bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Physik am Ende des 18. Jahrhunderts und Lazare Carnot
Authors: Giessmann Ernst‐J. 
Published: May 2007

AbstractEs ist kein Zufall, daß vor 200 Jahren solche Ereignisse zusammentrafen, wie die Herausbildung der klassischen Physik im modernen Sinne, die Einführung des metrischen Systems und die Gründung der Annalen. Die Doppelrevolution, die bürgerliche und industrielle Revolution, bestimmten auch die Entwicklung der Naturwissenschaften nachhaltig. L. Carnot wirkte für diesen Umbruch.
Friedrich Möglich ‐ sein Beitrag zum Aufbau der Physik in der DDR. Friedrich Möglich ‐ langjähriger Mitherausgeber und Chefredakteur der „Annalen der Physik”︁
Authors: Rompe Robert 
Published: May 2007

AbstractFriedrich Möglich, ein Schüler von Max von Laue und Erwin Schrödinger, übernahm 1947 die Chefredaktion der „Annalen der Physik”︁.
Moderne Entwicklung der NMR (Nuclear Magnetic Resonance)
Authors: Lösche Artur 
Published: May 2007

AbstractDie NMR‐Spektroskopie kann sich altersmäßig nicht mit den Annalen der Physik messen; sie entstand vor rd. 45 Jahren. Ihre Entwicklung wurde und wird durch unterschiedliche Erfahrungen, Erkenntnisse und Techniken bestimmt; sie zeigt, daß auch heute noch die Fortschritte von Spezialgebieten Impulse aus weiten Bereichen der Physik, der Naturwissenschaften und Technik beziehen. In entsprechender Weise machen Spezialzeitschriften das Erscheinen allgemeiner Fachzeitschriften nicht überflüssig. Diese Zusammenhänge sollen an einigen Beispielen der NMR demonstriert werden.
Study of Electromagnetic Properties of Nuclei and Structural Changes at High Spins in Yb Isotopes
Authors: Mansour N. , Awwad Z. , Bayomy T. , Diab A. 
Published: May 2007

AbstractHigh‐spin states of nuclei, populated by heavy‐ion reactions, are of interest because they reveal changes in the structur of nuclei under stress. In the first part much of our insight into the structure of high‐spin states is being provided by electromagnetic strength functions. In the second part, the level scheme of 158Yb has been extended to I = 37 by using the 98Mo (64Ni, 4n) reaction, and the backbending phenomena in Yb isotopes has been discussed.
Baryon‐Baryon Interaction in the Strangeness −1 and −2 Sector in the Non‐relativistic Quark Cluster Model
Authors: Faessler Amand , Straub Ulrich 
Published: May 2007

AbstractThe non‐relativistic quark cluster model is used to describe the baryon‐baryon interaction in the strangeness −1 sector (ΛN, ΣN system) and in the strangeness −2 sector (H‐dibaryon). The calculation in the strangeness −1 sector shows first of all that the cluster model can be successfully extended from the nucleon‐nucleon interaction to the hyperon‐nucleon interaction. In addition this calculation demonstrates at the same time the quality of the quark cluster model. The potentials consist of the one‐gluon exchange and the pseudoscalar‐meson exchange (both containing central and tensor parts), a phenomenological confinement plus an additional central phenomenological σ‐meson exchange. Adjusting one free parameter a very good fit of the experimental hyperon‐nucleon cross sections is achieved. In the second step this model is extended to the strangeness −2 sector. Here the H‐dibaryon is calculated, which is the most promising candidate for a bound six‐quark state. The H‐dibaryon is a linear combination of the three states Λ Λ, ΘN and ΣΣ. Performing the full coupled channel scattering and bound state calculation we predict the H‐dibaryon to be bound. We find a binding energy of (−15 ± 5) MeV below the ΛΛ threshold, i.e. the mass of the H‐dibaryon is predicted to be around 2216 MeV.
Ein Beitrag zur frühen Diskussion um den Äther und die Einsteinsche Relativitätstheorie
Authors: Schröder W. 
Published: May 2007

