bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inertia and Gravity: a New Approach to Dynamical Theory in General Relativity
Authors: Quale Andreas 
Published: July 2007

AbstractA new approach to gravitational field dynamics is proposed, as an alternative to the standard formulation of General Relativity. The spacetime metric tensor is split, into an externally fixed background geometry (inertia) and a local dynamical field (gravity); and a dynamical theory of matter and gravity in the inertial background is developed. The physical origin of inertia (Mach's Principle), and its observable properties, are discussed. The coordinate representations of inertia and gravity are found to have an internal gauge degree of freedom, due to the Equivalence Principle; the transformation properties of these fields, and the notion of covariant gauge conditions, are discussed. The dynamics of matter and gravitic fields is then investigated, using: (i) The group of motion of the inertial background, appearing as an externally fixed Lie symmetry in the matter and gravity action principles, which yields weakly conserved energy‐momentum‐like objects; and (ii) an internal symmetry gauge group, yielding strongly conserved “internal currents”. A fully covariant field‐theoretical formalism is used, in which all quantities and operations are tensorial; the well‐known difficulties of “coordinate effects” in the standard nontensorial formulation are thus avoided. The physical significance of various types of conservation laws is discussed; and a complete family of energy‐momentum tensors of gravity, covariantly conserved together with the matter energy‐momentum, is deduced from a tensorial action principle. Treating gravity as an independent dynamical interaction, on an equal footing with other (matter) interactions, we are then finally led to the conclusion that the gravitic energy‐momentum of a system is fully determined by the matter energy‐momentum; various physical implications of this are discussed in some detail.
Finite‐ and Infinite‐Dimensional Representations of the Lorentz Group
Authors: Carmeli M. , Malin S. 
Published: July 2007

AbstractFinite‐ and infinite‐dimensional representations of the Lorentz group are discussed and various topics in which this group is currently in use are mentioned. The infinitesimal approach of finding representations is reviewed and all finite‐dimensional spinor representations of the Lorentz group are obtained. Infinite‐dimensional representations are then discussed, including the principal, complementary, and complete series of representations. A generalized Fourier transformation is introduced which enables one to use the global approach to representation theory so as to express infinite‐dimensional representations in terms of matrices. This method is shown to lead to a generalization of the spinor form of finite‐dimensional representation to the infinite‐dimensional case. However, whereas the usual spinor representations are nonunitary, the obtained new form describes both unitary and non‐unitary representations, depending on the choice of certain parameters appearing in the representation formula.
Testing Theories of Chiral Symmetry
Authors: Wing‐Chiu Ng. 
Published: July 2007

AbstractWe investigate various physical consequences of theories of chiral symmetry. Predictions of the symmetry are given for the meson electroproduction process at an on‐shell kinematical point where unknown contributions are minimized. Sum rules are derived for the corrections. Then we present a sum rule for the ∑ term in meson‐baryon scattering from the assumptions of Bjorken limit, precocious asymptopia, and finite‐mass dispersion relations. We use the commutation relations of the gluon model as input for a numerical evaluation. Next the explicit canonical structure of the light‐cone restriction of the commutator of the weak current with its divergence is considered in the interacting quark‐gluon model quantized in the infinite–momentum frame. The implications on neutrino scattering are analyzed. W4 and W5 are predicted to scale nontrivially as v−2F4(ω) and v−2F5(ω), which provides a simple test of light‐cone current algebra feasible in the near future. The ∑ term for weak currents is deduced from a causal representation near the light‐cone, and a correction is also made in the W5 – sum rule obtained by naive infinite momentum techniques. As a by‐product we obtain improved derivations of the Adler neutrino sum rules.
Realizations of the Unitary Representations of the Inhomogeneous Space‐Time Groups I. General Structure
Authors: Niederer U. H. , O'Raifeartaigh L. 
Published: July 2007

