共查询到20条相似文献,搜索用时 15 毫秒
1.
The scaling behavior of the closed trajectories of a moving particle generated by randomly placed rotators or mirrors on a square or triangular lattice is studied numerically. On both lattices, for most concentrations of the scatterers the trajectories close exponentially fast. For special critical concentrations infinitely extended trajectories can occur which exhibit a scaling behavior similar to that of the perimeters of percolation clusters.At criticality, in addition to the two critical exponents =15/7 andd
f=7/4 found before, the critical exponent =3/7 appears. This exponent determines structural scaling properties of closed trajectories of finite size when they approach infinity. New scaling behavior was found for the square lattice partially occupied by rotators, indicating a different universality class than that of percolation clusters.Near criticality, in the critical region, two scaling functions were determined numerically:f(x), related to the trajectory length (S) distributionn
s, andh(x), related to the trajectory sizeR
s (gyration radius) distribution, respectively. The scaling functionf(x) is in most cases found to be a symmetric double Gaussian with the same characteristic size exponent =0.433/7 as at criticality, leading to a stretched exponential dependence ofn
S onS, nSexp(–S
6/7). However, for the rotator model on the partially occupied square lattice an alternative scaling function is found, leading to a new exponent =1.6±0.3 and a superexponential dependence ofn
S onS.h(x) is essentially a constant, which depends on the type of lattice and the concentration of the scatterers. The appearance of the same exponent =3/7 at and near a critical point is discussed. 相似文献
2.
正交电磁场中粒子的运动轨迹在拐点处按指数规律变化,使不同质量离子的轨迹有明显区别,由此可创建新的电磁核素分离法。从牛顿运动方程出发,基于单粒子轨道法阐述被分离核素在正交电磁场中的运动规律,重点找出轨迹的拐点。给出了多质量粒子束在正交电磁场中的质量聚焦特性,以Li离子为例,应用MATLAB模拟粒子束的运动轨迹,结果表明正交电磁场中可实现多质量束流的质量分离。总结出粒子轨迹方程的特点,为多质量束流分离结构的工程化实现提供参数。研究成果可应用到质量分离器、质谱分析仪及材料提纯等装置的研制中,同时对于特殊位形电磁场控制多质量束流等相关领域的研究亦有一定的参考价值。 相似文献
3.
S.V. Abdrashitov O.V. Bogdanov P.O. Kazinski T.A. Tukhfatullin 《Physics letters. A》2018,382(42-43):3141-3145
We propose to use channeling radiation (CR) from relativistic electrons as a source of high energy twisted photons in the MeV range. We calculate numerically the orbital angular momentum (OAM) of radiation produced by electrons with the energies MeV for the axial and planar channeling in the thin Si crystal. We obtain that the average OAM of CR in this case is approximately per photon with the photon energies about MeV. 相似文献
4.
S. N. Samoilov 《Russian Physics Journal》2008,51(12):1290-1293
Relativistic particle collisions are described by the 2-form of a cross product of particle momentum 1-forms.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 42–45, December, 2008. 相似文献
5.
F. Debbasch 《Physica A》2008,387(11):2443-2454
An alternative to the Jüttner distribution has been recently proposed by several authors. The literature on the topic is reviewed critically. It is found that the Jüttner distribution is correct and that the alternative distribution contradicts quantum field theory, statistical physics and continuum mechanics. 相似文献
6.
把Mei对称性方法用于电磁场中带电粒子的运动,从二维运动电荷的Mei对称性出发,运用比较系数法,得到与Mei对称性相应的生成元的普遍表达式及电磁场所满足的偏微分方程组.对一特例进行了讨论.
关键词:
二维运动电荷
电磁场
Mei对称性 相似文献
7.
Transverse-energy and charged-particle pseudorapidity densities at midrapidity and their ratio, dET/d|mid/dNch/d|mid, are evaluated in a statistical model with longitudinal and transverse flows for the wide range of colliders, from AGS to RHIC at
= 200 GeV. Evaluations are done at freeze-out parameters obtained from independent fits to observed particle yields and pT spectra. Decays of hadron resonances are treated thoroughly and are included in derivations of dET/d|mid and dNch/d|mid. The predictions of the model agree well with the experimental data. However, some (explicable) overestimation of the ratio has been observed. 相似文献
8.