Abstract„Wozu nun Geschichte der Physik…︁ Wir hoffen also, die Physik selbst besser zu verstehen, wenn wir ihre Entwicklung kennen. Wir erhoffen auch ein schärferes Augenmaß für ihre gegenwärtig ungelösten Probleme zu erlangen.”︁ (Friedrich Hund 1978)Die Ätherfrage bildete mit dem Aufkommen der Einsteinschen Resultate ein zentrales Problem für die Physiker (u. a. Lorentz, Drude, Minkowski, Wiechert u.a.). Am Beispiel einer bislang unveröffentlichten Arbeit von Wiechert wird dieses Problem, das zugleich auch für die Rezeption der Einsteinschen Studien wichtig ist, behandelt. Es zeigt sich, daß die „Ablösung”︁ der Äthervorstellung einen geraumen Zeitraum beanspruchte und wesentlich mehr darstellte, als nur den Bruch mit den „klassischen Vorstellungen”︁.
Why are Most Nuclei Prolate?
Authors: Zickendraht W. 
Published: May 2007

AbstractAfter seperating collective and single particle coordinates the Schrödinger equation of a system of A nucleons has a form related to the conventional unified model, but in contrast to that there are no redundant variables. Working with the transformed Schrödinger equation, using the strong coupling approximation and requiring constant nuclear volume one finds that two thirds of the nuclei should be prolate and that their largest deformations should be about 1.5 times larger than those for oblate nuclei.
Rate Equations for Light‐Induced Drift
Authors: Haverkort J. E. M. , Woerdman J. P. 
Published: May 2007

AbstractWe present a numerical model aiming at a realistic description of light‐induced drift of multilevel atoms in a buffer gas, specializing to case of Na atoms in a noble gas. The model is based on the optical Bloch equations in which the effect of collisions is incorporated by introducing Keilson‐Storer collision kernels. By marking a connection with kinetic theory all adjustable parameters may be fixed.
ESR and Optical Absorption of Ag in a N2 Matrix
Authors: Görlach E. , Rosendahl R. , Klein U. , Stöckmann H.‐J. , Schrimpf A. 
Published: May 2007

AbstractAg atoms isolated in N2 matrices were studied by simultaneous observation of optical absorption and electron spin resonance (ESR). In matrices with low Ag/N2 ratios two ESR signals were observed, both of which could be correlated to the well known absorption triplet corresponding to the 5s 2S → 5p 2P resonance transition. One of the two ESR signals disappeared irreversably upon annealing up to 20 K. The stable species is attributed to Ag atoms in a nanocrystalline environment whereas the unstable species corresponds to atoms in the non‐crystalline regions between the crystallites. In higher doped matrices a new Ag spectrum showed up, both in the optical absorption and in the ESR. It is assigned to Ag atoms with near‐by complexes, possibly Ag clusters.
Laser Cooling in the Center‐of‐Mass System: A Proposal for the Creation of a Monoenergetic Atomic Beam
Authors: Haslwanter Th. , Mlynek J. 
Published: May 2007

AbstractThe longitudinal velocity compression of a supersonic atomic beam (mean velocity v0; initial velocity spread Δvi) by light pressure from two counterpropagating laser fields is studied. A Monte‐Carlo simulation shows that the final velocity ratio v0/Δvf can exceed 1000 in a simple and compact experimental setup.
Application of the Multi‐Doorway Continuum Shell Model to the Magnetic Dipole Strength Distribution in 58Ni
Authors: Spangenberger H. , Beck F. , Richter A. 
Published: May 2007

AbstractThe usual continuum shell model is extended so as to include a statistical treatment of multi‐doorway processes. The total configuration space of the nuclear reaction problem is subdivided into the primary doorway states which are coupled by the initial excitation to the nuclear ground state and the secondary doorway states which represent the complicated nature of multi‐step reactions. The latter are evaluated within the exciton model which gives the coupling widths between the various finestructure subspaces. This coupling is determined by a statistical factor related to the exciton model and a dynamical factor given by the interaction matrix elements of the interacting excitons. The whole structure defines the multi‐doorway continuum shell model. In this work it is applied to the highly fragmented magnetic dipole strength in 58Ni observed in high resolution electron scattering.
Messen, Kalibrieren, Eichen in der Radiologie: Prinzipien und Praxis
Authors: Wagner Siegfried R. 
Published: May 2007

