models:standard_model:qed
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models:standard_model:qed [2018/03/28 08:50] jakobadmin ↷ Links adapted because of a move operation |
models:standard_model:qed [2018/05/12 09:21] (current) jakobadmin [Why is it interesting?] |
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| - | ====== Quantum Electrodynamics: $ \quad L = \bar {\Psi}(i \gamma^{\mu }\partial_{\mu} + q\gamma^{\mu}A_{\mu} - m)\Psi + \frac{1}{16 \pi}F_{\alpha \beta}F^{\alpha \beta} . $ ====== | + | <WRAP lag>$ \ L = \bar {\Psi}(i \gamma^{\mu }\partial_{\mu} + q\gamma^{\mu}A_{\mu} - m)\Psi + \frac{1}{16 \pi}F_{\alpha \beta}F^{\alpha \beta} $</WRAP> |
| + | ====== Quantum Electrodynamics ====== | ||
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| + | //see also [[models:standard_model]] and [[models:classical_electrodynamics]]// | ||
| <tabbox Intuitive> | <tabbox Intuitive> | ||
| + | Quantum electrodynamics is the correct model of electromagnetic interactions. It is a model in the framework of [[theories:quantum_field_theory|quantum field theory]]. | ||
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| + | ---- | ||
| - | * The best layman introduction to quantum electrodynamics is Quantum Electrodynamics by Richard P. Feynman | + | * The best non-technical introduction to quantum electrodynamics is Quantum Electrodynamics by Richard P. Feynman |
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| <tabbox Concrete> | <tabbox Concrete> | ||
| - | Quantum electrodynamics is a [[theories:quantum_field_theory|quantum field theory]] of electrodynamics. At its heart is a [[advanced_tools:gauge_symmetry|gauge symmetry]] called local $U(1)$ symmetry. | + | Quantum electrodynamics is a [[theories:quantum_field_theory:canonical|quantum field theory]] of electrodynamics. At its heart is a [[advanced_tools:gauge_symmetry|gauge symmetry]] called local $U(1)$ symmetry. |
| In practice, we use quantum electrodynamics to describe electrodynamical interactions between charged particles through elementary particles called photons. | In practice, we use quantum electrodynamics to describe electrodynamical interactions between charged particles through elementary particles called photons. | ||
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| Photons are the fundamental excitations of the electrodynamic field. | Photons are the fundamental excitations of the electrodynamic field. | ||
| - | There are two frameworks to calculate things in quantum electrodynamics: either using [[advanced_tools:feynman_diagrams|Feynman diagrams]] (= the [[frameworks:hamiltonian_formalism|Hamiltonian framework]]) or using [[advanced_tools:path_integral|path integrals]] (= the [[frameworks:lagrangian_formalism|Lagrangian framework]]). | + | There are two frameworks to calculate things in quantum electrodynamics: either using [[advanced_tools:feynman_diagrams|Feynman diagrams]] (= the [[formalisms:hamiltonian_formalism|Hamiltonian framework]]) or using [[theories:quantum_mechanics:path_integral|path integrals]] (= the [[formalisms:lagrangian_formalism|Lagrangian framework]]). |
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| In addition, it's one of the best-tested theories in the history of science and so far, passed all precision tests. | In addition, it's one of the best-tested theories in the history of science and so far, passed all precision tests. | ||
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| + | Electromagnetic interactions are responsible for the attraction between electrons and protons. This way they are responsible for the stability of atoms. | ||
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| <tabbox History> | <tabbox History> | ||
| + | * "QED and the Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga" by Schweber | ||
| * The notion “quantum electrodynamics” was invented by Paul Dirac in [[http://wwwhome.lorentz.leidenuniv.nl/~boyarsky/media/Proc.R.Soc.Lond.-1927-Dirac-243-65.pdf|The quantum theory of emission and absorption of radiation]] | * The notion “quantum electrodynamics” was invented by Paul Dirac in [[http://wwwhome.lorentz.leidenuniv.nl/~boyarsky/media/Proc.R.Soc.Lond.-1927-Dirac-243-65.pdf|The quantum theory of emission and absorption of radiation]] | ||
| </tabbox> | </tabbox> | ||
models/standard_model/qed.1522219820.txt.gz · Last modified: 2018/03/28 06:50 (external edit)
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