2,537 research outputs found
Reflection-less device allows electromagnetic warp drive
One of the striking properties of artificially structured materials is the
negative refraction, an optical feature that known natural materials do not
exhibit. Here, we propose a simple design, composed of two parallel layers of
materials with different refraction indices , that constructs perfect
reflection-less devices. The electromagnetic waves can tunnel from one layer to
the other, a feature that resembles a truncation of the physical space leading
to an electromagnetic warp drive. Since the refractive indices do not require
any large values, this method demonstrates for the first time the practical
feasibility of guiding electromagnetic fields in complete absence of reflection
phenomena and without degradation of transmission efficiency at all.Comment: 8 pages, 7 figure
Acceptance Corrections and Extreme-Independent Models in Relativistic Heavy Ion Collisions
Kopeliovich's suggestion [nucl-th/0306044] to perform nuclear geometry
(Glauber) calculations using different cross sections according to the
experimental configuration is quite different from the standard practice of the
last 20 years and leads to a different nuclear geometry definition for each
experiment. The standard procedure for experimentalists is to perform the
nuclear geometry calculation using the total inelastic N-N cross section, which
results in a common nuclear geometry definition for all experiments. The
incomplete acceptance of individual experiments is taken into account by
correcting the detector response for the probability of measuring zero for an
inelastic collision, which can often be determined experimentally. This clearly
separates experimental issues such as different acceptances from theoretical
issues which should apply in general to all experiments. Extreme-Independent
models are used to illustrate the conditions for which the two methods give
consistent or inconsistent results.Comment: 4 pages, 1 figure, published in Physical Review
Correlated Emission of Hadrons from Recombination of Correlated Partons
We discuss different sources of hadron correlations in relativistic heavy ion
collisions. We show that correlations among partons in a quasi-thermal medium
can lead to the correlated emission of hadrons by quark recombination and argue
that this mechanism offers a plausible explanation for the dihadron
correlations in the few GeV/c momentum range observed in Au+Au collisions at
RHIC.Comment: 4 pages, 2 figures; v2: typo on p.4 correcte
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