8,377 research outputs found
Light-Cone Gauge String Field Theory in Noncritical Dimensions
We study light-cone gauge string field theory in noncritical space-time
dimensions. Such a theory corresponds to a string theory in a Lorentz
noninvariant background. We identify the worldsheet theory for the longitudinal
coordinate variables and study its properties. It is a CFT with the
right value of Virasoro central charge, using which we propose a BRST invariant
formulation of the worldsheet theory.Comment: 27 pages, 2 figure
Light-cone Gauge NSR Strings in Noncritical Dimensions
Light-cone gauge NSR string theory in noncritical dimensions should
correspond to a string theory with a nonstandard longitudinal part.
Supersymmetrizing the bosonic case [arXiv:0909.4675], we formulate a
superconformal worldsheet theory for the longitudinal variables X^{\pm},
\psi^{\pm}. We show that with the transverse variables and the ghosts combined,
it is possible to construct a nilpotent BRST charge.Comment: 22 pages, 1 figur
Twist-3 Effects in Polarized Photon Structure
The polarized photon structure is described by two spin structure functions
and which can be studied in the future polarized ep
or ee colliders. Here we investigate the QCD twist-3 effects in
to the leading order in QCD.Comment: 4 pages, LaTeX2e, 2 eps figures, ws-ijmpa.cls file included, Talk
given at the 3rd Circum-Pan-Pacific Symposium on High Energy Spin Physics,
Beijing, October 8-13, 2001, to appear in the Proceeding
Light-cone Gauge Superstring Field Theory and Dimensional Regularization II
We propose a dimensional regularization scheme to deal with the divergences
caused by colliding supercurrents inserted at the interaction points, in the
light-cone gauge NSR superstring field theory. We formulate the theory in
dimensions and define the amplitudes as analytic functions of . With an
appropriately chosen three-string interaction term and large negative , the
tree level amplitudes for the (NS,NS) closed strings can be recast into a BRST
invariant form, using the superconformal field theory proposed in
Ref.[arXiv:0911.3704]. We show that in the limit they coincide with
the results of the first quantized theory. Therefore we obtain the desired
results without adding any contact interaction terms to the action.Comment: 23 pages; v2: minor modifications; v3: revised argument in section 3,
added appendix C, results unchanged; v4: added clarifications, two figures
and a footnote; v5: minor modification
Light-cone Gauge NSR Strings in Noncritical Dimensions II -- Ramond Sector
Light-cone gauge superstring theory in noncritical dimensions corresponds to
a worldsheet theory with nonstandard longitudinal part in the conformal gauge.
The longitudinal part of the worldsheet theory is a superconformal field theory
called X^{\pm} CFT. We show that the X^{\pm} CFT combined with the
super-reparametrization ghost system can be described by free variables. It is
possible to express the correlation functions in terms of these free variables.
Bosonizing the free variables, we construct the spin fields and BRST invariant
vertex operators for the Ramond sector in the conformal gauge formulation. By
using these vertex operators, we can rewrite the tree amplitudes of the
noncritical light-cone gauge string field theory, with external lines in the
(R,R) sector as well as those in the (NS,NS) sector, in a BRST invariant way.Comment: 33 pages; v2: minor modification
Atomic layer deposition of HfO2 on graphene from HfCl4 and H20
Atomic layer deposition of ultrathin HfO2 on unmodified graphene from HfCl4
and H2O was investigated. Surface RMS roughness down to 0.5 nm was obtained for
amorphous, 30 nm thick hafnia film grown at 180 degrees C. HfO2 was deposited
also in a two-step temperature process where the initial growth of about 1 nm
at 170 degrees C was continued up to 10-30 nm at 300 degrees C. This process
yielded uniform, monoclinic HfO2 films with RMS roughness of 1.7 nm for 10-12
nm thick films and 2.5 nm for 30 nm thick films. Raman spectroscopy studies
revealed that the deposition process caused compressive biaxial strain in
graphene whereas no extra defects were generated. An 11 nm thick HfO2 film
deposited onto bilayer graphene reduced the electron mobility by less than 10%
at the Dirac point and by 30-40% far away from it.Comment: 4 figures, accepted by CEJ
Influence of Mac Arthur Journal Donation Project on Serial Resources of Selected University Libraries in Nigeria
This study was carried out to assess the Mac Arthur Journal Donation Project in Selected University Libraries in Nigeria. Four research questions were posed in order to assess the Mac Arthur Journal Donation Project before, during and after the Donation. The research adopted survey method using questionnaire as instrument for data collection. Data collected were subjected to a descriptive analysis using frequency tables with graphical illustrations. The study discovered that the serial resources in these university libraries were inadequate before the intervention of Mac Arthur but improved substantially during and after the intervention. Consultation of serial resources was low before the intervention as majority of readers were dissatisfied with the serial resources that were available. The intervention brought an upward reversal in the resources and level of consultation. The study concluded that the intervention positively impacted on these university libraries through increased acquisition of current resources and their use. It recommended improved funding, training of staff, formation of consortia groups, library donations etc as measures to keep these university libraries alive
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