Calc QED Charge Particle Repulsion/Attraction

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SUMMARY

The discussion focuses on calculating quantum electrodynamics (QED) charge particle interactions using Feynman diagrams. Participants emphasize the importance of deriving transition-matrix elements (S-matrix elements) from these diagrams to compute cross sections of scattering processes. It is crucial to perform calculations to at least second order, as leading order results yield identical scattering outcomes. Recommended resources include M. D. Schwartz's "Quantum Field Theory and the Standard Model" for foundational understanding.

PREREQUISITES
  • Understanding of Feynman diagrams in quantum field theory
  • Knowledge of transition-matrix elements (S-matrix elements)
  • Familiarity with perturbative calculations in QED
  • Basic concepts of scattering processes and cross sections
NEXT STEPS
  • Study perturbative calculations in QED using Feynman diagrams
  • Learn about S-matrix elements and their significance in particle physics
  • Explore second-order calculations in quantum electrodynamics
  • Read M. D. Schwartz's "Quantum Field Theory and the Standard Model" for in-depth knowledge
USEFUL FOR

Physicists, students of quantum field theory, and anyone interested in understanding particle interactions and scattering processes in QED.

ILoveParticlePhysics
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TL;DR
What is the formula for calculating the repulsion/attraction of charged particles in quantum electrodynamics?
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You just draw the Feynman diagram and calculute it according to the rules derived from the formalism. Feynman diagrams are just an ingenious shortcut to do these perturbative calculations. What you get are transition-matrix elements (S-matrix elements) from which you can calculate cross sections of scattering processes.
 
Note that you will need to calculate this to at least second order, because at leading order the scattering is the same either way.
 
vanhees71 said:
You just draw the Feynman diagram and calculute it according to the rules derived from the formalism. Feynman diagrams are just an ingenious shortcut to do these perturbative calculations. What you get are transition-matrix elements (S-matrix elements) from which you can calculate cross sections of scattering processes.
So, I calculate and draw the Feynman diagram, from which I get the S matrix elements from which I get the cross section of scattering processes which tells me how everything is going to repel/attract, right?
 
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Vanadium 50 said:
Note that you will need to calculate this to at least second order, because at leading order the scattering is the same either way.
This might sound dumb, but what exactly is 2nd order.
 
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That looks like a good summary, but of course to really understand it, you should refer to some textbook on quantum field theory, e.g.,

M. D. Schwartz, Quantum field theory and the Standard
Model, Cambridge University Press, Cambridge, New York
(2014).
 
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ILoveParticlePhysics said:
This might sound dumb, but what exactly is 2nd order.

Um, you haven't done any QED calculations, have you? It would be better for you to fill in your background than having me define words you don't understand with other words you don't understand. The easiest calculation is probably e+e- --> mu+mu-. I'd start there.
 
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