6,422 research outputs found
Identifying Universality in Warm Inflation
Ideas borrowed from renormalization group are applied to warm inflation to
characterize the inflationary epoch in terms of flows away from the de Sitter
regime. In this framework different models of inflation fall into universality
classes. Furthermore, for warm inflation this approach also helps to
characterise when inflation can smoothly end into the radiation dominated
regime. Warm inflation has a second functional dependence compared to cold
inflation due to dissipation, yet despite this feature, it is shown that the
universality classes defined for cold inflation can be consistently extended to
warm inflation.Comment: 20 pages, 5 figures, 1 appendi
Entanglement between two superconducting qubits via interaction with non-classical radiation
We propose a scheme to physically interface superconducting nano-circuits and
quantum optics. We address the transfer of quantum information between systems
having different physical natures and defined in Hilbert spaces of different
dimensions. In particular, we investigate the transfer of the entanglement
initially in a non-classical state of a continuous-variable system to a pair of
superconducting charge qubits. This set-up is able to drive an initially
separable state of the qubits into an almost pure, highly entangled state
suitable for quantum information processing.Comment: 4 pages, RevTeX; revised versio
Plasma Waves in Anisotropic Superconducting Films Below and Above the Plasma Frequency
We consider wave propagation inside an anisotropic superconducting film
sandwiched between two semi-infinite non-conducting bounding dieletric media
such that along the c-axis, perpendicular to the surfaces, there is a plasma
frequency below the superconducting gap. Propagation is assumed to
be parallel to the surfaces in the dielectric medium, where amplitudes decay
exponentially.Below , the amplitude also evanesces inside the film,
and we retrieve the experimentally measured lower dispersion relation branch,
, and the recently proposed higher frequency
branch, .Above , propagation is of the
guided wave type, i.e., a dispersive plane wave confined inside the film that
reflects into the dielectric interfaces,and the modes are approximately
described by , where
is discussed here.Comment: 26 pages,4 figures.Submitte
Red and blue shift in spherical and axisymmetric spacetimes and astrophysical constraints
We compute the red and blue shifts for astrophysical and cosmological sources. In particular, we consider low, intermediate and high gravitational energy domains. Thereby, we handle the binary system Earth-Mars as low energy landscape whereas white dwarfs and neutron stars as higher energy sources. To this end, we take into account a spherical Schwarzschild-de Sitter spacetime and an axially symmetric Zipoy-Voorhees metric to model all the aforementioned systems. Feasible outcomes come from modeling neutron stars and white dwarfs with the Zipoy-Voorhees metric, where quadrupole effects are relevant, and framing solar system objects using a Schwarzschild-de Sitter spacetime. In the first case, large delta parameters seem to be favorite, leading to acceptable bounds mainly for neutron stars. In the second case, we demonstrate incompatible red and blue shifts with respect to lunar and satellite laser ranging expectations, once the cosmological constant is taken to Planck satellite's best fit. To heal this issue, we suggest coarse-grained experimental setups and propose Phobos for working out satellite laser ranging in order to get more suitable red and blue shift intervals, possibly more compatible than current experimental bounds. Implications to cosmological tensions are also debated
Effect of the boundary condition on the vortex patterns in mesoscopic three-dimensional superconductors - disk and sphere
The vortex state of mesoscopic three-dimensional superconductors is
determined using a minimization procedure of the Ginzburg-Landau free energy.
