bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic Polarizability of Ions in Silver Halide Diatomics
Authors: Islam A. K. M. A.
Published: May 2007

The electronic polarizability of ions in silver halide molecules is estimated including the influence of molecular environment. The calculation is also compared with results from other approaches. Finally some spectroscopic properties have been calculated to show the validity of the result of present calculation in the molecular environment.
Do Black Holes Physically Exist?
Authors: González‐Díaz P. F.
Published: May 2007

It is shown that, if the quantum resolution limit in the region of a collapsing body near the horizon is of the order of the Schwarzschild radius, a black hole in vacuum evaporates away instantaneously; hence white and black holes ought to be physically indistinguishable and should not physically exist.
Solutions of the Field Equations and Possible Meaning of the Hermitian Theory of Relativity
Authors: Antoci S.
Published: May 2007

A procedure is stated, which allows to build solutions of the Hermitian theory of relativity from known solutions of the general theory of relativity.

Solutions depending on three co‐ordinates, built from Minkowski metric, as well as Hermitian generalizations of the Weyl‐Levi Civita solution are shown. They suggest that the imaginary part of the fundamental tensor may encompass fields of different physical behaviour, like the electromagnetic field and a field responsible for forces which do not depend on the distance between charges which cannot exist as individuals.

In the generalizations of the Weyl‐Levi Civita solution these fields appear to be decoupled from gravitation in a peculiar way.
P. A. M. Dirac und die Begründung der relativistischen Quantentheorie
Authors: Rompe Robert , Treder Hans‐Jürgen
Published: May 2007

Die Vereinigung von spezieller Relativitätstheorie und Quantentheorie führte zu neuen Vorstellungen über das Vakuum, erklärte den Spin. Eine grundsätzliche Analyse zwischen beiden fundamentalen Theorien zeigt jedoch auch Inkonsistenzen, die nicht innerhalb der Quantenmechanik und Relativitätstheorie gelöst werden können. Sie sind mit der Frage verbunden: „Warum ist der Kosmos so groß und sind die Atome so klein?”︁.
Zur isotropen Turbulenz
Authors: Treder H.‐J.
Published: May 2007

Wir zeigen am Beispiel der isotropen Turbulenz, daß entsprechend der statistischen Theorie von A. N. Komolgoroff sowie von W. Heisenberg und C. F. v. Weizsäcker das mathematische Chaos ein Zustand von hohem Ordnungsgrad ist. Dieses „isotrope Chaos”︁ verschwindet in endlicher Zeit durch die Energie‐Dissipation entsprechend J. R. Mayers Grundversuch.

Einsteins Formel für die stochastischen Bewegungen bestimmt die Zeitdauer, in der das Chaos zu einer statischen Flüssigkeit mit erhöhter Temperatur wird.
Der physikalische Größenbegriff in der Dosimetrie ionisierender Strahlung
Authors: Wagner Siegfried R.
Published: May 2007

Nach kurzer Einführung des physikalischen Größenbegriffs wird seine Entwicklung in der Dosimetrie ionisierender Strahlung an Hand der Einheit „Röntgen”︁ und der Größen „Ionendosis”︁ und „Exposure”︁ dargestellt. Die Bedeutung der „Additivität”︁ für die Meßbarkeit einer Größe wird erläutert und auf die Notwendigkeit hingewiesen, Größen zu spezifizieren. Die Größen „Energiedosis”︁ und „Äquivalentdosis”︁ werden eingeführt, und am Beispiel des „Äquivalentsdosisindex”︁ wird gezeigt, welche Konsequenzen sich für die Praxis des Messens ergeben, wenn eine Größe nicht additiv ist.
Untersuchung Iasererzeugter Plasmen für die Kernfusion
Authors: Basov N. G. , Sklizkov G. V. , Brunner W. , Junge K.
Published: May 2007

Nach einer kurzen Darstellung der Grundlagen der lasergesteuerten Kernfusion werden die theoretischen und experimentellen Ergebnisse vorgestellt und diskutiert, die an der Hochleistungslaseranlage „Delphin 1”︁ gewonnen wurden. Es wird gezeigt, daß Targetstrukturen mit großem Aspektverhältnis A = R/ΔR für die Laserfusion besonders geeignet erscheinen. Untersucht wird der Einfluß der Filamentierung auf das Kompressionsverhalten wie auch die Filamentierung selbst, wobei eine anomale Erzeugung der 2. Harmonischen der einfallenden Laserstrahlung in einen unterkritischen Dichtebereich des Plasmas experimentell nachgewiesen werden konnte.
Thermolumineszenz in Dosimetrie und Geowissenschaften
Authors: Herforth L. , Hübner K. , Stolz W.
Published: May 2007

Es wird ein Überblick über neue Ergebnisse und Erfahrungen bei der Anwendung thermolumineszierender Stoffe in der Dosimetrie und in den Geowissenschaften gegeben.

Schwerpunkte bilden die Bestimmung der Eigenschaften und Wechselwirkungsparameter von Speicherphosphoren sowie ihr Einsatz zur Dosimetrie in Neutronen‐Gamma‐Feldern. Ferner werden einige Möglichkeiten beschrieben, mit Hilfe der Thermolumineszenz das Alter von Sedimenten, vulkanischen Gesteinen und von Steinmeteoriten zu bestimmen sowie Minerale unterschiedlicher Genese zu charakterisieren.
Die Hypothesen der Erdexpansion im Lichte paläogeophysikalischer Ergebnisse
Authors: Lauterbach Robert
Published: May 2007

