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Quantum Phase Transitions in the Interacting Boson Model: Integrability, level repulsion and level crossing

J. M. Arias·J. Dukelsky·J. E. Garcia-Ramos
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Abstract

We study the quantum phase transition mechanisms that arise in the Interacting Boson Model. We show that the second-order nature of the phase transition from U(5) to O(6) may be attributed to quantum integrability, whereas all the first-order phase transitions of the model are due to level repulsion with one singular point of level crossing. We propose a model Hamiltonian with a true first-order phase transition for finite systems due to level crossings.

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J. M. Arias, J. Dukelsky, J. E. Garcia-Ramos. 2003-09-02. Quantum Phase Transitions in the Interacting Boson Model: Integrability, level repulsion and level crossing. https://doi.org/10.1103/physrevlett.91.162502

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