80,234 research outputs found
Model inspired by population genetics to study fragmentation of brittle plates
We use a model whose rules were inspired by population genetics, the random
capability growth model, to describe the statistical details observed in
experiments of fragmentation of brittle platelike objects, and in particular
the existence of (i) composite scaling laws, (ii) small critical exponents \tau
associated with the power-law fragment-size distribution, and (iii) the typical
pattern of cracks. The proposed computer simulations do not require numerical
solutions of the Newton's equations of motion, nor several additional
assumptions normally used in discrete element models. The model is also able to
predict some physical aspects which could be tested in new experiments of
fragmentation of brittle systems.Comment: We have modified the text in order to make the description of the
model more clear. One Figure (Figure 1) was introduced showing the steps of
the dynamics of colonization. Twelve references were adde
Susceptibility of a two-level atom near an isotropic photonic band edge: transparency and band edge profile reconstruction
We discuss the necessary conditions for a two-level system in the presence of
an isotropic band edge to be transparent to a probe laser field. The two-level
atom is transparent whenever it is coupled to a reservoir constituted of two
parts - a flat and a non-flat density of modes representing a PBG structure. A
proposal on the reconstruction of the band edge profile from the experimentally
measured susceptibility is also presented.Comment: 15 pages, 3 figure
Characterization and quantification of symmetric Gaussian state entanglement through a local classicality criterion
A necessary and sufficient condition for characterization and quantification
of entanglement of any bipartite Gaussian state belonging to a special symmetry
class is given in terms of classicality measures of one-party states. For
Gaussian states whose local covariance matrices have equal determinants it is
shown that separability of a two-party state and classicality of one party
state are completely equivalent to each other under a nonlocal operation,
allowing entanglement features to be understood in terms of any available
classicality measure.Comment: 5 pages, 1 figure. Replaced with final published versio
Space-time Torsion and Neutrino Oscillations in Vacuum
The objective of this study is to verify the consistency of the prescription
of alternative minimum coupling (connection) proposed by the Teleparallel
Equivalent to General Relativity (TEGR) for the Dirac equation. With this aim,
we studied the problem of neutrino oscillations in Weitzenbock space-time in
the Schwarzschild metric. In particular, we calculate the phase dynamics of
neutrinos. The relation of spin of the neutrino with the space-time torsion is
clarified through the determination of the phase differences between spin
eigenstates of the neutrinos.Comment: 07 pages, no figure
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