Modern physics is characterized by two great theories, which make it fundamentally different from its predecessor: quantum theory and theory of relativity. In this book we want to bring to the reader's attention several solutions to problems connected to the quantum-relativistic interaction of particles. Remarkably, such solutions furnished rigorous and pertinent explanations of a large set of phenomena, both in microscopic world and galactic universe. Contents: PrefaceIntroductionClassical and Quantum Free FieldsThe Gravitational Transmutations HypothesisTomonaga–Schwinger Representation of Dynamics of a Quantum Physical System. Matrix Elements of the Field Operators and Feynman{Dyson-Type Rules for High-Spin ParticlesFundamentals of Gauge Theories. The Minimal Coupling PrincipleThe Gravitational Field Interacting with Other FieldsInteraction of Scalar, Spinorial, Spin-Vectorial and Tensorial Particles, and the Gravitational Field Described by the Schwarzschild MetricScattering of Electrons and Photogeneration of Gravitons in External Gravitational FieldInteraction of Scalar, Spinorial, Vectorial, Spin-Vectorial and Tensorial Particles with the Axially-Symmetric Gravitational Field Described by the Kerr MetricSoftware Package for Analytical Calculation of Differential Cross-Sections of Gravitational Scattering of High-Spin ParticlesAppendices: Isotopic FormalismThe Dirac Matrices and the Dirac EquationOperatorial TransformationsSingular FunctionsIntegration Formulas in Momentum SpaceMatrix Elements of the Field Operators and First-Order Vertices for the Gravitational Interaction of ParticlesExpressions of the Coeffcients-Functions of the Differential and Integral Scattering Cross-Sections of Particles in the External Axially-Symmetric Gravitational Field Described by the Kerr MetricValues of Several Physical Quantities in CGS and Natural (ħ = 1, c = 1) Unit Systems. Equivalence Between Different Units of Measurement Readership: Researchers and graduate students in quantum field theory and theoretical physics. Keywords: Quantum FieldsReview: Key Features: In this book we present several solutions to problems connected to the quantum-relativistic interaction of particles. Remarkably, such solutions furnished rigorous and pertinent explanations of a large set of phenomena, both in microscopic world and universe

Modern physics is characterized by two great theories, which make it fundamentally different from its predecessor: quantum theory and theory of relativity. In this book we want to bring to the reader's attention several solutions to problems connected to the quantum-relativistic interaction of particles. Remarkably, such solutions furnished rigorous and pertinent explanations of a large set of phenomena, both in microscopic world and galactic universe.

This monograph is devoted to the systematic presentation of foundations of the quantum field theory. Unlike numerous monographs devoted to this topic, a wide range of problems covered in this book are accompanied by their sufficiently clear interpretations and applications. An important significant feature of this monograph is the desire of the author to present mathematical problems of the quantum field theory with regard to new methods of the constructive and Euclidean field theory that appeared in the last thirty years of the 20th century and are based on the rigorous mathematical apparatus of functional analysis, the theory of operators, and the theory of generalized functions. The monograph is useful for students, post-graduate students, and young scientists who desire to understand not only the formality of construction of the quantum field theory but also its essence and connection with the classical mechanics, relativistic classical field theory, quantum mechanics, group theory, and the theory of path integral formalism.

