共查询到20条相似文献,搜索用时 579 毫秒
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《Physics letters. A》1998,246(6):505-510
Ising models obeying Glauber dynamics in a temporally oscillating magnetic field are analyzed. In the context of stochastic resonance, the response in the magnetization is calculated by means of both a mean-field theory with linear-response approximation, and the time-dependent Ginzburg-Landau equation. Analytic results for the temperature and frequency dependent response, including the resonance temperature, compare favorably with simulation data. 相似文献
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J.M. Eisenberg 《Nuclear Physics A》1982,389(3):595-604
Multiple scattering in the limit in which the constituent scatterers are far removed from each other is studied. It is seen how this situation leads, in the Watson multiple-scattering series, to the dominance of on-shell propagation between the constituents. It also yields a version of the Glauber multiple-scattering theory in which no assumption is made to the effect that the individual projectile-constituent scattering amplitudes are eikonal in form. This approach allows for the immediate extraction of Fresnel corrections to the Glauber result and explains several apparent contradictions as to the relationship between the Watson multiple-scattering series approximated with on-shell propagation only and the Glauber theory. 相似文献
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A modified microscopic Glauber theory has been extended to
investigation of the reaction and elastic differential cross sections
of various projectile-target collisions at low and intermediate
energies. Through a systematic study, we find that the inclusion
of the finite range interaction and Coulomb modifications plays
very important role in the Glauber theory to reproduce the
experimental data at these energy ranges. Usually the effect of
the Coulomb modification is to decrease the reaction cross sections, on the contrary that of the finite range interaction modification increases them. The angular distributions calculated by the Glauber theory including these two corrections are in
good agreement with the experimental data. 相似文献
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Effects of Glauber gluons, which cause the elastic scattering process between different jets, are studied in the frame of soft-collinear effective theory. Glauber modes are added into the action before being integrated out, which is helpful in studies on the Glauber couplings of collinear and soft particles. It is proved that the final state interactions cancel out for processes inclusive enough. So are interactions with the light cone coordinates x+ and x− greater than those of the hard collision. The eikonalization of Glauber couplings of active particles and absorption of these couplings into soft and collinear Wilson lines are discussed, which is related to the loop level definitions of Glauber gluons here. The active-spectator coherence is proved to be harmless to the inclusive summation of spectator-spectator and spectator-soft Glauber exchanges. Based on this result, spectator-spectator and spectator-soft Glauber exchanges cancel out in the processes considered here. Graphic aspects of the cancellation are also discussed to explain relations between the graphic and operator level cancellation of Glauber gluons. 相似文献
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本文重新推导了Glauber理论中弹性散射振幅公式。如果取直角光学位势作为零级近似,取Woods-Saxon光学位势作为正确的光学位势,发现在原来的散射振幅中,分部积分能够进一步进行下去。最后,得到了修正后的散射振幅公式,而无角度限制。
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T.T. Tien 《Physics letters. A》1978,64(4):369-372
The Glauber exchange effect is included into the calculations of differential cross sections in an analysis of 1–2 excitation of the hydrogen atom by electron impact within the conventional Glauber theory. An improvement of the theoretical results is obtained. 相似文献
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We present an expansion of the Glauber equation of motion in terms of cumulants of the
effective fields. We show that we recover a part of the fluctuations with a simple third
order expansion. We illustrate the method with an application to the 2D square lattice
Ising model with nearest neighbors. For the special case of perturbed non gaussian
effective fields, we show that only the first cumulants are significative. Furthermore it
can be shown that the resulting distribution is closer to the normal distribution than the
unperturbed fields one. It leads to the conclusion that we can consistently truncate the
expansion of the exact Glauber equation of motion. 相似文献
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Linear response theory is developed for systems whose time dependence is described by a master equation. The fluctuation dissipation theorem expressing the linear response of the system in terms of fluctuation properties of the system in equilibrium is derived. The time-dependent Ising spin system in interaction with a heat bath, the Glauber model, is discussed as a particular case of the formalism.The work of one of the authors (D.B.) was supported in part by the National Science Foundation under Contract GP 10536.On leave of absence from the Institute of Physics, Belgrade, Yugoslavia. 相似文献
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We prove convergence to a motion by mean curvature by scaling diffusively a nonlinear, nonlocal evolution equation. This equation was introduced earlier to describe the macroscopic behavior of a ferromagnetic spin system with Kac interaction which evolves with Glauber dynamics. The convergence is proven in any time interval in which the limiting motion is regular. 相似文献
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M.Y.H. Farag 《The European Physical Journal A - Hadrons and Nuclei》2001,12(4):405-411
Glauber's theory has been adopted to calculate the total heavy-ion reaction cross-sections at high energies. At relatively
low energies, Glauber's total reaction cross-section has been modified in order to take into account the Coulomb field effect
and is called modified Glauber model I. In addition to the Coulomb field effect, the nuclear effect has also been taken into
account in the Glauber model and is called modified Glauber model II. An analytical expression for the transparency function
for heavy-ion reactions, involving the nuclear densities of the colliding ions and the nucleon-nucleon cross- section, has
been obtained within the framework of the modified Glauber models I and II. The transparency and the total reaction cross-sections
of the 12C + 12C collisions are calculated at different bombarding energies. The obtained results are in good agreement with the experimental
data and with previous theoretical calculations.
