RMAPW-Verfahren und selbstkonsistente Bandstruktur von Gold

The "Relativistic Modified Augmented Plane Wave" (RMAPW) method of Bross and Hofmann (1969) was realized numerically in a slightly modified form and tested with the example of copper potential of Burdick (1963). With regard to future applications in the area of surface-bandstructures and surface-states this realization was done in a generalization of the RMAPW-method for complex k-vectors ("complex RMAPW") of Wachutka (1978). Starting from the "Overlapping Charge Density" (OCD) potential of gold in "Muffin Tin" (MT) form from Christensen and Seraphin (1971) in this work a selfconsistent gold potential in "Warped Muffin Tin" (WMT) form was computed. As a modell for the electron-electron interaction the effective local single-particle-potential in the context of the "Local Density Approximation" (LDA) with relativistic adjustments for the exchange-term of MacDonald and Vosko (1979) was used. On the basis of the energy spectrum, the density of states, and the anisotropy of the fermi-surface the approximations of WMT and DFF/LDA are discussed. The most essential result is, that with the selfconsistent potential there is in the energy-scale a movement of the occupied d-bands slightly upwards and a broadening of the d-bandwidth, in contrast to some experiments. Neddermeyer (1981) suggested a drastic upshift of the 7. band - for that proposal there is no evidence in this work. Because in this calculation exchange- and correlation-potentials are free from adjustable parameters, the author guesses, that in the difference between theory and experiment we have reached the limit of the local approximation (LDA). This publication is 99% identical with the PhD-thesis of the author at LMU Munich in March 1984. Minor add-ons are given in brackets [...]. A new appendix from 2012 adds some informations from the assets of the author and discusses some interesting newer PhD-theses about Copper and Gold, done at the Institut of Theoretical Solid State Physics (Prof. H. Bross) at LMU Munich

Aluminum as a source of background in low background experiments

Neutrinoless double beta decay would be a key to understanding the nature of neutrino masses. The next generation of High Purity Germanium experiments will have to be operated with a background rate of better than 10^-5 counts/(kg y keV) in the region of interest around the Q value of the decay. Therefore, so far irrelevant sources of background have to be considered. The metalization of the surface of germanium detectors is in general done with aluminum. The background from the decays of 22Na, 26Al, 226Ra and 228Th introduced by this metalization is discussed. It is shown that only a special selection of aluminum can keep these background contributions acceptable.Comment: 11 pages, 3 Tables, 11 Figures, accepted for publication in NIM

Spallation reactions. A successful interplay between modeling and applications

The spallation reactions are a type of nuclear reaction which occur in space by interaction of the cosmic rays with interstellar bodies. The first spallation reactions induced with an accelerator took place in 1947 at the Berkeley cyclotron (University of California) with 200 MeV deuterons and 400 MeV alpha beams. They highlighted the multiple emission of neutrons and charged particles and the production of a large number of residual nuclei far different from the target nuclei. The same year R. Serber describes the reaction in two steps: a first and fast one with high-energy particle emission leading to an excited remnant nucleus, and a second one, much slower, the de-excitation of the remnant. In 2010 IAEA organized a worskhop to present the results of the most widely used spallation codes within a benchmark of spallation models. If one of the goals was to understand the deficiencies, if any, in each code, one remarkable outcome points out the overall high-quality level of some models and so the great improvements achieved since Serber. Particle transport codes can then rely on such spallation models to treat the reactions between a light particle and an atomic nucleus with energies spanning from few tens of MeV up to some GeV. An overview of the spallation reactions modeling is presented in order to point out the incomparable contribution of models based on basic physics to numerous applications where such reactions occur. Validations or benchmarks, which are necessary steps in the improvement process, are also addressed, as well as the potential future domains of development. Spallation reactions modeling is a representative case of continuous studies aiming at understanding a reaction mechanism and which end up in a powerful tool.Comment: 59 pages, 54 figures, Revie

In memoriam Karl Kraus

Prof. Dr. Karl Kraus Forscher und Lehrer am Physikalischen Institut der Universität Würzburg Curriculum vitae und Publikationslist

Requirement for the masterprocess in the current context

Im Prozess des Masterings geht es darum, dass durch den Urheber erschaffene Musikstück für die Veröffentlichung vorzubereiten. Die Anforderungen an den Prozess ergeben sich aus den Wünschen des Kunden und den Anforderungen der Medien und Wiedergabesysteme, welche für das Wiedergeben der Musik genutzt werden. Durch den technischen Fortschritt haben sich die Anforderungen an das Mastering verändert. In der Vergangenheit war die Lautheitssteigerung einer der wichtigsten Teilaspekte des Masteringprozesses. Es hat sich gezeigt, dass der Trend zur Nutzung von Streamingdiensten geht, welche zum Großteil die Lautheit von Liedern anpassen. Es werden jedoch immer noch Medien verwendet, welche nicht die Lautheit von Liedern normalisieren, wodurch zwei unterschiedliche Ausrichtung des Masteringprozesses resultieren. Da die Lautheitsnormalisierung selten durch Anbieter der Medien dokumentiert ist, wurden durch eine experimentelle Messung die Eigenschaften der verschiedenen Medien ermittelt. Aus den Erkenntnissen der Recherchearbeit und den Messungen wurden Anforderungen an einen aktuellen Masteringprozess abgeleitet und konkrete Werte für die Ausrichtung des Masteringprozesses geschaffen. Um die bestmögliche Qualität und Wettbewerbsfähigkeit eines Musikstückes nach dem Masteringprozess zu gewährleisten, müssen unterschiedliche Versionen mit unterschiedlichen Anforderungen erstellt werden. Ist dies aus ökonomischen Gründen nicht möglich, kann ein Master angefertigt werden welches den gemeinsamen Anforderungen aller Medien nachkomm

Krümmungen und Indexsätze - auf den Spuren von Gauß-Bonnet, Cartan, Atiyah-Singer und Witten. Eine Einführung in Geometrie und Topologie für Physiker.

