Institution
Technical University of Dortmund
Education•Dortmund, Nordrhein-Westfalen, Germany•
About: Technical University of Dortmund is a education organization based out in Dortmund, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Context (language use) & Large Hadron Collider. The organization has 13028 authors who have published 27666 publications receiving 615557 citations. The organization is also known as: Dortmund University & University of Dortmund.
Topics: Context (language use), Large Hadron Collider, Computer science, Neutrino, Finite element method
Papers published on a yearly basis
Papers
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TL;DR: This survey paper compares native double precision solvers with emulated- and mixed-precision solvers of linear systems of equations as they typically arise in finite element discretisations and concludes that the mixed precision approach works very well with the parallel co-processors gaining speedup factors and area savings, while maintaining the same accuracy as a reference solver executing everything in double precision.
Abstract: In this survey paper, we compare native double precision solvers with emulated-and mixed-precision solvers of linear systems of equations as they typically arise in finite element discretisations. The emulation utilises two single float numbers to achieve higher precision, while the mixed precision iterative refinement computes residuals and updates the solution vector in double precision but solves the residual systems in single precision. Both techniques have been known since the 1960s, but little attention has been devoted to their performance aspects. Motivated by changing paradigms in processor technology and the emergence of highly-parallel devices with outstanding single float performance, we adapt the emulation and mixed precision techniques to coupled hardware configurations, where the parallel devices serve as scientific co-processors. The performance advantages are examined with respect to speedups over a native double precision implementation (time aspect) and reduced area requirements for a chip (space aspect). The paper begins with an overview of the theoretical background, algorithmic approaches and suitable hardware architectures. We then employ several conjugate gradient (CG) and multigrid solvers and study their behaviour for different parameter settings of the iterative refinement technique. Concrete speedup factors are evaluated on the coupled hardware configuration of a general-purpose CPU and a graphics processor. The dual performance aspect of potential area savings is assessed on a field programmable gate array (FPGA). In the last part, we test the applicability of the proposed mixed precision schemes with ill-conditioned matrices. We conclude that the mixed precision approach works very well with the parallel co-processors gaining speedup factors of four to five, and area savings of three to four, while maintaining the same accuracy as a reference solver executing everything in double precision.
166 citations
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TL;DR: In this article, the dephasing time of the ground state transition in In1−xGaxAs quantum dots was measured using a sensitive four-wave mixing technique, and the tunability of the radiative lifetime at low temperatures was demonstrated.
Abstract: We measure the dephasing time of the exciton ground-state transition in In1−xGaxAs quantum dots using a sensitive four-wave mixing technique. We find experimental evidence that the dephasing time is given only by the radiative lifetime at low temperatures. We demonstrate the tunability of the radiatively limited dephasing time from 400 ps up to 2 ns in a series of annealed In1−xGaxAs quantum dots with increasing quantum-confinement energy from 69 meV to 330 meV.
165 citations
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TL;DR: The first results from LHCb have made a significant impact on the flavour physics landscape and have definitively proved the concept of a dedicated experiment in the forward region at a hadron collider as mentioned in this paper.
Abstract: During 2011 the LHCb experiment at CERN collected 1.0 fb-1 of sqrt{s} = 7 TeV pp collisions. Due to the large heavy quark production cross-sections, these data provide unprecedented samples of heavy flavoured hadrons. The first results from LHCb have made a significant impact on the flavour physics landscape and have definitively proved the concept of a dedicated experiment in the forward region at a hadron collider. This document discusses the implications of these first measurements on classes of extensions to the Standard Model, bearing in mind the interplay with the results of searches for on-shell production of new particles at ATLAS and CMS. The physics potential of an upgrade to the LHCb detector, which would allow an order of magnitude more data to be collected, is emphasised.
165 citations
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TL;DR: A search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented, fitting the dilepton mass spectra in several exclusive signal regions.
Abstract: A search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented. The search uses a proton–proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to 36.1 $$\text {fb}^{-1}$$
of integrated luminosity recorded in 2015 and 2016 by the ATLAS detector at the LHC. This analysis focuses on the decays $$H^{\pm \pm }\rightarrow e^{\pm }e^{\pm }$$
, $$H^{\pm \pm }\rightarrow e^{\pm }\mu ^{\pm }$$
and $$H^{\pm \pm }\rightarrow \mu ^{\pm }\mu ^{\pm }$$
, fitting the dilepton mass spectra in several exclusive signal regions. No significant evidence of a signal is observed and corresponding limits on the production cross-section and consequently a lower limit on $$m(H^{\pm \pm })$$
are derived at 95% confidence level. With $$\ell ^{\pm }\ell ^{\pm }=e^{\pm }e^{\pm }/\mu ^{\pm }\mu ^{\pm }/e^{\pm }\mu ^{\pm }$$
, the observed lower limit on the mass of a doubly charged Higgs boson only coupling to left-handed leptons varies from 770 to 870 GeV (850 GeV expected) for $$B(H^{\pm \pm }\rightarrow \ell ^{\pm }\ell ^{\pm })=100\%$$
and both the expected and observed mass limits are above 450 GeV for $$B(H^{\pm \pm }\rightarrow \ell ^{\pm }\ell ^{\pm })=10\%$$
and any combination of partial branching ratios.
165 citations
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TL;DR: In this paper, a search for the b (b) over bar decay of the Standard Model Higgs boson is performed with the ATLAS experiment using the full dataset recorded at the LHC in Run 1.
Abstract: A search for the b (b) over bar decay of the Standard Model Higgs boson is performed with the ATLAS experiment using the full dataset recorded at the LHC in Run 1. The integrated luminosities used are 4.7 and 20.3 fb(-1) from pp collisions at root s = 7 and 8 TeV, respectively. The processes considered are associated (WIZ)H production, where W -> e nu/mu nu, Z -> ee/mu mu, and Z -> nu nu. The observed (expected) deviation from the backgroundonly hypothesis corresponds to a significance of 1.4 (2.6) standard deviations and the ratio of the measured signal yield to the Standard Model expectation is found to be mu = 0.52 +/- 0.32 (stat.) +/- 0.24 (syst.) for a Higgs boson mass of 125.36 GeV. The analysis procedure is validated by a measurement of the yield of (W/Z)Z production with Z -> b (b) over bar in the same final states as for the Higgs boson search, from which the ratio of the observed signal yield to the Standard Model expectation is found to be 0.74 +/- 0.09 (stat.) +/- 0.14 (syst.).
164 citations
Authors
Showing all 13240 results
Name | H-index | Papers | Citations |
---|---|---|---|
Hermann Kolanoski | 145 | 1279 | 96152 |
Marc Besancon | 143 | 1799 | 106869 |
Kerstin Borras | 133 | 1341 | 92173 |
Emmerich Kneringer | 129 | 1021 | 80898 |
Achim Geiser | 129 | 1331 | 84136 |
Valerio Vercesi | 129 | 937 | 79519 |
Jens Weingarten | 128 | 896 | 74667 |
Giuseppe Mornacchi | 127 | 894 | 75830 |
Kevin Kroeninger | 126 | 836 | 70010 |
Daniel Muenstermann | 126 | 885 | 70855 |
Reiner Klingenberg | 126 | 733 | 70069 |
Claus Gössling | 126 | 775 | 71975 |
Diane Cinca | 126 | 822 | 70126 |
Frank Meier | 124 | 677 | 64889 |
Daniel Dobos | 124 | 679 | 67434 |