QED Feynman (coupling number called j)

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The discussion focuses on Richard Feynman's description of the coupling number, denoted as j, which is approximately -0.1 for the electron, often referred to as "charge." In Quantum Electrodynamics (QED), the charge on the electron is represented as e^2=1/137, leading to e being approximately 0.1. The conversation highlights the use of natural units in QED, where the relationship e^2/(ħc)=1/137 is emphasized, along with the option to incorporate 1/(4πε₀) for further clarity.

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On page 92 (Figure 58) Feynman states:
"The amplitude for a coupling is a number that I will call j; it is about
negative .1 for the electron (this number is sometimes called the "charge").
Charge?? I don't get it.
Would appreciate an explanation?
 
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eb227 said:
On page 92 (Figure 58) Feynman states:
"The amplitude for a coupling is a number that I will call j; it is about
negative .1 for the electron (this number is sometimes called the "charge").
Charge?? I don't get it.
Would appreciate an explanation?
In what is called "natural units" in QED, the charge on the electron is given by e^2=1/137, so e would be about .1.
If you want to put in units, you would have e^2/(hbar c)=1/137.
You could even put in 1/fourpiepsilonzero if you want.
 

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