14,278 research outputs found
Fermions on Thick Branes in the Background of Sine-Gordon Kinks
A class of thick branes in the background of sine-Gordon kinks with a scalar
potential was constructed by R. Koley and S.
Kar [Classical Quantum Gravity \textbf{22}, 753 (2005)]. In this paper, in the
background of the warped geometry, we investigate the issue of localization of
spin half fermions on these branes in the presence of two types of
scalar-fermion couplings: and . By presenting the mass-independent potentials in the corresponding
Schr\"{o}dinger equations, we obtain the lowest Kaluza--Klein (KK) modes and a
continuous gapless spectrum of KK states with for both types of
couplings. For the Yukawa coupling , the effective
potential of the right chiral fermions for positive and is always
positive, hence only the effective potential of the left chiral fermions could
trap the corresponding zero mode. This is a well-known conclusion which had
been discussed extensively in the literature. However, for the coupling
, the effective potential of the right chiral
fermions for positive and is no longer always positive. Although the
value of the potential at the location of the brane is still positive, it has a
series of wells and barriers on each side, which ensures that the right chiral
fermion zero mode could be trapped. Thus we may draw the remarkable conclusion:
for positive and , the potentials of both the left and right chiral
fermions could trap the corresponding zero modes under certain restrictions.Comment: 22 pages, 21 figures, published version to appear in Phys. Rev.
Self-dual Vortices in the Abelian Chern-Simons Model with Two Complex Scalar Fields
Making use of -mapping topological current method, we discuss the
self-dual vortices in the Abelian Chern-Simons model with two complex scalar
fields. For each scalar field, an exact nontrivial equation with a topological
term which is missing in many references is derived analytically. The general
angular momentum is obtained. The magnetic flux which relates the two scalar
fields is calculated. Furthermore, we investigate the vortex evolution
processes, and find that because of the present of the vortex molecule, these
evolution processes is more complicated than the vortex evolution processes in
the corresponding single scalar field model.Comment: 9 pages, no figure
GRB 120729A: External Shock Origin for Both the Prompt Gamma-Ray Emission and Afterglow
Gamma-ray burst (GRB) 120729A was detected by Swift/BAT and Fermi/GBM, and then rapidly observed by Swift/XRT, Swift/UVOT, and ground-based telescopes. It had a single long and smooth \gamma-ray emission pulse, which extends continuously to the X-rays. We report Lick/KAIT observations of the source, and make temporal and spectral joint fits of the multiwavelength light curves of GRB 120729A. It exhibits achromatic light-curve behavior, consistent with the predictions of the external shock model. The light curves are decomposed into four typical phases: onset bump (Phase I), normal decay (Phase II), shallow decay (Phase III), and post-jet break (Phase IV). The spectral energy distribution (SED) evolves from prompt \gamma-ray emission to the afterglow with photon index from Γγ=1.36 to Γ≈1.75. There is no obvious evolution of the SED during the afterglow. ...(Please see article full tet for complete abstract.
The application research on improvement of genetic algorithm in linear CCD detection
When the linear array image sensor (CCD) is used for spot detection, the optimization of the detection signal is usually one of the problems that plague the user. In linear array imaging sensor (CCD) detection applications, optimization of the detection signal is usually one of the problems with the user. Based on the characteristics of linear array CCD detection signal, a genetic algorithm (GA) is established to solve the problem of mathematical model. In this paper, a new adaptive genetic algorithm (IGA) with directional adaptive guidance and adaptive control technology and threshold constraint technology are proposed for the lack of local optimization ability of the standard genetic algorithm (SGA), premature convergence and low accuracy. By applying IGA to the actual detection data, it is proved that IGA has certain advantages in solving the problem of linear CCD detection signal optimization. In the end of this paper, the performance of IGA, SGA and peak finding algorithm (SP) are analyzed and compared, which fully demonstrates the advantages of IGA in solving such problems
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