30,038 research outputs found
Higgs radiation off quarks in supersymmetric theories at e^+e^- colliders
Yukawa couplings between Higgs bosons and quarks in supersymmetric theories
can be measured in the processes e^+e^- -> Q Qbar + Higgs. We have determined
the cross sections of these processes in the minimal supersymmetric model
including the complete set of next-to-leading order QCD corrections for all
channels.Comment: 12 pages, latex, 3 figure
Towards Semantic Fast-Forward and Stabilized Egocentric Videos
The emergence of low-cost personal mobiles devices and wearable cameras and
the increasing storage capacity of video-sharing websites have pushed forward a
growing interest towards first-person videos. Since most of the recorded videos
compose long-running streams with unedited content, they are tedious and
unpleasant to watch. The fast-forward state-of-the-art methods are facing
challenges of balancing the smoothness of the video and the emphasis in the
relevant frames given a speed-up rate. In this work, we present a methodology
capable of summarizing and stabilizing egocentric videos by extracting the
semantic information from the frames. This paper also describes a dataset
collection with several semantically labeled videos and introduces a new
smoothness evaluation metric for egocentric videos that is used to test our
method.Comment: Accepted for publication and presented in the First International
Workshop on Egocentric Perception, Interaction and Computing at European
Conference on Computer Vision (EPIC@ECCV) 201
Multi-wavelength variability properties of Fermi blazar S5 0716+714
S5 0716+714 is a typical BL Lacertae object. In this paper we present the
analysis and results of long term simultaneous observations in the radio,
near-infrared, optical, X-ray and -ray bands, together with our own
photometric observations for this source. The light curves show that the
variability amplitudes in -ray and optical bands are larger than those
in the hard X-ray and radio bands and that the spectral energy distribution
(SED) peaks move to shorter wavelengths when the source becomes brighter, which
are similar to other blazars, i.e., more variable at wavelengths shorter than
the SED peak frequencies. Analysis shows that the characteristic variability
timescales in the 14.5 GHz, the optical, the X-ray, and the -ray bands
are comparable to each other. The variations of the hard X-ray and 14.5 GHz
emissions are correlated with zero-lag, so are the V band and -ray
variations, which are consistent with the leptonic models. Coincidences of
-ray and optical flares with a dramatic change of the optical
polarization are detected. Hadronic models do not have the same nature
explanation for these observations as the leptonic models. A strong optical
flare correlating a -ray flare whose peak flux is lower than the
average flux is detected. Leptonic model can explain this variability
phenomenon through simultaneous SED modeling. Different leptonic models are
distinguished by average SED modeling. The synchrotron plus synchrotron
self-Compton (SSC) model is ruled out due to the extreme input parameters.
Scattering of external seed photons, such as the hot dust or broad line region
emission, and the SSC process are probably both needed to explain the
-ray emission of S5 0716+714.Comment: 43 pages, 13 figures, 3 tables, to be appeared in Ap
Hole burning in a nanomechanical resonator coupled to a Cooper pair box
We propose a scheme to create holes in the statistical distribution of
excitations of a nanomechanical resonator. It employs a controllable coupling
between this system and a Cooper pair box. The success probability and the
fidelity are calculated and compared with those obtained in the atom-field
system via distinct schemes. As an application we show how to use the
hole-burning scheme to prepare (low excited) Fock states.Comment: 7 pages, 10 figure
Consistent Construction of Perturbation Theory on Noncommutative Spaces
We examine the effect of non-local deformations on the applicability of
interaction point time ordered perturbation theory (IPTOPT) based on the free
Hamiltonian of local theories. The usual argument for the case of quantum field
theory (QFT) on a noncommutative (NC) space (based on the fact that the
introduction of star products in bilinear terms does not alter the action) is
not applicable to IPTOPT due to several discrepancies compared to the naive
path integral approach when noncommutativity involves time. These discrepancies
are explained in detail. Besides scalar models, gauge fields are also studied.
For both cases, we discuss the free Hamiltonian with respect to non-local
deformations.Comment: 22 pages; major changes in Section 3; minor changes in the
Introduction and Conclusio
On the Connection Between Momentum Cutoff and Operator Cutoff Regularizations
Operator cutoff regularization based on the original Schwinger's proper-time
formalism is examined. By constructing a regulating smearing function for the
proper-time integration, we show how this regularization scheme simulates the
usual momentum cutoff prescription yet preserves gauge symmetry even in the
presence of the cutoff scales. Similarity between the operator cutoff
regularization and the method of higher (covariant) derivatives is also
observed. The invariant nature of the operator cutoff regularization makes it a
promising tool for exploring the renormalization group flow of gauge theories
in the spirit of Wilson-Kadanoff blocking transformation.Comment: 28 pages in plain TeX, no figures. revised and expande
Decomposition of stochastic flows with automorphism of subbundles component
We show that given a -structure on a differentiable manifold , if
the group of automorphisms of is big enough, then there exists the
quotient of an stochastic flows by , in the sense that where , the remainder has
derivative which is vertical but transversal to the fibre of . This
geometrical context generalizes previous results where is a Riemannian
manifold and is decomposed with an isometric component, see Liao
\cite{Liao1} and Ruffino \cite{Ruffino}, which in our context corresponds to
the particular case of an SO(n)-structure on .Comment: To appear in Stochastics and Dynamics, 201
Renormalization Group Approach to Field Theory at Finite Temperature
Scalar field theory at finite temperature is investigated via an improved
renormalization group prescription which provides an effective resummation over
all possible non-overlapping higher loop graphs. Explicit analyses for the
lambda phi^4 theory are performed in d=4 Euclidean space for both low and high
temperature limits. We generate a set of coupled equations for the mass
parameter and the coupling constant from the renormalization group flow
equation. Dimensional reduction and symmetry restoration are also explored with
our improved approach.Comment: 29 pages, can include figures in the body of the text using epsf.st
Sub and Super-Luminal Propagation of Intense Pulses in Media with Saturated and Reverse Absorption
We develop models for the propagation of intense pulses in solid state media
which can have either saturated absorption or exhibit reverse absorption . We
show that the experiments of Bigelow {\it et al.}[Phys. Rev. Lett. {\bf 90},
113903 (2003); Science {\bf 301}, 200 (2003).] on subluminal propagation in
Ruby and superluminal propagation in Alexandrite are well explained by
modelling them as three level and four level systems coupled to Maxwell
equations. We present results well beyond the traditional pump-probe approach.Comment: 4 pages, 6 figure
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