5,992 research outputs found
Detrimental adsorbate fields in experiments with cold Rydberg gases near surfaces
We observe the shift of Rydberg levels of rubidium close to a copper surface
when atomic clouds are repeatedly deposited on it. We measure transition
frequencies of rubidium to S and D Rydberg states with principal quantum
numbers n between 31 and 48 using the technique of electromagnetically induced
transparency. The spectroscopic measurement shows a strong increase of electric
fields towards the surface that evolves with the deposition of atoms. Starting
with a clean surface, we measure the evolution of electrostatic fields in the
range between 30 and 300 \mum from the surface. We find that after the
deposition of a few hundred atomic clouds, each containing ~10^6 atoms, the
field of adsorbates reaches 1 V/cm for a distance of 30 \mum from the surface.
This evolution of the electrostatic field sets serious limitations on cavity
QED experiments proposed for Rydberg atoms on atom chips.Comment: 4 pages, 3 figures Submitted to Phys. Rev.
Exclusive electromagnetic production of strangeness on the nucleon : review of recent data in a Regge approach
In view of the numerous experimental results recently released, we provide in
this letter an update on the performance of our simple Regge model for
strangeness electroproduction on the nucleon. Without refitting any parameters,
a decent description of all measured observables and channels is achieved. We
also give predictions for spin transfer observables, recently measured at
Jefferson Lab which have high sensitivity to discriminate between different
theoretical approaches.Comment: 5 pages, 5 figure
The contribution of 211 particles to the mechanical reinforcement mechanism of 123 superconducting single domains
Hardness and fracture toughness of Dy-123 single-domains were studied by
Vickers micro-indentation. A significant anisotropy of the mechanical
properties was observed. Hardness tests give higher values when performed in
(001) planes rather than in planes parallel to the c-axis. Moreover cracks
pattern around the indentation follows preferential orientation in planes
parallel to the c-axis whereas a classical ''four-cracks'' pattern is observed
in the (001) planes. It has been possible to show the crucial role played by
the 211-particles in the deviating mechanism of cracks and the relevance of the
211-particle distribution high homogeneity in the material.Comment: 14 pages, including 5 figures and 1 Table. submitted to Supercond.
Sci. Techno
Nonreciprocal Directional Dichroism and Toroidalmagnons in Helical Magnets
We investigate a dynamical magnetoelectric effect due to a magnetic resonance
in helical spin structures through the coupling between magnetization and
electric polarization via a spin current mechanism. We show that the magnon has
both the dynamical magnetic moment and the electric moment
(), i.e., a dynamical toroidal moment,
under external magnetic fields, and thus it is named the {\em toroidalmagnon}.
The toroidalmagnon exists in most conical spin structures owing to the
generality of the spin current mechanism. In the absorption of electromagnetic
waves, the toroidalmagnon excitation process generally induces a nonreciprocal
directional dichroism as a consequence of an interference of the magnetic and
electric responses.Comment: 5 pages, 2 figure
SDSS IV MaNGA: Dependence of Global and Spatially Resolved SFR-M ∗ Relations on Galaxy Properties
Indexación: Scopus.The galaxy integrated Hα star formation rate-stellar mass relation, or SFR(global)-M ∗(global) relation, is crucial for understanding star formation history and evolution of galaxies. However, many studies have dealt with SFR using unresolved measurements, which makes it difficult to separate out the contamination from other ionizing sources, such as active galactic nuclei and evolved stars. Using the integral field spectroscopic observations from SDSS-IV MaNGA, we spatially disentangle the contribution from different Hα powering sources for ∼1000 galaxies. We find that, when including regions dominated by all ionizing sources in galaxies, the spatially resolved relation between Hα surface density (ΣHα(all)) and stellar mass surface density (Σ∗(all)) progressively turns over at the high Σ∗(all) end for increasing M ∗(global) and/or bulge dominance (bulge-to-total light ratio, B/T). This in turn leads to the flattening of the integrated Hα(global)-M ∗(global) relation in the literature. By contrast, there is no noticeable flattening in both integrated Hα(H ii)-M ∗(H ii) and spatially resolved ΣHα(H ii)-Σ∗(H ii) relations when only regions where star formation dominates the ionization are considered. In other words, the flattening can be attributed to the increasing regions powered by non-star-formation sources, which generally have lower ionizing ability than star formation. An analysis of the fractional contribution of non-star-formation sources to total Hα luminosity of a galaxy suggests a decreasing role of star formation as an ionizing source toward high-mass, high-B/T galaxies and bulge regions. This result indicates that the appearance of the galaxy integrated SFR-M ∗ relation critically depends on their global properties (M ∗(global) and B/T) and relative abundances of various ionizing sources within the galaxies.http://iopscience.iop.org/article/10.3847/1538-4357/aaa9bc/met
Trapping of ultra-cold atoms with the magnetic field of vortices in a thin film superconducting micro-structure
We store and control ultra-cold atoms in a new type of trap using magnetic
fields of vortices in a high temperature superconducting micro-structure. This
is the first time ultra-cold atoms have been trapped in the field of magnetic
flux quanta. We generate the attractive trapping potential for the atoms by
combining the magnetic field of a superconductor in the remanent state with
external homogeneous magnetic fields. We show the control of crucial atom trap
characteristics such as an efficient intrinsic loading mechanism, spatial
positioning of the trapped atoms and the vortex density in the superconductor.
