18,708 research outputs found
CMS dashboard task monitoring: A user-centric monitoring view
We are now in a phase change of the CMS experiment where people are turning more intensely to physics analysis and away from construction. This brings a lot of challenging issues with respect to monitoring of the user analysis. The physicists must be able to monitor the execution status, application and grid-level messages of their tasks that may run at any site within the CMS Virtual Organisation. The CMS Dashboard Task Monitoring project provides this information towards individual analysis users by collecting and exposing a user-centric set of information regarding submitted tasks including reason of failure, distribution by site and
over time, consumed time and efficiency. The development was user-driven with physicists invited to test the prototype in order to assemble further requirements and identify weaknesses with the application
Dynamics and Scaling of 2D Polymers in a Dilute Solution
The breakdown of dynamical scaling for a dilute polymer solution in 2D has
been suggested by Shannon and Choy [Phys. Rev. Lett. {\bf 79}, 1455 (1997)].
However, we show here both numerically and analytically that dynamical scaling
holds when the finite-size dependence of the relevant dynamical quantities is
properly taken into account. We carry out large-scale simulations in 2D for a
polymer chain in a good solvent with full hydrodynamic interactions to verify
dynamical scaling. This is achieved by novel mesoscopic simulation techniques
Pairing symmetry of the one-band Hubbard model in the paramagnetic weak-coupling limit: a numerical RPA study
We study the spin-fluctuation-mediated superconducting pairing gap in a
weak-coupling approach to the Hubbard model for a two dimensional square
lattice in the paramagnetic state. Performing a comprehensive theoretical study
of the phase diagram as a function of filling, we find that the superconducting
gap exhibits transitions from p-wave at very low electron fillings to
d_{x^2-y^2}-wave symmetry close to half filling in agreement with previous
reports. At intermediate filling levels, different gap symmetries appear as a
consequence of the changes in the Fermi surface topology and the associated
structure of the spin susceptibility. In particular, the vicinity of a van Hove
singularity in the electronic structure close to the Fermi level has important
consequences for the gap structure in favoring the otherwise sub-dominant
triplet solution over the singlet d-wave solution. By solving the full gap
equation, we find that the energetically favorable triplet solutions are chiral
and break time reversal symmetry. Finally, we also calculate the detailed
angular gap structure of the quasi-particle spectrum, and show how
spin-fluctuation-mediated pairing leads to significant deviations from the
first harmonics both in the singlet d_{x^2-y^2} gap as well as the chiral
triplet gap solution.Comment: 11 pages 11 figure
Genetic algorithms for reliability-based optimization of water distribution systems
A new approach for reliability-based optimization of water distribution networks is presented. The approach links a genetic algorithm ~GA! as the optimization tool with the first-order reliability method ~FORM! for estimating network capacity reliability. Network capacity reliability in this case study refers to the probability of meeting minimum allowable pressure constraints across the network under uncertain nodal demands and uncertain pipe roughness conditions. The critical node capacity reliability approximation for network capacity reliability is closely examined and new methods for estimating the critical nodal and overall network capacity reliability using FORM are presented. FORM approximates Monte Carlo simulation reliabilities accurately and efficiently. In addition, FORM can be used to automatically determine the critical node location and corresponding capacity reliability. Network capacity reliability approximations using FORM are improved by considering two failure modes. This research demonstrates the novel combination of a GA with FORM as an effective approach for reliability-based optimization of water distribution networks. Correlations between random variables are shown to significantly increase optimal network costs.Bryan A. Tolson, Holger R. Maier, Angus R. Simpson and Barbara J. Lenc
Conditions for magnetically induced singlet d-wave superconductivity on the square lattice
It is expected that at weak to intermediate coupling, d-wave
superconductivity can be induced by antiferromagnetic fluctuations. However,
one needs to clarify the role of Fermi surface topology, density of states,
pseudogap, and wave vector of the magnetic fluctuations on the nature and
strength of the induced d-wave state. To this end, we study the generalized
phase diagram of the two-dimensional half-filled Hubbard model as a function of
interaction strength , frustration induced by second-order hopping
, and temperature . In experiment, and
can be controlled by pressure. We use the two-particle self-consistent approach
(TPSC), valid from weak to intermediate coupling. We first calculate as a
function of and the temperature and wave vector at which
the spin response function begins to grow exponentially.D-wave
superconductivity in a half-filled band can be induced by such magnetic
fluctuations at weak to intermediate coupling, but only if they are near
commensurate wave vectors and not too close to perfect nesting conditions where
the pseudogap becomes detrimental to superconductivity. For given there
is thus an optimal value of frustration where the
superconducting is maximum. The non-interacting density of states plays
little role. The symmetry d vs d of the superconducting
order parameter depends on the wave vector of the underlying magnetic
fluctuations in a way that can be understood qualitatively from simple
arguments
Dynamics of higher-order solitons in regular and PT-symmetric nonlinear couplers
Dynamics of symmetric and antisymmetric 2-solitons and 3-solitons is studied
in the model of the nonlinear dual-core coupler and its PT-symmetric version.
Regions of the convergence of the injected perturbed symmetric and
antisymmetric N-solitons into symmetric and asymmetric quasi-solitons are
found. In the PT-symmetric system, with the balanced gain and loss acting in
the two cores, borders of the stability against the blowup are identified.
Notably, in all the cases the stability regions are larger for antisymmetric
2-soliton inputs than for their symmetric counterparts, on the contrary to
previously known results for fundamental solitons (N=1). Dynamical regimes
(switching) are also studied for the 2-soliton injected into a single core of
the coupler. In particular, a region of splitting of the input into a pair of
symmetric solitons is found, which is explained as a manifestation of the
resonance between the vibrations of the 2-soliton and oscillations of energy
between the two cores in the coupler.Comment: To appear in EPL journa
Construção do conhecimento sobre os produtos da biodiversidade em um assentamento rural.
Editores tĂŠcnicos: MarcĂlio JosĂŠ Thomazini, Elenice Fritzsons, PatrĂcia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
Recent Progress on Exciton Polaritons in Layered TransitionâMetal Dichalcogenides
Exciton polaritons (EPs) are halfâlight, halfâmatter quasiparticles formed due to the coupling between photons and excitons in semiconductors. Their uniqueness lies at the strong lightâmatter interactions and longâdistance transport, thus promising for many novel applications in photonics, information, and quantum technologies. Recently, EPs in groupâVI transitionâmetal dichalcogenides (TMDs) have attracted a lot of research interest due to their roomâtemperature stability, longâdistance propagation, and controllability through electric gating, valleyâselective optical pumping, and precise thickness control. In this progress report, recent studies of EPs in TMDs are reviewed, highlighting their key properties and functionalities, and then discussing the potential directions for future research
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