QED – Quantum Electrodynamics  

In General > s.a. [electromagnetism]; QED phenomenology.
* Idea: The theory of the coupled, quantized Maxwell theory for the (vector) electromagnetic field coupled to (Dirac spinor) electron fields.
* 1952: Dyson's arguments suggest that the perturbation series in quantum electrodynamics cannot be convergent.
* 1955: Landau's argumene that the effective running coupling constant has a pole (Landau singularity) at some very high energy scale.
* Status: It is the most accurate theory we have, and gives extremely precise predictions; However, because its perturbation series diverge (they are asymptotic series) and of the Landau pole problem, it is considered as an effective low-energy theory, valid up to some cutoff energy.

Canonical Approach > s.a. fock space; geometric quantization; Wavelets.
* Approaches: Can be done in a fixed gauge, or à la Dirac.
@ General references: Dirac PR(65) [Heisenberg representation]; Arthurs PLA(79) [ito E and B]; Löffelholz et al JMP(03) [Gauss law and existence of propagator].
@ Loop representation: Ashtekar & Rovelli CQG(92); Ashtekar et al JGP(92) [self-dual representation]; Brügmann gq/93-in; Leal MPLA(96); Ashtekar & Corichi CQG(97)gq/96; Corichi & Krasnov MPLA(98)ht/97; Varadarajan PRD(00)gq [Fock space]; Carrión-Álvarez mp/04-PhD [unsmeared Wilson loops and Fock space]; > s.a. monopoles.
@ Flux uncertainty relations: Ashtekar & Corichi PRD(97)ht; Freed et al CMP(07)ht/06, AP(07)ht/06.
@ Special cases: Gambini et al PRD(98)ht/97 [2D compact, loop variables]; Bojowald JMP(00)ht/99 [spherical symmetry, and abelian BF]; Leal & López JMP(06)ht/04 [with magnetic monopole].

Covariant Approach
* Lagrangian: This approach requires adding a gauge-fixing term to the Lagrangian,

G = – –1 (Aa;a)2,

with a constant parameter ( = 1, Feynman gauge, which actually leads to the Lorenz gauge condition; → 0, Landau gauge); The equation of motion becomes [ab – (1––1) a b] Ab = 0 or, in the Feynman gauge; Aa = 0.
* Interpretation: Problems with the number of degrees of freedom can be handled with the Gupta-Bleuler formalism.
@ References: Schwinger PR(48), PR(49); Nambu PTP(50); Misra & Warawdekar PRD(05) [and light-front, 1-loop equivalence].

Other Approaches > s.a. quantum gauge theories; modified electrodynamics; stochastic quantum mechanics; Yang-Mills theories.
* Path integral: It can be done, but it introduces ghosts in the theory, because of gauge invariance.
@ General references: Thirring & Narnhofer RVMP(92) [covariant without ghosts]; Swanson FP(00) [canonical vs path integral]; Burch JMP(04)qp/03 [histories]; Arbatsky mp/04; Steinmann ht/04-in [Gupta-Bleuler vs Coulomb gauge formulations].
@ Perturbative: Steinhauser PRP(02) [multi-loop]; Dunne JHEP(04)ht/03 [2-loop, simplification]; Azam ht/04, MPLA(06)hp/05 [series divergence], hp/06-wd [and Landau pole]; Filippov qp/06-in [new approach].
@ Non-perturbative: Rochev JPA(00); > s.a. algebraic quantum field theory.
@ Discretized, on a lattice: Armand-Ugón & Fort PLB(92) [phase transition]; Kijowski & Thielmann JGP(96); Kijowski et al CMP(97) [observables and superselection]; > s.a. regge calculus.
@ Related topics: Czachor ht/02, & Syty qp/02 [non-canonical]; Noltingk JMP(02)gq/01 [BRST quantization of histories electrodynamics]; Manoukian & Viriyasrisuwattana IJTP(07) [photon propagation in spacetime].
> Related topics: see BRST; feynman propagator; modified formulations [including curved spacetime]; string phenomenology.

Theoretical Concepts and Effects > s.a. locality; phase; photons; renormalization; vacuum.
@ States: Buchholz LNP(82) [state space]; Alekseev & Perina PLA(97) [squeezing, chaos-assisted]; > s.a. Squeezed States.
@ Semiclassical: Sonego pr(91); Naudts & De Roeck mp/03 [with classical Aa]; Polonyi PRD(06)ht [crossover field theory], PRD(08); > s.a. quantum field theory states.
@ At finite temperature: Elmfors & Skagerstam PLB(95)ht/94; Cervi et al PRD(01) [Lorentz and CPT violation]; Andersen PRD(02) [low-T]; > s.a. effective action.
@ Radiation damping, decoherence: Breuer & Petruccione qp/02-in; > s.a. decoherence.
@ Interpretations: Kaloyerou PRP(94) [causal field]; Marshall qp/02 [classical]; > s.a. quantum field theory.
@ Non-classical aspects: Klyshko PLA(96); Roy & Roy JPA(97); Paris PLA(01)qp.
@ Gauge issues: Hojman AP(77) [true degrees of freedom in any gauge]; Esposito PRD(97)ht/96 [conformally invariant gauge]; Arnone et al JHEP(05)ht [manifestly gauge-invariant]; Solomon qp/06 [negative energy states in temporal gauge], qp/07 [spacelike energy-momentum vector].
@ Fluxes: Weigel JPA(06)ht [flux tubes]; Rañada & Trueba FP(06) [topological quantization].
@ Related topics: Crone & Sher AJP(91) [broken U(1)]; Anastopoulos & Zoupas PRD(98)ht/97 [eff for spinors]; Kondo PRD(98)ht [confining phase?]; Ribaric & Sustersic ht/00 [regularization]; Bagan et al PLB(00)ht [particle description]; Buchholz et al AP(01) [charge delocalization]; Lieb & Loss CMP(04)mp [polarization vectors]; Bordag PRD(04)ht [and boundary conditions]; Alexandre AP(04) [dynamical mass generation in QED3]; Aragão et al PLA(04) [highly peaked phase distribution]; Efimov TMP(04) [stability]; Herdegen APPB(05)ht/04 [asymptotic structure]; Ilderton NPB(06) [recurrence relations between amplitudes].
> Other effects: see correlations; entanglement; Landau Pole; particles and photons in quantum gravity.

References > s.a. history of quantum physics; light; path integral quantum field theory; quantum dirac fields; quantum field theory [including pilot-wave].
@ General: Dirac et al PZS(32); Feynman PR(49), PR(50), PR(51), Sci(66)aug; Prokhorov SPU(88); de la Torre EJP(05).
@ Texts, I: Feynman 85.
@ Texts, III: Thirring 58; Feynman 61; Ahiezer & Beresteckii 65; Källen 72; Cohen-Tannoudji et al 92; Milonni 94; Gribov & Nyiri 00; Steinmann 00 [perturbative]; Greiner & Reinhardt 02; Aitchison & Hey 04; Gingrich 06 [numerous exercises]; Grozin 07.
@ Sources, reprints: Schwinger ed-58; Miller 94.

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