5,318 research outputs found
Proton Decay from Excited States in Spherical Nuclei
Based on a single particle model which describes the time evolution of the
wave function during tunneling across a one dimensional potential barrier we
study the proton decay of Pb from excited states with non-vanishing
angular momentum . Several quantities of interest in this process like
the decay rate , the period of oscillation , the transient
time , the tunneling time and the average value of the proton
packet position are computed and compared with the WKB results.Comment: 12 pages, 4 figure
Statistical fluctuations for the fission process on its decent from saddle to scission
We reconsider the importance of statistical fluctuations for fission dynamics
beyond the saddle in the light of recent evaluations of transport coefficients
for average motion. The size of these fluctuations are estimated by means of
the Kramers-Ingold solution for the inverted oscillator, which allows for an
inclusion of quantum effects.Comment: 12 pages, Latex, 5 Postscript figures; submitted to PRC e-mail:
[email protected] www home page:
http://www.physik.tu-muenchen.de/tumphy/e/T36/hofmann.htm
Green's functions for parabolic systems of second order in time-varying domains
We construct Green's functions for divergence form, second order parabolic
systems in non-smooth time-varying domains whose boundaries are locally
represented as graph of functions that are Lipschitz continuous in the spatial
variables and 1/2-H\"older continuous in the time variable, under the
assumption that weak solutions of the system satisfy an interior H\"older
continuity estimate. We also derive global pointwise estimates for Green's
function in such time-varying domains under the assumption that weak solutions
of the system vanishing on a portion of the boundary satisfy a certain local
boundedness estimate and a local H\"older continuity estimate. In particular,
our results apply to complex perturbations of a single real equation.Comment: 25 pages, 0 figur
Pseudodoping of Metallic Two-Dimensional Materials by The Supporting Substrates
We demonstrate how hybridization between a two-dimensional material and its
substrate can lead to an apparent heavy doping, using the example of monolayer
TaS grown on Au(111). Combining calculations, scanning
tunneling spectroscopy experiments and a generic model, we show that strong
changes in Fermi areas can arise with much smaller actual charge transfer. This
mechanism, which we refer to as pseudodoping, is a generic effect for metallic
two-dimensional materials which are either adsorbed to metallic substrates or
embedded in vertical heterostructures. It explains the apparent heavy doping of
TaS on Au(111) observed in photoemission spectroscopy and spectroscopic
signatures in scanning tunneling spectroscopy. Pseudodoping is associated with
non-linear energy-dependent shifts of electronic spectra, which our scanning
tunneling spectroscopy experiments reveal for clean and defective TaS
monolayer on Au(111). The influence of pseudodoping on the formation of charge
ordered, magnetic, or superconducting states is analyzed.Comment: arXiv admin note: substantial text overlap with arXiv:1609.0022
The signature of subsurface Kondo impurities in the local tunnel current
The conductance of a tunnel point-contact in an STM-like geometry having a
single defect placed below the surface is investigated theoretically. The
effect of multiple electron scattering by the defect after reflections by the
metal surface is taken into account. In the approximation of s-wave scattering
the dependence of the conductance on the applied voltage and the position of
the defect is obtained. The results are illustrated for a model s-wave phase
shift describing Kondo-resonance scattering. We demonstrate that multiple
electron scattering by the magnetic impurity plays a decisive role in the
point-contact conductance at voltages near the Kondo resonance. We find that
the sign and shape of the Kondo anomaly depends on the position of the defect.Comment: 13 pages, 4 figures. To be published in J. Phys.: Cond. Ma
- …