Die über den Stand von 1971 hinausgehenden neuen Messungen und Modelle zur Erdexpansion werden diskutiert. Dabei kann die damals getroffene Feststellung, daß es ‐ wenn überhaupt ‐ nur eine „langsame”︁ Expansion der Erde gibt, bekräftigt werden.
Main Features of the Electron Kinetics in Collision Dominated Steady‐State rf Plasmas
Authors: Winkler R. , Wilhelm J. , Hess A.
Published: May 2007

This paper reports about systematic investigations of the velocity distribution function and resulting macroscopic quantities of the electrons in a weakly ionized and spatially homogeneous rf plasma in the molecular gas H2 and about a comparison with an analogous study of the rf plasma in the inert gas Ne for a wide field frequency range. These results are obtained by a strict treatment of the non‐stationary electron Boltzmann equation considering the action of the rf field as well as that of elastic and inelastic electron ‐ neutral gas particle collision processes. Furthermore, such investigations could be extended to very high field frequencies for the rf plasma in neon. This provides the basis for a general characterization of the complex temporal behaviour of the isotropic and anisotropic part of the velocity distribution as well as of the several macroscopic quantities in the range from low to very high field frequencies. The ration of the field frequency to two dissipation frequencies which describe the lumped dissipation of energy and impulse due to elastic and all inelastic collision processes and which are only determined by the atomic data of these processes governs the temporal behaviour of the electron kinetics in the rf plasma in any gas.
On the Recursion Operator for the Infinitesimal Symmetries for Autonomous and Non‐autonomous Systems
Authors: Chowdhury A. Roy , Ahmad Siraj
Published: May 2007

Recursion operators for infinitesimal symmetries for a class of nonlinear equations are obtained with the help of the Wronskian formalism of Calogero et al. Our consideration includes both autonomous and nonautonomous systems. The formalism helps us to obtain the symmetry generators and recursion operator for the coupled system of Boomeson equation which is otherwise quite difficult to obtain.
Infinitesimal Bäcklund Transformation and Conservation Laws for Non‐autonomous Systems
Authors: Mahato G. , Chowdhury A. Roy
Published: May 2007

We have observed that it is possible to extend the concept of the infinitesimal Bäcklund transformation of Steudel to the case of non‐autonomous systems. We have discussed the situation with the cylindrical KdV as example. The interesting point to note is that though the B.T. for Ckdv does not possess the usual property of generating one soliton in a single operation, yet it generates an infinite number of symmetries, which corroborates with those obtained through the expansion of the resolvant of the linear operator associated with the equation.
Bianchi I Cosmological Models for Gravitational Field Equations of Fourth Order
Authors: Müller Volker
Published: May 2007

All power asymptotes of anisotropic Bianchi I cosmological models in gravitation theories with linear and quadratic curvature terms in the Lagrange function are obtained. Depending on the dominance of the fourth order terms or matter plus fourth order terms, faster or slower expansion velocities result near the initial singularity. The latter gives solutions which avoid the horizon problem.
Equations of Motion of Glashow‐Salam‐Weinberg Theory after Spontaneous Symmetry Breaking
Authors: Ebner Dieter W.
Published: May 2007

While for quantum field theoretical calculations it is sufficient to know the Lagrangian, we give here the field equations of the unified gauge‐theory of weak and electromagnetic interactions after spontaneous symmetry breaking. With this approach, inhomogeneous Lorentz conditions for the massive vector bosons Zμ, W are obtained.
The Positron as a Probe for Studying Bulk and Defect Properties in Semiconductors
Authors: Dlubek G. , Brümmer O.
Published: May 2007

Positron lifetime measurements are used to study various doped and undoped III–V compound semiconductors like GaAs, GaP, InAs and InP. In some as‐grown crystals native vacancies (V, V) or their complexes with dopants (TeAsV, VPZnInV) are detected with maximum concentrations of a few 1018 cm−3. In undoped GaAs neutral As vacancies V are identified, the concentration of which varies locally. The vacancies have their origin in deviations from the stoichiometrie composition of the compound. They disappear at 500°C. At this temperature defects created by irradiation with fast neutrons anneal also out. The relation between the bulk positron lifetime and the density and polarization of valence electrons is analyzed. Further, the potential of the positron annihilation method in identifying and characterizing vacancy‐type defects in semiconductors is discussed.
Physikalische Probleme der Informationsübertragung über Lichtleiter
Authors: Junge Klaus
Published: May 2007

Die herkömmliche rein elektrische Übertragungstechnik über Kabel läßt technische und ökonomische Grenzen erkennen. Die Suche nach neuen Kanälen führte unter anderem in den optischen Bereich, zur Lichtleiter‐Nachrichtenübertragung. Hierfür sind in den letzten Jahren alle Elemente der ersten Generationen in umfangreicher Forschungsarbeit entwickelt worden. Dabei haben moderne Technologien der Mikroelektronik wesentlich zu den erzielten Ergebnissen bei der Herstellung der Lichtleit‐Fasern und der opto‐elektronischen Sende‐ und Empfangsbauelemente beigetragen. Abschließend werden Systemfragen und zukünftige Zielstellungen behandelt.
Inertia‐Free Mechanics and Lorentz Invariance: A Simple Example
Authors: Liebscher D.‐E.
Published: May 2007

We explain by use of an example in point mechanics, how the metric of space‐time may be produced dynamically in a system, for which no time and no metric is given a priori.
Technikwissenschaft – Erfinden und Entdecken
Authors: Linnemann Gerhard
Published: May 2007

