bluuebunny/crossref_metadata_2025_split huggingface dataset:
Begründung einer Integralgleichung für die Bewegung eines strahlenden Elektrons II: Nicht‐lineare Näherung
Authors: Petzold J. 
Published: May 2007

AbstractDie Strahlungsreaktion eines ausgedehnten, klassischen Teilchens wird in 3. Näherung analysiert. Das führt zu einer relativistischen Bewegungsgleichung, die eine ähnliche Form wie die in Teil I angegebene besitzt. Es bestehen jedoch Unterschiede im Zusammenhang zwischen der Ladungsverteilung und dem Kern der Integro‐Differentialgleichung.
Lifetimes of Excited Alkalilike Atoms Colliding by Van der Waals Forces with Inert Gas Atoms in the Groundstate
Authors: Siefart E. 
Published: May 2007

AbstractThe influence of Van der Waals forces on the lifetime of coherently excited hyperfine‐states |FimFi〉 and |FimFi〉 of alkalilike atoms i by collissions with inert gas atoms j in the groundstate |FjmFi〉 has been examined. To do this the timedependent Schrödinger equation has been solved on taking into account a static magnetic field, a radiation field and a Van der Waals force. Introducing an impact parameter model for the colliding atoms with small scattering angles which form a quasimolecule |μ〉 = |FimFiFjmFi 〉 an expression for the cross section σμμ has been derived which determines the halfwidth Γ μμ of the coherently excited states. On making use of the irreducible tensor representation the calculation of the cross‐section has been reduced to the calculation of multipole transitions. The result has been applied e. g. to the coherently excited 3d104p2P3/2‐states of Cu I colliding by dipole‐dipole interaction with inert gas atoms He I, and Ar I in the ground state. The values agree well with data which have been derived from zero‐level‐crossing experiments.
Damping of Quark‐Hadron Form Factors and Diffraction Scattering
Authors: Frenzel M. , Kallies W. , Lewin K. 
Published: May 2007

AbstractDamping of hadron bound state wave functions in relative quark momentum as necessary to describe the beginning of power scaling at momentum transfer t ⋍2–3 GEV2 is obtained approximately from a corresponding behaviour of four‐and six‐quark Green's functions in which is required by diffraction scattering.
On Direct and Pair Correlation Functions of the Crystalline State and the Crystal‐Liquid Phase Boundary
Authors: Klupsch Th. 
Published: May 2007

AbstractAssuming a non‐constant single particle density suitable to describe a bulk crystalline state and a crystal‐liquid phase boundary, the coupled ORNSTEIN‐ZERNIKE and PERCUS‐YEVICK equation to determine the direct and the pair correlation for a one‐component LENNARD‐JONES system are approximately solved. A hard core reference system is defined within a perturbation treatment; the corrections resulting from the true interaction can be calculated straighforward if the hard core solutions are known. The approximation involves a new class of exact solutions for the limiting case of strongly localized single particle densities.
On the Present Status of the Problem of Charge Dependence and Charge Asymmetry of the Nucleon‐Nucleon Force
Authors: Guratzsch H. , Kühn B. , Hahn K. 
Published: May 2007

AbstractThe charge dependence of the nucleon‐nucleon force can be derived from the low‐energy scattering parameters. The p‐p and n‐p parameters were measured in direct scattering experiments. The n‐n parameters ann = (‐16.70 ± 0.38) fm and rnn = (2.78 ± 0.13) fm have been determined from few particle reactions. The difference of the scattering lengths (ann ‐ ann) ≈ 7 fm demonstrates the violation of the charge independence. Information on the charge symmetry is still doubtful due to the inaccuracy of the charge correction for the p‐p parameters. Whereas the n‐n and the charge corrected p‐p parameters known at present yield a weaker n‐n force than the p‐p force, the opposite result follows from the binding energy difference for 3He and 3H and the meson theory of the nuclear forces.
On Treder‐Type Tetrad Theories of Gravitation I. Equivalence Principle and Invariance Properties
Authors: Bleyer U. 
Published: May 2007

