Partition Function Zeros of the Spin-One Ising Model on the Honeycomb Lattice in the Complex Temperature Plane

The spin-one Ising model on the honeycomb lattice has never been solved exactly in spite of its simplicity. Even its exact critical temperature is not known. The exact integer values for the density of states of the spin-one Ising model on the $L\times 2L$ honeycomb lattice are enumerated up to $L=14$. The partition function zeros in the complex temperature plane of the spin-one Ising model on the $L\times 2L$ honeycomb lattice are exactly obtained, using the density of states. The properties of the partition function zeros in the complex temperature plane are related to the behaviors of various thermodynamic functions, in particular, their singular behaviors. The unknown properties of the spin-one Ising model on the honeycomb lattice are investigated, based on its partition function zeros in the complex temperature plane.