1,187 research outputs found
Chiral filtration and Faraday rotation in multi-Weyl semimetals
In Weyl semimetals with broken inversion and time-reversal symmetries, the
Maxwell equations are modified by the presence of the axion terms
and where, in the simplest case of a two-node Weyl semimetal, is the vector that connects two Weyl nodes in momentum
space and is the separation in energy of the two Dirac points
of these nodes. These axion terms modify the behavior of electromagnetic waves
inside a Weyl semimetal leading to a number of unique optical properties such
as non-reciprocal propagation, circular and linear dichroism, birefringence and
Faraday and Kerr rotations in the absence of a magnetic field. These effects
can be used to design optical devices that act as broadband chiral filters,
circular polarizers or tunable optical isolators. In this paper, we study in
detail how the Faraday and Kerr rotations as well as the transmission and
reflection of light incident on a slab of Weyl semimetal can be controlled by
varying the different parameters characterizing the Weyl semimetal such as the
axion terms, the Fermi level and Fermi velocity, the background dielectric
constant, the scattering time for intraband scattering, the width of the
semimetal and the dielectric constant of the dielectrics on each side of the
semimetal slab. We extend our analysis to Weyl nodes with Chern number
.Comment: 18 pages, 14 figure
A homomorphism between link and XXZ modules over the periodic Temperley-Lieb algebra
We study finite loop models on a lattice wrapped around a cylinder. A section
of the cylinder has N sites. We use a family of link modules over the periodic
Temperley-Lieb algebra EPTL_N(\beta, \alpha) introduced by Martin and Saleur,
and Graham and Lehrer. These are labeled by the numbers of sites N and of
defects d, and extend the standard modules of the original Temperley-Lieb
algebra. Beside the defining parameters \beta=u^2+u^{-2} with u=e^{i\lambda/2}
(weight of contractible loops) and \alpha (weight of non-contractible loops),
this family also depends on a twist parameter v that keeps track of how the
defects wind around the cylinder. The transfer matrix T_N(\lambda, \nu) depends
on the anisotropy \nu and the spectral parameter \lambda that fixes the model.
(The thermodynamic limit of T_N is believed to describe a conformal field
theory of central charge c=1-6\lambda^2/(\pi(\lambda-\pi)).)
The family of periodic XXZ Hamiltonians is extended to depend on this new
parameter v and the relationship between this family and the loop models is
established. The Gram determinant for the natural bilinear form on these link
modules is shown to factorize in terms of an intertwiner i_N^d between these
link representations and the eigenspaces of S^z of the XXZ models. This map is
shown to be an isomorphism for generic values of u and v and the critical
curves in the plane of these parameters for which i_N^d fails to be an
isomorphism are given.Comment: Replacement of "The Gram matrix as a connection between periodic loop
models and XXZ Hamiltonians", 31 page
PIP-II SSR2 Cavities Fabrication and Processing Experience
The Proton Improvement Plan-II (PIP-II [1]) linac will include 35 Single
Spoke Resonators type 2 (SSR2). A preproduction SSR2 cryomodule will contain 5
jacketed cavities. Several units are already manufactured and prepared for cold
testing. In this work, data collected from the fabrication, processing and
preparation of the cavities will be presented and the improvements implemented
after the completion of the first unit will be highlighted
Biomechanical interactions of endodontically treated tooth implant-supported prosthesis under fatigue test with acoustic emission monitoring
International audienc
Brain atrophy and patch-based grading in individuals from the CIMA-Q study : a progressive continuum from subjective cognitive decline to AD
It has been proposed that individuals developing Alzheimer's disease (AD) first experience a phase expressing subjective complaints of cognitive decline (SCD) without objective cognitive impairment. Using magnetic resonance imaging (MRI), our objective was to verify whether SNIPE probability grading, a new MRI analysis technique, would distinguish between clinical dementia stage of AD: Cognitively healthy controls without complaint (CH), SCD, mild cognitive impairment, and AD. SNIPE score in the hippocampus and entorhinal cortex was applied to anatomical T1-weighted MRI of 143 participants from the Consortium pour l’identification précoce de la maladie Alzheimer -Québec (CIMA-Q) study and compared to standard atrophy measures (volumes and cortical thicknesses). Compared to standard atrophy measures, SNIPE score appeared more sensitive to differentiate clinical AD since differences between groups reached a higher level of significance and larger effect sizes. However, no significant difference was observed between SCD and CH groups. Combining both types of measures did not improve between-group differences. Further studies using a combination of biomarkers beyond anatomical MRI might be needed to identify individuals with SCD who are on the beginning of the clinical continuum of AD
Psychological adjustment of men with prostate cancer: A review of the literature
OBJECTIVE: Prostate cancer (PCA) is the most common malignancy and a major cause of death in men but, importantly, a substantial proportion will live for several years following diagnosis. However, they face the prospect of experiencing symptoms, side-effects of treatment and diminished quality of life. The patient's psychological adjustment is particularly complex, given the potential trajectory of the disease, from the point of diagnosis, with its immediate impact, to the phase of palliative care, with its attendant issue of facing mortality. Since a comprehensive review of the literature on psychological adjustment of men with PCA has not yet been done, we have documented relevant research, integrated findings and drawn conclusions, where possible, in order to map out clinical and research implications. METHOD: We searched 5 databases for the period 1994 - July 2006, during which most of the work in the field has been done. RESULTS: We found few studies of substance among the 60 we examined to draw conclusions about psychological adjustment to prostate cancer and its treatment. This is in marked contrast to the picture in breast cancer. While some patterns have emerged, many gaps remain to be filled. DISCUSSION: Aspects of methodology need attention, particularly longitudinal, prospective designs, incorporation of control groups and the use of valid and reliable measures. There is scope for qualitative studies as a complement to quantitative research
Subspace Identification with Multiple Data Sets
Most existing subspace identification algorithms assume that a single input to output data set is available. Motivated by a real life problem on the F18-SRA experimental aircraft, we show how these algorithms are readily adapted to handle multiple data sets. We show by means of an example the relevance of such an improvement
Assessment of White Spruce and Jack Pine Stem Curvature from a Nelder Spacing Experiment
This study presents a method for calculating stem curvature for trees with multiple deviations. Generally, tree curvature is assessed using the maximum deflection method. It consists of measuring the farthest point from a straight line drawn between the large and small ends of a stem. It works fairly well for a single deviation but gives poorer results for stems with several deviations. The stems used for developing this method were harvested from a 32-yr-old Nelder spacing experiment established near Woodstock, New Brunswick, Canada. A total of 96 trees were selected for this study from the white spruce (Picea glauca [Moench] Voss) and jack pine (Pinus banksiana Lamb.) that were planted on the same Nelder circle. This particular plantation design offered a gradient of initial spacings ranging from 640 to 12,000 stems/ha. Results of analysis revealed that initial spacing had an impact on tree curvature. Stem curvature increased with wider initial spacing. However, this influence varied between species and differed according to the method used to calculate curvature. The vector length calculation method showed that stem curvature in jack pine was more pronounced and more often encountered at lower densities than in white spruce. It was also observed that tree shape was influenced by the cardinal points with white spruce growing more in westerly and southerly directions
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