Statistical mechanics of the Cluster-Ising model
Abstract
We study a Hamiltonian system describing a three-spin-1/2 cluster-like interaction competing with an Ising-like anti-ferromagnetic 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 phase characterized by a string order. Any two-spin entanglement is found to vanish in both quantum phases because of a nontrivial correlation pattern. Neverthless, the residual multipartite entanglement is maximal in the cluster phase and dependent on the magnetization in the Ising phase. We study the block entropy at the critical point and calculate the central charge of the system, showing that the criticality of the system is beyond the Ising universality class.
Cite
@article{arxiv.1105.0853,
title = {Statistical mechanics of the Cluster-Ising model},
author = {Pietro Smacchia and Luigi Amico and Paolo Facchi and Rosario Fazio and Giuseppe Florio and Saverio Pascazio and Vlatko Vedral},
journal= {arXiv preprint arXiv:1105.0853},
year = {2011}
}
Comments
To be published in Physical Review A