Physical Review Letters
Critical Points for Dimer Models with 32 -Order Transitions
John F. Nagle
Abstract
A new extensive variable $A$ and its conjugate field II are introduced for the Kasteleyn dimer model on the honeycomb lattice via an isomorphic membrane-polymer chain model. The resultant phase diagram has a first-order phase line, thereby revealing a non-local order parameter in this model for the first time. The first-order line terminates in a critical point with critical exponents $\ensuremath{\alpha}={\ensuremath{\alpha}}^{\ensuremath{'}}=0$, $\ensuremath{\beta}=1=\ensuremath{\gamma}={\ensuremath{\gamma}}^{\ensuremath{'}}$, and $\ensuremath{\delta}=2$. The $\frac{3}{2}$-order exponents appear on the line $\ensuremath{\Pi}={\ensuremath{\Pi}}_{\mathrm{critical}}$.