Statistical mechanics of the cluster Ising model
Statistical mechanics of the cluster Ising model
We study a Hamiltonian system describing a three-spin-$1/2$ clusterlike interaction competing with an Ising-like antiferromagnetic interaction. We compute free energy, spin-correlation functions, and entanglement both in the ground and in thermal states. The model undergoes a quantum phase transition between an Ising phase with a nonvanishing magnetization and a cluster …