This is an introductory book on elementary particles and their interactions. It starts out with many-body Schrödinger theory and second quantization and leads, via its generalization, to relativistic fields of various spins and to gravity. The text begins with the best known quantum field theory so far, the quantum electrodynamics of photon and electrons (QED). It continues by developing the theory of strong interactions between the elementary constituents of matter (quarks). This is possible due to the property called asymptotic freedom. On the way one has to tackle the problem of removing various infinities by renormalization. The divergent sums of infinitely many diagrams are performed with the renormalization group or by variational perturbation theory (VPT). The latter is an outcome of the Feynman-Kleinert variational approach to path integrals discussed in two earlier books of the author, one representing a comprehensive treatise on path integrals, the other dealing with critial phenomena. Unlike ordinary perturbation theory, VPT produces uniformly convergent series which are valid from weak to strong couplings, where they describe critical phenomena. The present book develops the theory of effective actions which allow to treat quantum phenomena with classical formalism. For example, it derives the observed anomalous power laws of strongly interacting theories from an extremum of the action. Their fluctuations are not based on Gaussian distributions, as in the perturbative treatment of quantum field theories, or in asymptotically-free theories, but on deviations from the average which are much larger and which obey power-like distributions. Exactly solvable models are discussed and their physical properties are compared with those derived from general methods. In the last chapter we discuss the problem of quantizing the classical theory of gravity. Contents: FundamentalsField Formulation of Many-Body Quantum PhysicsInteracting Nonrelativistic ParticlesFree Relativistic Particles and FieldsClassical RadiationRelativistic Particles and Fields in External Electromagnetic PotentialQuantization of Relativistic Free FieldsContinuous Symmetries and Conservation Laws. Noether's TheoremScattering and Decay of ParticlesQuantum Field Theoretic Perturbation TheoryExtracting Finite Results from Perturbation Series. Regularization, RenormalizationQuantum ElectrodynamicsFormal Properties of Perturbation TheoryFunctional-Integral Representation of Quantum Field TheorySystematic Graphical Construction of Feynman DiagramsSpontaneous Symmetry BreakdownScalar Quantum ElectrodynamicsExactly Solvable O(N)-Symmetric ϕ4-Theory for Large NNonlinear σ-ModelThe Renormalization GroupCritical Properties of Nonlinear σ-ModelFunctional-Integral Calculation of Effective Action. Loop ExpansionExactly Solvable O(N)-Symmetric Four-Fermion Theory in 2+ε Dimensions Internal Symmetries of Strong InteractionsSymmetries Linking Internal and Spacetime PropertiesHadronization of Quark TheoriesWeak InteractionsNonabelian Gauge Theory of Strong InteractionsCosmology with General Curvature-Dependent LagrangianEinstein Gravity from Fluctuating Conformal GravityPurely Geometric Part of Dark Matter Readership: Students and researchers in theoretical physics.

During the past 15 years, quantum field theory and classical statistical mechanics have merged into a single field, and the need for nonperturbative methods for the description of critical phenomena in statistical mechanics as well as for problems in elementary particle physics are generally acknowledged. Such methods formed the central theme of the 1987 Cargese Advanced Study Institut. e on "Nonpert. urbat. ive Quantum Field Theory." The use of conformal symmet. ry has been of central interest in recent years, and was a main subject at. t. he ASI. Conformal invariant quantum field theory describes statistical mechanical systems exactly at a critical point, and can be analysed to a remarkable ext. ent. by group t. heoretical methods. Very strong results have been obtained for 2-dimensional systems. Conformal field theory is also the basis of string theory, which offers some hope of providing a unified t. heory of all interactions between elementary particles. Accordingly, a number of lectures and seminars were presented on these two topics. After syst. ematic introductory lectures, conformal field theory on Riemann surfaces, orbifolds, sigma models, and application of loop group theory and Grassmannians were discussed, and some ideas on modular geometry were presented. Other lectures combined' traditional techniques of constructive quant. um field theory with new methods such as the use of index-t. heorems and infinite dimensional (Kac Moody) symmetry groups. The problems encountered in a quantum mechanical description of black holes were discussed in detail.

An Introduction to Quantum Field Theory is a textbook intended for the graduate physics course covering relativistic quantum mechanics, quantum electrodynamics, and Feynman diagrams. The authors make these subjects accessible through carefully worked examples illustrating the technical aspects of the subject, and intuitive explanations of what is going on behind the mathematics. After presenting the basics of quantum electrodynamics, the authors discuss the theory of renormalization and its relation to statistical mechanics, and introduce the renormalization group. This discussion sets the stage for a discussion of the physical principles that underlie the fundamental interactions of elementary particle physics and their description by gauge field theories.