AbstractThe Principle of relativity and the equivalence principle are the most important foundation of any theory of gravitation. We can formulate these principles by the help of the LORENTZ and the EINSTEIN groups. If we start with an action functional, the demand of invariance of this action with respect to these groups makes possible to get detailed conclusions about the general structure of theories of gravitation. EINSTEIN'S idea, to interpret gravitation as deformation of the local inertial systems of the special theory of relativity, leads to bi‐tetrad theories, which we call TREDER‐type tetrad theories. In this theories a sufficient number of gauge parameters is introduced in order to ensure the invariance of the action functional without limitations for the field variables.
Gravitational Field Equations with Cross‐terms and Static Equilibrium Configurations
Authors: Müller Volker 
Published: May 2007

AbstractConsidering Einstein's equations modified by additional cross‐terms we calculate spherically symmetric equilibrium configurations of cold degenerated matter. The effects of such modifications proposed by TREDER [5] to describe properties of a unitary field theory depend on the sign of the coupling and on some critical energy density. If this density is higher than the nuclear density, we do not find significantly larger equilibrium masses than in general relativity. However the modifications of the gravitional dynamics resulting from the cross‐terms become physically significant.
Auto‐Ionizing States in MgI
Authors: El‐Sherbini Th. M. , Rahman A. A. 
Published: May 2007

AbstractHartree‐Fock calculations have been performed for the auto‐ionizing levels of the 3pns, 3pnp, 4snp (n = 4 to 7) and 3pnd (n = 3 to 7) series in MgI. The calculated energies of the auto‐ionizing states are compared with the available results from photo‐absorption measurements and ejected‐electron experiments.
Thermodynamic Functions of Nonideal Hydrogen Plasmas
Authors: Ebeling W. , Richert W. 
Published: May 2007

AbstractThe contribution of the charged components to the thermodynamic functions is analysed on the basis of the present theoretical knowledge. In the high‐temperature low‐density limit the Debye formula with quantum corrections is used. In the low‐temperature high‐density limit the Gellman‐Brueckner formula for the electrons and a lattice‐energy formula for the protons is used. Padée‐approximants are constructed which contain these limiting situations as special cases and describe also the region between them in certain aproximation.
Elastic Scattering of Polarized Neutrons by 3He at Low Energy
Authors: Drigo L. , Tornielli G. , Zannoni G. 
Published: May 2007

AbstractElastic scattering by 3He for 1.67, 2.43, 3.0, 3.4 and 7.8 MeV neutron beams of known polarization was measured at seven angles from 25° to 155° using a high pressure gas scintillation counter. The geometrical and multiple scattering effects were accounted for by the Monte Carlo technique. The corrected results were compared with previous experimental data and with the existing predictions based on microscopic calculations and phenomenological analyses.
Quantenphysikalischer Ursprung der Eichidee
Authors: Bopp Fritz 
Published: May 2007

