29 research outputs found
Schroedinger Invariance from Lifshitz Isometries in Holography and Field Theory
We study non-relativistic field theory coupled to a torsional Newton-Cartan
geometry both directly as well as holographically. The latter involves gravity
on asymptotically locally Lifshitz space-times. We define an energy-momentum
tensor and a mass current and study the relation between conserved currents and
conformal Killing vectors for flat Newton-Cartan backgrounds. It is shown that
flat NC space-time realizes two copies of the Lifshitz algebra that together
form a Schroedinger algebra (without the central element). We show why the
Schroedinger scalar model has both copies as symmetries and the Lifshitz scalar
model only one. Finally we discuss the holographic dual of this phenomenon by
showing that the bulk Lifshitz space-time realizes the same two copies of the
Lifshitz algebra.Comment: 5 pages, modified abstract, clarifications added, typos fixed, refs
update
Neue Aspekte in der Chemie von Übergangsmetallpolysulfidkomplexen: Synthese und Kristallstrukturen von Cp′3Nb3S12 und Cp′3Nb3S10O (Cp′ = t-BuC5H4)
Thermolysis of a mixture of Cp′4Nb2Sn (Cp′ = t-BuC5H4; n = 8, 9) results in the formation of the new niobium polysulfide complexes: Cp′3Nb3S12 (2), Cp′3Nb3S10O (3), Cp′3Nb3S10O (4) and Cp′4Nb4S13 (5). The structures of 2 and 3 have been established by X-ray diffraction studies. The complexes are characterized by an unusual variety of different sulfur ligands (up to five in 2), which is responsible for the absence of any metal-metal interaction
(2, 2, 8, 8-Tetramethyl-5-oxa-4,6-diphospha-3, 6-nonadien)tetrakis[dicarbonyl-(methylcyclopentadienyl)mangan], der erste komplexierte Bis(phosphavinyl)ether
Der Komplex eines neuartigen Liganden ist die Titelverbindung 1. Sie entsteht aus [(CH3C5H4)Mn(CO)2·thf] und (CH3)3C-C=P vermutlich unter H2O-Aufnahme. Im paramagnetischen Komplex 1 fungiert der Bis(phosphavinyl)ether als 8-Elektronendonor gegenüber den vier (CH3C5H4)Mn(CO)2-Einheiten
Recommended from our members
Interactive Visualization Of Very Large Datasets Using An Out-of-Core Point-based Approach
We present an out-of-core, point-based approach for interactive rendering of very large volumetric datasets. Our approach is based on the assumption that the density of voxels with the same function-value in large discretized volumetric scalar fields is high enough to be used to render contour and volume approximations using points to represent the voxels. This approach allows us to visualize isovalue-structures in high-resolution datasets at full resolution and interactive frame rates. In a pre-processing step, we sort the voxels by function-value and store them in a file together with a look-up table for later interactive retrieval. The displayed voxelsets can then be changed in real time by determining their locations in the file and loading them into memory. As we store position, and not function-value, the volumetric dimension of a dataset to be handled by our approach is limited by three factors: the number of points that can be rendered to achieve a sufficient frame rate, the number of bits used to store the position data, and the maximum file-size supported by the operating system. Depending on the spatial distribution of the voxels among the function-values selected, the result is either one or multiple contours or ``isoclouds''