Arias Carrasco, José MiguelDukelsky, J.García Ramos, José Enrique2012-02-072012-02-072003-10-14Arias Carrasco, J.M., Dukelsky, J., García Ramos, J.E. : "Quantum Phase Transitions in the Interacting Boson Model: Integrability, level repulsion and level crossing". Physical Review Letters. Vol. 91, n. 16 (2003). ISSN 0031-90070031-9007http://hdl.handle.net/10272/5465We 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.engAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/BosonesBoson modelQuantum phase transitionsjournal articleopen access