Question on Montonen-Olive duality

[metroplex021]

Hi folks,

I've been reading about Montonen-Olive duality and understand that two different classical theories can give rise to the same QFT. In particular, we can have a classical theory of electrically charged particles giving rise to a magnetic monopole, and a classical theory of magnetic monopoles giving rise to a composite charged particle -- and have these both as limits of one QFT. The literature on this issue makes clear that the first theory will be the h->0 limit of the QFT with the magnetic charge held fixed, and the second theory will be the h->0 limit of the QFT with the electrical charged held fixed.

But what I don't understand is *why* it is that, when we have a theory of electrically charged particles we regard h as a function of charge and hold the magnetic charged fixed when taking the limit; and vice versa for the theory of magnetic charges. Can anyone give me even a qualitative explanation of why this is the case? I'd appreciate it very much!

Thanks

 

[Greg Bernhardt]

I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?

 

[andrien]

It is more of a philosophical question rather than a real science question. It is actually a matter of convenience in which you want to treat it.

If for example you are doing Feynman diagram, then you should better keep track with electrical charge because it is small and your perturbation theory will do fine. However if you want to use magnetic charge, then your coupling strength will be higher ( in case you just use Dirac quantization condition), and your perturbation theory will break down. Both are equally correct, but it is a matter of convenience.