906 research outputs found
Solar system constraints on Rindler acceleration
We discuss the classical tests of general relativity in the presence of
Rindler acceleration. Among these tests the perihelion shifts give the tightest
constraints and indicate that the Pioneer anomaly cannot be caused by a
universal solar system Rindler acceleration. We address potential caveats for
massive test-objects. Our tightest bound on Rindler acceleration that comes
with no caveats is derived from radar echo delay and yields |a|<3nm/s^2.Comment: 7 pages, v2: minor changes, added references, v3: corrected typos,
extended Table 1, corrected bound on measurement of gravitational redshif
Scanning Raman spectroscopy of graphene antidot lattices: Evidence for systematic p-type doping
We have investigated antidot lattices, which were prepared on exfoliated
graphene single layers via electron-beam lithography and ion etching, by means
of scanning Raman spectroscopy. The peak positions, peak widths and intensities
of the characteristic phonon modes of the carbon lattice have been studied
systematically in a series of samples. In the patterned samples, we found a
systematic stiffening of the G band mode, accompanied by a line narrowing,
while the 2D mode energies are found to be linearly correlated with the G mode
energies. We interpret this as evidence for p-type doping of the nanostructured
graphene
Linear Programming in the Semi-streaming Model with Application to the Maximum Matching Problem
In this paper, we study linear programming based approaches to the maximum
matching problem in the semi-streaming model. The semi-streaming model has
gained attention as a model for processing massive graphs as the importance of
such graphs has increased. This is a model where edges are streamed-in in an
adversarial order and we are allowed a space proportional to the number of
vertices in a graph.
In recent years, there has been several new results in this semi-streaming
model. However broad techniques such as linear programming have not been
adapted to this model. We present several techniques to adapt and optimize
linear programming based approaches in the semi-streaming model with an
application to the maximum matching problem. As a consequence, we improve
(almost) all previous results on this problem, and also prove new results on
interesting variants
Nonequilibrium effects due to charge fluctuations in intrinsic Josephson systems
Nonequilibrium effects in layered superconductors forming a stack of
intrinsic Josephson junctions are investigated. We discuss two basic
nonequilibrium effects caused by charge fluctuations on the superconducting
layers: a) the shift of the chemical potential of the condensate and b) charge
imbalance of quasi-particles, and study their influence on IV-curves and the
position of Shapiro steps.Comment: 17 pages, 2 figures, revised version slightly shortene
Reflectivity and Microwave Absorption in Crystals with Alternating Intrinsic Josephson Junctions
We compute the frequency and magnetic field dependencies of the reflectivity
in layered superconductors with two alternating intrinsic Josephson
junctions with different critical current densities and quasiparticle
conductivities for the electric field polarized along the c-axis. The parameter
describing the electronic compressibility of the layers and the charge
coupling of neighboring junctions was extracted for the
SmLaSrCuO superconductor from two independent
optical measurements, the fit of the loss function at zero magnetic
field and the magnetic field dependence of the peak positions in .
The experiments are consistent with a free electron value for near
the Josephson plasma frequencies.Comment: 4 pages, 4 postscript figures, misprints in table correcte
Real-time optical micro-manipulation using optimized holograms generated on the GPU
Holographic optical tweezers allow the three dimensional, dynamic, multipoint
manipulation of micron sized dielectric objects. Exploiting the massive
parallel architecture of modern GPUs we can generate highly optimized holograms
at video frame rate allowing the interactive micro-manipulation of 3D
structures.Comment: 13 pages, 8 figure
Early Prediction of Movie Box Office Success based on Wikipedia Activity Big Data
Use of socially generated "big data" to access information about collective
states of the minds in human societies has become a new paradigm in the
emerging field of computational social science. A natural application of this
would be the prediction of the society's reaction to a new product in the sense
of popularity and adoption rate. However, bridging the gap between "real time
monitoring" and "early predicting" remains a big challenge. Here we report on
an endeavor to build a minimalistic predictive model for the financial success
of movies based on collective activity data of online users. We show that the
popularity of a movie can be predicted much before its release by measuring and
analyzing the activity level of editors and viewers of the corresponding entry
to the movie in Wikipedia, the well-known online encyclopedia.Comment: 13 pages, Including Supporting Information, 7 Figures, Download the
dataset from: http://wwm.phy.bme.hu/SupplementaryDataS1.zi
Scenicness assessment of onshore wind sites with geotagged photographs and impacts on approval and cost-efficiency
Funding Information: We gratefully acknowledge the contributions of D. Schlund, who carried out some of the wind analysis whilst a Student Assistant at KIT, as well as C. Moutard, on whose Master’s Thesis at DTU this article builds (Assessing the ‘acceptable’ onshore wind potential in the UK, 2019, https://findit.dtu.dk/en/catalog/2451029061). M. D’Andrea, K. Paidis and T. Jaenicke supported the preparation of early versions of the manuscript whilst Student Assistants at DTU. I.M. gratefully acknowledges financial support from Kraks Fond, Copenhagen ([email protected]). T.P. and H.S.M. are grateful for support from The Alan Turing Institute under the EPSRC grant EP/N510129/1 (including awards TU/B/000006 and TU/B/000008).Peer reviewedPostprin
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Neck Circumference and the Development of Cardiovascular Disease Risk Factors in the Framingham Heart Study
Theory for the coupling between longitudinal phonons and intrinsic Josephson oscillations in layered superconductors
In this publication a microscopic theory for the coupling of intrinsic
Josephson oscillations in layered superconductors with longitudinal
c-axis-phonons is developed. It is shown that the influence of lattice
vibrations on the c-axis transport can be fully described by introducing an
effective longitudinal dielectric function. Resonances in the
I-V-characteristic appear at van Hove singularities of both acoustical and
optical longitudinal phonon branches. This provides a natural explanation of
the recently discovered subgap structures in the I-V-characteristic of highly
anisotropic cuprate superconductors. The effect of the phonon dispersion on the
damping of these resonances and the coupling of Josephson oscillations in
different resistive junctions due to phonons are discussed in detail.Comment: submitted to Phys. Rev. B, corrections following referee repor
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