AbstractBetrachtet man die Quantenphysik als Zusammenspiel von elementaren Erzeugungs‐ und Vernichtungsprozessen, so sind Eichfeldtheorien nicht nur möglich, sondern auch notwendig. Die komplex konjugierten Phasenfaktoren jedes Paares von Erzeugungs‐ und Vernichtungsoperatoren sind nämlich. willkürlich wählbar. Darum müssen Quantenfeldtheorien vollständig phaseninvariant sein. Das ist ohne Eichfelder nicht möglich.Dem steht im Wege, daß die Diracgleichung nicht einmal global vollständig phaseninvariant ist. Multipliziert man nämlich die Komponenten der Erzeugungs‐ und Vernichtungsoperatoren mit verschiedenen konstanten Phasenfaktoren, so ändern sich die Diracmatrizen. Nur die Diracschen Vertauschungsrelationen bleiben invariant. Doch sind die Diracgleichungen vor und nach der Transformation physikalisch äquivalent. Man kann also sagen: Systeme freier Fermionen werden erst durch die Klasse aller äquivalenten Diracgleichungen vollständig dargestellt.Da die Diracschen Vertauschungsrelationen gegen beliebige unitäre Transformationen invariant sind, ist die Klasse äquivalenter Diracgleichungen U 4‐invariant. Unitäre Diagonalmatrizen liefern willkürliche Phasentransformationen der Spinorkomponenten, so daß die zur Gruppe U 4 gehörigen Eichfelder zu eine allgemein phaseninvarianten Theorie führen. Sie ist so eng mit der QED verwandt, daß wir von einer „erweiterten Quantenelektrodynamik”︁, EQE, sprechen können.Hier soll nur gezeigt werden, daß die EQE existiert. Dabei liefert die invariante Untergruppe U 1 von U 4 die QED. Die komplementäre Untergruppe SU 4 umschließt vier Untergruppen SU 3, drei Untergruppen O 4 und sechs Untergruppen SU 2. Letztere könnten den drei Paaren von Quarks und den drei Paaren von Leptonen entsprechen, wobei sich die Quarkpaare zu einer Gruppe SU 3 zusammenschließen. Mehr als zweimal drei Paare von elementaren Fermionen gibt es in der EQE nicht. Sie wird zwar kaum mit der vereinigten QED und QCD identisch sein. Doch sollte sie Vergleichbares leisten.Tatsächlich folgt die EQE aus einer bereits vorhandenen, wenn auch wenig beachteten Symmetrie der empirisch bewährten Diractheorie. Sie ist darum einerseits im Sinne der Newtonschen Definition des Begriffs hypothesenfrei. Andererseits kann sie wegen der erforderlichen Phaseninvarianz kaum wegdiskutiert werden, was immer sie am Ende bedeuten mag. Die Erfindung neuer Symmetrien und die Anerkennung einer Unzahl unabhängiger Spinorkomponenten ist jedenfalls zunächst entbehrlich.
Gibt es Plancksche Sekunden des Kosmos?
Authors: Treder H.‐J. 
Published: May 2007

AbstractAuf Grund der Planckschen Grenzen für die Energien der Quanten sind die minimalen Dimensionen des Kosmos nicht durch die Planckschen Einheiten, sondern durch die Heisenbergschen Abmessungen gegeben.
Über Volumendefekte und Krümmung in Riemannschen Mannigfaltigkeiten mit Anwendungen in der Relativitätstheorie
Authors: Gackstatter Fritz , Gackstatter Barbara 
Published: May 2007

AbstractJ. Bertrand und V. Puiseux haben gezeigt, wie man durch interne geodätische Messungen die Gaußsche Krümmung K einer Fläche bestimmen kann: Man konstruiert zu einem Punkt P den geodätischen Abstandskreis vom Radius r, mißt den Umfang L, dann kann K aus dem Defekt 2πr ‐ L berechnet werden. Ähnliche Relationen gibt es bei n‐dimensionalen Riemannschen Mannigfaltigkeiten mit positiv definiert Metrik, H. Vermeil hat gezeigt, daß man aus gewissen Volumendefekten die skalare Krümmung R bestimmen kann. In der vorliegenden Arbeit werden 4‐dimensionale Riemannsche Mannigfaltigkeiten mit Signatur (− + + +) studiert. Hier gibt es Zusammenhänge zwischen Volumendefekten, skalarer Krümmung R und physikalischen Größen der allgemeinen Relativitätstheorie.
Weshalb ist der Kosmos so groß?
Authors: Treder Hans‐Jürgen 
Published: May 2007

AbstractAusgehend von Eddingtons dimensionsloser Zahl ω ≈ 1040 und den Planckschen Fundamentalgrößen diskutieren wir eine Formel für die Massen M(n) im Universum. Für n = 0, 1, 2, 3, 4 ergeben sich Massenwerte, die im Kosmos realisiert sind. Die Formel wird auch für die negativen Zahlen n = −1, −2 diskutiert.
The Unified SU(2) × U(1) × U′(1)‐models of Electroweak Interaction of Leptons
Authors: Guliyev N. A. , Jafarov I. G. , Khalil‐Zade F. T. , Mehtiyev B. I. , Yakhyayev R. Sh. 
Published: May 2007