AbstractThe aim of these two papers (I and II) is to try to give a unified systematic description of the different quantum mechanical realization of the unitary representations of the inhomogeneous space‐time groups.Paper I, which is more general, deals with the interrelationships between the Mackey, the Wigner and the covariant realizations of induced representations, first for general groups, and then for semi‐direct products. The Euclidean, Galilean and Poincaré groups are treated in some detail as examples.Paper II gives a systematic treatment of the various covariant wavefunctions (Dirac, Bargmann‐Wigner, etc.) that can be used to describe a single irreducible representation of the Poincaré group. It is self‐contained and deals first with momentum space, and then with first and second quantized fields. In both papers the treatment is index‐free.
Description of Non‐Polynomial Quantum Field Theories by Superpropagator Method
Authors: Volkov M. K. 
Published: July 2007

AbstractThe description of superpropagator method and its applications to the mesodynamics, weak interaction, electrodynamics involving gravity and the chiral invariant field theory is given. The low‐energy behaviour of particles is described, taking into account the loop Feynman diagrams. The renormalizations of physical quantities are finite and are expressed in terms of coupling constants. Partly this work was reported at the Third International Conference on Non‐Local Quantum Field Theory in 1973 at Alushta, USSR.
Phase of a Microscopic Electromagnetic Field and Its Measurement
Authors: Paul H. 
Published: July 2007

AbstractA novel approach to the quantum mechanical description of phase properties of a one‐mode low‐intensity radiation field is presented. The procedure is based upon the correspondence between Glauber states and classical waves of fixed phase ϕ and amplitude a, and, in contrast to the conventional quantum mechanical phase concepts, allows to make contact between certain operators ℰm corresponding to the classical quantities exp {imφ} (m = ± 1, ± 2, …) and realistic measurements. In the observation, a large amplification of the microscopic field by means of a linear quantum amplifier plays a decisive role. Since the amplified field is a macroscopic one, the measurement of phase is not problematic, and hence, in particular, average values «exp {imϕ}» can be determined experimentally. The main result of our analysis is that the mean values «exp {imϕ}» are equal to the quantum mechanical expectation values for the operators ℰm with respect to the field before amplification. To obtain this result it became necessary to calculate Glauber's P function for the amplified field in case of an arbitrary state for the initial field.
Construction of Covariant Bases for Two‐Particle Reactions
Authors: Tchrakian D. H. 
Published: July 2007

AbstractA method for the construction of the Lorentz‐covariant bases occurring in the decomposition of spinor amplitudes (M‐functions) of four massive particle processes is given. Each particle of spin‐ is described by a spinor state of the type‐(s, 0) and/or (0, s), but the essential parts of our method apply whatever the type of spinor state used, and the necessary relations between the hitherto familiar types of spinor states are given, by means of which the relationship between the resulting sets of invariant amplitudes can be made explicit. By way of illustration four worked examples are presented.
Wave Equations on a de Sitter Fiber Bundle
Authors: Drechsler W. 
Published: July 2007

AbstractA gauge theory of strong interaction is developed based on fields defined on a fiber bundle. The structural group of the bundle is taken to be the L4,1 de Sitter group. An internal variable ε, varying in the fiber over a space‐time point x, is introduced as a means to describe – with the help of a semiclassical wave function PS(x, ε) defined on the bundle space – the internal structure of extended hadrons in a framework using differential geometric techniques. Three basic nonlinear wave equations for PS(x, ε) are established which are of integro‐differential type. The nonlinear coupling terms in these de Sitter gauge invariant equations represent physically a generalized spin orbit coupling or a generalized spin spin coupling for the motion taking place in the fiber. The motivation for using a bigger space for the definition of hadronic matter wave functions as well as the implications of this geometric approach to strong interaction physics is discussed in detail, in particular with respect to the problem of hadronic constituents. The proposed fiber bundle formalism allows a dynamical description of extended structures for hadrons without implying the necessity of introducing any constituents.
Electromagnetic Interactions of High Energy Cosmic Ray Muons
Authors: Grupen C. 
Published: July 2007

