23,026 research outputs found
Signatures of charmonium modification in spatial correlation functions
We study spatial correlation functions of charmonium in 2+1 flavor QCD using
an improved staggered formulation. Contrary to the temporal correlation
functions the spatial correlation functions exhibit a strong temperature
dependence above the QCD transition temperature. Above this temperature they
are sensitive to temporal boundary conditions. Both features become significant
at a temperature close to 1.5 Tc and suggest corresponding modifications of
charmonium spectral functions.Comment: 12 pages, LaTeX, 3 figure
ARPES observation of isotropic superconducting gaps in isovalent Ru-substituted Ba(FeRu)As
We used high-energy resolution angle-resolved photoemission spectroscopy to
extract the momentum dependence of the superconducting gap of Ru-substituted
Ba(FeRu)As ( K). Despite a strong
out-of-plane warping of the Fermi surface, the magnitude of the superconducting
gap observed experimentally is nearly isotropic and independent of the
out-of-plane momentum. More precisely, we respectively observed 5.7 meV and 4.5
meV superconducting gaps on the inner and outer -centered hole Fermi
surface pockets, whereas a 4.8 meV gap is recorded on the M-centered electron
Fermi surface pockets. Our results are consistent with the model with
a dominant antiferromagnetic exchange interaction between the next-nearest Fe
neighbors.Comment: 5 pages, 4 figure
Scalar Quarkonia at Finite Temperature
Masses and decay constants of the scalar quarkonia, with
quantum numbers are calculated in the framework of
the QCD sum rules approach both in vacuum and finite temperature. The masses
and decay constants remain unchanged up to but they start to
diminish with increasing the temperature after this point. At near the critic
or deconfinement temperature, the decay constants reach approximately to 25% of
their values in vacuum, while the masses are decreased about 6% and 23% for
bottom and charm cases, respectively. The results at zero temperature are in a
good consistency with the existing experimental values and predictions of the
other nonperturbative approaches. Our predictions on the decay constants in
vacuum as well as the behavior of the masses and decay constants with respect
to the temperature can be checked in the future experiments.Comment: 12 Pages, 9 Figures and 2 Table
First Principles Calculation of Anomalous Hall Conductivity in Ferromagnetic bcc Fe
We perform a first principles calculation of the anomalous Hall effect in
ferromagnetic bcc Fe. Our theory identifies an intrinsic contribution to the
anomalous Hall conductivity and relates it to the k-space Berry phase of
occupied Bloch states. The theory is able to account for both dc and
magneto-optical Hall conductivities with no adjustable parameters.Comment: 4 pages, 6 figures, author list correcte
Superconducting gap in the presence of bilayer splitting in underdoped Bi(Pb)2212
The clearly resolved bilayer splitting in ARPES spectra of the underdoped
Pb-Bi2212 compound rises the question of how the bonding and antibonding sheets
of the Fermi surface are gapped in the superconducting state. Here we compare
the superconducting gaps for both split components and show that within the
experimental uncertainties they are identical. By tuning the relative intensity
of the bonding and antibonding bands using different excitation conditions we
determine the precise {\bf k}-dependence of the leading edge gap. Significant
deviations from the simple cos()-cos() gap function for the
studied doping level are detected.Comment: 5 pages, 4 figures (revtex4
Basic tasks of sentiment analysis
Subjectivity detection is the task of identifying objective and subjective
sentences. Objective sentences are those which do not exhibit any sentiment.
So, it is desired for a sentiment analysis engine to find and separate the
objective sentences for further analysis, e.g., polarity detection. In
subjective sentences, opinions can often be expressed on one or multiple
topics. Aspect extraction is a subtask of sentiment analysis that consists in
identifying opinion targets in opinionated text, i.e., in detecting the
specific aspects of a product or service the opinion holder is either praising
or complaining about
Bosonic Mode Mixing in the Superconducting State Spectral Function of Bi_2Sr_2CaCu_2O_{8+delta}
Photoemission spectra of Bi_2Sr_2CaCu_2O_{8+delta} below T_c show two
features near the (pi,0) point of the zone: a sharp peak at low energy and a
higher binding energy hump. We find that the sharp peak persists at low energy
even as one moves towards (0,0), while the broad hump shows significant
dispersion which correlates well with the normal state dispersion. We argue
that these features are naturally explained by the mixing of electrons with a
bosonic mode which appears only below T_c, and speculate that the latter may be
related to the resonance seen in recent neutron data.Comment: 4 pages, revtex, 4 postscript figure
- …