Umrissen wird das allgemeine Ziel der Technikwissenschaft, konstruktiv zu verwerten und „nicht‐natürlich”︁ Entdeckbares zu „erfinden”︁. Wir befinden uns in einer Umwälzung der Technik im Verlauf der wissenschaftlich‐technischen Revolution, auf dem Wege zu einem neuen Techniktyp. Dieser schafft und nutzt die „künstliche”︁ Intelligenz. Dazu benötigt der in der Technik tätige Mensch spezielle Kenntnisse und Erfahrungen in kreativ‐konstruktiver, ‐gestalterischer und erfinderischer Sicht mit dem Einsatz spezieller Strukturen und Sprachen. Vorschläge zur Arbeitsweise in der Technik werden gegeben.
Die Projektor‐Monte‐Carlo‐Methode, Test eines neuen Verfahrens zur Auswertung von Gittereichfeldtheorien mit Fermionen in der Hamilton‐Formulierung
Authors: Ranft J.
Published: May 2007

Die bisher bekannten Methoden zur Monte‐Carlo‐Simulation von Gittereichfeldtheorien unter Einbeziehung von Fermionen sind sehr aufwendig und ineffektiv. Deshalb ist die Entwicklung und der Test von Monte‐Carlo‐Methoden zur Behandlung von Fermionen von großem Interesse. In der vorliegenden Arbeit wird die Projektor‐Monte‐Carlo‐Methode erstmals auf eine Eichfeldtheorie mit Fermionen, und zwar auf das massive Schwinger‐Modell, d. h. die Quantenelektrodynamik in 1 + 1 Dimensionen, angewandt. Die berechneten Erwartungswerte für die mittlere Energie und für das Fermionenkondensat stimmen mit den Ergebnissen überein, die mit Hilfe der lokalen Hamiltonschen Monte‐Carlo Methode erhalten wurden. Im Gegensatz zur letzteren Methode sollte es jedoch möglich sein, die Projektor‐Monte‐Carlo‐Methode auch auf Eichfeldtheorien in 2 + 1 und 3 + 1 Dimensionen anzuwenden.
Herausforderungen der Kosmosforschung an die Physik
Authors: Stiller H. , Möhlmann D. , Sauer K. , Wiebicke H. , Franck S.
Published: May 2007

Die Kosmosforschung mit ihren physikalischen Experimenten und Beobachtungen direkt im Kosmos gibt für die Physik neuartige Möglichkeiten und damit neue Beiträge zur fundamentalen Frage des Aufbaus der Materie und ihrer Kosmogonie.
Long‐Range Energy Transfer in the Case of Inhomogeneous Spatial Distributions and Indirect Donor‐Donor Interaction
Authors: Schubert Max
Published: May 2007

On the basis of Förster kinetics concerning long‐range energy transfer caused by dipole‐dipole interaction the √t‐deactivation‐law has been derived under the assumption of a homogeneous spatial acceptor distribution (at the end of the forties). Recently, in particular ultra‐short time fluorescence and absorption measurements have shown that on the one hand this law holds in a wide range of physical conditions, but that under other circumstances the experimental results strongly deviate from the √t‐law. In the present paper it is shown that a unified treatment of inhomogeneous distributions and indirect donor‐donor interaction via the acceptors can qualitatively, and in certain cases also quantitatively, remove the discrepancies mentioned. The analysis yields new parameters of dynamical processes.
The Total n‐p Capture Cross Section Measured at En = 25 MeV
Authors: Stiehler Thomas , Mösner Jürgen , Schmidt Günter , Möller Karsten , Neubert Waldemar , Pilz Wolfgang , Kühn Berthold , Hutsch Jochen
Published: May 2007

The total cross section of the capture reaction n + p → d + γ has been measured at En = 25 MeV using a hydrogen gas target containing two multiwire proportional counters and a scintillation counter telescope. The resulting value δtot = (26.6 ± 1.5) μb is in line with the other n‐p capture data in the energy range 14‐73 MeV. The experimental data are compared with theoretical predictions.
Superfluorescence from a System of Atoms in Front of a Mirror
Authors: Steudel H.
Published: May 2007

The initiation of superfluorescence from atoms in front of a plane mirror is investigated both for a 3 × 3 × 3 lattice and for random distributions of N = 40 atoms. Growth rates of dominant radiation modes are computed, and the corresponding radiation patterns are depicted. As a main result some preference of radiation directions parallel to the mirror plane is found.
Gauge Fields in General Parametrical Approach and Their Finslerian Reduction
Authors: Asanov G. S.
Published: May 2007

The covariance principle of general relativity is extended to internal space. Associated gauge fields and tensors are systematically described, whereupon the variational principle is set up for all gauge fields by applying a Palatini‐type method, thereby giving rise to an attractive self‐contained theory in which the Einstein equations are intrinsically synthesized with the generalized Yang‐Mills equations. General gauge‐covariant physical field equations are formulated, showing that currents, external + internal spin tensors, and energy‐momentum tensors can be introduced unambiguously under these general conditions and that the associated conservation laws can be derived. The electromagnetic field finds its gauge‐geometric origin as the gauge field related to internal densities. To be operative with the tensor indices of external and internal types, this general theory must be bimetric. The assumptions that the gauge‐covariant derivatives of metric tensors should vanish simplify the theory to the level of a Finslerian gauge approach.
Topology and Fermionic Condensate
Authors: Kulikov I. , Pronin P.
Published: May 2007

The purpose of this paper is to investigate an influence of a space‐time topology on the formation of fermionic condensate 〈φφ〉 in the model with four‐fermion interaction (φφ)2. The value for the space‐time with topology of R1 × R1 × S1 is found. Moreover a relation of the value of fermionic condensate to a periodic length is studied. In this connection the possibility of a relation of the topologic deposits to structure of hadrons is discussed.
Gravity as a Theory of Defects in a Crystal with Only Second Gradient Elasticity
Authors: Kleinert H.
Published: May 2007

We show that a crystal with defects in which the lowest order elastic constants vanish, behaves like an Einstein universe. The role of the Einstein curvature tensor is played by the conserved defect tensor.
A Rule for the Equilibrium of Forces in the Hermitian Theory of Relativity
Authors: Antoci S.
Published: May 2007