AbstractThis paper investigates the electromagnetic interactions of muons. The various processes such as knock‐on electron‐, bremsstrahlung‐, direct electron pair production, and nuclear interactions are described in detail. The energy range concerned extends from 109 eV up to 1015 eV for primary muons and from 108 eV up to 1014 eV for energy transfers to the secondaries.On the one hand the measurement of muon interactions represents a test of quantum electrodynamics. On the other hand the high energies available in cosmic rays would possibly lead to the measurement of new processes or the detection of new particles. One hopes to find in the high energy domain the answer to the question why the muon exists at all and if there are properties (apart from differences in mass, lifetime, and lepton number) which distinguish it from a mere heavy electron.The different experimental techniques are described and the various experimental results on muon interactions are presented and compared with relevant QED‐theories.Observed deviations between theory and experiment and anomalies in muon interactions are critically investigated and discussed in the light of experimental difficulties and interpretation problems. In general, agreement between theory and experiment is found, i.e. QED‐theories describe the results adequately. However, some experiments claim to have detected anomalies in muon physics in the cosmic ray beam. But the hypotheses on new processes and new particles in the high energy range do not withstand a critical analysis. It is concluded that the observed deviations can be understood in the framework of conventional theories.
Hadron Production by a Thermodynamical Quark Bootstrap
Authors: Wolf R. 
Published: July 2007

AbstractThe Gell‐Mann‐Zweig rule indicates how hadrons can be produced by quarks. This can be formulated in a bootstrap equation. A second equation which is necessary in order to eliminate one variable is found by a simple assumption about the behaviour of the quarks inside of the hadrons. Two models – a pure mesonic and a pure baryonic quark bootstrap – are presented in this paper. This material is a portion of the Ph. D. thesis submitted to the department of physics of the Universität Kaiserslautern.
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Nucleon‐Nucleon Scattering as High Energies
Authors: Kroll P. 
Published: July 2007

AbstractThe present status of the phenomenology of elastic and quasielastic nucleon‐nucleon and nucleon‐antinucleon scattering at high energies is reviewed. In particular the use of fixed‐t analyticity, models with rising cross‐sections and the impact parameter analysis are discussed.
Statistical Bootstrap Approach to Hadronic Matter and Multiparticle Reactions
Authors: Ilgenfritz E.‐M. , Kripfganz J. , Möhring H.‐J. 
Published: July 2007

AbstractWe present the main ideas behind the statistical bootstrap model and recent developments within this model related to the description of fireball cascade decay.Mathematical methods developed in this model might be useful in other phenomenological schemes of strong interaction physics; they are described in detail.We discuss the present status of applications of the model to various hadronic reactions.When discussing the relations of the statistical bootstrap model to other models of hadron physics we point out possibly fruitful analogies and dynamical mechanisms which are modelled by the bootstrap dynamics under definite conditions. This offers interpretations for the critical temperature typical for the model and indicates further fields of application.
Stimulierte Resonanz‐Raman‐Streuung an angeregten und nicht angeregten Molekülen
Authors: Herrmann J. 
Published: July 2007

AbstractA review of the theory of the stimulated resonance Raman scattering (SRRS) is given.The calculation of the gains for the SRRS with the ground level (SRRS I) or an excited one (SRRS II) as initial states shows that there are some restrictions for their appearance. Due to the strong resonance absorption of the pumping wave and the disturbing influence of stimulated fluorescence the SRRS I is not observable in a Franck‐Condon excitation and in an absorption of Lorentzian line shape.The SRRS II has a sufficiently large gain on the condition τel ≪vib (τel, τvib – transversal relaxation time of the electronic or vibronic transition). In case of a strong deviation of the wings of the absorption profile from the Lorentzian shape, however, the SRRS I is favoured rather than the two other processes.Another possibility to avoid the resonance absorption of the pumping wave exists for the transversal excitation of the SRRS. Thereby the limit of application of the SRRS may be extended to other substances which are no saturable absorbers.Apart from the saturable absorption and the transversal excitation the self‐induced transparency is the third possibility to generate SRRS of ultrashort light pulses.
Quantenfeldtheorie im de Sitter‐Raum
Authors: Mielke Eckehard W. 
Published: July 2007

