4,162 research outputs found
High loop renormalization constants for Wilson fermions/Symanzik improved gauge action
We present the current status of our computation of quark bilinear
renormalization constants for Wilson fermions and Symanzik improved gauge
action. Computations are performed in Numerical Stochastic Perturbation Theory.
Volumes range from 10^4 to 32^4. Renormalization conditions are those of the
RI'-MOM scheme, imposed at different values of the physical scale. Having
measurements available at several momenta, irrelevant effects are taken into
account by means of hypercubic symmetric Taylor expansions. Finite volumes
effects are assessed repeating the computations at different lattice sizes. In
this way we can extrapolate our results to the continuum limit, in infinite
volume.Comment: 8 pages, 3 figures, talk presented at the 27th International
Symposium on Lattice Field Theory (Lattice 2009), Beijing, China, 26-31 Jul
200
Brambilla et al. Reply to a Comment by J. Reinhardt et al. on "Probing the equilibrium dynamics of colloidal hard spheres above the mode-coupling glass transition"
G. Brambilla et al. Reply to a Comment by J. Reinhardt et al. questioning the
existence of equilibrium dynamics above the critical volume fraction of
colloidal hard spheres predicted by mode coupling theory.Comment: To appear in Phys. Rev. Lett. Reply to a Comment by J. Reinhardt et
al. (see arXiv:1010.2891), which questions the existence of equilibrium
dynamics above the critical volume fraction of glassy colloidal hard spheres
predicted by mode coupling theor
The Distrimobs approach for parallelization of pedestrian mobility computations
Simulating pedestrian mobility is a typical centralized problem where each agent must interact with a plurality of other agents in order to make decisions about its local path planning. Distrimobs is a parallel- and distributed-agent–based pedestrian mobility simulator able to represent thousands of agents while keeping a good scalability. The aim of the Distrimobs simulator is to simulate the whole
Carnival of Venice. In this work we present the Distrimobs approach for parallelization of the computations and some experimental results of performance intensive scenarios. These results highlight the scalability and the computational complexity of the simulator
BANK EROSION AND INSTABILITY MONITORING WITH A LOW COST TERRESTRIAL LASER SCANNER
ABSTRACT: Among the dominant processes taking place in a river basin, especially mountain ones, sediments
creation and transport play a key role in morphological processes. Studies usually focus on big mass movements,
such as landslides and debris flows, or on wide spread slope erosion due to rainfalls, while bank erosion is
neglected or not considered essential for sediment budget at basin scale. Nevertheless, authors consider bank
erosion a process that deserve more careful studies; not only the sediment share from bank erosion is not
negligible in steep mountain rivers, but also the process can threat structures on river sides due the possibility to
have limited, but still significant, mass collapse of bank sections during intense events. The paper present an
attempt to monitor bank erosion in a section of a river in Northern Italy Alps and to put it in relation with
weather and water discharge. Survey campaign was set up at regular time intervals, or after particularly intense
rainfalls, and uses a Terrestrial Laser Scanner (TLS) to acquire the bank surface. The tool was developed
internally, at Politecnico di Milano, to meet requirements about low cost level and good accuracy. Successive
acquisitions of point clouds were elaborated, via an ad-hoc MatLab code, to determine erosion, or deposition,
volumes of sediments. These volumetric results have been evaluated in relation with rainfalls and freeze-thaw
cycles looking for a relationship between environmental conditions and bank failures. Some interesting results
are shown, such as a relation between erosion rates and temperature or water flow in the river. The path to a
complete process understanding and modelling is long, however the results reported can be considered a first
step towards objective
Quantum spatial correlations in high-gain parametric down-conversion measured by means of a CCD camera
We consider travelling-wave parametric down-conversion in the high-gain
regime and present the experimental demonstration of the quantum character of
the spatial fluctuations in the system. In addition to showing the presence of
sub-shot noise fluctuations in the intensity difference, we demonstrate that
the peak value of the normalized spatial correlations between signal and idler
lies well above the line marking the boundary between the classical and the
quantum domain. This effect is equivalent to the apparent violation of the
Cauchy-Schwartz inequality, predicted by some of us years ago, which represents
a spatial analogue of photon antibunching in time. Finally, we analyse
numerically the transition from the quantum to the classical regime when the
gain is increased and we emphasize the role of the inaccuracy in the
determination of the symmetry center of the signal/idler pattern in the
far-field plane.Comment: 21 pages, 11 figures, submitted to J. Mod. Opt. special issue on
Quantum Imagin
- …