422 research outputs found
Particle transport simulation of density behavior during lower-hybrid current drive experiments on the Versator II tokamak
On graded polynomial identities with an antiautomorphism
AbstractLet G be a commutative monoid with cancellation and let R be a strongly G-graded associative algebra with finite G-grading and with antiautomorphism. Suppose that R satisfies a graded polynomial identity with antiautomorphism. We show that R is a PI algebra
Particle confinement and the anomalous Doppler instability during combined inductive and lower-hybrid current drive
First integrals of Ginzburg-Landau equations and stability criteria for vortex-free state in unconventional superconductors
The first integrals of the Ginzburg-Landau equations for a vortex-free state
of superconductors with different mixed symmetries of the order parameter are
found. The general boundary conditions for the order parameter at the ideal
interface between the superconductor and vacuum are derived. Based on these
integrals and boundary conditions, we analyze the stability criteria for
vortex-free state in unconventional superconductors. The threshold field above
which the Abrikosov vortices can enter the superconductor is found to be higher
or equal to the thermodynamic critical field for all states under study.Comment: 8 pages, pdf file, no figure
Electromagnetic properties of graphene junctions
A resonant chiral tunneling (CT) across a graphene junction (GJ) induced by
an external electromagnetic field (EF) is studied. Modulation of the electron
and hole wavefunction phases by the external EF during the CT
processes strongly impacts the CT directional diagram. Therefore the a.c.
transport characteristics of GJs depend on the EF polarization and frequency
considerably. The GJ shows great promises for various nanoelectronic
applications working in the THz diapason.Comment: 4 pages 3 figure
Numerical study of the one-dimensional quantum compass model
The ground state magnetic phase diagram of the one-dimensional quantum
compass model (QCM) is studied using the numerical Lanczos method. A detailed
numerical analysis of the low energy excitation spectrum is presented. The
energy gap and the spin-spin correlation functions are calculated for finite
chains. Two kind of the magnetic long-range orders, the Neel and a type of the
stripe-antiferromagnet, in the ground state phase diagram are identified. Based
on the numerical analysis, the first and second order quantum phase transitions
in the ground state phase diagram are identified.Comment: 6 pages, 8 figures. arXiv admin note: text overlap with
arXiv:1105.211
Three dimensional tracking for volumetric spectral-domain optical coherence tomography
We present a three-dimensional (3D) tracker for a clinical ophthalmic spectral domain optical coherence tomography (SD-OCT) system that combines depth-tracking with lateral tracking, providing a stabilized reference frame for 3D data recording and post acquisition analysis. The depth-tracking system is implemented through a real-time dynamic feedback mechanism to compensate for motion artifact in the axial direction. Active monitoring of the retina and adapting the reference arm of the interferometer allowed the whole thickness of the retina to be stabilized to within +/- 100 mu m. We achieve a relatively constant SNR from image to image by stabilizing the image of the retina with respect to the depth dependent sensitivity of SD-OCT. The depth tracking range of our system is 5.2 mm in air and the depth is adjusted every frame. Enhancement in the stability of the images with the depth-tracking algorithm is demonstrated on a healthy volunteer.X1119sciescopu
Horizontal symmetry in Higgs sector of GUT with U(1)_A symmetry
In a series of papers, we pointed out that an anomalous gauge
symmetry naturally solves various problems in grand unified theories (GUTs) and
that a horizontal gauge symmetry, or , not only realizes the
unification of three generation quarks and leptons in fewer multiplets but also
solves the supersymmetric flavor problem. In this paper, we examine the
possibility that the Higgs sectors of the GUT symmetry and of the horizontal
symmetry are unified, that is, there are some Higgs fields whose vacuum
expectation values (VEVs) break both the GUT gauge symmetry and the horizontal
symmetry at the same time. Although the scale of the VEVs become too large to
suppress the flavor changing neutral current processes sufficiently, the
unification is possible. In addition, for the models, the
gauge anomaly is cancelled in the unified models without introducing additional
fields in contrast with the previous models in which the Higgs sectors are not
unified.Comment: 35 page
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