Includes bibliographical references (p. 263-266).

Basic preliminaries. 1. Quantum field theory - why and how. 1.1. Schwinger's action principle. 1.2. Free-field kinematics -- 2. Functional preliminaries. 2.1. Functional differentiation. 2.2. Linear translation. 2.3. Quadratic (Gaussian) translation. 2.4. Functional integration. 2.5. Cluster decomposition. 2.6. Two useful relations -- 3. Functional field theory. 3.1. The generating functional. 3.2. A gauge digression: SU(N)-QCD. 3.3. Coupled fermion and boson fields. 3.4. Fields at the same point -- 4. The generating functional and the S-matrix. 4.1. The generating functional operator. 4.2. Asymptotic conditions. 4.3. The S-matrix. 4.4. A Bremsstrahlung example -- 5. Schwinger/Fradkin representations. 5.1. Formalism. 5.2. Gauge structure. 5.3. The Bloch-Nordsieck - IR - eikonal approximation. 5.4. A convenient reformulation -- Quantum electrodynamics. 6. Radiative corrections of the photon propagator. 6.1. Functional approach to the photon propagator. 6.2. Higher-order radiative correction. 6.3. The DP model for a single closed fermion loop. 6.4. The extended DP model, and the finiteness of Z[symbol]. 6.5. Summary -- 7. Radiative corrections to the electron propagator. 7.1. Introduction. 7.2. Formulation. 7.3. Computation. 7.4. Summary -- 8. A QED symmetry-breaking model of vacuum energy. 8.1. Introduction. 8.2. Formulation. 8.3. Approximation. 8.4. Computation. 8.5. Application to dark energy. 8.6. Partial summary -- Quantum chromodynamics. 9. Explicit, non-perturbative gauge invariance. 9.1. From QED to QCD. 9.2. Gluon summations and explicit gauge invariance. 9.3. Effective locality -- 10. QCD transverse fluctuations. 10.1. Introduction. 10.2. A phenomenological expression of transverse imprecision. 10.3. Bundle diagrams -- 11. Quark binding potential. 11.1. Use of the eikonal approximation. 11.2. Estimation of the "model pion" mass -- 12. Nucleon scattering and binding. 12.1. Introduction. 12.2. Formulation. 12.3. A qualitative binding potential. 12.4. Binding estimations. 12.5. Summary and speculation -- Astrophysical speculations. 13. Inflation as the precursor of dark energy. 13.1. Introduction. 13.2. Computation. 13.3. A cosmological speculation. 13.4. Summary -- 14. Quantum tachyon dynamics. 14.1. Introduction. 14.2. QTD as a QFT. 14.3. Functional QTD. 14.4. Photon emission and reabsorption. 14.5. Kinematic of tachyon-particle reactions. 14.6. From Ehrenfest's theorem to loop annihilation. 14.7. NASA's Fermi bubbles. 14.8. Summary.

A monograph, which can also be used as a textbook for graduate students, this book contains new and novel applications of Schwinger's well-known functional solutions, made possible by the use of Fradkin's little-known functional representations, together with recent research work of the author and his colleagues.

Electronic reproduction. Singapore : World Scientific Publishing Co., 2014. System requirements: Adobe Acrobat Reader. Mode of access: World Wide Web. Available to subscribing institutions.