University of Stuttgart

About: University of Stuttgart is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Laser & Finite element method. The organization has 27715 authors who have published 56370 publications receiving 1363382 citations. The organization is also known as: Universität Stuttgart.

Stochastic Optimization Model to Study the Operational Impacts of High Wind Penetrations in Ireland

Abstract: A stochastic mixed integer linear optimization scheduling model minimizing system operation costs and treating load and wind power production as stochastic inputs is presented. The schedules are updated in a rolling manner as more up-to-date information becomes available. This is a fundamental change relative to day-ahead unit commitment approaches. The need for reserves dependent on forecast horizon and share of wind power has been estimated with a statistical model combining load and wind power forecast errors with scenarios of forced outages. The model is used to study operational impacts of future high wind penetrations for the island of Ireland. Results show that at least 6000 MW of wind (34% of energy demand) can be integrated into the island of Ireland without significant curtailment and reliability problems.

Communication: Extended multi-state complete active space second-order perturbation theory: Energy and nuclear gradients

Abstract: The extended multireference quasi-degenerate perturbation theory, proposed by Granovsky [J. Chem. Phys. 134, 214113 (2011)], is combined with internally contracted multi-state complete active space second-order perturbation theory (XMS-CASPT2). The first-order wavefunction is expanded in terms of the union of internally contracted basis functions generated from all the reference functions, which guarantees invariance of the theory with respect to unitary rotations of the reference functions. The method yields improved potentials in the vicinity of avoided crossings and conical intersections. The theory for computing nuclear energy gradients for MS-CASPT2 and XMS-CASPT2 is also presented and the first implementation of these gradient methods is reported. A number of illustrative applications of the new methods are presented.

Reference Architectures for the Internet of Things

Abstract: The Internet of Things (IoT) is about innovative functionality and better productivity by seamlessly connecting devices. But a major threat is the lack of architecture standards for the industrial Internet and connectivity in the IoT. This article reviews recent IoT architecture evolution and what it means for industry projects.

Strong dipolar effects in a quantum ferrofluid

Abstract: A paper in this issue addresses a hot topic in the physics of ultracold atoms — quantum ferrofluids, which are superfluid quantum gases that consist of polarized dipoles, either electric or magnetic. The symmetry-breaking interaction between such dipoles is expected to lead to new physical phenomena. Now a group from Stuttgart University has succeeded in producing a chromium Bose–Einstein condensate with strong anisotropic magnetic dipole–dipole interaction between the atoms, which induces a pronounced change of the aspect ratio of the cloud. This much-sought form of matter should enable fundamental studies of physical systems in previously unexplored regimes. This paper reports the realization of a chromium Bose-Einstein condensate (BEC) with strong anisotropic magnetic dipole–dipole interaction between the atoms, which induces a pronounced change of the aspect ratio of the cloud. The experiment opens the way for exploration of the unique properties of quantum ferrofluids. Symmetry-breaking interactions have a crucial role in many areas of physics, ranging from classical ferrofluids to superfluid 3He and d-wave superconductivity. For superfluid quantum gases, a variety of new physical phenomena arising from the symmetry-breaking interaction between electric or magnetic dipoles are expected1. Novel quantum phases in optical lattices, such as chequerboard or supersolid phases, are predicted for dipolar bosons2,3. Dipolar interactions can also enrich considerably the physics of quantum gases with internal degrees of freedom4,5,6. Arrays of dipolar particles could be used for efficient quantum information processing7. Here we report the realization of a chromium Bose–Einstein condensate with strong dipolar interactions. By using a Feshbach resonance, we reduce the usual isotropic contact interaction, such that the anisotropic magnetic dipole–dipole interaction between 52Cr atoms becomes comparable in strength. This induces a change of the aspect ratio of the atom cloud; for strong dipolar interactions, the inversion of ellipticity during expansion (the usual ‘smoking gun’ evidence for a Bose–Einstein condensate) can be suppressed. These effects are accounted for by taking into account the dipolar interaction in the superfluid hydrodynamic equations governing the dynamics of the gas, in the same way as classical ferrofluids can be described by including dipolar terms in the classical hydrodynamic equations. Our results are a first step in the exploration of the unique properties of quantum ferrofluids.