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models:standard_model:qed [2018/03/15 10:50]
jakobadmin [Why is it interesting?]
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>​
  
-<tabbox Why is it interesting?> ​+====== Quantum Electrodynamics ======
  
-Quantum electrodynamics (QED) is the best theory of electromagnetic interactions that we have. +//see also [[models:​standard_model]] and [[models:​classical_electrodynamics]]//​
  
-It's a crucial part of the [[models:​standard_model|standard model]] and accurately describes how elementary particles like electrons interact with each other and with light. ​ 
  
-In addition, it's one of the best-tested theories ​in the history ​of science and so far, passed all precision tests.+<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]]
  
  
 +----
  
-<tabbox Layman>  +  ​* The best non-technical ​introduction to quantum electrodynamics is Quantum Electrodynamics by Richard P. Feynman ​
- +
-  ​* The best layman ​introduction to quantum electrodynamics is Quantum Electrodynamics by Richard P. Feynman ​+
   ​   ​
-<​tabbox ​Student+<​tabbox ​Concrete
  
-Quantum electrodynamics is a [[theories:​quantum_theory:​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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-<​tabbox ​Researcher+<​tabbox ​Abstract
 **Additional Conserved Charge** **Additional Conserved Charge**
  
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-<​tabbox ​FAQ+<​tabbox ​Why is it interesting?​ 
 + 
 +Quantum electrodynamics (QED) is the best theory of electromagnetic interactions that we have.  
 + 
 +It's a crucial part of the [[models:​standard_model|standard model]] and accurately describes how elementary particles like electrons interact with each other and with light.  
 + 
 +In addition, it's one of the best-tested theories in the history of science and so far, passed all precision tests. 
 + 
 + 
 +Electromagnetic interactions are responsible for the attraction between electrons and protons. This way they are responsible for the stability of atoms.
   ​   ​
 <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.1521107424.txt.gz · Last modified: 2018/03/15 09:50 (external edit)