When the behaviour of the singularities, which are used to represent masses, charges or currents in exact solutions to the field equations of the Hermitian theory of relativity, is restricted by a no‐jump rule, conditions are obtained, which determine the relative positions of masses, charges and currents. Due to these conditions the Hermitian theory of relativity appears to provide a unified description of gravitational, colour and electromagnetic forces.
On the Significance of the Internal Quasi‐Lorentz‐Group in Continuum Mechanics
Authors: Leihkauf H.
Published: May 2007

We give a short discussion of usual representation of geometric approach to modern continuum mechanics. As a consequence we propose a formulation of this theorie based on the internal quasi‐Lorentz‐group. The aim of our method is to get an unitary geometrisation of the theory of condensed structures. The result is: For an internal observer the theory of the real solid is the theory of totally geodesic three‐dimensional hypersurfaces in a genuin four‐dimensional non Riemannian “sound space time”.
Electron Kinetics with Attachment and Ionization from Higher Order Solutions of Boltzmann's Equation
Authors: Winkler R. , Braglia G. L. , Wilhelm J.
Published: May 2007

An appropriate approach is presented for solving the Boltzmann equation for electron swarms and nonstationary weakly ionized plasmas in the hydrodynamic stage, including ionization and attachment processes. Using a Legendre‐polynomial expansion of the electron velocity distribution function the resulting eigenvalue problem has been solved at any even truncation‐order. The technique has been used to study velocity distribution, mean collision frequencies, energy transfer rates, nonstationary behaviour and power balance in hydrodynamic stage, of electrons in a model plasma and a plasma of pure SF6.

The calculations have been performed for increasing approximation‐orders, up to the converged solution of the problem.

In particular, the transition from dominant attachment to prevailing ionization when increasing the field strength has been studied.

Finally the establishment of the hydrodynamic stage for a selected case in the model plasma has been investigated by solving the nonstationary, spatially homogeneous Boltzmann equation in twoterm approximation.
Symmetry Breaking Due to Conformally Invariant Scalar Field
Authors: Bleyer U. , Nikolaenko V. M.
Published: May 2007

In the framework of Weyl invariant gravitational field theory including torsion coupled to a scalar field with arbitrary selfinteraction it will be shown that any solution of such a generalized Goldstone model contains the conformally invariant field of a massless scalar particle. Due to this fact it may happen that dynamical symmetry breaking becomes impossible.
Dynamic Field‐Theoretic Approach to a Disordered Model Superconductor
Authors: Kolley E. , Kolley W.
Published: May 2007

On the basis of the attractive Hubbard model with a Gaussian random potential we describe superconductivity in the presence of quenched disorder. A dynamic path‐integral formalism with an 8‐component Keldysh‐Nambu spinor is shown to be convenient for solving the averaging problem without the recourse to the replica trick. The effective action is bosonized in terms of collective variables, namely local Q‐matrices and real space pair fields. Saddle point values are calculated in two simplified limits.
Über das monotone Verhalten gewisser Zustandssummen bei Temperaturausgleich
Authors: Zylka Christian
Published: May 2007

Wir lenken die Aufmerksamkeit darauf, daß die kanonische Zustandsumme Z(β1, β2, …, βn) ≡ Z(β) eines aus n unabhängigen Teilsystemen zusammengesetzten thermodynamischen Systems eine schurkonvexe Funktion ist. Dabei bezeichnet βi die inverse Temperatur des i‐ten Teilsystems. Falls die innere Energie proportional zu β ist ‐ wie etwa bei Spinsystemen in Hochtemperatur‐Näherung ‐ so folgt aus der Schurkonvexität, daß beliebiger Temperaturausgleich zwischen den Teilsystemen stets zu einem Abfallen von Z(β) führt.
On the Lie Symmetry, Conservation Laws and Painlevé Analysis for the Viscous Transonic Equation
Authors: Mukherjee Jayasree , Choudhury A. Roy
Published: May 2007

The properties of the nonlinear viscous transonic equation is analysed in detail. The Painlevé test shows that it is not completely integrable. The equation does not reduce to a member of Painlevé class by any similarity transformation of variables.
A Multilevel Shape Fit Analysis of Neutron Transmission Data
Authors: Naguib K. , Sallam O. H. , Adib M. , Ashry A.
Published: May 2007

A multilevel shape fit analysis of neutron transmission data is presented. A multilevel computer code SHAPE is used to analyse clean transmission data obtained from time‐of‐flight (TOF) measurements. The shape analysis deduces the parameters of the observed resonances in the energy region considered in the measurements. The shape code is based upon a least square fit of a multilevel Briet‐Wigner formula and includes both instrumental resolution and Doppler broadenings. Operating the SHAPE code on a test example of a measured transmission data of 151Eu, 153Eu and natural Eu in the energy range 0.025‐1 eV accquired a good result for the used technique of analysis.
On the Stability of Davey‐Stewartson System ‐ A Dressing Operator Approach
Authors: Sen Shibani , Chowdhury A. Roy
Published: May 2007

The problem of stability associated with perturbations around solitonic excitations of Davey‐Stewartson equation in three dimension is discussed within the framework of dressing operator approach of Zakharov. The system is stable so far as long time behaviour is concerned and unstable for large transverse directions depending upon the sign of the eigenvalue of the linearized problem.
The Odd SO(3,3) Fusions and the Gauge Principle
Authors: Scheurich H.
Published: May 2007

