Quantum phase transitions in networks of Lipkin-Meshkov-Glick models

A. V. Sorokin; V. M. Bastidas; T. Brandes

doi:10.1103/physreve.90.042141

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arXiv · 1407.2530

Quantum phase transitions in networks of Lipkin-Meshkov-Glick models

A. V. Sorokin·V. M. Bastidas·T. Brandes

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Abstract

We study the quantum critical behavior of networks consisting of Lipkin-Meshkov-Glick models with an anisotropic ferromagnetic coupling. We focus on the low-energy properties of the system within a mean-field approach and the quantum corrections around the mean-field solution. Our results show that the weak-coupling regime corresponds to the paramagnetic phase when the local field dominates the dynamics, but the local anisotropy leads to the existence of an exponentially-degenerate ground state. In the strong-coupling regime, the ground state is twofold degenerate and possesses long-range magnetic ordering. Analytical results for a network with the ring topology are obtained.

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A. V. Sorokin, V. M. Bastidas, T. Brandes. 2014-07-09. Quantum phase transitions in networks of Lipkin-Meshkov-Glick models. https://doi.org/10.1103/physreve.90.042141

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