Arias Carrasco, José MiguelDukelsky, J.García Ramos, José EnriqueVidal, Julien2012-02-062012-02-062007-01-02Arias Carrasco, J.M., Dukelsky, J., García Ramos, J.E., Vidal, J.: "Two-level interacting boson models beyond the mean field". Physical Review C . Vol. 75, n. 1 (2007). ISSN 0556-28130556-2813http://hdl.handle.net/10272/5458The phase diagram of two-level boson Hamiltonians, including the Interacting Boson Model (IBM), is studied beyond the standard mean field approximation using the Holstein-Primakoff mapping. The limitations of the usual intrinsic state (mean field) formalism concerning finite-size effects are pointed out. The analytic results are compared to numerics obtained from exact diagonalizations. Excitation energies and occupation numbers are studied in different model space regions (Casten triangle for IBM) and especially at the critical points.engAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/BosonesFísica nuclearBoson modeljournal articleopen access