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advanced_tools:feynman_diagrams [2018/04/14 09:30] aresmarrero [Intuitive] |
advanced_tools:feynman_diagrams [2018/07/07 10:22] (current) jakobadmin [Concrete] |
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<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. | ||
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+ | {{ :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. | ||
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* 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 | ||
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+ | Take note that the usage of Feynman diagrams is not limited to Quantum Mechanics. See: | ||
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+ | * 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. | ||
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<tabbox Abstract> | <tabbox Abstract> | ||
- | <note tip> | + | * [[https://arxiv.org/abs/math/0406251|Feynman Diagrams for Pedestrians and Mathematicians]] by M. Polyak |
- | The motto in this section is: //the higher the level of abstraction, the better//. | + | |
- | </note> | + | |
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