The origin of the gauge principle generating electroweak and gravistrong interactions is shown to lie already in the quaternionic vacuum. The leptonic Dirac equations gauged in respect of the electroweak and the linearized gravistrong field are derived from the SO(3,3) fusion 6 × 4 = 20 + 4 as a part of 4 × 4 × 4. The procedure leading to respective equations including self‐interactions and gauge coupling to the full nonlinear gravistrong field via 20″ × 4 = 60 + 20 as a part of 4 × 4 × 4 × 4 × 4 is outlined.
The Internal Bremsstrahlung Accompanying the Electron Capture Decay of 57Co
Authors: Basha A. M. , El‐Konsol S. , Khalil F.
Published: May 2007

The internal bremsstrahlung (IB) spectrum accompanying the electron capture decay of 57Co have been measured. The measured spectrum was then analyzed into its constituting gamma lines. The proper corrections for the analyzed IB (EC) spectrum have been taken into account. A comparison between the present experimental results of the IB (EC) probability per electron capture and those calculated theoretically according to Martin and Glauber theory have been done. This comparison shows a good agreement throught the investigated range of energy (300 up to 650 keV).
Spin Instability in Nuclear Matter and the Skyrme Interaction
Authors: Mansour H. M. M.
Published: May 2007

In the present work the problem of spin instability of nuclear matter with the Skyrme interaction is analyzed. The three‐body part of the interaction is replaced by using a density dependent potential which is a modification to that given previously by Dabrowski. The symmetry energies are calculated and their rearrangement corrections. Good agreement is obtained with previous calculations.
Neutron Matter Properties Using Skyrme Interaction
Authors: Mansour H. M. M. , Guirguis Jannette W. , Abdelmageed A. I. , Hager S. A.
Published: May 2007

The purpose of the present work is to extend earlier nuclear matter calculations to study the properties of neutron matter. The binding energy per particle, symmetry energy, single particle potential, effective mass, and magnetic susceptibility are calculated using a modified Skyrme interaction. These are calculated as a function of the Fermi momentum kf in the range 0 < kf < 2 fm−1. Two sets of the interaction parameters are obtained by fitting the interaction parameters using the available information on neutron matter. Relativistic corrections to the order 1/c2 are also calculated. The relativistic corrections are very small and they increase as kf is increased.
On the Lie Group of Projective Canonical Transformations
Authors: Flach G. , Kirschbaum D.
Published: May 2007

The transformation properties of the projective canonical group are considered. It is shown that the group acts transitiv on functions defined on configuration space but not transitiv on those defined on the phase space. We prove moreover that this group is the largest finite‐dimensional Lie group of point transformations determined on the configuration space.
Homoclinic Bifurcations in Simple Parametrically Driven Systems
Authors: Bruhn B.
Published: May 2007

In this paper we consider the onset of chaotic particle motion in a perturbed Morse potential and the homoclinic bifurcations in a parametrically driven Lorenz system. The Melnikov‐Keener method is used to derive bifurcation conditions for the parameters of the dynamical systems. For some selected parameter values the theoretical predictions are checked by numerical experiments.
Inflation and the Rotation Problem
Authors: Soleng Harald H.
Published: May 2007

The effect of an inflaton scalar field on cosmic rotation is discussed. It is shown that any physically reasonable inflaton scalar will dilute the cosmic vorticity by a factor of R−3γ when the false vacuum decays into matter. Since vorticity decays during inflation as R3γ‐5, this leads to a total decay by a factor of R5, which is not dependent on the equation of state of the rotating non‐vacuum component of the energy‐momentum tensor.
To Inheritances of the Inflationary Cosmologies
Authors: Molnár P. , Mészáros M.
Published: May 2007

In this paper it is shown that the suppositions of p = u/3 and RT‐const at the same time imply contradiction in Standard Cosmology and Inflationary Models. Because of this the origin of 3K black‐body radiation will take new explaining.
Liénard‐Wiechertsche Potentiale für Multipolquellen
Authors: Mitskiévič N. V.
Published: May 2007

Die Liénard‐Wiechertsche Formel wird auf den Fall einer punktförmiger Multipolquelle verallgemeinert, die zeitabhängige Multipolmomente willkürlicher Stufen hat und einer beliebigen zeitartigen Weltlinie folgt. Die erhaltenen Potentiale sind strenge Lösungen von Gleichungen der Felder willkürlicher ganzzahliger Tensorstufe s. Wenn s ⩾ 2 ist, so wird die Freiheit der Bewegung der Quelle von den Feldgleichungen eingeschränkt.
IR Spectroscopic Study of the Mixed Crystal System (LixAg1‐x)NO3
Authors: El‐Kabbany F. , Taha S. , Tosson M.
Published: May 2007

A spectroscopic analysis of the various IR internal modes for the mixed crystal system of lithium nitrate and silver nitrate were carried out. The study aims mainly to find out the effect of partial replacement of Ag+ ion by Li+ ion on the internal fundamental modes of vibrations of the NO3− group in both of the ordering and disordering states of these two metallic nitrate compounds.

The characteristic variations observed are attributed to differences in polarizability from cationic sphere around the nitrate group. An interesting increase of the maximum frequency observed on passing from pure components to mixtures is attributed to a change in force constant.
On the Epistemological Status of Cosmology Anthropic Principle, Cosmological Numbers, and the Subject of Cosmology
Authors: Wahsner Renate
Published: May 2007

It is shown that cosmology destroys the fundamental on which it lies as a natural‐scientific discipline if it introduces subjectivistic principles as one of them is the so‐called Anthropic Principle that superseds the Copernican turn of sciences. Likewise conceptions are proved as conceptions that contradict the physical cosmology which conceive that the “World harmony” or the physical‐uniform grasping of the world can be derived from numbers or relations of numbers. This is due to the fact that these conceptions liquadate the advantage of physics to get via measurements statements about reality.
Erzwingt die Quantenmechanik eine drastische Änderung unseres Weltbilds? Gedanken und Experimente nach Einstein, Podolsky und Rosen
Authors: Frodl Peter
Published: May 2007

Von den Anfängen der Quantenmechanik bis heute gibt es Versuche, sie als statistische Theorie über Ensembles individueller ‚klassischer’︁ Systeme zu interpretieren. Die Bedingungen, unter denen Theorien verborgener Parameter zu deterministischen Beschreibungen dieser individuellen Systeme als ‚klassisch’︁ angesehen werden können, wurden von Einstein, Podolsky und Rosen 1935 formuliert: 1. Physikalische Systeme sind im Prinzip separierbar. 2. Zu jeder physikalischen Größe, deren Wert man ohne Störung des betrachteten Systems mit Sicherheit voraussagen kann, existiert ein ihr entsprechendes Element der physikalischen Realität.