AbstractThe possible variants of the unified models of electroweak interaction of leptons in the framework of the broken gauge SU(2) × U(1) × U′(1)‐symmetry are constructed. In the first part analysis of SU(2) × U(1) × U′(1)‐symmetry breaking by the different combinations of two types of Goldstone‐Higgs fields: isodoublet φ and isosinglet Φ complex isovector ξ and Φ φ and ξ is considered. The second part is devoted to the construction of the feasible leptonic models in which the masses of the introduced leptons can be generated by symmetry breaking due to the fields considered in the first part. In the third part acceptability of these models from the point of view of available experimental data of cross‐sections of muonic neutrino and antineutrino scattering on electron has been investigated.
Optical Pumping of Metastable Argon Ions in a Hollow Cathode Discharge
Authors: Elbel M. , Quad R. , Simon M. 
Published: May 2007

AbstractMetastable Argon ions which are produced by electron impact in a gas discharge, are optically pumped by irradiation with circularly polarized laser light in a magnetic field parallel to the laser beam. The pumping effect was made evident by monitoring the fluorescent light emitted after excitation. In particular, the polarization of the pumping light was alternately changed between circular and linear and synchronous changes of the fluorescent intensity were recorded. The obtained signal changed its sign, when the magnetic field was turned from parallel to perpendicular to the laser beam. From the intercept of the signal with the axis of the magnetic field the mean life of the metastable level could be inferred. It was shifted with rising pressure toward shorter values thus giving evidence of the dominating part played by collisions in the relaxation process. From the ratio of the signal and the total fluorescence the achieved orientation could be determined. It tells the ratio of the rates of pumping and relaxation. The relaxation time was found between 15 and 7 ns for Argon pressures ranging from 0.2 to 0.6 torr. The pumping time was two orders of magnitude larger than that.
Neutron Interference: Influence of the Mirror on the Spin
Authors: Audretsch J. , Lämmerzahl C. 
Published: May 2007

AbstractAdvanced neutron interferometry includes the spinor properties of the neutrons. This makes it necessary to consider the influence of the mirrors on the spinor propagation. It is shown how the effect of an arbitrary mirror can be uniquely decomposed into a known kinematical part which is necessarily present, and a dynamical part which goes back to an interaction the neutron experiences in its rest‐space. For any particular realization of a mirror this dynamical part can be determined experimentally. An argument is given as to why it vanishes for the usual perfect‐crystal interferometer. The first relativistic approximations of the spinor reflection formula are discussed.
Anharmonic Effects in Radiationless Vibronic Energy Relaxation
Authors: Madzgalla I. , Süsse K.‐E. , Welsch D.‐G. 
Published: May 2007

AbstractA general expression for the vibronic energy relaxation rate, which includes the effect of coupling to external dissipative systems in a consistent way, is derived. In order to study the effect of anharmonic accepting modes of vibration on the internal conversion this rate expression is specified to the case of Morse‐type anharmonic displaced and distorted potential energy surfaces. Particularly, in the case of molecules such as bencene, the vibronic coupling of which is weak, the effect of strong enhancement of the decay rate due to anharmonicities as discussed in the literature could not been found.
On the Origin of Spacetime Distribution of Quasars I. The Simplest Model
Authors: Popić R. V. 
Published: May 2007

AbstractThe assumption that galaxies and massive black holes were both created in an early cosmological era, and allowing that quasars had to be made in their collisions, is tested comparing this theory with the observational data on the distribution of number of quasars N with respect to the cosmological redshift Z. The theoretical model is sensitive to Zc‐value of redshift at creational time, Zm‐value(s) of redshift at peak(s) of the distribution N(Z) and λ ‐ the decay constant of quasars. The peaks of distribution N(Z) are connected with the peaks in the mass spectrum of galaxies.
Streuung elektromagnetischer Wellen an rauhen Oberflächen mit anisotroper Autokorrelationsfunktion
Authors: Arnz M. , Ponath H.‐E. 
Published: May 2007

