459 research outputs found
History and Doctrines of the Ajivikas, a Vanished Indian Religion.
Abstract Not Provided
A Precision Calculation of the Next-to-Leading Order Energy-Energy Correlation Function
The O(alpha_s^2) contribution to the Energy-Energy Correlation function (EEC)
of e+e- -> hadrons is calculated to high precision and the results are shown to
be larger than previously reported. The consistency with the leading logarithm
approximation and the accurate cancellation of infrared singularities exhibited
by the new calculation suggest that it is reliable. We offer evidence that the
source of the disagreement with previous results lies in the regulation of
double singularities.Comment: 6 pages, uuencoded LaTeX and one eps figure appended Complete paper
as PostScript file (125 kB) available at:
http://www.phys.washington.edu/~clay/eecpaper1/paper.htm
Causality constraints in AdS/CFT from conformal collider physics and Gauss-Bonnet gravity
We explore the relation between positivity of the energy constraints in
conformal field theories and causality in their dual gravity description. Our
discussion involves CFTs with different central charges whose description, in
the gravity side, requires the inclusion of quadratic curvature corrections. It
is enough, indeed, to consider the Gauss-Bonnet term. We find that both sides
of the AdS/CFT correspondence impose a restriction on the Gauss-Bonnet
coupling. In the case of 6d supersymmetric CFTs, we show the full matching of
these restrictions. We perform this computation in two ways. First by
considering a thermal setup in a black hole background. Second by scrutinizing
the scattering of gravitons with a shock wave in AdS. The different helicities
provide the corresponding lower and upper bounds. We generalize these results
to arbitrary higher dimensions and comment on some hints and puzzles they
prompt regarding the possible existence of higher dimensional CFTs and the
extent to which the AdS/CFT correspondence would be valid for them.Comment: 31 pages, 5 figures; v2: typos fixed, cosmetic amendments and
references adde
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Non-stoichiometric oxide and metal interfaces and reactions
We have employed a combination of experimental surface science techniques and density functional calculations to study the reduction of TiO2(110) surfaces through the doping with submonolayer transition metals. We concentrate on the role of Ti adatoms in self doping of rutile and contrast the behaviour to that of Cr. DFT+U calculations enable identification of probable adsorption structures and their spectroscopic characteristics. Adsorption of both metals leads to a broken symmetry and an asymmetric charge transfer localised around the defect site of a mixed localised/delocalised character. Charge transfer creates defect states with Ti 3d character in the band gap at similar to 1-eV binding energy. Cr adsorption, however, leads to a very large shift in the valence-band edge to higher binding energy and the creation of Cr 3d states at 2.8-eV binding energy. Low-temperature oxidation lifts the Ti-derived band-gap states and modifies the intensity of the Cr features, indicative of a change of oxidation state from Cr3+ to Cr4+. Higher temperature processing leads to a loss of Cr from the surface region, indicative of its substitution into the bulk
IL-23 drives a pathogenic T cell population that induces autoimmune inflammation
Interleukin (IL)-23 is a heterodimeric cytokine composed of a unique p19 subunit, and a common p40 subunit shared with IL-12. IL-12 is important for the development of T helper (Th)1 cells that are essential for host defense and tumor suppression. In contrast, IL-23 does not promote the development of interferon-γ–producing Th1 cells, but is one of the essential factors required for the expansion of a pathogenic CD4+ T cell population, which is characterized by the production of IL-17, IL-17F, IL-6, and tumor necrosis factor. Gene expression analysis of IL-23–driven autoreactive T cells identified a unique expression pattern of proinflammatory cytokines and other novel factors, distinguishing them from IL-12–driven T cells. Using passive transfer studies, we confirm that these IL-23–dependent CD4+ T cells are highly pathogenic and essential for the establishment of organ-specific inflammation associated with central nervous system autoimmunity
Optimizing for periodicity: a model-independent approach to flux crosstalk calibration for superconducting circuits
Flux tunability is an important engineering resource for superconducting
circuits. Large-scale quantum computers based on flux-tunable superconducting
circuits face the problem of flux crosstalk, which needs to be accurately
calibrated to realize high-fidelity quantum operations. Typical calibration
methods either assume that circuit elements can be effectively decoupled and
simple models can be applied, or require a large amount of data. Such methods
become ineffective as the system size increases and circuit interactions become
stronger. Here we propose a new method for calibrating flux crosstalk, which is
independent of the underlying circuit model. Using the fundamental property
that superconducting circuits respond periodically to external fluxes,
crosstalk calibration of N flux channels can be treated as N independent
optimization problems, with the objective functions being the periodicity of a
measured signal depending on the compensation parameters. We demonstrate this
method on a small-scale quantum annealing circuit based on superconducting flux
qubits, achieving comparable accuracy with previous methods. We also show that
the objective function usually has a nearly convex landscape, allowing
efficient optimization
Event shapes in e+e- annihilation and deep inelastic scattering
This article reviews the status of event-shape studies in e+e- annihilation
and DIS. It includes discussions of perturbative calculations, of various
approaches to modelling hadronisation and of comparisons to data.Comment: Invited topical review for J.Phys.G; 40 pages; revised version
corrects some nomenclatur
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