We obtain the vortex pattern for a mesoscopic superconducting sphere and find
that vortex lines are naturally bent and are closest to each other at the
equatorial plane. For a superconducting disk with finite height, and under an
applied magnetic field perpendicular to its major surface, we find that our
method gives results consistent with previous calculations. The matching
fields, the magnetization and , are obtained for models that differ
according to their boundary properties. A change of the Ginzburg-Landau
parameters near the surface can substantially enhance as shown here.Comment: 7 pages, 4 figures (low resolution
Rigidity and intermediate phases in glasses driven by speciation
The rigid to floppy transitions and the associated intermediate phase in
glasses are studied in the case where the local structure is not fully
determined from the macroscopic concentration. The approach uses size
increasing cluster approximations and constraint counting algorithms. It is
shown that the location and the width of the intermediate phase and the
corresponding structural, mechanical and energetical properties of the network
depend crucially on the way local structures are selected at a given
concentration. The broadening of the intermediate phase is obtained for
networks combining a large amount of flexible local structural units and a high
rate of medium range order.Comment: 4 pages, 4 figure
Multiple sites of thrombosis without thrombocytopenia after a second dose of Pfizer-BioNTech COVID-19 vaccine
In the current international scientific panorama, rare cases of venous thrombotic complications following mRNA vaccine administration have been reported, consisting mainly of cerebral sinus thromboses and acute venous thromboembolism. The present paper describes the case of a 75-year-old woman in good health who developed cerebral venous thrombosis, deep venous thrombosis, and bilateral pulmonary emboli after receiving a second dose of Pfizer-BioNTech COVID-19 vaccine. A series of laboratory tests performed during hospitalization yielded interesting results, allowing us to exclude thrombophilic risk factors and to certify the absence of thrombocytopenia in the patient. Although COVID-19 vaccination is the most important tool in stopping the pandemic, pharmacovigilance is crucial for detecting potential multisystem thrombotic events, even for mRNA vaccines
Conformity and controversies in the diagnosis, staging and follow-up evaluation of canine nodal lymphoma: a systematic review of the last 15 years of published literature
Diagnostic methods used in the initial and post-treatment evaluation of canine lymphoma are heterogeneous and can vary within countries and institutions. Accurate reporting of clinical stage and response assessment is crucial in determining the treatment efficacy and predicting prognosis. This study comprises a systematic review of all available canine multicentric lymphoma studies published over 15 years. Data concerning diagnosis, clinical stage evaluation and response assessment procedures were extracted and compared. Sixty-three studies met the eligibility criteria. Fifty-five (87.3%) studies were non-randomized prospective or retrospective studies. The survey results also expose variations in diagnostic criteria and treatment response assessment in canine multicentric lymphoma. Variations in staging procedures performed and recorded led to an unquantifiable heterogeneity among patients in and between studies, making it difficult to compare treatment efficacies. Awareness of this inconsistency of procedure and reporting may help in the design of future clinical trials
Model-based demosaicking for acquisitions by a RGBW color filter array
Microsatellites and drones are often equipped with digital cameras whose
sensing system is based on color filter arrays (CFAs), which define a pattern
of color filter overlaid over the focal plane. Recent commercial cameras have
started implementing RGBW patterns, which include some filters with a wideband
spectral response together with the more classical RGB ones. This allows for
additional light energy to be captured by the relevant pixels and increases the
overall SNR of the acquisition. Demosaicking defines reconstructing a
multi-spectral image from the raw image and recovering the full color
components for all pixels. However, this operation is often tailored for the
most widespread patterns, such as the Bayer pattern. Consequently, less common
patterns that are still employed in commercial cameras are often neglected. In
this work, we present a generalized framework to represent the image formation
model of such cameras. This model is then exploited by our proposed
demosaicking algorithm to reconstruct the datacube of interest with a Bayesian
approach, using a total variation regularizer as prior. Some preliminary
experimental results are also presented, which apply to the reconstruction of
acquisitions of various RGBW cameras
Virtually Abelian Quantum Walks
We introduce quantum walks on Cayley graphs of non-Abelian groups. We focus
on the easiest case of virtually Abelian groups, and introduce a technique to
reduce the quantum walk to an equivalent one on an Abelian group with coin
system having larger dimension. We apply the technique in the case of two
quantum walks on virtually Abelian groups with planar Cayley graphs, finding
the exact solution.Comment: 10 pages, 3 figure
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