AbstractNach einleitender Erläuterung der unterschiedlichen Meßbedingungen in der Strahlentherapie und im Strahlenschutz werden die metrologischen Probleme am Beispiel der Größenkategorie Äquivalentdosis diskutiert. Als spezielle Größen werden „effektive Äquivalentdosis”︁ und „Umgebungs‐Äquivalentdosis”︁ eingeführt. Es wird gezeigt, wie „richtiges”︁ Messen durch ein konsistentes System von Bauartanforderungen an Meßgeräte, durch Kalibrieren und durch Eichen gewährleistet werden kann. Die Bedeutung von Meßunsicherheiten und Fehlergrenzen wird erläutert und ihre Auswirkung auf die Interpretation von Meßergebnissen behandelt.
Study of Radiative Deexcitation Processes in the Muonic Helium(4) Ion at 14 and 40 Atmospheres
Authors: Rosenkranz J. , Arnold K.‐P. , Gladisch M. , Hofmann J. , Mundinger H.‐J. , Orth H. , zu Putlitz G. , Stickel M. , Schäfer W. , Schwarz W. , Hughes V. W. 
Published: May 2007

AbstractTo search for a long living 2S1/2 state in the muonic helium ion at helium gas pressures of 14 and 40 atmospheres, radiative muon transitions were registered in a time resolved mode using sodium iodide crystals. Special care was taken to avoid gas impurities which are known to reduce the 2s lifetime significantly. In addition to the prompt photons of the K‐series, a delayed component was detected. The lifetime and yield of this component agree with theoretical values for ions not perturbed by the surrounding medium. However, test measurements carried out with other target gases clearly demonstrate that practically all of the delayed events observed in pure helium are not caused by the radiative decay of a longliving 2s state.
Theoretical Experiments on Multiphoton‐Assisted Electron‐Atom Scattering
Authors: Grobe R. , Moore C. I. , Su Q. , Greenwood W. G. , Eberly J. H. 
Published: May 2007

AbstractWe present the results of numerical experiments in which electron‐atom scattering occurs in the presence of a strong laser field. We compare our results for both forward and backward scattering with previous theoretical work in both strong‐field and weak‐field regimes.
Flugzeit‐Massenspektrometer mit gitterfreien Ionenspiegeln und Elektronenstoß‐Ionenquellen
Authors: Wollnik H. , Grüner U. , Li G. 
Published: May 2007

AbstractEs werden Flugzeit‐Massenspektrometer mit Massenauflösungsvermögen von m/Δm ≈︁ 103 bis ≈︁ 104 beschrieben, in denen Ionen untersucht werden können, die durch Elektronenstoß gebildet worden sind. Wichtige Teile solch eines Massenspektrometers sind eine Ionenquelle, in der die zwischen den Extraktionspulsen gebildeten Ionen effektiv gespeichert werden, sowie ein gitterfreier Ionenspiegel, der die Ionenflugzeit unabhängig von Energieabweichungen macht und der gute laterale Fokussierungseigenschaften besitzt.
Study of the Effect of Iron Loaded with B4C on the Total Gamma Doses Emitted from Laminated Shield
Authors: Makarious A. S. , Maayouf R. M. A. , Megahid R. M. , El‐Sayed Abdo A. 
Published: May 2007

AbstractIn this work a comparative study of the effect of iron loaded with B4C on the suppression of gamma‐rays in a laminated shield of water, iron and either ordinary or limenite concrete have been carried out. It was found that B4C loaded with iron has a remarkable effect on the suppression of gamma doses all through the laminated shield. The suppression is more pronounced in the concrete layer. It was also found that the decrease of gamma doses in ilmenite concrete is ∼ 1.7 that one for ordinary concrete.
Über mögliche Grenzen einer Gravitationstheorie
Authors: de Zela Francisco 
Published: May 2007

