5,150 research outputs found
Computational relativistic quantum dynamics and its application to relativistic tunneling and Kapitza-Dirac scattering
Computational methods are indispensable to study the quantum dynamics of
relativistic light-matter interactions in parameter regimes where analytical
methods become inapplicable. We present numerical methods for solving the
time-dependent Dirac equation and the time-dependent Klein-Gordon equation and
their implementation on high performance graphics cards. These methods allow us
to study tunneling from hydrogen-like highly charged ions in strong laser
fields and Kapitza-Dirac scattering in the relativistic regime
NASA Thesaurus supplement: A four part cumulative supplement to the 1988 edition of the NASA Thesaurus (supplement 3)
The four-part cumulative supplement to the 1988 edition of the NASA Thesaurus includes the Hierarchical Listing (Part 1), Access Vocabulary (Part 2), Definitions (Part 3), and Changes (Part 4). The semiannual supplement gives complete hierarchies and accepted upper/lowercase forms for new terms
Hadron Spectrum from Lattice QCD
A brief review is given of the lattice QCD calculation of the hadron
spectrum. The status of current attempts toward inclusion of dynamical up, down
and strange quarks is summarized focusing on our own work. Recent work on the
possible existence of pentaquark states are assessed. We touch upon the PACS-CS
Project for building our next machine for lattice QCD, and conclude with a
near-term physics and machine prospects.Comment: Talk given at the International Conference on QCD and Hadronic
Physics, Beijing, June 16-20, 2005. References added and correcte
Single particle detection of protein molecules using dark-field microscopy to avoid signals from nonspecific adsorption
A massively parallel single particle sensing method based on core-satellite formation of Au nanoparticles was introduced for the detection of interleukin 6 (IL-6). This method exploits the fact that the localized plasmon resonance (LSPR) of the plasmonic nanoparticles will change as a result of core-satellite formation, resulting in a change in the observed color. In this method, the hue (color) value of thousands of 67 nm Au nanoparticles immobilized on a glass coverslip surface is analyzed by a Matlab code before and after the addition of reporter nanoparticles containing IL-6 as target protein. The average hue shift as the result of core-satellite formation is used as the basis to detect small amount of proteins. This method enjoys two major advantages. First it is able to analyze the hue values of thousands of nanoparticles in parallel in less than a minute. Secondly the method is able to circumvent the effect of non-specific adsorption, a major issue in the field of biosensing
Computational Particle Physics for Event Generators and Data Analysis
High-energy physics data analysis relies heavily on the comparison between
experimental and simulated data as stressed lately by the Higgs search at LHC
and the recent identification of a Higgs-like new boson. The first link in the
full simulation chain is the event generation both for background and for
expected signals. Nowadays event generators are based on the automatic
computation of matrix element or amplitude for each process of interest.
Moreover, recent analysis techniques based on the matrix element likelihood
method assign probabilities for every event to belong to any of a given set of
possible processes. This method originally used for the top mass measurement,
although computing intensive, has shown its power at LHC to extract the new
boson signal from the background.
Serving both needs, the automatic calculation of matrix element is therefore
more than ever of prime importance for particle physics. Initiated in the
eighties, the techniques have matured for the lowest order calculations
(tree-level), but become complex and CPU time consuming when higher order
calculations involving loop diagrams are necessary like for QCD processes at
LHC. New calculation techniques for next-to-leading order (NLO) have surfaced
making possible the generation of processes with many final state particles (up
to 6). If NLO calculations are in many cases under control, although not yet
fully automatic, even higher precision calculations involving processes at
2-loops or more remain a big challenge.
After a short introduction to particle physics and to the related theoretical
framework, we will review some of the computing techniques that have been
developed to make these calculations automatic. The main available packages and
some of the most important applications for simulation and data analysis, in
particular at LHC will also be summarized.Comment: 19 pages, 11 figures, Proceedings of CCP (Conference on Computational
Physics) Oct. 2012, Osaka (Japan) in IOP Journal of Physics: Conference
Serie
CELES: CUDA-accelerated simulation of electromagnetic scattering by large ensembles of spheres
CELES is a freely available MATLAB toolbox to simulate light scattering by
many spherical particles. Aiming at high computational performance, CELES
leverages block-diagonal preconditioning, a lookup-table approach to evaluate
costly functions and massively parallel execution on NVIDIA graphics processing
units using the CUDA computing platform. The combination of these techniques
allows to efficiently address large electrodynamic problems (
scatterers) on inexpensive consumer hardware. In this paper, we validate near-
and far-field distributions against the well-established multi-sphere
-matrix (MSTM) code and discuss the convergence behavior for ensembles of
different sizes, including an exemplary system comprising particles
CELES: CUDA-accelerated simulation of electromagnetic scattering by large ensembles of spheres
partially_open5sìCELES is a freely available MATLAB toolbox to simulate light scattering by many spherical particles. Aiming at high computational performance, CELES leverages block-diagonal preconditioning, a lookup-table approach to evaluate costly functions and massively parallel execution on NVIDIA graphics processing units using the CUDA computing platform. The combination of these techniques allows to efficiently address large electrodynamic problems (> 10(4) scatterers) on inexpensive consumer hardware. In this paper, we validate near- and far-field distributions against the well-established multi-sphere T-matrix (MSTM) code and discuss the convergence behavior for ensembles of different sizes, including an exemplary system comprising 10(5) particles. (C) 2017 Elsevier Ltd. All rights reserved.openhttps://github.com/disordered-photonics/celesEgel, A; Pattelli, L; Mazzamuto, G; Wiersma, DS; Lemmer, UEgel, A; Pattelli, L; Mazzamuto, G; Wiersma, Ds; Lemmer,
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