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61.
We establish a general relation between the statistics of the local Green’s function for systems with chaotic wave scattering and uniform energy loss (absorption) and the two-point correlator of its resolvents for the same system without absorption. Within the random matrix approach, this kind of a fluctuation dissipation relation allows us to derive the explicit analytic expression for the joint distribution function of the real and imaginary part of the local Green’s function for all symmetry classes as well as at an arbitrary degree of time-reversal symmetry breaking in the system. The outstanding problem of orthogonal symmetry is further reduced to simple quadratures. The results can be applied, in particular, to the experimentally accessible impedance and reflection in a microwave cavity attached to a single-mode antenna. 相似文献
62.
We introduce a short-range correlation density functional defined with respect to a multi-determinantal reference which is
meant to be used in a multi-determinantal extension of the Kohn–Sham scheme of density functional theory based on a long-range/short-range
decomposition of the Coulomb electron–electron interaction. We construct the local density approximation for this functional
and discuss its performance on the He atom. 相似文献
63.
O. Uwira A. Müller J. Linkemann T. Bartsch C. Brandau M. Schmitt A. Wolf D. Schwalm R. Schuch W. Zong H. Lebius W.G. Graham J. Doerfert D.W. Savin 《Hyperfine Interactions》1997,108(1-3):149-154
Recombination of Au49+, Au50+, and Au51+ ions has been studied at the TSR. With Au50+ ions a storage lifetime of only 2 to 4 s was observed with the magnetically expanded electron beam of the cooler at a density
of ne = 107 cm-3. This short storage time is a consequence of the highest recombination rate coefficient ever observed with an atomic ion
(1.8·10-6 cm3 s-1 at zero relative energy Erel = 0 between electrons and ions). At about 30 meV a huge dielectronic recombination resonance is found with a record small
width of only about 15 meV. Such resonances fortuitously occurring near Erel=0 are probably the main reason for the enhanced recombination rates observed with Au50+, with Pb53+ (in a recent experiment at LEAR) as well as with other complex ions. For Au49+ and Au51+ the recombination rates are smaller by an order of magnitude.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
64.
P. Beiersdorfer G. V. Brown J. Crespo López-Urrutia V. Decaux S. R. Elliott D. W. Savin A. J. Smith G. S. Stefanelli K. Widmann K. L. Wong 《Hyperfine Interactions》1996,99(1):203-215
An overview is given of the current spectroscopic effort on the Livermore electron beam ion trap facilities. The effort focuses on four aspects: spectral line position, line intensity, temporal evolution, and line shape. Examples of line position measurements include studies of the K-shell transitions in heliumlike Kr34+ and the 2s-2p intrashell transitions in lithiumlike Th87+ and U89+, which provide benchmark values for testing the theory of relativistic and quantum electrodynamical contributions in high-Z ions. Examples of line intensity measurements are provided by measurements of the electron-impact excitation and dielectronic recombination cross sections of the heliumlike transition-metal ions Ti20+ through Co25+. A discussion of radiative lifetime measurements of metastable levels in heliumlike ions is given to illustrate our time-resolved spectroscopy techniques in the microsecond range. We also present a measurement of the spectral lineshape that illustrates the very low ion temperatures that can be achieved in an EBIT. 相似文献
65.
AM Jayannavar 《Pramana》2002,58(2):173-181
We present a simple model of transmission across a metallic mesoscopic ring. In one of its arm an electron interacts with
a single magnetic impurity via an exchange coupling. We show that entanglement between electron and spin impurity states leads
to reduction of Aharonov-Bohm oscillations in the transmission coefficient. The spin-conductance is asymmetric in the flux
reversal as opposed to the two-probe electrical conductance which is symmetric. In the same model, in contradiction to the
naive expectation of a current magnification effect, we observe enhancement as well as suppression of this effect depending
on the system parameters. The limitations of this model to the general notion of dephasing or decoherence in quantum systems
are pointed out. 相似文献
66.
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69.
M.E. Williams T.H. Kruse P. Goode F.T. Baker J.L. Matthews W. Savin 《Nuclear Physics A》1973,213(2):317-331
Differential cross sections have been measured for 41(d, t)40K and 41K(p, d)40K at 15 MeV using a magnetic spectrograph with electronic detection by proportional-counter-scintillator telescopes or semiconductor detectors. Knowledge of the structure of the 40K multiplets () and () permits the determination of amplitudes and relative phases for various configurations and neutron correlations in the 41K ground state. Spectroscopic factors for neutron pick-up to states in 40K are strongly influenced by the interference of transition amplitudes. In the (d, t) reaction T= 1, 2p-2h states are also observed. 相似文献
70.