AbstractBased on well‐known concepts, groundwork is laid for a quantum field theory in the de Sitter space‐time considered as an exact soluble model of a more general theory in curved space‐time.With respect to the horospherical coordinate system, invariant field equations for arbitrary spin are derived by means of induced representations of the symmetry group SO0(1,4). The additional terms, induced into the first order systems of relativistic wave equations by the space‐time curvature, are formally interpreted as external fields. Normalized c‐number solutions of the spin‐dependent Klein‐Gordon equation and of the Dirac equation are calculated explicitly.The analysis of the singular functions of quantum field theory is based on generalized eigenfunction expansions and, in the case of the Feynman propagator of scalar fields, on the method of Schwinger and De Witt, as well.An axiomatic approach to the quantization of neutral scalar fields is presented. Except for massless fields, the resulting “second quantization” is distinguished by a causal commutation function and a unique vacuum.Recent developments in the regularization problem of the stress‐energy tensor are reviewed. With respect to the de Sitter space‐time the conclusion has been drawn that the quantum theory of “free” scalar fields is renormalizable on the one‐loop level.
Null Surface Quantization and Quantum Field Theory in Asymptotically Flat Space‐Time
Authors: Frolov V. P. 
Published: July 2007

AbstractA quantum theory of the free scalar, electromagnetic and gravitational fields in a curved asymptotically flat space‐time is developed. It is shown that the Penrose conformal technique makes it possible to reformulate the null infinity quantization as a problem of the quantization on the proper null surface in the corresponding Penrose space. The Schwinger dynamical principle is exploited to derive the corresponding null surface commutation relations. The general covariant and gauge‐independent form of the commutation relations is also given. The existence of the asymptotic symmetry (BMS) group in the asymptotically flat space‐time is used to define uniquely the “in” and “out” vacuum states. The explicit expressions for the S‐matrix operator and for the S‐matrix elements in the asymptotically simple space‐time are given. The functional integration method is used to find the expression for the density matrix describing the observations at ∮+ in the weakly asymptotically simple space‐time when the information loss due to the event horizons or the existence of bare singularities is possible. The application of the developed approach to the problem of quantum evaporation of black holes (Hawking effect) is briefly discussed.
Massless Fields as Unitary Representations of the Poincaré Group
Authors: Niederer U. 
Published: July 2007

AbstractRelativistic zero‐mass fields are described as manifestly covariant unitary irreducible representations of the Poincaré group. The wave‐equations, which are a necessary condition for unitarity, are constructed for spinor fields of arbitrary spin and for tensor fields of integer spin. Poincaré covariance together with causality and positive energy are used to determine the commutators of quantized fields up to a positive multiple and to prove the spin‐statistics theorem. The use of potentials for boson fields is discussed and it is shown that, at the expense of manifest covariance, potentials may be introduced as zero‐mass limits of the massive Wigner representations.
Master Equation Approach to the Hopping Transport Theory
Authors: Bányai L. , Aldea A. 
Published: July 2007

AbstractThe fundamentals of the hopping transport theory are analyzed within the Master equation framework, that allows a clarification of the underlying assumptions and approximations. The common nature of the approximations, inherent both in hopping and weak scattering problems, is revealed. Some of the delicate limit problems are illustrated in exactly solvable models. The dangers in applying ordinary perturbation theory to the d.c. conductivity are shown. Through the introduction of the Master equation with external sources a proof of the Miller‐Abrahams resistance‐network analogy is given. There is also a discussion of the “local equilibrium” distribution, with some reference to thermoelectric phenomena.
Invariant Forms of the Lorentz Group
Authors: Lazo‐Tueve D. , Rühl W. 
Published: July 2007

