1,076 research outputs found
Time-dependent Aharonov-Bohm effect on the noncommutative space
We study the time-dependent Aharonov-Bohm effect on the noncommutative space.
Because there is no net Aharonov-Bohm phase shift in the time-dependent case on
the commutative space, therefore, a tiny deviation from zero indicates new
physics. Based on the Seiberg-Witten map we obtain the gauge invariant and
Lorentz covariant Aharonov-Bohm phase shift in general case on noncommutative
space. We find there are two kinds of contribution: momentum-dependent and
momentum-independent corrections. For the momentum-dependent correction, there
is a cancellation between the magnetic and electric phase shifts, just like the
case on the commutative space. However, there is a non-trivial contribution in
the momentum-independent correction. This is true for both the time-independent
and time-dependent Aharonov-Bohm effects on the noncommutative space. However,
for the time-dependent Aharonov-Bohm effect, there is no overwhelming
background which exists in the time-independent Aharonov-Bohm effect on both
commutative and noncommutative space. Therefore, the time-dependent
Aharonov-Bohm can be sensitive to the spatial noncommutativity. \draftnote{The
net correction is proportional to the product of the magnetic fluxes through
the fundamental area represented by the noncommutative parameter , and
through the surface enclosed by the trajectory of charged particle.} More
interestingly, there is an anti-collinear relation between the logarithms of
the magnetic field and the averaged flux (N is the number of
fringes shifted). This nontrivial relation can also provide a way to test the
spatial noncommutativity. For , our estimation on the
experimental sensitivity shows that it can reach the scale. This
sensitivity can be enhanced by using stronger magnetic field strength, larger
magnetic flux, as well as higher experimental precision on the phase shift.Comment: 12 pages, 1 figure; v2, accepted version by PL
Exploiting Image Local And Nonlocal Consistency For Mixed Gaussian-Impulse Noise Removal
Most existing image denoising algorithms can only deal with a single type of
noise, which violates the fact that the noisy observed images in practice are
often suffered from more than one type of noise during the process of
acquisition and transmission. In this paper, we propose a new variational
algorithm for mixed Gaussian-impulse noise removal by exploiting image local
consistency and nonlocal consistency simultaneously. Specifically, the local
consistency is measured by a hyper-Laplace prior, enforcing the local
smoothness of images, while the nonlocal consistency is measured by
three-dimensional sparsity of similar blocks, enforcing the nonlocal
self-similarity of natural images. Moreover, a Split-Bregman based technique is
developed to solve the above optimization problem efficiently. Extensive
experiments for mixed Gaussian plus impulse noise show that significant
performance improvements over the current state-of-the-art schemes have been
achieved, which substantiates the effectiveness of the proposed algorithm.Comment: 6 pages, 4 figures, 3 tables, to be published at IEEE Int. Conf. on
Multimedia & Expo (ICME) 201
Image Restoration Using Joint Statistical Modeling in Space-Transform Domain
This paper presents a novel strategy for high-fidelity image restoration by
characterizing both local smoothness and nonlocal self-similarity of natural
images in a unified statistical manner. The main contributions are three-folds.
First, from the perspective of image statistics, a joint statistical modeling
(JSM) in an adaptive hybrid space-transform domain is established, which offers
a powerful mechanism of combining local smoothness and nonlocal self-similarity
simultaneously to ensure a more reliable and robust estimation. Second, a new
form of minimization functional for solving image inverse problem is formulated
using JSM under regularization-based framework. Finally, in order to make JSM
tractable and robust, a new Split-Bregman based algorithm is developed to
efficiently solve the above severely underdetermined inverse problem associated
with theoretical proof of convergence. Extensive experiments on image
inpainting, image deblurring and mixed Gaussian plus salt-and-pepper noise
removal applications verify the effectiveness of the proposed algorithm.Comment: 14 pages, 18 figures, 7 Tables, to be published in IEEE Transactions
on Circuits System and Video Technology (TCSVT). High resolution pdf version
and Code can be found at: http://idm.pku.edu.cn/staff/zhangjian/IRJSM
Improved Total Variation based Image Compressive Sensing Recovery by Nonlocal Regularization
Recently, total variation (TV) based minimization algorithms have achieved
great success in compressive sensing (CS) recovery for natural images due to
its virtue of preserving edges. However, the use of TV is not able to recover
the fine details and textures, and often suffers from undesirable staircase
artifact. To reduce these effects, this letter presents an improved TV based
image CS recovery algorithm by introducing a new nonlocal regularization
constraint into CS optimization problem. The nonlocal regularization is built
on the well known nonlocal means (NLM) filtering and takes advantage of
self-similarity in images, which helps to suppress the staircase effect and
restore the fine details. Furthermore, an efficient augmented Lagrangian based
algorithm is developed to solve the above combined TV and nonlocal
regularization constrained problem. Experimental results demonstrate that the
proposed algorithm achieves significant performance improvements over the
state-of-the-art TV based algorithm in both PSNR and visual perception.Comment: 4 Pages, 1 figures, 3 tables, to be published at IEEE Int. Symposium
of Circuits and Systems (ISCAS) 201
Image Super-Resolution via Dual-Dictionary Learning And Sparse Representation
Learning-based image super-resolution aims to reconstruct high-frequency (HF)
details from the prior model trained by a set of high- and low-resolution image
patches. In this paper, HF to be estimated is considered as a combination of
two components: main high-frequency (MHF) and residual high-frequency (RHF),
and we propose a novel image super-resolution method via dual-dictionary
learning and sparse representation, which consists of the main dictionary
learning and the residual dictionary learning, to recover MHF and RHF
respectively. Extensive experimental results on test images validate that by
employing the proposed two-layer progressive scheme, more image details can be
recovered and much better results can be achieved than the state-of-the-art
algorithms in terms of both PSNR and visual perception.Comment: 4 pages, 4 figures, 1 table, to be published at IEEE Int. Symposium
of Circuits and Systems (ISCAS) 201
Investigating the topological structure of quenched lattice QCD with overlap fermions by using multi-probing approximation
The topological charge density and topological susceptibility are determined
by multi-probing approximation using overlap fermions in quenched SU(3) gauge
theory. Then we investigate the topological structure of the quenched QCD
vacuum, and compare it with results from the all-scale topological density, the
results are consistent. Random permuted topological charge density is used to
check whether these structures represent underlying ordered properties.
Pseudoscalar glueball mass is extracted from the two-point correlation function
of the topological charge density. We study ensembles of different lattice
spacing with the same lattice volume , the results are
compatible with the results of all-scale topological charge density, and the
topological structures revealed by multi-probing are much closer to all-scale
topological charge density than that by eigenmode expansion.Comment: 12 pages,34 figure
- …