Technical University of Dortmund

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: Large Hadron Collider & Neutrino. The organization has 13028 authors who have published 27666 publications receiving 615557 citations. The organization is also known as: Dortmund University & University of Dortmund.

Band-Gap Assignment in Sn O 2 by Two-Photon Spectroscopy

Abstract: We present for the first time two-photon measurements on rutile Sn${\mathrm{O}}_{2}$. The detailed polarization analysis yields ${{\ensuremath{\Gamma}}_{3}}^{+}$ symmetry for the direct forbidden $1S$ exciton and the upper valence band. Our results clear up the long-standing controversy concerning the symmetry of the upper valence band.

Results from pion calibration runs for the H 1 liquid argon calorimeter and comparisons with simulations

Abstract: We present results on calibration runs performed with pions at the CERN SPS for different modules of the H 1 liquid argon calorimeter which consists of an electromagnetic section with lead absorbers and a hadronic section with steel absorbers. The data cover an energy range from 3.7 to 205 GeV. Detailed comparisons of the data and simulation with GHEISHA 8 in the framework of GEANT 3.14 are presented. The measured pion induced shower profiles are well described by the simulation. The total signal of pions on an energy scale determined from electron measurements is reproduced to better than 3% in various module configurations. After application of weighting functions, determined from Monte Carlo data and needed to achieve compensation, the reconstructed measured energies agree with simulation to about 3%. The energies of hadronic showers are reconstructed with a resolution of about 50% √E ⨸ 2% . This result is achieved by inclusion of signals from an iron streamer tube tail catcher behind the liquid argon stacks.

Resampling methods for meta-model validation with recommendations for evolutionary computation

Abstract: Meta-modeling has become a crucial tool in solving expensive optimization problems. Much of the work in the past has focused on finding a good regression method to model the fitness function. Examples include classical linear regression, splines, neural networks, Kriging and support vector regression. This paper specifically draws attention to the fact that assessing model accuracy is a crucial aspect in the meta-modeling framework. Resampling strategies such as cross-validation, subsampling, bootstrapping, and nested resampling are prominent methods for model validation and are systematically discussed with respect to possible pitfalls, shortcomings, and specific features. A survey of meta-modeling techniques within evolutionary optimization is provided. In addition, practical examples illustrating some of the pitfalls associated with model selection and performance assessment are presented. Finally, recommendations are given for choosing a model validation technique for a particular setting.

Optical control of one and two hole spins in interacting quantum dots

Abstract: Researchers demonstrate fast, single-qubit gates using a sequence of 13 ps pulses. Two vertically stacked InAs/GaAs quantum dots were coupled through coherent tunnelling and charged with controlled numbers of holes. The interaction between hole spins was investigated by Ramsey fringe experiments, showing a tunable interaction range of tens of gigahertz.

Measurement of Atmospheric Neutrino Oscillations at 6-56 GeV with IceCube DeepCore.

Abstract: We present a measurement of the atmospheric neutrino oscillation parameters using three years of data from the IceCube Neutrino Observatory. The DeepCore infill array in the center of IceCube enabl ...