81,790 research outputs found
Weak interactions and quasi-stable particle energy loss
We discuss the interplay between electromagnetic energy loss and weak
interactions in the context of quasistable particle particle propagation
through materials. As specific examples, we consider staus, where weak
interactions may play a role, and taus, where they don't.Comment: 4 pages, 4 figures, to appear in the proceedings of the Second
Workshop on TeV Particle Astrophysics (August 2006, Madison, WI
Periodic Modulation of Extraordinary Optical Transmission through Subwavelength Hole Arrays using Surrounding Bragg Mirrors
The enhanced light transmission through an array of subwavelength holes
surrounded by Bragg mirrors is studied, showing that the mirrors act to confine
the surface plasmons associated with the Extraordinary Optical Transmission
effect, forming a surface resonant cavity. The overall effect is increased
light transmission intensity by more than a factor of three beyond the already
enhanced transmission, independent of whether the Bragg mirrors are on the
input or the output side of the incident light. The geometry of the Bragg
mirror structures controls the enhancement, and can even reduce the
transmission in half. By varying these geometric parameters, we were able to
periodically modulate the transmission of light for specific wavelengths,
consistent with the propagation and interference of surface plasmon waves in a
resonant cavity. FDTD simulations and a wave propagation model verify this
effect.Comment: 9 pages, 5 figure
Bose-Einstein Condensation Temperature of Homogenous Weakly Interacting Bose Gas in Variational Perturbation Theory Through Seven Loops
The shift of the Bose-Einstein condensation temperature for a homogenous
weakly interacting Bose gas in leading order in the scattering length `a' is
computed for given particle density `n.' Variational perturbation theory is
used to resum the corresponding perturbative series for Delta/Nu in a
classical three-dimensional scalar field theory with coupling `u' and where the
physical case of N=2 field components is generalized to arbitrary N. Our
results for N=1,2,4 are in agreement with recent Monte-Carlo simulations; for
N=2, we obtain Delta T_c/T_c = 1.27 +/- 0.11 a n^(1/3). We use seven-loop
perturbative coefficients, extending earlier work by one loop order.Comment: 8 pages; typos and errors of presentation fixed; beautifications;
results unchange
Effect of humidity on transonic flow
An experimental investigation of the effects of humidity-induced condensation on shock/boundary-layer
interaction has been conducted in a transonic wind-tunnel test. The test geometry considered was a wall-mounted
bump model inserted in the test section of the wind tunnel. The formation of a λ-shape condensation shock wave was
shown from schlieren visualization and resulted in a forward movement of the shock wave, reduced shock wave
strength, and reduced separation. Empirical correlations of the shock wave strength and humidity/dew point
temperature were established. For humidity levels below 0.15 or a dew point temperature of 268 K, the effect of
humidity was negligible. The unsteady pressure measurements showed that if a condensation shock wave formed and
interacted with a main shock wave, the flow becomes unsteady with periodic flow oscillations occurring at 720 Hz
Asymmetric Fermion Superfluid with Inter- and Intra-Species Pairings
We investigate the phase structure of an asymmetric fermion superfluid with
inter- and intra-species pairings. The introduction of the intra-species
pairing mechanism in canonical ensemble changes significantly the phase diagram
and brings in a new state with coexisting inter- and intra-species pairings.
Different from the case with only inter-species pairing, all the fermion
excitations are fully gapped in the region with intra-species pairing.Comment: 5 pages, 4 figure
The tensor structure on the representation category of the triplet algebra
We study the braided monoidal structure that the fusion product induces on
the abelian category -mod, the category of representations of
the triplet -algebra . The -algebras are a
family of vertex operator algebras that form the simplest known examples of
symmetry algebras of logarithmic conformal field theories. We formalise the
methods for computing fusion products, developed by Nahm, Gaberdiel and Kausch,
that are widely used in the physics literature and illustrate a systematic
approach to calculating fusion products in non-semi-simple representation
categories. We apply these methods to the braided monoidal structure of
-mod, previously constructed by Huang, Lepowsky and Zhang, to
prove that this braided monoidal structure is rigid. The rigidity of
-mod allows us to prove explicit formulae for the fusion product
on the set of all simple and all projective -modules, which were
first conjectured by Fuchs, Hwang, Semikhatov and Tipunin; and Gaberdiel and
Runkel.Comment: 58 pages; edit: added references and revisions according to referee
reports. Version to appear on J. Phys.
Geometries for Possible Kinematics
The algebras for all possible Lorentzian and Euclidean kinematics with
isotropy except static ones are re-classified. The geometries
for algebras are presented by contraction approach. The relations among the
geometries are revealed. Almost all geometries fall into pairs. There exists correspondence in each pair. In the viewpoint of
differential geometry, there are only 9 geometries, which have right signature
and geometrical spatial isotropy. They are 3 relativistic geometries, 3
absolute-time geometries, and 3 absolute-space geometries.Comment: 40 pages, 7 figure
Binding-incompetent adenovirus facilitates molecular conjugate-mediated gene transfer by the receptor-mediated endocytosis pathway
Molecular conjugate vectors may be constructed that accomplish high efficiency gene transfer by the receptor-mediated endocytosis pathway. In order to mediate escape from lysosomal degradation, we have incorporated adenoviruses into the functional design of the conjugate. In doing so, however, we have introduced an additional ligand, which can bind to receptors on the cell surface, undermining the potential for cell specific targeting. To overcome this, we have treated the adenovirus with a monoclonal anti-fiber antibody, which renders the virus incapable of binding to its receptor. The result is a multi-functional molecular conjugate vector, which has preserved its binding specificity while at the same time being capable of preventing lysosomal degradation of endosome-internalized conjugate-DNA complexes. This finding indicates that adenoviral binding is not a prerequisite for adenoviral-mediated endosome disruption
Electronic Structures of CaAlSi with Different Stacking AlSi Layers by First-Principles Calculations
The full-potential linear augmented plane-wave calculations have been applied
to investigate the systematic change of electronic structures in CaAlSi due to
different stacking sequences of AlSi layers. The present ab-initio calculations
have revealed that the multistacking, buckling and 60 degrees rotation of AlSi
layer affect the electronic band structure in this system. In particular, such
a structural perturbation gives rise to the disconnected and cylindrical Fermi
surface along the M-L lines of the hexagonal Brillouin zone. This means that
multistacked CaAlSi with the buckling AlSi layers increases degree of
two-dimensional electronic characters, and it gives us qualitative
understanding for the quite different upper critical field anisotropy between
specimens with and without superstructure as reported previously.Comment: 4 pages, 4 figures, to be published in J. Phys. Soc. Jp
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