AbstractDiese Arbeit versucht, eine Antwort auf die Frage zu geben, wieso Gravitationsphänomene gerade durch eine Theorie beschrieben werden, in welcher eine Riemannsche Metrik vorkommt, die den Einsteinschen Gleichungen genügen muß. Als Antwort wird nach einer Verbindungslinie gesucht, welche vom Maupertuisschen Prinzip ausgehend in den Einsteinschen Gleichungen endet. Der metrische Tensor wird zunächst rein formal eingeführt, als richtungsabhängige Finslersche Metrik, und dann, als Folge der Invarianz gegenüber punktalen Lorentz‐Drehungen, auf den Riemannschen Fall zurückgeführt.Die Konstruktion legt den Schluß nahe, daß der Gravitationsbegriff bei atomaren Dimensionen sinnlos werden kann, wegen der zentralen Rolle, welche die Teilchenbewegung im Ganzen spielt.
White and Grey Holes in Higher‐Dimensional Representation of Extended Space‐Time Manifolds of General Relativity
Authors: Trofimenko A. P. , Gurin V. S. 
Published: May 2007

AbstractThe extended Kerr‐Newman manifold is analysed including subluminal and superluminal space‐time regions. For the united description of different regions separated by horizons complex space‐time is introduced. In such manifold various anticollapsing objects (white and grey holes) are considered.
Polarization Bistability due to Optical Feedback
Authors: Belkner P. , Schütte F.‐J. 
Published: May 2007

AbstractAn optical ring cavity filled with an isotropic medium is driven externally. Two waves of the same frequency but of different polarization are coupled nonlinearly by a Kerr type interaction. It is theoretically shown that the symmetry of the linear polarized input field may be broken spontaneously. Beyond an intensity threshold the output field gets elliptic polarization. Right and left elliptic states are stable. The system shows polarization bistability.
Radiative Corrections to Non‐Abelian Gauge Theory in Homogeneous Self‐Dual Backgrounds
Authors: Eberlein C. , Kaiser H. J. , Wieczorek E. 
Published: May 2007

AbstractWe study the Euclidean version of non‐Abelian gauge theories in homogeneous background fields with due regard of negative and zero modes of the gauge field kernel. For general gauge group and general background but without external currents we prove a relation between the propagators belonging to different gauge fixings. Specializing to a self‐dual homogeneous background we derive nonperturbatively the propagators. Next we calculate the matter field contribution to the renormalized polarization tensor using a modified dimensional regularization scheme. We prove the validity of a modified Ward identity.
Relaxation of Translational Energy in Binary Mixtures of Dilute Gases Composed of Hard Spheres
Authors: Cukrowski A. S. , Fritzsche S. 
Published: May 2007

AbstractAnalytical expressions for the relaxation time τ necessary for the equilibration of translational energies of components in binary mixtures of dilute gases composed of hard spheres are derived. An expression for the collision number Z describing the mean number of collisions of one particle during the relaxation time is also given. The derivation has been performed for the very beginning of the relaxation and we choose the initial translational energy of the sort which is in excess to be equal to zero. Computer results obtained by a direct simulation method of solution of the Boltzmann equation do not only confirm these results but also show them to be valid for a relatively long part of the equilibration.
Das singuläre Modell der über der Oberfläche von Kryodielektrikas lokalisierten Elektronenzustände
Authors: Dorofeyev O. F. , Lysov B. A. , Pavlova O. S. , Ternov I. M. 
Published: May 2007

