6,125 research outputs found
Selected vector-meson decay-distributions in reactions of polarized photons with protons
We develop a formalism for studying vector meson () photo-production at
the proton () with polarized photons, , through an
analysis of the decay distribution in the channel . We show
that this decay distribution differs noticeably from the distributions of
purely hadronic decays, like , .
Formulas for the decay distributions are presented which are suitable for data
analysis and interpretation.Comment: 3 pages, 2 figure
Isoscalar-Isovector Interferences in Reactions as a Probe of Baryon Resonance Dynamics
The isoscalar-isovector () interferences in the exclusive
reactions and near the
threshold leads to a distinct difference of the dielectron invariant mass
distributions depending on beam energy. The strength of this effect is
determined by the coupling of resonances to the nucleon vector-meson channels
and other resonance properties. Therefore, a combined analysis of these
reactions can be used as a tool for determining the baryon resonance dynamics
Metallic proximity effect in ballistic graphene with resonant scatterers
We study the effect of resonant scatterers on the local density of states in
a rectangular graphene setup with metallic leads. We find that the density of
states in a vicinity of the Dirac point acquires a strong position dependence
due to both metallic proximity effect and impurity scattering. This effect may
prevent uniform gating of weakly-doped samples. We also demonstrate that even a
single-atom impurity may essentially alter electronic states at low-doping on
distances of the order of the sample size from the impurity.Comment: 9 pages, 2 figure
Microscopic theory of spin-orbit torques and skyrmion dynamics
We formulate a general microscopic approach to spin-orbit torques in thin
ferromagnet/heavy-metal bilayers in linear response to electric current or
electric field. The microscopic theory we develop avoids the notion of spin
currents and spin-Hall effect. Instead, the torques are directly related to a
local spin polarization of conduction electrons, which is computed from
generalized Kubo-St\v{r}eda formulas. A symmetry analysis provides a one-to-one
correspondence between polarization susceptibility tensor components and
different torque terms in the Landau-Lifshitz-Gilbert equation for
magnetization dynamics. The spin-orbit torques arising from Rashba or
Dresselhaus type of spin-orbit interaction are shown to have different
symmetries. We analyze these spin-orbit torques microscopically for a generic
electron model in the presence of an arbitrary smooth magnetic texture. For a
model with spin-independent disorder we find a major cancelation of the
torques. In this case the only remaining torque corresponds to the
magnetization-independent Edelstein effect. Furthermore, our results are
applied to analyze the dynamics of a Skyrmion under the action of electric
current.Comment: 13 pages, 4 figure
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