2,650 research outputs found
One-rank interaction kernel of the two-nucleon system for medium and high energies
A new version of the separable kernel of the nucleon-nucleon interaction in
the Bethe-Salpeter approach is presented. The phase shifts are fitted to recent
experimental data for singlet and uncoupled triplet partial waves of the
neutron-proton scattering with total angular momenta J=0,1. The results are
compared with other model calculations.Comment: 10 pages, 5 figures, 3 table
Electro-Reflectance Spectra of Blue Bronze
We show that the infrared reflectance of the quasi-one dimensional
charge-density-wave (CDW) conductor K0.3MoO3 (blue bronze) varies with position
when a voltage greater than the CDW depinning threshold is applied. The spatial
dependence and spectra associated with these changes are generally as expected
from the electro-transmission [B.M. Emerling, et al, Eur. Phys. J. B 16, 295
(2000)], but there are some differences which might be associated with changes
in the CDW properties on the surface. We have examined the electro-reflectance
spectrum associated with CDW current investigation for light polarized parallel
to the conducting chains for signs of expected current-induced intragap states,
and conclude that the density of any such states is at least an order of
magnitude lower than expected.Comment: 1)submitted to Eur. Phys. J B 2) revised (July 24) to a) better
emphasize results and b) with new figure insets to make paper more
self-containe
Schreier Graphs for a Self-Similar Action of the Heisenberg Group
We construct a faithful self-similar action of the discrete Heisenberg group with the following properties: This action is self-replicating, finite-state, level-transitive, and noncontracting. Moreover, there exist orbital Schreier graphs of action on the boundary of the tree with different degrees of growth.Побудовано точну самоподiбну дію дискретної групи Гейзенберга з наступними властивостями. Дія є рекурентною, скінченностановою, сферично транзитивною, нестискуючою та існують графи Шрайєра дії групи на межі дерева з різними степенями зростання
Study of Scintillator Strip with Wavelength Shifting Fiber and Silicon Photomultiplier
The performance of the cm plastic scintillator
strip with wavelength shifting fiber read-out by two novel photodetectors
called Silicon PhotoMultipliers (SiPMs) is discussed. The advantages of SiPM
relative to the traditional multichannel photomultiplier are shown. Light yield
and light attenuation measurements are presented. This technique can be used in
muon or calorimeter systems.Comment: 9 pages, 5 figure
Spin distribution of nuclear levels using static path approximation with random-phase approximation
We present a thermal and quantum-mechanical treatment of nuclear rotation
using the formalism of static path approximation (SPA) plus random-phase
approximation (RPA). Naive perturbation theory fails because of the presence of
zero-frequency modes due to dynamical symmetry breaking. Such modes lead to
infrared divergences. We show that composite zero-frequency excitations are
properly treated within the collective coordinate method. The resulting
perturbation theory is free from infrared divergences. Without the assumption
of individual random spin vectors, we derive microscopically the spin
distribution of the level density. The moment of inertia is thereby related to
the spin-cutoff parameter in the usual way. Explicit calculations are performed
for 56^Fe; various thermal properties are discussed. In particular, we
demonstrate that the increase of the moment of inertia with increasing
temperature is correlated with the suppression of pairing correlations.Comment: 12 pages, 8 figures, accepted for publication in Physical Review
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