AbstractAusgehend von der in [1] gegebenen Streutheorie wird eine allgemeine Theorie der Streuung elektromagnetischer Wellen an einer rauhen Grenzfläche dargelegt. Für den allgemeinen Fall beliebig anisotroper Rauhigkeits‐Autokorrelationsfunktionen (AKF) werden die Spektraldichten aller Erreger‐ und Streulicht‐Polarisationsvarianten ermittelt.Am Spezialfall einer elliptisch‐anisotropen Oberflächenrauhigkeits‐AKF wird die Messung der Lage der AKF‐Hauptachsen geschildert und die Auswertestrategie zur Ermittlung der AKF aus Streuindikatrix‐Messungen angegeben.
Power Asymptotes of Homogeneous Cosmological Models in Einstein's Theory of Gravitation
Authors: Müller V. , Schmidt H.‐J. 
Published: May 2007

AbstractCompleting the discussion of an earlier treatment (Borzeszkowski, Müller (1978)) homogeneous cosmological models of Bianchi‐types II, III, IV, VI and the models of Kantowski‐Sachs‐type are investigated. All asymptotes of the metric which have a power like dependence on the synchronized time near the cosmological singularity are listed. We assume an ideal fluid as source with the flow velocity orthogonal to the slices of homogeneity, and an equation of state π = βϱ 0 ⩽ β ⩽ 1. We utilize the fact that certain Bianchi types can be obtained by a limiting process from other ones. Special anisotropic matter‐dominated solutions have been found besides the well‐known Kasner asymptote.
A Study of the Thermal Hysteresis in AgNO3
Authors: El‐Kabbany F. , Badr Y. , Said G. , Taha S. , Mahrous S. 
Published: May 2007

AbstractThe reversible phase transformation of AgNO3 is studied. Dielectric constant, d.c. resistivity, differential thermal analysis (DTA) and dilatometric measurements show the occurrence of a reversible phase transition II→I at 160°C with heat of transformation H = 0.78 kcal/mol. The thermal hysteresis in this reversible transformation is examined, the magnitude of the temperature hysteresis does not exceed 12°C. An acceptable agreement is observed between the measured values of the transition temperature obtained by three different experimental techniques. The dilatometric analysis shows that this transition is accompanied by thermal shrinkage with relative shrinkage coefficient 8 × 10−4. Thermal analysis are also used to get thermodynamic and kinetic data of this phase transition. The temperature dependence of the dielectric constant and d.c. resistivity for single crystals as well as polycrystalline samples of AgNO3 have clearly located and confirm the phase transitions II→I→II with a strong support to its thermal hysteresis character. The conduction mechanism is found to be activated by energy 0.12 eV for phase I and 0.36 eV for phase II. The observed thermal behaviour of the various measured parameters is attributed to orientational disorder of the nitrate group leading to an order‐disorder phase transition which is reported here for first time in AgNO3.
Demokrit – Planck
Authors: Rompe Robert , Treder Hans‐Jürgen 
Published: May 2007

AbstractEs gibt eine Physik, die an die Konstante h gebunden ist und die mit der Atomistik zusammenhängt. Diese h‐Physik geht eindeutig auf Planck zurück. Aber, aus dieser Physik folgt die Atomistik als Existenz lokalisierter geladener Teilchen unterschiedlichen Massen nicht, vor allem nicht die des Ladungsquants, so daß also Demokrit mehr behauptet hat, als die Quantenphysik zu beantworten kompetent ist.
Spin‐Phonon Interaction beyond the Limit of Spin‐wave Approximation
Authors: Chân Nguyẽñ Ngoc 
Published: May 2007

