1,944 research outputs found
Twist-3 contributions to processes in perturbative QCD approach
As one of the simplest hadronic processes, () could be a good testing ground for our understanding of
the perturbative and nonperturbative structure of QCD, and will be studied with
high precision at BELLE-\RNum{2} in the near future. In this paper, we revisit
these processes with twist-3 corrections in the perturbative QCD approach based
on the factorization theorem, in which transverse degrees of freedom as
well as resummation effects are taken into account. The influence of the
distribution amplitudes on the cross sections are discussed in detail. Our work
shows that not only the transverse momentum effects but also the twist-3
corrections play a significant role in the processes in the intermediate energy region. Especially in the few GeV
region, the twist-3 contributions become dominant in the cross sections. And it
is noteworthy that both the twist-3 result of the cross
section and that of the cross section agree well with the BELLE
and ALEPH measurements. For the pion and kaon angular distributions, there
still exist discrepancies between our results and the experimental
measurements. Possible reasons for these discrepancies are discussed briefly.Comment: 19 pages, 7 figures and 2 tables. Contents improved and more
discussions adde
Polygamy relations of multipartite systems
We investigate the polygamy relations of multipartite quantum states. General
polygamy inequalities are given in the th power of
concurrence of assistance, th power of entanglement of
assistance, and the squared convex-roof extended negativity of assistance
(SCRENoA)
Analytical controllability of deterministic scale-free networks and Cayley trees
According to the exact controllability theory, the controllability is
investigated analytically for two typical types of self-similar bipartite
networks, i.e., the classic deterministic scale-free networks and Cayley trees.
Due to their self-similarity, the analytical results of the exact
controllability are obtained, and the minimum sets of driver nodes (drivers)
are also identified by elementary transformations on adjacency matrices. For
these two types of undirected networks, no matter their links are unweighted or
(nonzero) weighted, the controllability of networks and the configuration of
drivers remain the same, showing a robustness to the link weights. These
results have implications for the control of real networked systems with
self-similarity.Comment: 7 pages, 4 figures, 1 table; revised manuscript; added discussion
about the general case of DSFN; added 3 reference
Cosmological constraints on holographic dark energy models under the energy conditions
We study the holographic and agegraphic dark energy models without
interaction using the latest observational Hubble parameter data (OHD), the
Union2.1 compilation of type Ia supernovae (SNIa), and the energy conditions.
Scenarios of dark energy are distinguished by the cut-off of cosmic age,
conformal time, and event horizon. The best-fit value of matter density for the
three scenarios almost steadily located at by the joint
constraint. For the agegraphic models, they can be recovered to the standard
cosmological model when the constant which presents the fraction of dark
energy approaches to infinity. Absence of upper limit of by the joint
constraint demonstrates the recovery possibility. Using the fitted result, we
also reconstruct the current equation of state of dark energy at different
scenarios, respectively. Employing the model criteria
, we find that conformal time model is the worst,
but they can not be distinguished clearly. Comparing with the observational
constraints, we find that SEC is fulfilled at redshift with confidence level. We also find that NEC gives a meaningful
constraint for the event horizon cut-off model, especially compared with OHD
only. We note that the energy condition maybe could play an important role in
the interacting models because of different degeneracy between and
constant .Comment: 8 pages, 4 figures, accepted for publication in PR
Structural Prior Guided Generative Adversarial Transformers for Low-Light Image Enhancement
We propose an effective Structural Prior guided Generative Adversarial
Transformer (SPGAT) to solve low-light image enhancement. Our SPGAT mainly
contains a generator with two discriminators and a structural prior estimator
(SPE). The generator is based on a U-shaped Transformer which is used to
explore non-local information for better clear image restoration. The SPE is
used to explore useful structures from images to guide the generator for better
structural detail estimation. To generate more realistic images, we develop a
new structural prior guided adversarial learning method by building the skip
connections between the generator and discriminators so that the discriminators
can better discriminate between real and fake features. Finally, we propose a
parallel windows-based Swin Transformer block to aggregate different level
hierarchical features for high-quality image restoration. Experimental results
demonstrate that the proposed SPGAT performs favorably against recent
state-of-the-art methods on both synthetic and real-world datasets
Tighter uncertainty relations based on modified weighted Wigner-Yanase-Dyson skew information of quantum channels
We use a novel formation to illustrate the () modified
weighted Wigner-Yanase-Dyson (() MWWYD) skew information
of quantum channels. By using operator norm inequalities, we explore the sum
uncertainty relations for arbitrary quantum channels and for unitary
channels. These uncertainty inequalities are shown to be tighter than the
existing ones by a detailed example. Our results are also applicable to the
modified weighted Wigner-Yanase-Dyson (MWWYD) skew information and the
() modified weighted Wigner-Yanase-Dyson (()
MWWYD) skew information of quantum channels as special cases.Comment: 12 pages, 2 figure
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