Coulomb gas method

Summary

The Coulomb gas method is a technique for two-dimensional critical lattice models. It rewrites the partition function of a model as that of a gas of point charges with logarithmic interactions. Equivalently, it uses a Gaussian free field with charges. The Gaussian theory can be solved exactly, so one can read off critical exponents and other universal quantities. It explains the Berezinskii–Kosterlitz–Thouless transition of the XY model and gives exact predictions for loop models, Potts models and self-avoiding walks.