Dusuel, SébastienVidal, JulienArias Carrasco, José MiguelDukelsky, J.García Ramos, José Enrique2012-03-022012-03-022005-12-30Dusuel, S., Vidal, J., Arias Carrasco, J.M., Dukelsky, J., García Ramos, J. E.: "Continuous unitary transformations in two-level boson systems". Physical Review C. Vol. 72, n. 6 (2005). ISSN 0556-28130556-2813http://hdl.handle.net/10272/5500Two-level boson systems displaying a quantum phase transition from a spherical (symmetric) to a deformed (broken) phase are studied. A formalism to diagonalize Hamiltonians with O(2L + 1) symmetry for large number of bosons is worked out. Analytical results beyond the simple mean-field treatment are deduced by using the continuous unitary transformations technique. In this scheme, a 1/N expansion for different observables is proposed and allows one to compute the finite-size scaling exponents at the critical point. Analytical and numerical results are compared and reveal the power of the present approach to compute the finite-size corrections in such a context.engAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/BosonesQuantum phase transitionsInteracting Boson Modeljournal article10.1103/PhysRevC.72.064332open access