AbstractWe study trilinear and multilinear invariant forms for the homogeneous Lorentz group. The residues of these trilinear forms generate particular trilinear forms themselves. They appear also if we sum Taylor expansions partially into a series of expressions each of which is covariant under infinitesimal Lorentz transformations. Multilinear invariant forms are submitted to harmonic analysis in different channels. They are thus expressed by invariant functions. Invariant functions for different channels are related by integral equations involving 6χ‐symbols, 9χ‐symbols etc. as “crossing kernels”. It is shown by construction that all invariant functions and nχ‐symbols can be represented as finite sums of Barnes type integrals. As example we analyze explicitly the four‐point Schwinger function of the massless Euclidean Thirring field with arbitrary spin and dimension.
An Approximation Scheme for Constructing π°π° Amplitudes from ACU Requirements
Authors: Schwarz F. 
Published: July 2007

AbstractThe requirements of analyticity, crossing symmetry and unitarity (ACU) are used as input to construct amplitudes for the scattering of neutral π mesons. They are obtained explicitly as polynomials in certain conformally transformed variables which ensure the correct analyticity structure. Crossing symmetry is expressed as a set of linear relations between the expansion coefficients. The same is true for the threshold behaviour of the partial waves and the behaviour for large energies of either the partial waves and the amplitudes itself. To enforce the positivity of the partial waves (up to a certain l) a new set of variables is introduced. It is obtained by solving the system of linear inequalities expressing the positivity condition. In this way one gets explicit expressions for all amplitudes satisfying the ACU requirements to some approximation. The rigorous constraints obtained from these ACU requirements are used to test the accuracy of this construction. The properties of all amplitudes are investigated in detail. It is indicated how this approximation scheme may be improved to any degree of accuracy and how it may be generalized to the full isospin case.
On the Algebraic Structure of Globally or Locally SU(2) Invariant Lattice Field Theories
Authors: Rühl W. 
Published: July 2007

AbstractThe local contribution to the action of the O(3) σ model in D = 2 or pure SU(2) gauge models in D ≧ 3 dimensions are expanded and integrated on the group. There results a field of variables j, a 3nj coefficient W({j}) with n → ∞ and dynamical factors f(j, β). We prove that for the gauge models a local decomposition of W({j}) into a product of 3nj coefficients with n = 2D(D – 2) exists. We study generating functions for W({j}) or the 3nj coefficients and develop an algorithm for their computation. Some of these generating functions are explicitly calculated.
Nonexistence of Multiple‐Instanton Solution of the Massless 4D ϕ4 Theory
Authors: Actor Alfred 
Published: July 2007

AbstractThe massless ϕ4 theory in four Euclidean dimensions is shown not to have a multiple‐instanton solution — even though it does have a single‐instanton solution. Our criterion for a multiple‐instanton solution of this nontopological theory is that the energy‐momentum tensor of the solution be identically zero. Arguments are given that a similar result holds in any number of dimensions for a one‐component scale‐invariant scalar theory.
Hermitean Oscillator‐like Realizations of Classical Algebras and Superalgebras in Hilbert Space with Positive Definite Metric
Authors: Nowicki Anatol 
Published: July 2007

AbstractThe hermitean oscillator‐like realizations of classical algebras in terms of bosonic and fermionic creation and annihilation operators are given. The hermitean realizations of classical superalgebras using boson‐fermion oscillators are explicitely described. The assumption of positive definite metric in a Hilbert space of the oscillators states is exploited. Due to this fact, the realizations of superalgebras in the Hilbert space can be constructed only for: the real orthosymplectic superalgebra osp (N; 2M; R); the unitary compact superalgebra su (N; M); the unitary noncompact one SU(N; K, M); and the quaternionic unitary superalgebra uuα(N; M; H).