Correlated percolation with long-range interactions.

Abstract

We study the critical behavior of the q-state Potts model with long-range interactions decaying asymptotically as \ensuremath{\sim}${R}^{\mathrm{\ensuremath{-}}(d+\ensuremath{\sigma})}$ in the presence of random-${T}_{c}$ impurities correlated over large distances such that the correlations fall off as \ensuremath{\sim}${R}^{\mathrm{\ensuremath{-}}(d\mathrm{\ensuremath{-}}a)}$, a<d. We find that the renormalization-group scaling equations have a new fixed point in the appropriate double \ensuremath{\epsilon}, x expansion, where \ensuremath{\epsilon}=3\ensuremath{\sigma}-d and x=a-\ensuremath{\sigma}. This fixed point, however, is never both stable and physical.