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Artículo
Continuous unitary transformations in two-level boson systems
(American Physical Society, 2005-12-01)
Two-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 ...
Artículo
Scalar two-level boson model to study the interacting boson model phase diagram in the Casten triangle
(American Physical Society, 2006)
We introduce a simple two-level boson model with the same energy surface as the Q-consistent interacting boson model Hamiltonian. The model can be diagonalized for large number of bosons and the results used to check ...
Artículo
Relationship between X(5) models and the interacting boson model
(The American Physical Society, 2010)
The connections between the X(5) models [the original X(5) using an infinite square well, X(5)-β8, X(5)-β6, X(5)-β4, and X(5)-β2], based on particular solutions of the geometrical Bohr Hamiltonian with harmonic potential ...
Artículo
Disentangling phase transitions and critical points in the proton-neutron interacting boson model by catastrophe theory
(Elsevier, 2014)
We introduce the basic concepts of catastrophe theory needed to derive analytically the phase diagram of the proton–neutron interacting boson model (IBM-2). Previous studies [1–3] were based on numerical solutions. We here ...
Artículo
Intrinsic state for an extended version of the interacting boson model
(American Physical Society, 2000-03-01)
An intrinsic-state formalism for the interacting boson model IBM-4 is presented. A basis of deformed bosons is introduced which allows the construction of a general trial wave function that has Wigner’s spin-isospin SU(4) ...
Artículo
Phase diagram for a cubic-Q interacting boson model Hamiltonian: Signs of triaxiality
(American Physical Society, 2011)
An extension of the Interacting Boson Model that includes the cubic (QI×QI×Q I)(0) term is proposed. The potential energy surface for the cubic quadrupole interaction is explicitly calculated within the coherent state ...
Artículo
Phase diagram of the two-fluid Lipkin model: A "butterfly" catastrophe
(American Physical Society, 2016-03-31)
Background: In the past few decades quantum phase transitions have been of great interest in nuclear physics. In this context, two-fluid algebraic models are ideal systems to study how the concept of quantum phase transition ...
Artículo
Relation between E(5) models and the interacting boson model
(The American Physical Society, 2008)
The connections between the E(5) models [the original E(5) using an infinite square well, E(5)-β4, E(5)-β6, and E(5)-β8], based on particular solutions of the geometrical Bohr Hamiltonian with γ-unstable potentials, and ...
Artículo
An extended Agassi model: Algebraic structure, phase diagram, and large size limit
(Institute of Physics Publishing, 2019)
The Agassi model (Agassi 1968 Nucl. Phys. A 116 49) is a schematic two-level model that involves pairing and monopole-monopole interactions. It is, therefore, an extension of the well known Lipkin-Meshkov-Glick model (Lipkin ...
Artículo
Excited-state phase transition and onset of chaos in quantum optical models
(American Physical Society, 2011)
We study the critical behavior of excited states and its relation to order and chaos in the Jaynes-Cummings and Dicke models of quantum optics. We show that both models exhibit a chain of excited-state quantum phase ...