Quantum gravity in 4-e dimension

[eljose79]

let be e>0 but small so quantum gravity is renormalizable then what would be the calculation of mass and charge of it depending on e,now let,s take the limit e--->0 what would we have?...

 

[marlon]

Excuse me ?

marlon

 

[nrqed]

let be e>0 but small so quantum gravity is renormalizable then what would be the calculation of mass and charge of it depending on e,now let,s take the limit e--->0 what would we have?...

Excuse me ?

marlon

To Marlon: he (or she) means [itex] \epsilon [/itex] in the sense of dimensional regularization, as is obvious from the title of his post.

To the original poster: any calculation would of course be finite if [itex] \epsilon [/itex] is large enough. As [itex] \epsilon [/itex], quantities will become infinite but that's not particular to quantum gravity. The same thing happens in QED, QCD, etc. What is special to quantum gravity is that you can't eliminate those divergences by redefining a finite number of parameters in the theory (in contrast with QED, QCD etc.), you need to redefine more and more parameters as you calculate more and more loops. That's what makes it nonrenormalizable and therefore "bad". But as an effective field theory, quantum gravity is as good as any other field theory.

Pat