AbstractWir schlagen ein neues Modell zur Beschreibung der in der Nähe der Oberfläche von Kryodielektrika lokalisierten Elektronenzustände vor. Dabei wird die Nichteindeutigkeit der selbstadjungierten Erweiterung des Hamilton‐Operators der elektrostatischen Bildkräfte an der flachen Grenze Dielektrikum‐Vakuum benutzt. Im Unterschied zum bekannten Modell von Grimes enthält das von uns vorgeschlagene Modell nur einen einzigen phänomenologischen Parameter, den Vermischungswinkel. Es zeigt sich, daß die entsprechende Wahl des Vermischungswinkels es erlaubt, die spektroskopischen Daten von elektrischen Dipolübergängen zwischen den Einteilchen‐Elektronenzuständen, die über der Oberfläche flüssigen 4He und 3He sowie festen Wasserstoffe lokalisiert sind, vollständig zu beschreiben.
Unitary Information Ether and its Possible Applications
Authors: Horodecki R. 
Published: May 2007

AbstractThe idea of information ether as the unitary information field is developed. It rests on the assumption that the notion of information is a fundamental category in the description of reality and that it can be defined independently from the notion of probability itself. It is shown that the information ether provides a deterministic background for the nonlinear wave hypothesis and quantum cybernetics.
On a Lorentz Non‐Invariant Generalization of the Dirac Equation
Authors: Bleyer Ulrich 
Published: May 2007

AbstractA generalized Dirac equation is presented as a model theory of disturbed Lorentz invariance. The physical properties of this model and experimental consequences are discussed. A program is described how such Lorentz noninvariant equations may be produced by cosmological induction of local causal structure.
On the Locality of the No Hair Conjecture and the Measure of the Universe
Authors: Pacher Tibor , Stein‐Schabes Jaime A. 
Published: May 2007

AbstractWe reanalize the recently proposed proof by Jensen and Stein‐Schabes [1] of the No Hair Theorem for inhomogeneous spacetimes, putting a special emphasis on the asymptotic behaviour of the shear and curvature. We conclude that the theorem only holds locally and estimate the minimum size a region should be in order for it to inflate. We discuss in some detail the assumptions used in the theorem. In the last section we speculate about the possible measure of the set of spacetimes that would undergo inflation.
Charged Black Holes and Multidimensional Gravity
Authors: Bronnikov K. A. 
Published: May 2007

AbstractA multidimensional generalization of the Reissner‐Nordström solution of general relativity is obtained for the case of n Ricci‐flat internal spaces. A two‐parameter family of black‐hole solutions for an arbitrary dimensionality D is selected. Nontrivial black holes with D > 4 are shown to exist only with a nonzero electric charge. Observational consequences are discussed, in particular, a violation of Coulomb's law.
Enhanced Nonclassical Third‐Order Spatial Intensity Correlations in Three‐Beam Interferences<
Authors: Richter Th. 
Published: May 2007

AbstractThe joint probability of detecting simultaneously three photons at two and three points in the superposition field of three independent plane waves with the same frequency but random phases is calculated and compared with the results of a classical wave theory. Significant differences occur for sufficiently weak fields. We find that the differences between the quantum mechanical and classical predictions concerning the third order intensity correlation functions are more pronounced in a three‐beam than in a two‐beam interference experiment.
Reduction of Higher Derivative Lagrangians
Authors: Schäfer G. 
Published: May 2007

AbstractPerturbative higher time‐derivative N‐body Lagrangians are treated. By the aid of the redefinition of position variables the higher derivatives are reduced to ordinary derivatives directly on the Lagrangian level. This method clarifies the meaning of using equations and/or constants of motion in higher derivative terms in perturbative Lagrangians.
Relaxation timescales for conformational substates in disordered polymers
Authors: Fernández Ariel 
Published: May 2007

AbstractWe study the kinetics of interconversion of conformational substates in RNA folding by means of a Monte‐Carlo simulation. We establish a scaling law relating the size of the barriers with the length of a random uncorrelated RNA chain. The way the relaxation timescales diverge in the thermodynamic limit coincides with the behavior of nonergodic relaxation timescales for spin glasses.
Local‐moment and itinerant antiferromagnetism in the heavy‐fermion system Ce(Cu1−xNix)2Ge2
Authors: Loidl A. , Krimmel A. , Knorr K. , Sparn G. , Lang M. , Geibel C. , Horn S. , Grauel A. , Steglich F. , Welslau B. , Grewe N. , Nakotte H. , de Boer F. R. , Murani A. P. 
Published: May 2007