Zusammen sind sie, wie Bell 1964 gezeigt hat, prinzipiell unverträglich mit der Quantenmechanik und unhaltbar angesichts neuerer Experimente. Diese erweisen einmal mehr die Quantenmechanik als richtige Theorie. Um ihre Ergebnisse zu verstehen, müssen wir entweder die in der klassischen Physik als selbstverständlich angesehene Annahme der Separierbarkeit physikalischer Systeme aufgeben oder unseren Begriff der physikalischen Realität revidieren. Eine Untersuchung des Begriffs der Separabilität und einige Überlegungen zum Problem der Messung von Observablen zeigen, daß eine Änderung des Begriffs der physikalischen Realität unumgänglich ist. Der revidierte Realitätsbegriff sollte mit klassischer Physik und Quantenmechanik verträglich sein, um ein einheitliches Weltbild zu ermöglichen.
Torsion Effects on Neutrino Emission from Dense Collapsing Cores
Authors: de Sabbata Venzo , Sivaram C.
Published: May 2007

We consider the effects of torsion on the emission of neutrinos in a hot dense neutron medium and we explore the consequences for the case of SN1987A neutrinos.
On Causal Disjointness Relations and Causal Nets of Algebras on the Lattice ℤn+1
Authors: Baumgaertel H.
Published: May 2007

This mathematical paper reviews basic facts on nets of algebras on lattices. Causal disjointness relations on the lattice ℤn+1 are represented. The relation is cleared between causal disjointness and orthogonality. A CAR‐algebra is represented.
Minimal Surface Approach to Static Gravitational Fields in General Relativity
Authors: Neugebauer G.
Published: May 2007

The gravitational fields of rigidly rotating perfect fluids are minimal surfaces in a Riemannian Potential space with the metric
equation image
Here the minimal surface approach is applied to static gravitational fields.
Rational Conformal Field Theories and Zamolodchikov‐Fateev Parafermions
Authors: Paunov Roman , Todorov Ivan
Published: May 2007

The charged fields in a local chiral algebra with a (single) U(1)‐current appear, in general, as tensor products of a U(1)‐vertex operator and a (generalized) parafermionic current of the type introduced by Zamolodchikov and Fateev in 1985. Inequalities among parafermionic conformal weights Δv are established without any assumption about Hilbert space positivity. In a theory with a unique zero energy (vacuum) state and a non‐degenerate inner product we deduce the non‐negativity of Δv. It is shown that if the reduced theories coincide with the standard Zx parafermions
equation image
the local extensions of the U(1)‐conformal current algebra are given by the coset space construction SU(2)x X U(1)/U(1) with appropriate levels of the U(1) algebras.
Properties of a Charged Particle in the Presence of Conducting Boundaries
Authors: Robaschik D. , Wieczorek E.
Published: May 2007

Recent results of quantum field theoretic calculations of the influence of conducting boundaries on particle properties are reviewed.
Die Elementarkonstanten und die Mathematik
Authors: Rompe Robert , Treder Hans‐Jürgen
Published: May 2007

Die Elementarkonstanten im Sinne von Max Planck sind von ähnlicher Bedeutung wie die reinen Zahlen der Mathematik. Die Newtonschen Prinzipien und die Elementarkonstanten zusammen sind der Grundbau der physikalischen Theoriebildung.
The Functional Integral on the Lattice Gauge Orbit Space
Authors: Rudolph Gerd
Published: May 2007

We construct a complete set of lattice invariants for the bosonic sector of the Georgi‐Glashow model and propose a lattice approximation of the physical action in terms of these invariants. In particular, we describe topologically non‐trivial configurations on the lattice level. Finally, we give a lattice approximation of the functional integral measure in terms of invariants, which enables us to formulate the functional integral on the lattice gauge orbit space.
Construction of Local and Non‐Local Conservation Laws for Non‐Linear Field Equations
Authors: Vladimirov V. S. , Volovich I. V.
Published: May 2007

A method of constructing conserved currents for non‐linear field equations is presented. More explicitly, for non‐linear equations, which can be derived from compatibility conditions of some linear system with a parameter, a procedure of obtaining explicit expressions for local and non‐local currents is developed. Some examples including the supersymmetric Yang‐Mills theory are considered.
The Evolution of Quantum Field Theory
Authors: Shirkov D. V.
Published: May 2007

A review of concepts and principles defining the structure of the theory of fundamental interactions in the microcosm:

physical content of the notion of Quantum Field;

the influence of principles of renormalisability, quantum dynamics and supersymmetry on the structure of QFT;

present status and problematics of the particle‐interaction theory.
Symplectic Formalism for the Thermodynamics of Irreversible Processes
Authors: Vojta G.
Published: May 2007

