3,447 research outputs found
The Quantum Affine Origin of the AdS/CFT Secret Symmetry
We find a new quantum affine symmetry of the S-matrix of the one-dimensional
Hubbard chain. We show that this symmetry originates from the quantum affine
superalgebra U_q(gl(2|2)), and in the rational limit exactly reproduces the
secret symmetry of the AdS/CFT worldsheet S-matrix.Comment: 22 page
Secret Symmetries in AdS/CFT
We discuss special quantum group (secret) symmetries of the integrable system
associated to the AdS/CFT correspondence. These symmetries have by now been
observed in a variety of forms, including the spectral problem, the boundary
scattering problem, n-point amplitudes, the pure-spinor formulation and quantum
affine deformations.Comment: 20 pages, pdfLaTeX; Submitted to the Proceedings of the Nordita
program `Exact Results in Gauge-String Dualities'; Based on the talk
presented by A.T., Nordita, 15 February 201
Asymptotic Bethe equations for open boundaries in planar AdS/CFT
We solve, by means of a nested coordinate Bethe ansatz, the open-boundaries
scattering theory describing the excitations of a free open string propagating
in , carrying large angular momentum , and ending on
a maximal giant graviton whose angular momentum is in the same plane. We thus
obtain the all-loop Bethe equations describing the spectrum, for finite but
large, of the energies of such strings, or equivalently, on the gauge side of
the AdS/CFT correspondence, the anomalous dimensions of certain operators built
using the epsilon tensor of SU(N). We also give the Bethe equations for strings
ending on a probe D7-brane, corresponding to meson-like operators in an
gauge theory with fundamental matter.Comment: 30 pages. v2: minor changes and discussion section added, J.Phys.A
version
Reply to "Comment on 'Charge transport in disordered semiconducting polymers driven by nuclear tunneling'"
The authors reply to the Comment by Nenashev et al
Contour deformation trick in hybrid NLIE
The hybrid NLIE of AdS_5 x S^5 is applied to a wider class of states. We find
that the Konishi state of the orbifold AdS_5 x (S^5/Z_S) satisfies A_1 NLIE
with the source terms which are derived from contour deformation trick. For
general states, we construct a deformed contour with which the contour
deformation trick yields the correct source terms.Comment: 39 pages, 6 figures, v2: discussion on analyticity constraints
replaced by consistent deformed contou
Combined EXAFS, XRD, DRIFTS, and DFT Study of Nano Copper Based Catalysts for CO2 Hydrogenation
Highly monodispersed CuO nanoparticles (NPs) were synthesized via continuous hydrothermal flow synthesis (CHFS) and then tested as catalysts for CO2 hydrogenation. The catalytic behavior of unsupported 11 nm sized nanoparticles from the same batch was characterized by diffuse reflectance infrared fourier transform spectroscopy (DRIFTS), extended X-ray absorption fine structure (EXAFS), X-ray diffraction (XRD), and catalytic testing, under CO2/H2 in the temperature range 25–500 °C in consistent experimental conditions. This was done to highlight the relationship among structural evolution, surface products, and reaction yields; the experimental results were compared with modeling predictions based on density functional theory (DFT) simulations of the CuO system. In situ DRIFTS revealed the formation of surface formate species at temperatures as low as 70 °C. DFT calculations of CO2 hydrogenation on the CuO surface suggested that hydrogenation reduced the CuO surface to Cu2O, which facilitated the formation of formate. In situ EXAFS supported a strong correlation between the Cu2O phase fraction and the formate peak intensity, with the maxima corresponding to where Cu2O was the only detectable phase at 170 °C, before the onset of reduction to Cu at 190 °C. The concurrent phase and crystallite size evolution were monitored by in situ XRD, which suggested that the CuO NPs were stable in size before the onset of reduction, with smaller Cu2O crystallites being observed from 130 °C. Further reduction to Cu from 190 °C was followed by a rapid decrease of surface formate and the detection of adsorbed CO from 250 °C; these results are in agreement with heterogeneous catalytic tests where surface CO was observed over the same temperature range. Furthermore, CH4 was detected in correspondence with the decomposition of formate and formation of the Cu phase, with a maximum conversion rate of 2.8% measured at 470 °C (on completely reduced copper), supporting the indication of independent reaction pathways for the conversion of CO2 to CH4 and CO that was suggested by catalytic tests. The resulting Cu NPs had a final crystallite size of ca. 44 nm at 500 °C and retained a significantly active surface
Tensor Regression with Applications in Neuroimaging Data Analysis
Classical regression methods treat covariates as a vector and estimate a
corresponding vector of regression coefficients. Modern applications in medical
imaging generate covariates of more complex form such as multidimensional
arrays (tensors). Traditional statistical and computational methods are proving
insufficient for analysis of these high-throughput data due to their ultrahigh
dimensionality as well as complex structure. In this article, we propose a new
family of tensor regression models that efficiently exploit the special
structure of tensor covariates. Under this framework, ultrahigh dimensionality
is reduced to a manageable level, resulting in efficient estimation and
prediction. A fast and highly scalable estimation algorithm is proposed for
maximum likelihood estimation and its associated asymptotic properties are
studied. Effectiveness of the new methods is demonstrated on both synthetic and
real MRI imaging data.Comment: 27 pages, 4 figure
Josephson Plasma Resonance as a Structural Probe of Vortex Liquid
Recent developments of the Josephson plasma resonance and transport c-axis
measurements in layered high T superconductors allow to probe Josephson
coupling in a wide range of the vortex phase diagram. We derive a relation
between the field dependent Josephson coupling energy and the density
correlation function of the vortex liquid. This relation provides a unique
opportunity to extract the density correlation function of pancake vortices
from the dependence of the plasma resonance on the -component of the
magnetic field at a fixed -axis component.Comment: 4 pages, 1 fugure, accepted to Phys. Rev. Let
Induction of labor with Foley catheter and risk of subsequent preterm birth : follow‐up study of two randomized controlled trials (PROBAAT‐1 and ‐2)
Acknowledgements We thank all the women who participated in the PROBAAT trials and all participating institutions and their staff for their contribution to this follow-up study. Funding The original PROBAAT-2 trial was funded by FondsNutsOhra. For the PROBAAT-1 trial and this follow-up study, no funding was received. MV received a doctoral grant for teachers by the Netherlands Organisation for Scientific Research (023.011.051). BM is supported by a NHMRC Practitioner Fellowship (GNT1082548). Funding sources had no role in design, execution, analyses, interpretation, or decision to submit results.Peer reviewedPublisher PD
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