7,875 research outputs found
Meta-Stable Brane Configurations with Seven NS5-Branes
We present the intersecting brane configurations consisting of NS-branes,
D4-branes(and anti D4-branes) and O6-plane, of type IIA string theory
corresponding to the meta-stable nonsupersymmetric vacua in four dimensional
N=1 supersymmetric SU(N_c) x SU(N_c') x SU(N_c'') gauge theory with a symmetric
tensor field, a conjugate symmetric tensor field and bifundamental fields. We
also describe the intersecting brane configurations of type IIA string theory
corresponding to the nonsupersymmetric meta-stable vacua in the above gauge
theory with an antisymmetric tensor field, a conjugate symmetric tensor field,
eight fundamental flavors and bifundamentals. These brane configurations
consist of NS-branes, D4-branes(and anti D4-branes), D6-branes and O6-planes.Comment: 34pp, 9 figures; Improved the draft and added some footnotes; Figure
1, footnote 7 and captions of Figures 7,8,9 added or improved and to appear
in CQ
Quantum finite-size effects for dyonic magnons in the AdS_4 x CP^3
We compute quantum corrections to finite-size effects for various dyonic
giant magnons in the AdS_4 x CP^3 in two different approaches. The off-shell
algebraic curve method is used to quantize the classical string configurations
in semi-classical way and to compute the corrections to the string energies.
These results are compared with the F-term L\"uscher formula based on the
S-matrix of the AdS_4 / CFT_3. The fact that the two results match exactly
provides another stringent test for the all-loop integrability conjecture and
the exact S-matrix based on it.Comment: 21 pages, No figures, corrected typos, added some reference
Green's function approach to transport through a gate-all-around Si nanowire under impurity scattering
We investigate transport properties of gate-all-around Si nanowires using
non-equilibrium Green's function technique. By taking into account of the
ionized impurity scattering we calculate Green's functions self-consistently
and examine the effects of ionized impurity scattering on electron densities
and currents. For nano-scale Si wires, it is found that, due to the impurity
scattering, the local density of state profiles loose it's interference
oscillations as well as is broaden and shifted. In addition, the impurity
scattering gives rise to a different transconductance as functions of
temperature and impurity scattering strength when compared with the
transconductance without impurity scattering.Comment: 8 pages, 4 figure
N=8 SCFT and M Theory on AdS_4 x RP^7
We study M theory on AdS_4 \times \RP^7 corresponding to 3 dimensional
superconformal field theory which is the strong coupling limit of
3 dimensional super Yang-Mills theory. For SU(N) theory, a wrapped M5 brane on
\RP^5 can be interpreted as baryon vertex. For theory, by
using the property of (co-)homology of \RP^7, we classify various wrapping
branes and consider domain walls and the baryon vertex.Comment: 17 pages, Changed baryon like operator as M5 branes in M theory
rather than D6 brane in IIA theory. To appear in Phys.Rev.
Enhancement of service life of polymer electrolyte fuel cells through application of nanodispersed ionomer
Copyright © 2020 The Authors, some rights reserved.In polymer electrolyte fuel cells (PEFCs), protons from the anode are transferred to the cathode through the ionomer membrane. By impregnating the ionomer into the electrodes, proton pathways are extended and high proton transfer efficiency can be achieved. Because the impregnated ionomer mechanically binds the catalysts within the electrode, the ionomer is also called a binder. To yield good electrochemical performance, the binder should be homogeneously dispersed in the electrode and maintain stable interfaces with other catalyst components and the membrane. However, conventional binder materials do not have good dispersion properties. In this study, a facile approach based on using a supercritical fluid is introduced to prepare a homogeneous nanoscale dispersion of the binder material in aqueous alcohol. The prepared binder exhibited high dispersion characteristics, crystallinity, and proton conductivity. High performance and durability were confirmed when the binder material was applied to a PEFC cathode electrode11sciescopu
Interplay of charge and orbital ordering in manganese perovskites
A model of localized classical electrons coupled to lattice degrees of
freedom and, via the Coulomb interaction, to each other, has been studied to
gain insight into the charge and orbital ordering observed in lightly doped
manganese perovskites. Expressions are obtained for the minimum energy and
ionic displacements caused by given hole and electron orbital configurations.
The expressions are analyzed for several hole configurations, including that
experimentally observed by Yamada et al. in La_{7/8}Sr_{1/8}MnO_3. We find
that, although the preferred charge and orbital ordering depend sensitively on
parameters, there are ranges of the parameters in which the experimentally
observed hole configuration has the lowest energy. For these parameter values
we also find that the energy differences between different hole configurations
are on the order of the observed charge ordering transition temperature. The
effects of additional strains are also studied. Some results for
La_{1/2}Ca_{1/2}MnO_3 are presented, although our model may not adequately
describe this material because the high temperature phase is metallic.Comment: 12 pages in RevTex, 5 figures in PS files, to appear in Phys. Rev. B
(New paragraphs and references added, typos corrected
Correlations of the elements of the neutrino mass matrix
Assuming Majorana nature of neutrinos, we re-investigate, in the light of the
recent measurement of the reactor mixing angle, the allowed ranges for the
absolute values of the elements of the neutrino mass matrix in the basis where
the charged-lepton mass matrix is diagonal. Apart from the derivation of upper
and lower bounds on the values of the matrix elements, we also study their
correlations. Moreover, we analyse the sensitivity of bounds and correlations
to the global fit results of the neutrino oscillation parameters which are
available in the literature.Comment: 37 pages, 146 figures, minor corrections, 17 additional figures,
version for publication in JHE
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