共查询到20条相似文献,搜索用时 15 毫秒
1.
The one-loop polarization operator of neutral gluons in the background constant Abelian isotopic, H
3, and hypercharge, H
8, chromomagnetic fields combined with A
0 electrostatic potential at high temperature is calculated. The case when A
0 = 0 is investigated separately. The proper time method is applied. It is found that neutral gluons do not acquire magnetic masses in the background fields, in contrast to the charged ones. The application of the results are discussed.Received: 6 October 2004, Revised: 13 December 2004, Published online: 9 February 2005A.V. Strelchenko: Permanent address: Dniepropetrovsk National University, Naukova 13 Str., Dniepropetrovsk 49050, Ukraine. 相似文献
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K. Vavřina 《Czechoslovak Journal of Physics》1971,21(3):275-284
The paper describes measurements of the current-voltage characteristic of polycrystalline selenium layers at high current density values. At first it is shown that the composition of a counter electrode (Sn, Cd, CdSn) does not influence the character of the dependence of the current density vs. voltage. When measuring the influence of thickness of polycrystalline layers of selenium on the behaviour of the current-voltage characteristic, three regions on the current-voltage characteristic were observed. For the lowest voltage the current density isjU/d and so Ohm's law can be used. For higher voltagejU1.35/d1.175. For the highest voltage the relationjU
2/d1.5 was found. It will probably be possible to explain the results of measurements by means of the existence of space-charge-limited current.I should like to express my sincere gratitude to the specialists from the Institute of the Rectifiers Research at B~chovice for their very careful preparation of the samples, which made possible to carry out really reproducible and comparable measurements. 相似文献
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H. -Th. Elze K. Kajantie T. Toimela 《Zeitschrift fur Physik C Particles and Fields》1988,37(4):601-609
Chromomagnetic fields are studied using linear response theory. We show that the spurious pole at |k|≈g 2 T of the static transverse gluon propagator at finite temperature is cancelled, when the full magnetic permeability function is calculated toO(g 2). Consequently the chromomagnetic fields induced by static external perturbations behave regularly and, to this order, similarly to magnetic fields in QED. We further discuss the relevance of this cancellation for perturbative calculations. 相似文献
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I.M. Dremin L.I. Sarycheva K.Yu. Teplov 《The European Physical Journal C - Particles and Fields》2006,46(2):429-432
The collective effect of emission by the forward moving partons of high energy Cherenkov gluons in nucleus-nucleus collisions
at RHIC and LHC energies is considered. It can reveal itself as peaks in the pseudorapidity distribution of jets at midrapidities,
or as a ring-like structure of individual events in event-by-event analysis. The pseudorapidity distribution of centers of
dense isolated groups of particles in the HIJING model is determined. It can be considered as the background for Cherenkov
gluons. If peaks above this background are found in experiments, they indicate new collective effects.
In memory of E.L. Feinberg 相似文献
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Matthew A. C. Lamont 《The European Physical Journal C - Particles and Fields》2009,62(1):203-210
The nuclear wave-function is dominated at low- and medium-x by gluons. As the rapid growth of the gluon distribution towards low x, as derived from current theoretical estimates, would violate unitarity, there must be a mechanism that tames this explosive
growth. This is most efficiently studied in colliders running in e+A mode, as the nucleus is an efficient amplifier of saturation effects occurring with high gluon densities. In fact, large
A can lead to these effects manifesting themselves at energies a few orders of magnitude lower than in e+p collisions. In order to study these effects, there are proposals to build an e+A machine in the USA, operating over a large range of masses and energies. These studies will allow for an in-depth comparison
to A+A collisions where results have given tantalising hints of a new state of matter with partonic degrees of freedom. In
order to explain these results quantitatively, the gluons and their interactions must be understood fully as they are the
dominant source of hard probes at both RHIC and LHC energies. 相似文献
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The intrinsic character of the correlation between hardness and thermodynamic properties of solids has been established. The proposed thermodynamic model of hardness allows one to easily estimate hardness and bulk moduli of known or even hypothetical solids from the data on Gibbs energy of atomization of the elements or on the enthalpy at the melting point. The correctness of this approach is illustrated by an example of the recently synthesized superhard diamond-like BC5 and orthorhombic modification of boron, γ-B28. The pressure and/or temperature dependences of hardness were calculated for a number of hard and superhard phases, i.e. diamond, cBN, B6O, B4C, SiC, Al2O3, β-B2O3 and β-rh boron. Excellent agreement between experimental and calculated values is observed for temperature dependences of Vickers and Knoop hardness. In addition, the model predicts that some materials can become harder than diamond at pressures in the megabar range. 相似文献