The fundamentals of a Lagrangian and Hamiltonian formalism for the thermodynamics of irreversible processes are developed. An abstract frame for linear and nonlinear processes is formulated in the Onsager scheme for discontinuous systems. It is always possible to construct a locally defined nondegenerate symplectic structure which is characterized by the entropy production. As an example, thermodynamic systems with kinetic energy possessing evolution equations with time derivatives of second order are treated in the Onsager‐Machlup formulation. Modifications of the formalism by complexification of the thermodynamic phase space and introduction of a Kähler manifold are discussed.
A Riemann‐Hilbert Approach to the Inverse Problem for Three Dimensional Heisenberg Spin‐Chain
Authors: Chowdhury A. Roy , Mitra Pritha
Published: May 2007

Three dimensional Heisenberg Spin Chain along with the Tjon‐Wright ansatz admit a Lax pair with pole in the eigenvalue plane. We have developed the corresponding inverse problem through the technique of Riemann‐Hilbert approach. The analytic structure is determined through the reduction technique, associated with the Lax pair.
Lernen von und bei Max von Laue
Authors: Thiessen P. A.
Published: May 2007

Erinnerungen an die Entstehungsgeschichte und die Frühzeiten der Röntgenstrukturanalyse.
First Order Approximation of the 5‐dimensional Projective Unified Field Theory
Authors: Schmutzer E. , Kroll P.
Published: May 2007

The new version of a 5‐dimensional Projective Unified Field Theory is presented up to the first order approximation with respect to the gravitational constant and referring to nonrelativistic velocities. Since exact solutions of this theory can only be found for exceptional cases, this approximation procedure provides a practicable approach to physical applications of the theory.
Elementary Constants of Nature
Authors: Hantzsche E.
Published: May 2007

Elementary constants of nature play a decisive role in physics, though they are not taken notice in most physical investigations, compared with the much more interesting variables: They are normally regarded as a kind of self‐evident ingredients or accessories of physical laws. However, from a more general point of view such a neglect is not justified. In this commenting paper several aspects of the occurrence, the meaning and measurement, of the origin, the character and the properties of elementary constants are discussed, as well as the use of such constants to define “natural” unit systems. The question of variability is mentioned, and finally the deep roots of fundamental constants in nature are emphasized.
Lifetime‐Measurements of Selectively Excited Molecular Levels
Authors: Bieniak B. , Hinske H. P. , Paulus H. , Zevgolis D. , Demtröder W.
Published: May 2007

A synchroneously pumped mode‐locked cavity‐dumped dye laser, which delivers nearly Fourier‐limited output pulses with 20 W peak power, 500 ps pulsewidth and 1.5 GHz spectral bandwidth is used to populate selected rovibronic levels in excited electronic states of alkali molecules. The laser induced fluorescence is filtered through a monochromator and the lifetimes of individual rovibronic levels are determined with the single photon delayed coincidence technique. The influence of different perturbations on the lifetimes is investigated and discussed.
A 12‐GHz Standard Clock on Trapped Ytterbium Ions
Authors: Casdorff R. , Enders V. , Blatt R. , Neuhauser W. , Toschek P. E.
Published: May 2007

The ground‐state hyperfine transition ΔmF = 0 of trapped Yb+ ions has been measured as 12642812119.6 (0.4) Hz. The frequency instability of a microwave, controlled by this resonance, is characterised by the standard deviation 2·10−11· (τ/sec)−1/2, where τ is the time separation of probes. The performance of this frequency standard or “clock” exceeds the stability of commercial cesium clocks and still offers major potential for improvement.
Semiclassical Coupled Channels Theory
Authors: Grawert G. , Müller St.
Published: May 2007

A semiclassical theory for heavy ion scattering in the Fresnel diffraction regime covering coupled elastic and inelastic channels is developed. The scattering is described as diffraction off the rainbow trajectory along which the development of the internal degrees of freedom is calculated. Simple formulae for the transition amplitudes are derived and interpreted in terms of matching conditions, time scales and potential strengths at closest approach. Polarization potentials comprising of real and absorptive terms and of tensors of various ranks are constructed. Analyzing power data for elastic and inelastic scattering of polarized 7Li on 120Sn are analyzed.
Theoretical Analysis of the Einstein Relation in n‐Channel Inversion Layers on A3IIB2V Semiconductors under Magnetic Quantization
Authors: Ghatak K. P. , Mitra B. , Mondal M.
Published: May 2007

We have investigated the Einstein relation in n‐channel inversion layers on A3IIB2V semiconductors at low temperatures on the basis of a newly derived dispersion relation of the carriers under arbitrary magnetic quantization for the general case which occurs from the consideration of the anisotropies of the band parameters within the frame work of k · p formalism. It is found by incorporating both the effects of electron spin and broadening of Landau levels, using n‐Cd3As2 as an example, that the theoretical formulation is in qualitative agreement with the suggested experimental method of determining the Einstein relation in degenerate semiconductors having arbitrary dispersion law. In addition, the corresponding well‐known results for bulk specimens of two band Kane model both in the presence and absence of magnetic quantization, are also obtained from the generalized expressions as special cases.
Relativistic Single Particle Kinetic Theory
Authors: Long David G.
Published: May 2007

Single particle kinetic theory is the study of the dynamics of a single particle moving through a medium. The only mechanism for change in this theory is through two‐body collisions between the single particle and the particles of the medium given by the collision term of Boltzmann's equation in kinetic theory. This article contains a summery of relativistic dynamics and a method of projecting the relativistic dynamical system into phase space. This enables us to express relativistic kinetic theory in terms of phase space variables and also to apply the techniques of approximation in the non‐relativistic theory to the relativistic domain.
Quasiclassical 1/N Energy‐Formulas for Relativistic Two‐Body Systems
Authors: Papp E.
Published: May 2007

