2,472 research outputs found
g-Factor anisotropy of hole quantum wires induced by the Rashba interaction
We present calculations of the g factors for the lower conductance steps of
3D hole quantum wires. Our results prove that the anisotropy with magnetic
field orientation, relative to the wire, originates in the Rashba spin-orbit
coupling. We also analyze the relevance of the deformation, as the wire evolves
from 3D towards a flat 2D geometry. For high enough wire deformations, the
perpendicular g factors are greatly quenched by the Rashba interaction. On the
contrary, parallel g factors are rather insensistive to the Rashba interaction,
resulting in a high g factor anisotropy. For low deformations we find a more
irregular behavior which hints at a sample dependent scenario.Comment: 7 pages, 6 figures (expanded from previous version
Multichannel effects in Rashba quantum wires
We investigate intersubband mixing effects in multichannel quantum wires in
the presence of Rashba spin-orbit coupling and attached to two terminals. When
the contacts are ferromagnetic and their magnetization direction is
perpendicular to the Rashba field, the spin-transistor current is expected to
depend in a oscillatory way on the Rashba coupling strength due to spin
coherent oscillations of the travelling electrons. Nevertheless, we find that
the presence of many propagating modes strongly influences the spin precession
effect, leading to (i) a quenching of the oscillations and (ii) strongly
irregular curves for high values of the Rashba coupling. We also observe that
in the case of leads' magnetization parallel to the Rashba field, the
conductance departs from a uniform value as the Rashba strength increases. We
also discuss the Rashba interaction induced current polarization effects when
the contacts are not magnetic and investigate how this mechanism is affected by
the presence of several propagating channels.Comment: 8 pages, 7 figure
Collective oscillations in quantum rings: a broken symmetry case
We present calculations within density functional theory of the ground state
and collective electronic oscillations in small two-dimensional quantum rings.
No spatial symmetries are imposed to the solutions and, as in a recent
contribution, a transition to a broken symmetry solution in the intrinsic
reference frame for an increasingly narrow ring is found. The oscillations are
addressed by using real-time simulation. Conspicuous effects of the broken
symmetry solution on the spectra are pointed out.Comment: ReVTeX, 5 embedded eps, two gifs. Accepted in EPJ
La polifonía litúrgica en la obra de Higini Anglès
El profesor Josep M. Llorens presenta la aportación musicológica de Higini Anglés como la piedra fundamental que corona la naciente musicología hispánica después de las aportaciones de Saldoni, Eslava, Soriano, Riaño, Barbieri, Mitjana y el maestro Felip Pedrell
A new technique based on mini-UAS for estimating water and bottom radiance contributions in optically shallow waters
The mapping of nearshore bathymetry based on spaceborne radiometers is commonly used for QC ocean colour products in littoral waters. However, the accuracy of these estimates is relatively poor with respect to those derived from Lidar systems due in part to the large uncertainties of bottom depth retrievals caused by changes on bottom reflectivity. Here, we present a method based on mini unmanned aerial vehicles (UAS) images for discriminating bottom-reflected and water radiance components by taking advantage of shadows created by different
structures sitting on the bottom boundary. Aerial surveys were done with a drone Draganfly X4P during October 1 2013 in optically shallow waters of the Saint Lawrence Estuary, and during low tide. Colour images with a spatial resolution
of 3 mm were obtained with an Olympus EPM-1 camera at 10 m height. Preliminary results showed an increase of the relative difference between bright and dark pixels (dP) toward the red wavelengths of the camera's receiver. This is
suggesting that dP values can be potentially used as a quantitative proxy of bottom reflectivity after removing artefacts related to Fresnel reflection and bottom adjacency effects.Peer ReviewedPostprint (published version
Metamorfosis bobardianas
La arquitecta italo-brasileña Lina Bo Bardi fue creadora de nuevas atmósferas urbanas cargadas de magia y misterio. Su trabajo
originó un diálogo entre la contundencia de su lenguaje y un contemporáneo equilibrio de paisaje y ciudad: una metamorfosis
entre la arquitectura y la naturaleza
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