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Claude Deutsch 《Journal of statistical physics》1983,32(1):115-122
The two-dimensional and one-component plasma (OCP) model withr ?1 interactions is investigated in the high-temperature limit, where the thermal wavelength gets larger than the classical distance of closest approach. Nonnegligible diffraction effects are rigorously taken care of (up toe 2) through a temperature-dependent effective interaction. Debye thermodynamics, analyzed in terms of a classical plasma parameter Λ, is shown to diverge as Λ Inh, whenh→0. There is no classical limit. A result at variance with the corresponding one in three dimensions. 相似文献
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The knowledge of elasticity of the minerals is useful for interpreting the structure and composition of the lower mantle and
also in seismic studies. The purpose of the present study is to discuss a simple and straightforward method for evaluating
thermoelastic properties of minerals at high temperatures. We have extended the Kumar’s formulation by taking into the account
the concept of anharmonicity in minerals above the Debye temperature (θ
D). In our present study, we have investigated the thermophysical properties of two minerals (pyrope-rich garnet and MgAl2O4) under high temperatures and calculated the second-order elastic constant (C
ij
) and bulk modulus (K
T) of the above minerals, in two cases first by taking Anderson–Gruneisen parameter (δ
T) as temperature-independent and then by treating δ
T as temperature-dependent parameter. The results obtained when δ
T is temperature-dependent are in close agreement with experimental data. 相似文献
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Studies of nanocluster coalescence at high temperature 总被引:1,自引:0,他引:1
H.B. Liu M. José-Yacaman R. Perez J.A. Ascencio 《Applied Physics A: Materials Science & Processing》2003,77(1):63-67
Molecular Dynamics simulations and high resolution electron microscope observations were used to determine the mechanism of
nanocluster coalescence in detail. In the simulations, the tight-binding second momentum approximation potential was used
to describe the interatomic interactions. The calculations not only reproduced the experimentally observed translation and
reorientation during the coalescing process, but also made it possible to determine the time scale of each step in the process
and to observe details of the process that could not be obtained from the experiment. For high temperature coalescence, a
new mechanism differing from classical theory is proposed.
Received: 14 October 2002 / Accepted: 16 October 2002 / Published online: 28 March 2003
RID="*"
ID="*"Corresponding author. Fax: +52-55/3003-6414, E-mail: ascencio@imp.mx 相似文献
19.
We investigate how thermalization of gluons depends on the initial conditions assumed in ultrarelativistic heavy-ion collisions
at RHIC. The study is based on simulations employing the pQCD inspired parton cascade solving the Boltzmann equation for gluons.
We consider independently produced minijets with p
T > p
0 = 1.3-2.0GeV and a color glass condensate as possible initial conditions for the freed gluons. It turns out that full kinetic
equilibrium is achieved slightly sooner in denser systems and its timescale tends to saturate. Compared with the kinetic equilibration
we find a stronger dependence of chemical equilibration on the initial conditions. 相似文献
20.
Fabrizio Tinebra 《Annalen der Physik》1997,509(3):234-259
During the thermal evolution of the universe, symmetry of the vacuum state in the presence of quantum fields should have changed at various stages. A possible indication of this effect on the DFSZ invisible axion model of the Peccei-Quinn CP conserving mechanism is presented here. To start with, the background theory of this mechanism in the cosmic evolution has been fully reviewed, as well as the leading cosmological arguments setting limits on the mass and coupling of such a particle. The CP conserving lagrangian of the invisible axion model also includes instanton gauge field configurations. In our opinion, these configurations could behave non trivially while decreasing the temperature as a consequence of the vacuum symmetry modifications. The interplay between symmetry modifications and cosmic evolution may thus lead to yet unclear effects. In fact, the model considered here is really quite a baby version of the real world, so that only preliminary indications and bare consistency arguments have been done from it. Nevertheless, the underlying idea, a possible neutral Higgs fields approximate resonance condition, seems to survive even in more sophisticated models. 相似文献