arXiv:1902.03226 · Journal of Mathematical Physics
A quantum Markov chain approach to phase transitions for quantum Ising model with competing XY-interactions on a Cayley tree
Farrukh Mukhamedov, Abdessatar Barhoumi, Abdessatar Souissi, El Gheteb Soueidi
Abstract
The main aim of the present paper by means of the quantum Markov chain (QMC) approach is to establish the existence of a phase transition for the quantum Ising model with competing XY interaction. In this scheme, the C*-algebraic approach is employed to the phase transition problem. Note that these kinds of models do not have one-dimensional analogs, i.e., the considered model persists only on trees. It turns out that if the Ising part interactions vanish, then the model with only competing XY-interactions on the Cayley tree of order two does not have a phase transition. By phase transition, we mean the existence of two distinct QMCs that are not quasi-equivalent and their supports do not overlap. Moreover, it is also shown that the QMC associated with the model has a clustering property, which implies that the von Neumann algebras corresponding to the states are factors.