Quickly tractable energy‐formulas for relativistic two‐body systems are established to first 1/N‐order in terms of general classical Hamiltonians (m1 ≥ m2). Arbitrary spherically‐symmetrical vector and/or scalar potentials are assumed. Such Hamiltonians, which have to be converted into related non‐relativistic ones, play the role of a dominant zeroth‐order approximation (an exact description) in the case of two fermions (two bosons). Proofs have also been given that the 1/N‐method is quite suitable for the systematic description of order‐dependent contributions to the energy of Coulomb‐Bethe‐Salpeter systems, now to α6‐order.
Strong Gravity and Strings
Authors: Sivaram C. , de Sabbata Venzo
Published: May 2007

Starke Gravitation and Strings.
Die quantenmechanische Interpretation der allgemeinkovarianten Dirac‐Gleichung und die 8‐parametrische Gruppe der Spinor‐Transformationen
Authors: Gorbatsievich A. K.
Published: May 2007

Es wird die bezüglich der im allgemeinen nicht unimodularen Spinor‐Transformationen kovariante Dirac‐Gleichung untersucht. Es wird gezeigt, daß diese Gleichung selbst in kartesischen Koordinaten in der flachen Raum‐Zeit nur dann als eine Ortsdarstellung der quantenmechanischen Bewegungsgleichungen in einem abstrakten Hilbertraum interpretiert werden kann, wenn die diese Darstellung realisierenden Hilbertraum‐Basisvektoren nicht orthonormiert sind.
Self‐Consistent Calculations of Landau Levels for Symmetric p‐Type Inversion Layers
Authors: Latussek V. , Bangert E. , Landwehr G.
Published: May 2007

A method for calculating the Landau levels of symmetric p‐type inversion layers is presented. Using the envelope function approach in the Hartree approximation the magnetic field is incorporated into the Hamiltonian. In order to characterize the energy levels and to obtain a detailed understanding of the unusual Landau scheme, an analysis of the wave functions is made. Special effects are discussed for the inversion layers adjacent to the grain boundary of a Ge‐bicrystal, with two occupied subbands. The simulation of Shubnikov‐de Haas data by a density of states analysis shows that the different oscillatory periods are not directly related to the subband occupations.
Resonances and Gamow States in Non‐Local Potentials
Authors: Mondragon A. , Hernandez E. , Arcos J. M. Velazquez
Published: May 2007

For a large class of non‐local, non separable potentials with non‐compact support, the solution of the radial integrodifferential equation may be reduced to the solution of a homogeneous linear integral equation of Fredholm type with a quadratically integrable kernel. In this way we derive expansions of the wave functions and the Green's function of the Schrödinger equation with a non‐local potential in terms of bound states, resonant states and a continuum of scattering functions with complex wave number. The rules of normalization, orthogonality and completeness satisfied by the eigenstates of the Schrödinger equation belonging to complex eigenvalues with Im En < 0, (Gamow or resonant states) are also derived. Finally, by means of a realistic example, it is shown how to use these expansions to exhibit the resonant behaviour of the differential cross section. Explicit expressions for the transition amplitudes and the partial widths in terms of expectation values of operators computed with Gamow functions are given.
Several large‐scale superperiodicities on highly oriented pyrolytic graphite observed by scanning tunneling microscopy
Authors: Yang X. , Bromm Ch. , Geyer U. , von Minnigerode G.
Published: May 2007

On freshly cleaved highly oriented pyrolytic graphite we observed large‐scale superperiodicities by a scanning tunneling microscope at room temperature in air. Several hexagonal superstructures with periods of 30 nm, 4.2 nm, 2.4 nm, and 2.0 nm, respectively, and a strip‐like superstructure with a period of 1 nm were obtained. With exception of the largest hexagonal superperiodicity (30 nm spacing), all other superstructures are superimposed on the atomic corrugation of graphite. The origin of these superstructures is not clear yet. We assume that they arise from crystal defects in graphite. The hexagonal superstructure may be caused by the Moiré effect due to the rotational misorientation of the two top layers or of two successive layers near the surface.
A variational treatment of the periodic Anderson model with antiferromagnetic order
Authors: Brenig W. , Müller‐Hartmann E.
Published: May 2007

We discuss a variational ground state wave function for the symmetric periodic Anderson model with commensurate spin density order. The energy of this ansatz is evaluated in closed form. Our approach generalizes a variational treatment proposed recently by Strack and Vollhardt and results in significantly lower energy. Contrary to the Gutzwiller ansatz the wave function recovers the Schrieffer‐Wolff limit for large Coulomb repulsion. We clarify the relation of our approach to unrestricted Hartree‐Fock and present a comparison with existing quantum Monte Carlo calculations for one dimension.
Constructing the Feynman integrand
Authors: Khandekar D. C. , Streit L.
Published: May 2007

Recently general conditions have been given which imply the existence of the Feynman integral as a Hida distribution. Here we perform an explicit construction of these distributions for a large class of Schrödinger problems.
Kinetics of fractal Ising clusters ‐ a Monte Carlo study
Authors: Stauffer D.
Published: May 2007

For short times and small clusters we check the validity of the 1935 Becker‐Döring equation by Monte Carlo simulations in the square Ising model at and near its critical point; some discrepancies are found.
On a simple formula for the energy of the lowest octupole state
Authors: Zamfir N. V. , von Brentano P. , Casten R. F.
Published: May 2007

A recently introduced way of parameterizing the energies of 3 states in many even‐even nuclei, based on the microscopic structure of the low‐energy octupole mode, is slightly modified so it now includes all (non‐doubly magic) nuclei with A ⩾ 30.
Generalized conformal invariance conditions on a sigma model of the open bosonic string including the first massive mode
Authors: Förste S.
Published: May 2007

Conformal invariance conditions on a sigma model of the open bosonic string including the tachyon, the abelian gauge field an the first excited massive mode are calculated up to order a′. Inner symmetries are used to compute conformal invariance conditions from renormalization group beta functions.