We study the problem of a possible change in the number of constraints in linear relativistic wave equations (-iβ
μ
∂
μ
+m)ψ=0 for particles of unique mass, on introduction of minimal coupling to an external electromagnetic field. Complementing our
earlier work in which we obtained conditions for non-loss of constraints in equations characterised by the minimalβ-algebraβ
0
5 =β
0
3 we derive here the conditions for such theories not to generate more constraints than in the free case. The results are illustrated
by considering specific equations and a fallacy in certain conclusions of Kobayashi and Shamaly on this problem is pointed
out. 相似文献
9.
10.
We study classical and quantum dynamics of a kicked relativistic particle confined in a one dimensional box. It is found that in classical case for chaotic motion the average kinetic energy grows in time, while for mixed regime the growth is suppressed. However, in case of regular motion energy fluctuates around certain value. Quantum dynamics is treated by solving the time-dependent Dirac equation with delta-kicking potential, whose exact solution is obtained for single kicking period. In quantum case, depending on the values of the kicking parameters, the average kinetic energy can be quasi periodic, or fluctuating around some value. Particle transport is studied by considering spatio-temporal evolution of the Gaussian wave packet and by analyzing the trembling motion. 相似文献
11.
In this paper we have studied the motion of charged particles in a dipole magnetic field on the Schwarzscbild background geometry.
A detailed analysis has been made in the equatorial plane through the study of the effective potential curves. In the case
of positive canonical angular momentum the effective potential has two maxima and two minima giving rise to a well-defined
potential well rear the event horizon. This feature of the effective potential categorises the particle orbits into four classes,
depending on their energies. (i) Particles, coming from infinity with energy less than the absolute maximum ofV
eff, would scatter away after being turned away by the magnetic field. (ii) Whereas those with energies higher than this would
go into the central star seeing no barrier. (iii) Particles initially located within the potential well are naturally trapped,
and they execute Larmor motion in bound gyrating orbits. (iv) and those with initial positions corresponding to the extrema
ofV
eff follow circular orbits which are stable for non-relativistic particles and unstable for relativistic ones. We have also considered
the case of negative canonical angular momentum and found that no trapping in bound orbits occur for this case.
In the case when particles are not confined to the equatorial plane we have found that the particles execute oscillatory motion
between two mirror points if the magnetic field is sufficiently high, but would continuously fall towards the event horizon
otherwise.
An erratum to this article is available at . 相似文献
12.
13.
研究了在相对论领域内,超强激光场的不同条件(频率、强度、脉冲波形磁场分量)对氘原子电离几率的影响,研究表明:电离几率随激光强度的增加而增加,随激光频率的增加而减少。而激光脉冲波形对电离几率的影响仅在激光无磁场分量时比较显著。激光场的磁场分量对原子的电离有一定的影响。 相似文献
14.
Phase-dependent inversionless gain in a four-level atomic system with a closed interaction loop
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A four-level atomic system with a closed interaction loop connected
by two coherent driving fields and a microwave field is
investigated. The results show that inversionless gain can be
achieved on a higher frequency transition outside the closed
interaction loop, and the gain behaviour can be modulated by the
phase of the closed loop as well as the amplitude of the microwave
field. The phase sensitivity property in such a scheme is similar to
that in an analogous configuration with spontaneously generated
coherence, but it is beyond the rigorous condition of
near-degenerate levels with non-orthogonal dipole moments.
Therefore this scheme is much more convenient in experimental
realization. 相似文献
15.
