User Tools

Site Tools


advanced_tools:feynman_diagrams

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
advanced_tools:feynman_diagrams [2018/04/14 09:30]
aresmarrero [Intuitive]
advanced_tools:feynman_diagrams [2018/07/07 10:22] (current)
jakobadmin [Concrete]
Line 3: Line 3:
 <tabbox Intuitive> ​ <tabbox Intuitive> ​
  
-{{ :​advanced_tools:​320px-feynmandiagram.png?​nolink&​400|}} +{{ :​advanced_tools:​320px-feynmandiagram.png?​nolink&​300|}}
-{{ :​advanced_notions:​quantum_field_theory:​virtualparticles.png?​nolink&​350|}}+
  
  
-Feynman diagrams are a pictorial way to keep track of terms in [[theories:​quantum_field_theory|quantum field theory]] calculations. Each element of a Feynman diagram represents a different term in our calculation.+ 
 +Feynman diagrams are a pictorial way to keep track of terms in [[theories:​quantum_field_theory:canonical|quantum field theory]] calculations. Each element of a Feynman diagram represents a different term in our calculation.
  
 The thing is that we can't calculate things in quantum field theory exactly, but only using a perturbation approach (Taylor series). The first term in this approximation to the correct result yields the biggest contribution and thus is the most important part.  The thing is that we can't calculate things in quantum field theory exactly, but only using a perturbation approach (Taylor series). The first term in this approximation to the correct result yields the biggest contribution and thus is the most important part. 
 +
 +{{ :​advanced_notions:​quantum_field_theory:​virtualparticles.png?​nolink&​250|}}
  
 An example can be seen on the right-hand side. In this example two electrons scatter. They do this by exchanging a photon $\gamma$, which is denoted by a wiggly line. After the exchange of the photon the two electrons move away from each other with different momenta. ​ An example can be seen on the right-hand side. In this example two electrons scatter. They do this by exchanging a photon $\gamma$, which is denoted by a wiggly line. After the exchange of the photon the two electrons move away from each other with different momenta. ​
Line 26: Line 28:
   * R.D. Mattuck: A Guide to Feynman Diagrams in the Many-body Problem   * R.D. Mattuck: A Guide to Feynman Diagrams in the Many-body Problem
   * For the derivation of the Feynman rules for a given theory see section 2 of [[http://​cds.cern.ch/​record/​186259/​|Diagrammar]] by Veltman and '​tHooft   * For the derivation of the Feynman rules for a given theory see section 2 of [[http://​cds.cern.ch/​record/​186259/​|Diagrammar]] by Veltman and '​tHooft
 +
 +Take note that the usage of Feynman diagrams is not limited to Quantum Mechanics. See:
 +
 +  * A. Thorndike, “Using Feynman diagrams to solve the classical harmonic oscillator,​” Am. J. Phys. 68 (2), 155-159 (2000)
 +  * R. Penco and D. Mauro, “Perturbation theory via Feynman diagrams in classical mechanics,​” hep-th/​0605061. ​
  
 ---- ----
Line 35: Line 42:
 <tabbox Abstract> ​ <tabbox Abstract> ​
  
-<note tip> +  * [[https://arxiv.org/abs/math/​0406251|Feynman Diagrams for Pedestrians and Mathematicians]] by MPolyak 
-The motto in this section is: //the higher the level of abstraction,​ the better//. +
-</​note>​+
  
   ​   ​
advanced_tools/feynman_diagrams.1523691040.txt.gz · Last modified: 2018/04/14 07:30 (external edit)