29,217 research outputs found
Weak reactions on 12C within the Continuum Random Phase Approximation with partial occupancies
We extend our previous studies of the neutrino-induced reactions on 12C and
muon capture to include partial occupation of nuclear subshells in the
framework of the continuum random phase approximation. We find, in contrast to
the work by Auerbach et al., that a partial occupation of the p1/2 subshell
reduces the inclusive cross sections only slightly. The extended model
describes the muon capture rate and the 12C(nu_e,e-)12N cross section very
well. The recently updated flux and the improved model bring the calculated
12C(nu_mu,mu^-)12N cross section (~ 17.5 10^{-40} cm^2) and the data (12.4 +/-
0.3(stat.) +/- 1.8(syst.) 10^{-40} cm^2) closer together, but does not remove
the discrepancy fully.Comment: 12 pages, 2 figure
Local uncertainty relations serving as measures of entanglement in a bipartite two-level system
We comment on the recent suggestion to use a family of local uncertainty
relations as a standard way of quantifying entanglement in two-qubit systems.
Some statements made on the applicability of the proposed "measures" are overly
optimistic. We exemplify how these specific "measures" fall short, and present
a minor modification of the general theory which uses the same experimentally
gathered information, but in a slightly different, better way.Comment: 5 pages, 1 figur
Estimates of weak and electromagnetic nuclear decay signatures for neutrino reactions in Super-Kamiokande
We estimate possible delayed β decay signatures of the neutrino induced reactions on 16O in a two-step model: the primary neutrino (ν,l) process, where l is the lepton in the final state, is described within the random phase approximation, while the subsequent decay of the excited nuclear state in the final channel is treated within the statistical model. We calculate partial reaction cross sections leading to β unstable nuclei. We consider neutrino energies up to 500 MeV, relevant for atmospheric neutrino detection in Super-Kamiokande, and supernova neutrino spectra
Quasielastic neutrino scattering from oxygen and the atmospheric neutrino problem
We examine several phenomena beyond the scope of Fermi-gas models that affect
the quasielastic scattering (from oxygen) of neutrinos in the 0.1 -- 3.0 GeV
range. These include Coulomb interactions of outgoing protons and leptons, a
realistic finite-volume mean field, and the residual nucleon-nucleon
interaction. None of these effects are accurately represented in the Monte
Carlo simulations used to predict event rates due to and neutrinos
from cosmic-ray collisions in the atmosphere. We nevertheless conclude that the
neglected physics cannot account for the anomalous to ratio observed
at Kamiokande and IMB, and is unlikely to change absolute event rates by more
than 10--15\%. We briefly mention other phenomena, still to be investigated in
detail, that may produce larger changes.Comment: In Revtex version 2. 14 pages, 3 figures (available on request from
J. Engel, tel. 302-831-4354, [email protected]
Propagation considerations in land mobile satellite transmission
It appears likely that the Land Mobile Satellite Services (LMSS) will be authorized by the FCC for operation in the 800 to 900 MHz (UHF) and possibly near 1500 MHz (L-band). Propagation problems are clearly an important factor in the effectiveness of this service, but useful measurements are few, and produced contradictory interpretations. A first order overview of existing measurements is presented with particular attention to the first two NASA balloon to mobile vehicle propagation experiments. Some physical insight into the interpretation of propagation effects in LMSS transmissions is provided
Nonclassicality filters and quasiprobabilities
Necessary and sufficient conditions for the nonclassicality of bosonic
quantum states are formulated by introducing nonclassicality filters and
nonclassicality quasiprobability distributions. Regular quasiprobabilities are
constructed from characteristic functions which can be directly sampled by
balanced homodyne detection. Their negativities uncover the nonclassical
effects of general quantum states. The method is illustrated by visualizing the
nonclassical nature of a squeezed state.Comment: Significantly revised version, more emphasis on practical applicatio
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