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51.
T. V. Dudnikova A. I. Komech E. A. Kopylova Suhov 《Communications in Mathematical Physics》2002,225(1):1-32
Consider the Klein–Gordon equation (KGE) in ℝ
n
, n≥ 2, with constant or variable coefficients. We study the distribution μ
t
of the random solution at time t∈ℝ. We assume that the initial probability measure μ0 has zero mean, a translation-invariant covariance, and a finite mean energy density. We also assume that μ0 satisfies a Rosenblatt- or Ibragimov–Linnik-type mixing condition. The main result is the convergence of μ
t
to a Gaussian probability measure as t→∞ which gives a Central Limit Theorem for the KGE. The proof for the case of constant coefficients is based on an analysis
of long time asymptotics of the solution in the Fourier representation and Bernstein's “room-corridor” argument. The case
of variable coefficients is treated by using an “averaged” version ofthe scattering theory for infinite energy solutions,
based on Vainberg's results on local energy decay.
Received: 4 January 2001 / Accepted: 2 July 2001 相似文献
52.
K.?A.?SubbotinEmail author V.?B.?Dudnikova O.?N.?Zaitseva V.?M.?Lazarenko V.?N.?Kolokol’tsev V.?I.?Tovtin E.?V.?Zharikov 《Optics and Spectroscopy》2012,112(4):537-544
The effect of 21-MeV electron irradiation on the optical absorption characteristics of Czochralski-grown forsterite (Mg2SiO4) single crystals (both undoped and chromium-doped) has been investigated. The irradiation is found to induce additional optical
absorption (AOA) in the crystals in the range of 225–1200 nm due to the formation of color centers based on intrinsic host
point defects and the change in the oxidation state of chromium ions. The AOA spectra have been decomposed into elementary
bands. The influence of the chromium concentration in crystals, the oxygen content in the growth atmosphere, and additional
doping with lithium on the behavior of these bands has been analyzed. A possible structure of the color centers responsible
for the AOA is discussed. It is shown that the electron irradiation somewhat decreases the intensity of the characteristic
absorption bands of tri- and tetravalent chromium ions and gives rise to a new absorption band in Mg2SiO4:Cr and Mg2SiO4:Cr,Li crystals heavily doped with chromium. 相似文献
53.
54.
T. V. Liseykina V. Yu. Bychenkov G. I. Dudnikova F. Pegoraro 《Applied physics. B, Lasers and optics》2005,81(4):537-542
Two-dimensional particle-in-cell (PIC) simulations of laser-triggered ion acceleration in overdense plasma at moderate intensity (≃1.4×1018 W/cm2) and pulse duration (≃0.5 ps) are presented. We focus on the comparison of the efficiency of ion acceleration for normal and oblique incidence of the laser light, for backward and forward directions of ion emission, and for large and small focal spots. We discuss the correlation between the properties of accelerated ions and hot electrons, and identify the tendency of the ion spectra in the forward direction to those typical for the isothermal and adiabatic regimes of plasma expansion. 相似文献
55.
T. V. Dudnikova A. I. Komech N. E. Ratanov Y. M. Suhov 《Journal of statistical physics》2002,108(5-6):1219-1253
The paper considers the wave equation, with constant or variable coefficients in
n
, with odd n3. We study the asymptotics of the distribution
t
of the random solution at time t as t . It is assumed that the initial measure
0 has zero mean, translation-invariant covariance matrices, and finite expected energy density. We also assume that
0 satisfies a Rosenblatt- or Ibragimov–Linnik-type space mixing condition. The main result is the convergence of
t
to a Gaussian measure
as t , which gives a Central Limit Theorem (CLT) for the wave equation. The proof for the case of constant coefficients is based on an analysis of long-time asymptotics of the solution in the Fourier representation and Bernstein's room-corridor argument. The case of variable coefficients is treated by using a version of the scattering theory for infinite energy solutions, based on Vainberg's results on local energy decay. 相似文献
56.
57.
58.
T. V. Dudnikova 《Theoretical and Mathematical Physics》2011,169(3):1668-1682
We study the dynamics of lattice systems in ℤd, d ≥ 1. We assume that the initial data are random functions. We introduce the family of initial measures {μ0ɛ, ɛ > 0}. The measures μ0ɛ are assumed to be locally homogeneous or “slowly changing” under spatial shifts of the order o(ɛ−1
) and inhomogeneous under shifts of the order ɛ−1
. Moreover, correlations of the measures μ0ɛ decrease uniformly in ɛ at large distances. For all τ ∈ ℝ \ 0, r ∈ ℝd, and κ > 0, we consider distributions of a random solution at the instants t = τ/ɛκ at points close to [r/ɛ] ∈ ℤd. Our main goal is to study the asymptotic behavior of these distributions as ɛ → 0 and to derive the limit hydrodynamic equations of the Euler and Navier-Stokes type. 相似文献
59.
This paper reports on the results of investigations of the coefficients of chromium distribution between a crystal and a melt
of forsterite, the absorption and luminescence spectra, and the electron paramagnetic resonance spectra of chromium centers
in Mg2SiO4: Cr, Mg2SiO4: Cr: Sc, and Mg2SiO4: Cr: Li crystals. It has been established that the concentration dependences of these properties vary upon changing over
from the range of trace concentrations of chromium, scandium, or lithium impurities in the melt to the range of higher concentrations
of these impurities. The observed phenomenon is explained by the interaction of impurities with intrinsic defects of the crystal,
which is called as the microimpurity trapping effect. According to the performed estimations, the concentration of predominant
intrinsic defects (magnesium Frenkel defects) in the forsterite crystals grown from the melt is equal to (7.5 ± 0.3) × 10−6 atomic fractions. The energy of the formation of magnesium Frenkel defects can be estimated as 4.2 ± 0.2 eV. 相似文献
60.
G. I. Dudnikova V. Yu. Bychenkov W. Rozmus R. Fedosejevs A. Maksimchuk 《Laser Physics》2008,18(9):1025-1030
Plasma produced by short laser pulses from thin homogeneous foils with light and heavy ions is capable of generating quasi-monoenergetic light ions. This happens for the tail of light ions near the front of heavy ions. It was found that this effect is well pronounced for a moderate laser intensity (~1018 W/cm2) and pulse duration (~1 ps) by using a 2D particle-in-cell simulation of the laser interaction with thin CD2 foils. Quasi-monoenergetic deuterons form a jet from the rear side of the foil with the energy ~1 MeV. The conversion efficiency to these quasi-monoenergetic ions is 10?3. 相似文献