311 research outputs found
Electromagnetic characterization of conformal antennas
The ultimate objective of this project is to develop a new technique which permits an accurate simulation of microstrip patch antennas or arrays with various feed, superstrate and/or substrate configurations residing in a recessed cavity whose aperture is planar, cylindrical or otherwise conformed to the substructure. The technique combines the finite element and boundary integral methods to formulate a system suitable for solution via the conjugate gradient method in conjunction with the fast Fourier transform. The final code is intended to compute both scattering and radiation patterns of the structure with an affordable memory demand. With upgraded capabilities, the four included papers examined the radar cross section (RCS), input impedance, gain, and resonant frequency of several rectangular configurations using different loading and substrate/superstrate configurations
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2D Visualization of the Psoriasis Transcriptome Fails to Support the Existence of Dual-Secreting IL-17A/IL-22 Th17 T Cells.
The present paradigm of psoriasis pathogenesis revolves around the IL-23/IL-17A axis. Dual-secreting Th17 T cells presumably are the predominant sources of the psoriasis phenotype-driving cytokines, IL-17A and IL-22. We thus conducted a meta-analysis of independently acquired RNA-seq psoriasis datasets to explore the relationship between the expression of IL17A and IL22. This analysis failed to support the existence of dual secreting IL-17A/IL-22 Th17 cells as a major source of these cytokines. However, variable relationships amongst the expression of psoriasis susceptibility genes and of IL17A, IL22, and IL23A were identified. Additionally, to shed light on gene expression relationships in psoriasis, we applied a machine learning nonlinear dimensionality reduction strategy (t-SNE) to display the entire psoriasis transcriptome as a 2-dimensonal image. This analysis revealed a variety of gene clusters, relevant to psoriasis pathophysiology but failed to support a relationship between IL17A and IL22. These results support existing theories on alternative sources of IL-17A and IL-22 in psoriasis such as a Th22 cells and non-T cell populations
An approach to exact solutions of the time-dependent supersymmetric two-level three-photon Jaynes-Cummings model
By utilizing the property of the supersymmetric structure in the two-level
multiphoton Jaynes-Cummings model, an invariant is constructed in terms of the
supersymmetric generators by working in the sub-Hilbert-space corresponding to
a particular eigenvalue of the conserved supersymmetric generators. We obtain
the exact solutions of the time-dependent Schr\"{o}dinger equation which
describes the time-dependent supersymmetric two-level three-photon
Jaynes-Cummings model (TLTJCM) by using the invariant-related unitary
transformation formulation. The case under the adiabatic approximation is also
discussed.
Keywords: Supersymmetric Jaynes-Cummings model; exact solutions; invariant
theory; geometric phase factor; adiabatic approximationComment: 7 pages, Late
Are magnetic monopoles at the origin of magneto-electricity in spin ices?
The possibilities of combining several degrees of freedom inside a unique
material have recently been highlighted in their dynamics and proposed as
information carriers in quantum devices where their cross-manipulation by
external parameters such as electric and magnetic fields could enhance their
functionalities. An emblematic example is that of electromagnons, spin-waves
dressed with electric dipoles, that are fingerprints of multiferroics.
Point-like objects have also been identified, which may take the form of
excited quasiparticles. This is the case for magnetic monopoles, the exotic
excitations of spin ices, that have been recently proposed to carry an electric
dipole although experimental evidences remain elusive. Presently, we
investigate the electrical signature of a classical spin ice and a related
compound that supports quantum fluctuations. Our in-depth study clearly
attributes magnetoelectricity to the correlated spin ice phase distinguishing
it from extrinsic and single-ion effects. Our calculations show that the
proposed model conferring magnetoelectricity to monopoles is not sufficient,
calling for higher order contributions
Entangled two cavity modes preparation via a two-photon process
We propose a scheme for entangling two field modes in two high-Q optical
cavities. Making use of a virtual two-photon process, our scheme achieves
maximally entangled states without any real transitions of atomic internal
states, hence it is immune to the atomic decay.Comment: 4 pages, latex, 7 figure
The magnetic mass of transverse gluon, the B-meson weak decay vertex and the triality symmetry of octonion
With an assumption that in the Yang-Mills Lagrangian, a left-handed fermion
and a right-handed fermion both expressed as quaternion make an octonion which
possesses the triality symmetry, I calculate the magnetic mass of the
transverse self-dual gluon from three loop diagram, in which a heavy quark pair
is created and two self-dual gluons are interchanged.
The magnetic mass of the transverse gluon depends on the mass of the pair
created quarks, and in the case of charmed quark pair creation, the magnetic
mass becomes approximately equal to at MeV. A possible time-like magnetic gluon mass
from two self-dual gluon exchange is derived, and corrections in the B-meson
weak decay vertices from the two self-dual gluon exchange are also evaluated.Comment: 22 pages, 9 figure
Resummation scheme for 3d Yang-Mills and the two-loop magnetic mass for hot gauge theories
Perturbation theory for non-Abelian gauge theories at finite temperature is
plagued by infrared divergences caused by magnetic soft modes ,
which correspond to the fields of a 3d Yang-Mills theory. We revisit a gauge
invariant resummation scheme to solve this problem by self-consistent mass
generation using an auxiliary scalar field, improving over previous attempts in
two respects. First, we generalise earlier SU(2) treatments to SU(N). Second,
we obtain a gauge independent two-loop gap equation, correcting an error in the
literature. The resulting two-loop approximation to the magnetic mass
represents a correction to the leading one-loop value, indicating a
reasonable convergence of the resummation.Comment: 16 pages, 3 figure
The Fuzzy Disc
We introduce a finite dimensional matrix model approximation to the algebra
of functions on a disc based on noncommutative geometry. The algebra is a
subalgebra of the one characterizing the noncommutative plane with a * product
and depends on two parameters N and theta. It is composed of functions which
decay exponentially outside a disc. In the limit in which the size of the
matrices goes to infinity and the noncommutativity parameter goes to zero the
disc becomes sharper. We introduce a Laplacian defined on the whole algebra and
calculate its eigenvalues. We also calculate the two--points correlation
function for a free massless theory (Green's function). In both cases the
agreement with the exact result on the disc is very good already for relatively
small matrices. This opens up the possibility for the study of field theories
on the disc with nonperturbative methods. The model contains edge states, a
fact studied in a similar matrix model independently introduced by
Balachandran, Gupta and Kurkcuoglu.Comment: 17 pages, 8 figures, references added and correcte
Scalar Field Theory on Fuzzy S^4
Scalar fields are studied on fuzzy and a solution is found for the
elimination of the unwanted degrees of freedom that occur in the model. The
resulting theory can be interpreted as a Kaluza-Klein reduction of CP^3 to S^4
in the fuzzy context.Comment: 16 pages, LaTe
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