34,959 research outputs found
Absence of Klein's paradox for massive bosons coupled by nonminimal vector interactions
A few properties of the nonminimal vector interactions in the
Duffin-Kemmer-Petiau theory are revised. In particular, it is shown that the
space component of the nonminimal vector interaction plays a peremptory role
for confining bosons whereas its time component contributes to the leakage.
Scattering in a square step potential with proper boundary conditions is used
to show that Klein's paradox does not manifest in the case of a nonminimal
vector coupling
Solid flow drives surface nanopatterning by ion-beam irradiation
Ion Beam Sputtering (IBS) is known to produce surface nanopatterns over
macroscopic areas on a wide range of materials. However, in spite of the
technological potential of this route to nanostructuring, the physical process
by which these surfaces self-organize remains poorly under- stood. We have
performed detailed experiments of IBS on Si substrates that validate dynamical
and morphological predictions from a hydrodynamic description of the
phenomenon. Our results elucidate flow of a nanoscopically thin and highly
viscous surface layer, driven by the stress created by the ion-beam, as a
description of the system. This type of slow relaxation is akin to flow of
macroscopic solids like glaciers or lead pipes, that is driven by defect
dynamics.Comment: 12 pages, 4 figure
CCD Photometry of Delta Scuti stars 7 Aql and 8 Aql
As a continuation of the study of the Delta Scuti stars 7 Aql and 8 Aql; new
CCD photometric data were acquired in 2007. We present a period analysis on
these data that confirm the dominant modes detected in each star in the
framework of the STEPHI XII campaign in 2003.Comment: 9 pages, 7 figures, 2 tables; Accepted for publication in
Communications in Asteroseismology, Vol 153, 200
An effective singular oscillator for Duffin-Kemmer-Petiau particles with a nonminimal vector coupling: a two-fold degeneracy
Scalar and vector bosons in the background of one-dimensional nonminimal
vector linear plus inversely linear potentials are explored in a unified way in
the context of the Duffin-Kemmer-Petiau theory. The problem is mapped into a
Sturm-Liouville problem with an effective singular oscillator. With boundary
conditions emerging from the problem, exact bound-state solutions in the spin-0
sector are found in closed form and it is shown that the spectrum exhibits
degeneracy. It is shown that, depending on the potential parameters, there may
or may not exist bound-state solutions in the spin-1 sector.Comment: 1 figure. arXiv admin note: substantial text overlap with
arXiv:1009.159
Fermion localization on branes with generalized dynamics
In this letter we consider a specific model of braneworld with nonstandard
dynamics diffused in the literature, specifically we focus our attention on the
matter energy density, the energy of system, the Ricci scalar and the thin
brane limit. As the model is classically stable and capable of localize
gravity, as a natural extension we address the issue of fermion localization of
fermions on a thick brane constructed out from one scalar field with
nonstandard kinetic terms coupled with gravity. The contribution of the
nonstandard kinetic terms in the problem of fermion localization is analyzed.
It is found that the simplest Yukawa coupling support
the localization of fermions on the thick brane. It is shown that the zero mode
for left-handed can be localized on the thick brane depending on the values for
the coupling constant .Comment: 6 pages, 3 figure
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