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advanced_tools:feynman_diagrams [2018/04/14 09:30] aresmarrero [Intuitive] |
advanced_tools:feynman_diagrams [2018/05/05 12:38] jakobadmin ↷ Links adapted because of a move operation |
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- | 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. |