The measured trap characteristics are in good agreement with our numerical
simulations.Comment: 4pages, comments are welcom
Situational analysis of the subjective well-being of university software developers in Puebla
Integral well-being is vital for the optimal functioning of people. The requirements for a software developer in the performance of their professional activity are varied and complex. These requirements range from working in multidisciplinary and multilingual teams, going through the challenge of technological advances of the discipline to commit to quality and innovation. To face these demands, it is essential that the developers have an optimal functioning, where the experience emotional and satisfaction with life play an important role. The objective of this article is to analyze the subjective well-being of university software developers in Puebla. The research is a quantitative cross-correlation study to identify statistically significant relationships between the different welfare variables. The study involved 47 university software developers from the city of Puebla. We use Pearson's multivariate correlation to validate the instruments and find relationships between variables, and Chi-squared statistics to calculate the dependency between them. The results reveal that the university software developers experience with higher incidence and intensity, the positive affections over the negatives. The affective balance (Net Affect), calculated as the difference of the weighted averages by duration between positive affective states and negative, was positive (mean = 1.31). "Concentrated" is the positive affective state with the highest incidence and with the highest reported intensity. "Tired" is the most experienced negative affect and highest in intensity. Developers spend 40% of their time experiencing negative affective states (U-index) and are moderately satisfied with their lives in general
Discovery of the broad-lined Type Ic SN 2013cq associated with the very energetic GRB 130427A
Long-duration gamma-ray bursts (GRBs) at z < 1 are in most cases found to be
accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The
highest-energy GRBs are mostly located at higher redshifts, where the
associated SNe are hard to detect observationally. Here we present early and
late observations of the optical counterpart of the very energetic GRB 130427A.
Despite its moderate redshift z = 0.3399+/-0.0002, GRB 130427A is at the high
end of the GRB energy distribution, with an isotropic-equivalent energy release
of Eiso ~ 9.6x10^53 erg, more than an order of magnitude more energetic than
other GRBs with spectroscopically confirmed SNe. In our dense photometric
monitoring, we detect excess flux in the host-subtracted r-band light curve,
consistent with what expected from an emerging SN, ~0.2 mag fainter than the
prototypical SN 1998bw. A spectrum obtained around the time of the SN peak
(16.7 days after the GRB) reveals broad undulations typical of SNe Ic-BL,
confirming the presence of a SN, designated SN 2013cq. The spectral shape and
early peak time are similar to those of the high expansion velocity SN 2010bh
associated with GRB 100316D. Our findings demonstrate that high-energy
long-duration GRBs, commonly detected at high redshift, can also be associated
with SNe Ic-BL, pointing to a common progenitor mechanism.Comment: 12 pages, 4 figures, 1 table, accepted for publication in Ap
Color Octet Contribution to J/psi Photoproduction Asymmetries
We investigate photoproduction asymmetries in the framework of the
NRQCD factorization approach. It is shown that the color octet contribution
leads to large uncertainties in the predicted asymmetries which rules out the
possibility to precisely measure the gluon polarization in the nucleon through
this final state. For small values of the color octet parameters being
compatible with photoproduction data it appears possible that a
measurement of asymmetries could provide a new test for the NRQCD
factorization approach, on one hand, or a measurement of the polarized gluon
distribution from low inelasticity events , on the otherComment: 12 pages, LaTeX, with 6 figs. Final version published in Phys.Rev.
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