The behaviour of a relativistic scalar particle in a possible scenario that arises from the violation of the Lorentz symmetry is investigated. The background of the Lorentz symmetry violation is defined by a tensor field that governs the Lorentz symmetry violation out of the Standard Model Extension. Thereby, we show that a Coulomb-type potential can be induced by Lorentz symmetry breaking effects and bound states solutions to the Klein–Gordon equation can be obtained. Further, we discuss the effects of this Coulomb-type potential on the confinement of the relativistic scalar particle to a linear confining potential by showing that bound states solutions to the Klein–Gordon equation can also be achieved, and obtain a quantum effect characterized by the dependence of a parameter of the linear confining potential on the quantum numbers {n,l} of the system. 相似文献
16.
M. Abdel Aziz 《Physics letters. A》2012,376(3):169-178
The dispersion properties of a transverse electric (TE) surface waves propagating along the interface between a magneto-quantum plasma-relativistic beam system and vacuum are studied by using the quantum hydrodynamic model. The general dispersion relations are derived and analyzed in some special cases of interest. Moreover, the effects of density gradients for the beam and plasma on the dispersion properties of surface waves are investigated. The kind of dispersion relations depends strongly on the ambient magnetic field Bo via the gyro-frequency ωc, the quantum parameters, and the width of the plasma layer as well as the relativistic factor for the electron beam. It is found that the quantum effects play a crucial role to facilitate the propagation of TE surface waves. 相似文献
17.
Based on the Standard Model Extension, we investigate relativistic quantum effects on a scalar particle in backgrounds of the Lorentz symmetry violation defined by a tensor field. We show that harmonic-type and linear-type confining potentials can stem from Lorentz symmetry breaking effects, and thus, relativistic bound state solutions can be achieved. We first analyse a possible scenario of the violation of the Lorentz symmetry that gives rise to a harmonic-type potential. In the following, we analyse another possible scenario of the breaking of the Lorentz symmetry that induces both harmonic-type and linear-type confining potentials. In this second case, we also show that not all values of the parameter associated with the intensity of the electric field are permitted in the search for polynomial solutions to the radial equation, where the possible values of this parameter are determined by the quantum numbers of the system and the parameters associated with the violation of the Lorentz symmetry. 相似文献
18.
In an axially deformed relativistic mean-field calculation of single-particle energy spectra ofN = 8 (Li-Mg) andN = 14,16 (C-Mg) isotonic chain and the one- and two-neutron separation energies of various isotopes of Li-Mg, new magic numbers
are found to exist atN = 6 andN = 16 and/orN = 14, which are in addition to theN = 8 andN = 20 magic numbers. In neutron-rich nuclei, the shell gap atN = 6 is larger than atN = 8 and a large gap is observed forN = 16 or 14 for the neutron-rich andN = 14 for proton-rich nuclei. Large shell gaps are also found to exist atN = 14 and 16 orN = 16 alone for nuclei near theβ-stability line. The above results are independent of the parameter sets TM2, NL3 and NL-SH used here. Similarly, new large
shell gaps are predicted atZ = 616 and/or 14 for protons. 相似文献
19.
From the Copson and Linet solution for the electrostatic field due to a point charge near a Schwarzschild black hole, we have
deduced the field due to two equal charges placed symmetrically (diametrically opposite) about the hole. It turns out that
the motion of a test-charged particle is completely solvable only in the equatorial plane, because theϑ-equation does not yield the first integral forϑ ≠π/2. We have however considered circular orbits about the axis forϑ=constant ≠π/2 by requiring bothϑ andr to remain fixed all through the motion. Forϑ ≠π/2 orbits, in contrast to the similar classical situation, there occur forbiddenϑ-ranges. This seems to be a relativistic effect. 相似文献
20.
Shi Shusu Du Jiaxin Liu Lianshou 《The European Physical Journal A - Hadrons and Nuclei》2007,33(1):53-56
The inversion-asymmetry of the particle emission source in relativistic heavy-ion collision under the Bertsch-Pratt convention
is discussed and explicitly exhibited by a Monte Carlo model. The Gaussian source function popularly used in the HBT analysis
of relativistic heavy-ion collisions is invalid in this case. An inversion-asymmetric source function is suggested. A method
for extracting the inversion-asymmetry degree of the source together with the source size from experimental data is proposed. 相似文献