共查询到20条相似文献,搜索用时 412 毫秒
1.
E. S. Kokoulina V. A. Nikitin Y. P. Petukhov A. V. Karpov A. Ya. Kutov 《Physics of Atomic Nuclei》2010,73(12):2116-2124
New results of the search for collective phenomena have been obtained and analyzed in the present report. The experimental
studies are carried out on U-70 accelerator of IHEP in Protvino. It is suggested that these phenomena can be discovered at
the energy range of 50–70 GeV in the extreme multiplicity region since the high-density matter can form in this very region.
The collective behavior of secondary particles is considered to manifest itself in the Bose-Einstein condensation of pions,
Vavilov-Cherenkov gluon radiation, excess of soft-photon yield, and other unique phenomena. The perceptible peak in the angular
distribution has been revealed. It was interpreted as the gluon radiation and so the parton matter refraction index was determined.
The new software was designed for the track reconstruction based on Kalman Filter technique. This algorithm allows one to
estimate more precisely the track parameters (especially momentum). The search for Bose-Einstein condensation can be continued
by using the selected events with the multiplicity of more than eight charged particles. The gluon dominance model predictions
have shown good agreement with the multiplicity distribution at high multiplicity and confirmed the guark-gluon medium formation
under these conditions. 相似文献
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The role of filamentation instability of quark-gluon plasma, in explaining collective phenomena in relativistic heavy-ion
collisions, has been analyzed. Using equations of SU(2) two fluid color hydrodynamics it is shown that this instability can
significantly enhance nuclear stopping and might contribute to collective sideward flows. 相似文献
4.
Microscopic calculations of the dipole giant resonance in fissioning nuclei give a splitting of the dipole strength into three collective branches, contrary to two branches as predicted by the hydrodynamical model. These collective phenomena have been studied with simplifying separable interactions and sum-rule approaches, and found to be fairly independent of mass number and shell structure. The detailed dependence of excitation energies, dipole strengths and transition densities on the fission coordinate could give rise to interesting phenomena, particularly in electrofission experiments. 相似文献
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O. Alvarez-Llamoza K. Tucci M. G. Cosenza M. Pineda 《The European physical journal. Special topics》2007,143(1):245-247
The phenomena of synchronization and nontrivial collective behavior are studied
in a model of coupled chaotic maps with random global coupling. The mean field
of the system is coupled to a fraction of elements randomly chosen at any given
time. It is shown that the reinjection of the mean field to a fraction of
randomly selected elements can induce synchronization and nontrivial collective
behavior in the system. The regions where these collective states emerge on the
space of parameters of the system are calculated. 相似文献
7.
超导体中的电子结成库珀对,凝聚到可以用一个宏观波函数来描绘的能量基态,该波函数的位相是代表了成百万库珀对集体运动的宏观变量.以约瑟夫森结为基础元件的超导约瑟夫森器件,使人们能够控制并测量一个超导体的位相和库珀对数目,因此是研究宏观量子现象的理想系统.文章回顾了约瑟夫森器件中的宏观量子现象研究的发展历程,介绍了当前超导约瑟夫森器件在量子计算中的重要应用,并对它们的未来作了简要的展望. 相似文献
8.
We report a phenomenon that electromagnetic spin–orbit interactions can be tailored by dielectric nanoparticles, and self-similar giant spin-Hall effect has been observed in the dielectric particle cluster. The near-field phase singularities and phase vorticity in the longitudinal component of scattered field can also be controlled by such a dielectric structure. The origin of phenomena is believed to be due to the collective resonance excitation in the dielectric particle cluster. It is expected to find applications in optics information processing and designing new nanophotonic devices. 相似文献
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O.N. Martyanov V.F. Yudanov R.N. Lee S.A. Nepijko H.J. Elmers C.M. Schneider G. Schönhense 《Applied Physics A: Materials Science & Processing》2005,81(4):679-683
The ferromagnetic resonance (FMR) method is used to study the collective phenomena in two-dimensional periodic arrays of disk-shaped Co particles. A study of geometrically similar structures with different periods reveals a broadening of the FMR resonance lines due to the excitation of additional size-dependent non-uniform spin waves. It is shown that these collective spin-wave modes are based on dipole–dipole interactions between the ferromagnetic particles in the array. Qualitative and quantitative data on magnetic interparticle interactions can thus be obtained from FMR spectra for two-dimensional periodic arrays of ferromagnetic particles. PACS 73.21.-b, 75.75.+a, 76.50.+g 相似文献
11.
Fracturing processes within solid Earth materials are inherently a complex phenomenon so that the underlying physics that control fracture initiation and evolution still remain elusive. However, universal scaling relations seem to apply to the collective properties of fracturing phenomena. In this article we present a statistical physics approach to fracturing based on the framework of non-extensive statistical physics (NESP). Fracturing phenomena typically present intermittency, multifractality, long-range correlations and extreme fluctuations, properties that motivate the NESP approach. Initially we provide a brief review of the NESP approach to fracturing and earthquakes and then we analyze stress and stress direction time series within Arctic sea ice. We show that such time series present large fluctuations and probability distributions with “fat” tails, which can exactly be described with the q-Gaussian distribution derived in the framework of NESP. Overall, NESP provide a consistent theoretical framework, based on the principle of entropy, for deriving the collective properties of fracturing phenomena and earthquakes. 相似文献
12.