„Krümmungen und Indexsätze - auf den Spuren von Gauß-Bonnet, Cartan, Atiyah-Singer und Witten. Eine Einführung in Geometrie und Topologie für Physiker.“ This publication is a propaedeutic monograph about Gauss-Bonnet theorems and Atiyah-Singer indextheorems (ASI). Prerequisites are advanced undergraduate level in mathematical physics and some interest and time. Topics are the development of the notions of curvature and topological invariants through the ages and their application to physics. The beginnings in this field were given by Euklid, Archimedes, Harriot, Girard, Newton, Frenet-Serret. Next we come to Euler with his topological invariant 'Euler charcteristic', Gauss & Bonnet with their theory of 2-dimensional surfaces and Riemann with his 'Differential Geometry'. Then the story goes on with 'Homotopy', 'Simplicial Homology', 'Singular Homology', 'Cohomology', 'Hodge theory', 'Lie-Groups', 'Fibre Bundles', 'Gauge theory', 'Characteristic Classes' until a pathintegral-proof of the ASI for the chiral euklidean Dirac-Operator á la Witten et al. We owe all this (and much more) to Élie Cartan, Poincaré, Einstein, Hopf, Brower, de Rham, Hodge, Lie, Lorentz, Dirac, Ehresmann, Yang & Mills, Chern, Weil, Pontrjagin, Todd, Hirzebruch, Atiyah & Singer and Witten. Our motto in the words of Spivak is: „All the way with Gauss-Bonnet“. Due to the didactical intention of this introduction all proofs are worked out in details. So, enjoy yourself! :-

Reduktion und Äquivalenz generalisierter relationaler Schemata - theoretische Grundlagen und algorithmische Lösungen

Der Datenbankentwurf hat die Aufgabe, einen Ausschnitt der realen Welt auf Datenbanksysteme abzubilden. Zur Lösung dieser Aufgabe werden unter anderem zwei Datenbankmodelle entworfen, das konzeptuelle Datenmodell und das logische Datenmodell. Die existierenden Ansätze zur Abbildung des konzeptuellen, semantischen Datenmodells ins logische, operationale Datenmodell sind unvollständig. Der Informationsverlust, der aus dieser Unvollständigkeit resultiert, ist kein akzeptabler Zustand

Zeta-Funktionen in der Physik - eine Einführung

"Zetafunctions in Physics - an Introduction" is an introductory monograph about Riemann-Zetafunction, Spectral Zetafunctions and Dynamical Zetafunctions in Physics on an advanced undergraduate level. Topics are: harmonic oszillator (not much surprising), phase operators and coherent states, pathintegrals of single- and many-particle systems, regularization with Spectral Zetafunction and Casimir-effect, heat-kernel-expansion and regularization and renormalization of the Phi(4,4)-theory in 1-loop approximation, Dynamical or Ruelle Zetafunctions in dynamical systems and Gutzwillers traceformula. Mathematical appendices deal with: Gammafunction, Riemann-Zetafunction, Mellin-transformation, asymptotic expansions, heat-kernel-expansion and (analytic) index-theorem for elliptic differential operators, Fredholm-theory of elliptic pseudo-differential operators. Due to the didactic intention of this introduction all proofs are worked out in details. So, enjoy yourself

RMAPW-Verfahren und selbstkonsistente Bandstruktur von Gold

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Krümmungen und Indexsätze - auf den Spuren von Gauß-Bonnet, Cartan, Atiyah-Singer und Witten. Eine Einführung in Geometrie und Topologie für Physiker.

This publication is a propaedeutic monograph about Gauss-Bonnet theorems and Atiyah-Singer indextheorems (ASI). Prerequisites are advanced undergraduate level in mathematical physics and some interest and time. Topics are the development of the notions of curvature and topological invariants through the ages and their application to physics. The beginnings in this field were given by Euklid, Archimedes, Harriot, Girard, Newton, Frenet-Serret. Next we come to Euler with his topological invariant 'Euler charcteristic', Gauss & Bonnet with their theory of 2-dimensional surfaces, Riemann with his 'Differential Geometry' and Einstein-Cartan with gravity based on curvature + torsion (ECSK)'. Then the story goes on with 'Homotopy', 'Simplicial Homology', 'Singular Homology', 'Cohomology', 'Hodge theory', 'Lie-Groups', 'Fibre Bundles', 'Gauge theory', 'Characteristic Classes' until a pathintegral-proof of the ASI for the chiral euklidean Dirac-Operator á la Witten et al. The extended 2. edition adds 'Clifford-Algebras', 'Nieh-Yan characteristic class', '3+1 Gravity', 'Palatini-Holst- & Plebański-Gravity' and the 'BF-model'. We owe all this (and much more) to Élie Cartan, Poincaré, Einstein, Hopf, Brower, de Rham, Hodge, Lie, Lorentz, Dirac, Ehresmann, Yang & Mills, Chern, Weil, Pontrjagin, Todd, Hirzebruch, Atiyah & Singer and Witten. Our motto is in the words of Spivak: "All the way with Gauss-Bonnet". The language is German. Due to the didactical intention of this introduction all proofs are worked out in details. So, enjoy yourself! :-