Introduction to renormalization
arXiv:cond-mat/0606139
Abstract
In these lectures I discuss peculiarities of the critical behaviour of ``non-ideal'' systems as it is explained by the renormalization group approach. Examples considered here include account of the single-ion anisotropy, structural disorder, frustrations. I introduce main ideas of renormalization and show how it serves the explanation of typical features of criticality in the above systems: softening of the phase transition, changes in the universality class, complicated effective critical behaviour.
Lecture given at the Mochima spring school on foundations of statistical and mesoscopic physics, Mochima, Venezuela, June 2006