4,310 research outputs found
Infrared excesses in stars with and without planets using revised photometry
We present an analysis on the potential prevalence of mid infrared excesses
in stars with and without planetary companions. Based on an extended database
of stars detected with the satellite, we studied two stellar
samples: one with 236 planet hosts and another with 986 objects for which
planets have been searched but not found. We determined the presence of an
excess over the photosphere by comparing the observed flux ratio at 22 m
and 12 m () with the corresponding synthetic value, derived
from results of classical model photospheres. We found a detection rate of
0.85 at 22 m (2 excesses) in the sample of stars with planets and
0.1 (1 detection) for the stars without planets. The difference of the
detection rate between the two samples is not statistically significant, a
result that is independent of the different approaches found in the literature
to define an excess in the wavelength range covered by
observations. As an additional result, we found that the fluxes
required a normalisation procedure to make them compatible with synthetic data,
probably pointing out a revision of the data calibration.Comment: 10 pages, 6 figures, 3 tables. Accepted for publication in MNRA
Theoretical description of two ultracold atoms in finite 3D optical lattices using realistic interatomic interaction potentials
A theoretical approach is described for an exact numerical treatment of a
pair of ultracold atoms interacting via a central potential that are trapped in
a finite three-dimensional optical lattice. The coupling of center-of-mass and
relative-motion coordinates is treated using an exact diagonalization
(configuration-interaction) approach. The orthorhombic symmetry of an optical
lattice with three different but orthogonal lattice vectors is explicitly
considered as is the Fermionic or Bosonic symmetry in the case of
indistinguishable particles.Comment: 19 pages, 5 figure
Site and lattice resonances in metallic hole arrays
A powerful analytical approach is followed to study light transmission
through subwavelength holes drilled in thick perfect-conductor films, showing
that full transmission (100%) is attainable in arrays of arbitrarily narrow
holes as compared to the film thickness. The interplay between resonances
localized in individual holes and lattice resonances originating in the array
periodicity reveals new mechanisms of transmission enhancement and suppression.
In particular, localized resonances obtained by filling the holes with
high-index-of-refraction material are examined and experimentally observed
through large enhancement in the transmission of individual holes.Comment: 5 figure
¡Tigre Blanco, héroe del Barrio!: Living and Dying Latina/o in a Superhero World
no abstract availabl
¡Tigre Blanco, héroe del Barrio!: Living and Dying Latina/o in a Superhero World
no abstract availabl
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