AbstractElastic and inelastic neutron‐scattering studies on the system Ce(Cu1−xNix)2Ge2 are reported. These measurements are complemented by measurements of the magnetic susceptibility, high‐field magnetization, heat capacity, thermal expansion, electrical resistivity and thermopower. The results reveal an interesting T‐x phase diagram consisting of two different antiferromagnetic phases for x < 0.2 and 0.2 < x < 0.75, respectively, and a heavy‐Fermi‐liquid regime at higher Ni concentrations. The experimental results are interpreted in terms of an alloying‐induced transition from local‐moment to itinerant heavy‐fermion magnetism. Fingerprints of this latter phase are a strongly reduced ordered moment and a short incommensurate ordering wave vector, in accord with theoretical predictions. A surprisingly good agreement between theory and experiment is found for x > 0.5. Further experimental evidence for different types of antiferromagnetic ordering derives from a line‐shape analysis of the quasielastic neutron‐scattering intensity, from magnetization and thermopower experiments.
Magneto‐electrogyration in cubic Sr(NO3)2, Ba(NO3)2, and Pb(NO3)2
Authors: Kaminsky W. , Fahnenstich A. , Haussühl S. 
Published: May 2007

AbstractThe simultaneous application of electric and magnetic fields on single crystals of Sr‐, Ba‐and Pb‐dinitrate yields an additional term to the pure electrogyration and Faraday effect. The symmetric part of the fourth‐rank tensor of this magneto‐electrogyration has been completely determined with the aid of a high‐resolution computer‐aided polarimetric device. In Pb(NO3)2 a maximum magneto‐electrogyration of about 10% of the magnitude of electrogyration is observed when a magnetic field of 1000 kA/m (1.2 Tesla) is applied along [111]. The effects in Sr(NO3)2 and Ba(NO3)2 are much smaller. Index of refraction, electrogyration, Faraday effect, and the new magneto‐electrogyration obey the same sequence: Pb(NO3)2 > Ba(NO3)2 > Sr(NO3)2.
Eigenvalue problem for arbitrary linear combinations of a boson annihilation and creation operator
Authors: Wünsche Alfred 
Published: May 2007

AbstractThe eigenvalue problem for arbitrary linear combinations kα + μα† of a boson annihilation operator α and a boson creation operator α† is solved. It is shown that these operators possess nondegenerate eigenstates to arbitrary complex eigenvalues. The expansion of these eigenstates into the basic set of number states | n >, (n = 0, 1, 2, …), is found. The eigenstates are normalizable and are therefore states of a Hilbert space for | ζ | < 1 with ζ  μ/k and represent in this case squeezed coherent states of minimal uncertainty product. They can be considered as states of a rigged Hilbert space for | ζ | ⩾ 1. A completeness relation for these states is derived that generalizes the completeness relation for the coherent states | α 〉. Furthermore, it is shown that there exists a dual orthogonality in the entire set of these states and a connected dual completeness of the eigenstates on widely arbitrary paths over the complex plane of eigenvalues. This duality goes over into a selfduality of the eigenstates of the hermitian operators kα + k* α† to real eigenvalues. The usually as nonexistent considered eigenstates of the boson creation operator α† are obtained by a limiting procedure. They belong to the most singular case among the considered general class of eigenstates with ζ  μ/k as a parameter.
Resonant Raman scattering from a spin density wave insulator
Authors: Kampf A. P. , Brenig W. 
Published: May 2007

AbstractWe present a calculation of the electronic Raman cross section for the scattering of light across the energy gap of an antiferromagnetic insulator. The antiferromagnet is described in terms of a spin density wave state for the Hubbard model at half filling. We consider the coupling of the light to the current density and the inverse mass tensor on equal footing. A comparison of the cross section for different scattering geometries is given.