由Internet构成的复杂网络的动力学特性主要受到用户需求行为的影响,具备时域的统计规律性. 通过对区域群体用户需求行为的时域实验统计分析,发现用户对Web网站的访问频度及其生成的二分网络的入度分布也呈现幂律分布和集聚现象,其幂指数介于1.7到1.8之间. 建立了虚拟资源网络VRN和物理拓扑网络PTN双层模型,分析了双层模型映射机理,并对网络用户需求行为进行建模. 虚拟资源网络VRN对物理拓扑网络PTN映射过程的不同机理,模拟了Internet资源网络到物理网络的不同影响模式. 幂律分布的用户需求特性会
关键词:
复杂网络
无标度拓扑
用户需求
相变 相似文献
13.
H. Kleinert 《Fortschritte der Physik》1982,30(7):351-400
We point out that large-amplitude collective excitations, tunneling phenomena, condensation of higher particle clusters, and excitation spectra beyond Landau's theory of Fermi liquid are most conveniently described in terms of successive effective actions. These are functionals depending explicitly on two-particle, four-particle, etc. correlations which have a simple quasi-classical expansion. Their extrema account for the above described phenomena. Contrary to the path integral approach to collective phenomena, the lowest approximation contains exchange and pairing effects and is therefore suited for systems in which the time-dependent Hartree-Fock-Bogoljubov equations are required for a proper understanding of the phenomena. 相似文献
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H. Stöcker G. Buchwald L.P. Csernai G. Graebner J.A. Maruhn Walter Greiner 《Nuclear Physics A》1982,387(1):205-217
Nuclear collisions at ELAB > 50 MeV/n are studied using the nuclear fluid dynamical and the cascade model. Evidence for the predicted compression effects has been found in recent experimental data: The preferential sidewards emission of light fragments as well as the azimuthal p-p correlations indicate the presence of collective flow phenomena. The analysis of future 4π exclusive experiments in terms of the kinetic flow tensor can yield information about the equation of state of the compressed nuclear matter. We also discuss the role of pions and strange particles as probes for the properties of nuclear matter at high excitation energy. 相似文献
16.
Discriminating geoelectrical signals measured in seismic and aseismic areas by using Ito models 总被引:3,自引:0,他引:3
Geoelectrical signals can be considered as the end-product of complex and collective interactions among system elements. Their dynamical behavior could be different if they are measured in seismic or aseismic areas. Using the Ito equations, which represent a good macroscopic model of phenomena in which microscopic interactions are adequately averaged, we show that geoelectrical data recorded in seismic areas are well discriminated by those measured in aseismic areas. Our findings contribute to a better dynamical characterization of geoelectrical signals. 相似文献
17.
Theoretical and experimental problems of multiparticle production are analyzed in the high-multiplicity region. Interesting
collective phenomena may be revealed in this region. Preliminary results of the Thermalization Project are being reported.
The text was submitted by the authors in English. 相似文献
18.
N. Minkov S. B. Drenska P. P. Raychev R. P. Roussev D. Bonatsos 《Physics of Atomic Nuclei》2001,64(6):1098-1104
We propose a collective Hamiltonian that incorporates interactions capable of generating rotations in nuclei with simultaneous presence of octupole and quadrupole deformations. It is demonstrated that the model formalism could be applied to reproduce the staggering effects observed in nuclear octupole bands. On this basis, we propose that the interactions involved would provide a relevant handle in the study of collective phenomena in nuclei and other quantum mechanical systems with reflection asymmetry correlations. 相似文献
19.
Manheimer W.M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2001,29(4):639-648
Theoretical estimates of electron cyclotron shot noise in gyroklystrons have recently been confirmed at low currents. However at high beam current, the noise temperature is always reduced. We examine the effect of transverse collective effects on the shot noise. There are two collective effects; shielding, which reduces the noise; and instability, which increases it. It is shown that the effect of transverse shielding is negligible unless the gyrotron beam is extremely cold. Regarding instability, if the bare shot noise amplitude is denoted Ξ, then the shot noise, including the effect of instability, can be expressed as Ξ(1+A exp Γ), where Γ is the integrated growth. The effect of instability is then measured by two parameters, Γ and A. For a cold gyrotron beam, A is about 0.3, meaning about 10 dB of power growth is needed for the instability to manifest itself. Thermal effects both reduce A and Γ. For realistic gyrotron beams, about 20-25 dB of power e folds would be necessary for instability to manifest itself. To summarize, the theory developed explains the absence of instability in the measurements, but indicates that phenomena other than transverse shielding are responsible for the noise reduction 相似文献
20.
Ch. Kleint 《Surface science》1988,200(2-3):472-489
Traced back to the early discoveries by Schottky and Johnson, a review will be given on the present state of electron emission noise phenomena and related fluctuations. Special emphasis is laid upon adsorbate induced noise under UHV conditions which can be investigated, at least in principle, down to single adparticle fluctuations. On the other hand, with increasing submonolayer coverage, adparticle interactions can play an important role which might even lead to collective phenomena. Different noise sources and models to describe them will be discussed. The examples for illustration are mainly taken from field emission investigations and will cover shot noise, prediffusion adparticle flip-flop, Brownian motion or concentration fluctuations in a patch, tunneling diffusion, trap and surface state governed emission noise and indications of phase transitions and soliton or domain wall movements. Some relations to current noise in solid state devices and to other noise sources and their characteristics will be mentioned. 相似文献