Strongly interacting vs Weakly interacting particles

deepurple

I am a mathematician, and I am trying to figure out a physics paper for my research. I am not a physicist but I have some college background on physics.

I am trying to understand the difference between strongly interacting systems compared to weakly interacting systems.. These are used very ubiquitously in the paper, and they seem to be obvious for the right audience.

Could you please brief me on the subject? ( I hope I post to the correct forum)

genneth

Essentially, something is weakly interacting if you can perform a perturbative calculation. More accurately, a perturbative approximation, since most of the time the expansion is only asymptotically convergent. Strongly interacting is whenever this is not possible.

Usually, we perform expansions about Gaussian theories, since they are exactly solvable. This then leads to the usual formalisms with Feynmann diagrams or Dyson equations. In principle however, there is nothing to stop you doing perturbation theory about other points of theory space.

deepurple

Thanks for the response.. This was all I need