AbstractBy solving the system of equations for the doubletime Green functions, an expression for the energy spectrum of the spinsystem with the correction due to spin‐phonon interaction is derived. The utilized commutation relations for spin‐operators are more complicated than in the case of the spin‐wave approximation. In the lower temperature region, our expression becomes the one obtained by the spin‐wave approximation. The temperature dependence and the wave‐vector dependence of the broadening of the energy level are evaluated.
Photo‐ and Electro‐Production of a New Light Boson
Authors: Kim D. Y. , Zahir M. S. , Valluri S. R. 
Published: May 2007

AbstractIn GSI experiments, a light pseudoscalar boson of mass Φ 1.6 MeV may have been observed. In order to examine this possibility from a different aspect we propose to study the photo‐and electro‐production process of Φ‐particles. We calculate the cross section of neutral and charged Φ‐particles. We examine the possible role of these production mechanisms in the heavy ion collision processes.
On the Combinatorial Foundations of Regge‐Calculus
Authors: Budach Lothar 
Published: May 2007

AbstractLipschitz‐Killing curvatures of piecewise flat spaces are combinatorial analogues of Lipschitz‐Killing curvatures of Riemannian manifolds. In the following paper rigorous combinatorial representations and proofs of all basic results for Lipschitz‐Killing curvatures not using analytic arguments are given. The principal tools for an elementary representation of Regge calculus can be developed by means of basic properties of dihedral angles.
Radiation damping in closed expanding universes
Authors: Bernui Armando 
Published: May 2007

AbstractThe dynamics of a coupled model (harmonic oscillator‐relativistic scalar field) in Conformal Robertson‐Walker (k = +1) spacetimes is investigated. The exact radiation‐reaction equation of the source‐including the retarded radiation terms due to the closed space geometry – is obtained and analyzed. A suitable family of Lyapunov functions is constructed to show that, if the spacetime expands monotonely, then the source's energy damps. A numerical simulation of this equation for expanding Universes, with and without Future Event Horizon, is performed.
A self‐consistent cluster study of the Emery model
Authors: Gros Claudius , Valentí Roser 
Published: May 2007

AbstractWe calculate Fermi‐surface properties of the Cuprate superconductors within the three band Hubbard model (also called the Emery model) using a cluster expansion for the proper selfenergy. The Fermi‐surface topology is in agreement with angular‐resolved photoemission data for dopings ∼ 20%. We discuss possible violations of the Luttinger sum‐rule for smaller dopings and the role of van‐Hove singularities in the density of states of the Zhang‐Rice singlets. We calculate the shift in the chemical potential upon doping and find quantitative agreement with recent experiments.
A finite size scaling study of the five‐dimensional Ising model
Authors: Rickwardt Ch. , Nielaba P. , Binder K. 
Published: May 2007

AbstractFor systems above the marginal dimension d*, where mean field theory starts to become valid, such as Ising models in d = 5 for which d* = 4, hyperscaling is invalid and hence it was suggested that finite size scaling is not ruled by the correlation length ξ (∝ |t| −1/2 in Landau theory, t being the distance from the critical point) but by a “thermodynamic length” l (∝ |t| −2/d). Early simulation work by Binder et al. using nearest neighbor hypercubic L5 lattices with L ⩽ 7 yielded some evidence for this prediction, but the renormalized coupling constant gL = −3 + 〈M4〉/〈M2〉2 at Tc was gL ≈ −1.0 instead of the prediction of Brézin and Zinn‐Justin, gL(Tc) = −3 + Γ4(1/4)/(8 π2) ≈ −0.812. In the present work, we try to shed light on this controversy obtaining much more precise Monte Carlo data using multihistogram techniques and lattices as large as L = 17 (i.e., 1419857 Ising spins). While our value of Tc agrees nicely with recent high temperature series work (KBTc/J ≈ 8.7774 ± 0.0035), the coupling at Tc {gL(Tc) ≈ −0.958 ± 0.050} confirms the work for small lattices and disagrees with the analytical prediction. Hence the data are better consistent with a shift of the effective critical temperature Tc(L) ‐ Tc(∝) ∝ L−d/2 rather than with L−(d−2) according to the analytical theory. If the latter behavior is correct, it can hence be seen for extremely large systems only.