Received: 26 January 2001 / Accepted: 15 October 2001 相似文献
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测量了27,28P和相应同中子异位素在28Si靶上的中能反应截面.测得N=12和13同中子异位素的反应截面在Z=15处突然增大.对Z≤14同中子异位素和28P的实验数据结果可以用改进的光学极限近似的Glauber理论很好地描述.28P的反应截面能够用扩大核芯以改进的Glauber理论来解释.但是,用改进光学极限和少体近似的Glauber理论却低估了27P的实验数据.理论分析表明,扩大的核芯加质子晕可能是响应27P+28Si反应截面增强的机制. The reaction cross sections of~(27,28)P and the corresponding isotones on Si target were measured at intermediate energies. The measured reaction cross sections of the N=12 and 13 isotones show an abrupt increase at Z=15. The experimental results for the isotones with Z≤14 and~(28)P can be described well by the modified Glauber theory of the optical limit approach. The enhancement of the reaction cross section for~(28)P could be explained by the modified Glauber theory with an enlarged core. Theoretical ana... 相似文献
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Optical micromaser action is considered in atomic clusters that can be involved in separable and entangled initial correlations. An equation describing the evolution of the Glauber quasi-probability for a light field is constructed in the Fokker-Planck approximation. The statistics of radiation emitted by a cavity is analyzed. 相似文献
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According to the prediction made by A.B. Migda, a pion condensate should already be present in ordinary finite nuclei, We have studied the effect of pion condensate in high energy proton-nucleus scattering by using the Glauber multiple scattering theory, A calculation has been performed for P-40Ca elastic scattering at the incident energy of 1 GeV and compared with the data available. The results strongly indicate that pion condensate does not have an adequate, opportunity to manifest itself in high energy proton-nucleus scattering, at least so for small angle scattering. 相似文献
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B. Schürmann 《Nuclear Physics B》1973,67(2):425-444
Starting from a Watson-type multiple scattering series we study first-order corrections to the Glauber high-energy collision model. These are obtained by replacing the free-space Green function between successive scatterings by the second-order eikonal propagator. We distinguish between Fresnel corrections and eikonal-type corrections. Due to large cancellation effects the eikonal contribution is very small compared to the Fresnel contribution. First-order corrections to Glauber theory are calculated explicitly for high-energy elastic scattering of protons from light nuclei (4He, 12C, 16O). 相似文献
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A. Klar 《Nuclear Physics A》1981,367(3):369-380
The effect of short-range nucleon-nucleon correlations on inclusive inelastic cross sections is studied within the framework of Glauber theory. The correction term resulting from two-particle correlations corresponds to scattering from a deuteron-like cluster. The net effect is found to be negligibly small. 相似文献
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V. K. Lukyanov E. V. Zemlyanaya K. V. Lukyanov E. I. Zhabitskaya M. V. Zhabitsky 《Physics of Atomic Nuclei》2014,77(1):100-109
Differential cross sections for elastic pion scattering on a number of nuclei at energies between 130 and 290 MeV are calculated. For this purpose, use is made of a microscopic optical pion-nucleus potential that was obtained on the basis of the Glauber theory of high-energy scattering and which is determined by the density distribution of pointlike target nucleons and by the pion-nucleon scattering amplitude. The calculation of the cross sections in question is based on solving the respective relativistic wave equation. Three parameters of the pion-nucleon amplitude are fitted in performing a comparison with experimental data. These are the total cross section for pion-nucleon scattering, the ratio of the real to the imaginary part of the forward pion-nucleon scattering amplitude, and the slope parameter. The resulting values of these parameters are then compared with their counterparts for scattering on free nucleons. The character of nuclear-matter-induced changes in these parameters is studied. 相似文献