MV) compound YbInCu4 was investigated by electrical resistivity and ac specific heat at low temperatures and high pressures. At atmospheric pressure, its Kadowaki-Woods (KW) ratio, A/\gamma ^2, is 16 times smaller than the universal value R_{KW}(=1.0 x 10^-5 \mu \Omega cm mol^2 K^2 mJ^-2), but sharply increases to 16.5R_{KW} at 27 kbar. The pressure-induced change in the KW ratio and deviation from R_{KW} are analyzed in terms of the change in f-orbital degeneracy N and carrier density n. This analysis is further supported by a dramatic change in residual resistivity \rho_0 near 25 kbar, where \rho_0 jumps by a factor of 7.Comment: 4pages, 3figure

    Towards Efficient Full Pose Omnidirectionality with Overactuated MAVs

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    Omnidirectional MAVs are a growing field, with demonstrated advantages for aerial interaction and uninhibited observation. While systems with complete pose omnidirectionality and high hover efficiency have been developed independently, a robust system that combines the two has not been demonstrated to date. This paper presents VoliroX: a novel omnidirectional vehicle that can exert a wrench in any orientation while maintaining efficient flight configurations. The system design is presented, and a 6 DOF geometric control that is robust to singularities. Flight experiments further demonstrate and verify its capabilities.Comment: 10 pages, 6 figures, ISER 2018 conference submissio

    Montessori Education and a Neighborhood School: A Case Study of Two Early Childhood Education Classrooms

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    Project SYNC (Systems, Yoked through Nuanced Collaboration) details perspectives of a community of stakeholders committed to the enhancement of early childhood (i.e., prekindergarten through grade 3) education. Although there is a growing number of public-school programs informed by the Montessori philosophy, Montessori educational experiences often take place within affluent communities. SYNC aimed to enhance the prekindergarten through grade 3 educational experiences for traditionally underserved students by transforming two traditional early childhood classrooms to Montessori settings within a diverse, Title I school. Montessori pedagogy, curricula, and materials aligned with the school’s dedicated commitment to social justice. The study, one in a series, explored the impact of Montessori education on a neighborhood school community as evidenced through stakeholder opinions, project implementation, and teacher attitudes. Project data illustrate that a Montessori educational experience created learning opportunities that supported children from culturally and ethnically diverse communities in a traditional, Title I elementary school

    The Second Virial Coefficient of Spin-1/2 Interacting Anyon System

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    Evaluating the propagator by the usual time-sliced manner, we use it to compute the second virial coefficient of an anyon gas interacting through the repulsive potential of the form g/r2(g>0)g/r^2 (g > 0). All the cusps for the unpolarized spin-1/2 as well as spinless cases disappear in the ω→0\omega \to 0 limit, where ω\omega is a frequency of harmonic oscillator which is introduced as a regularization method. As gg approaches to zero, the result reduces to the noninteracting hard-core limit.Comment: 9 pages, 2 figs include

    The Solar pp and hep Processes in Effective Field Theory

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    The strategy of modern effective field theory is exploited to pin down accurately the flux SS factors for the pppp and hephep processes in the Sun. The technique used is to combine the high accuracy established in few-nucleon systems of the "standard nuclear physics approach" (SNPA) and the systematic power counting of chiral perturbation theory (ChPT) into a consistent effective field theory framework. Using highly accurate wave functions obtained in the SNPA and working to \nlo3 in the chiral counting for the current, we make totally parameter-free and error-controlled predictions for the pppp and hephep processes in the Sun.Comment: 5 pages, aipproc macros are included. Talk given at International Nuclear Physics Conference 2001, Berkeley, California, July 30 - August 3, 200
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