13,407 research outputs found
Neutrino Mass Matrix Textures: A Data-driven Approach
We analyze the neutrino mass matrix entries and their correlations in a
probabilistic fashion, constructing probability distribution functions using
the latest results from neutrino oscillation fits. Two cases are considered:
the standard three neutrino scenario as well as the inclusion of a new sterile
neutrino that potentially explains the reactor and gallium anomalies. We
discuss the current limits and future perspectives on the mass matrix elements
that can be useful for model building.Comment: 25 pages, 18 figure
Analysis of the Scanning Tunneling Microscopy Images of the Charge Density Wave Phase in Quasi-one-dimensional Rb0.3MoO3
The experimental STM images for the CDW phase of the blue bronze RbMoO3 have
been successfully explained on the basis of first-principles DFT calculations.
Although the density of states near the Fermi level strongly concentrates in
two of the three types of Mo atoms Mo-II and Mo-III, the STM measurement mostly
probes the contribution of the uppermost O atoms of the surface, associated
with the Mo-IO6 octahedra. In addition, it is found that the surface
concentration of Rb atoms plays a key role in determining the surface nesting
vector and hence the periodicity of the CDW modulation. Significant
experimental inhomogeneities of the b* surface component of the wavevector of
the modulation, probed by STM, are reported. The calculated changes in the
surface nesting vector are consistent with the observed experimental
inhomogeneities.Comment: 4 pages 5 Figure
Studies of the photoionization cross sections of CH_4
We present cross sections and asymmetry parameters for photoionization of the 1t_2 orbital of CH_4 using staticâexchange continuum orbitals of CH^+_4 to represent the photoelectron wave function. The calculations are done in the fixedânuclei approximation at a single internuclear geometry. To approximate the nearâthreshold behavior of these cross sections, we assumed that the photoelectron spectrum is a composite of three electronic bands associated with the JahnâTeller components of the distorted ion. The resulting cross sections reproduce the sharp rise seen at threshold in the experimental data and are in good agreement with experiment at higher energy. The agreement between the calculated and measured photoelectron asymmetry parameters is, however, less satisfactory
Surface-state electron dynamics in noble metals
Theoretical investigations of surface-state electron dynamics in noble metals
are reported. The dynamically screened interaction is computed, within
many-body theory, by going beyond a free-electron description of the metal
surface. Calculations of the inelastic linewidth of Shockley surface-state
electrons and holes in these materials are also presented. While the linewidth
of excited holes at the surface-state band edge () is
dominated by a two-dimensional decay channel, within the surface-state band
itself, our calculations indicate that major contributions to the
electron-electron interaction of surface-state electrons above the Fermi level
come from the underlying bulk electrons.Comment: 17 pages, 7 figures, to appear in Prog. Surf. Sc
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