Large-q series expansion for the ground state degeneracy of the q-state Potts antiferromagnet on the (3.12^2) lattice

Abstract

We calculate the large-$q$ series expansion for the ground state degeneracy (= exponent of the ground state entropy) per site of the $q$-state Potts antiferromagnet on the $(3 \cdot 12^2)$ lattice, to order $O(y^{19})$, where $y=1/(q-1)$. We note a remarkable agreement, to $O(y^{18})$, between this series and a rigorous lower bound derived recently.Comment: 10 pages, Latex, 3 encapsulated postscript figures, to appear in Phys. Rev.