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QED vs Point Charge of the Electron 
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#1
Dec1105, 11:32 PM

P: 162

If the electron is a point charge, then its' charge to mass ratio approaches infinity. How does the Standard Model (QED) deal with this?



#3
Dec1205, 05:20 PM

P: 34




#4
Dec1205, 06:04 PM

Sci Advisor
HW Helper
P: 1,332

QED vs Point Charge of the Electron
I would assume Buckeye is referring to the fact that a point particle has a divergent electromagnetic self energy. What has not been mentioned is that the charge of the electron also diverges. As marlon said, both these divergences are dealt with by first acknowledging our ignorance of the high energy physics and then by renormalizing both parameters at each order in perturbation theory. The predictive power of the theory is restored.



#5
Dec1205, 08:51 PM

P: n/a




#6
Dec1205, 11:54 PM

P: 162

If we treat the electron as a charge with a finite size, do we need to renormalize?



#7
Dec1305, 12:47 AM

Emeritus
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PF Gold
P: 6,236

What happens then is that the *relationship* between low energy quantities remains unchanged. In nonrenormalizable theories, this doesn't happen: we depend for the low energy behaviour crucially on the details of the cutoff (of the arbitrary structure we introduced). 


#8
Dec1305, 06:09 AM

P: 4,006

Trust me, the source is reliable regards marlon 


#9
Dec1305, 06:57 AM

Emeritus
PF Gold
P: 8,147

Reliable? Famous perhaps, but also maybe cranky? It doesn't follow because somebody made a wonderful discovery back when, that he is today a reliable guide on controversial issues. Recall Dirac and his later life adventures.



#10
Dec1305, 07:15 AM

P: 4,006

regards marlon 


#11
Dec1305, 02:56 PM

P: 162

Yes, No or Option C? 


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