Evolution of Nuclear Observables in the Spherical-Deformed Phase Transition and the Interacting Boson Model

2004 ◽  
Author(s):  
N. V. Zamfir
Keyword(s):  
Phase Transition ◽  
Interacting Boson Model ◽  
Boson Model

scholarly journals Line of approximate SU(3) symmetry inside the symmetry triangle of the Interacting Boson Model

2020 ◽  
Vol 19 ◽  
pp. 16
Author(s):  
D. Bonatsos ◽  
S. Karampagia ◽  
R. F. Casten
Keyword(s):  
Phase Transition ◽  
Critical Line ◽  
Interacting Boson Model ◽  
Rigid Rotator ◽  
Symmetry Line ◽  
First Order ◽  
Boson Number ◽  
Boson Model ◽  
Shape Phase Transition ◽  
First Time

The U(5), SU(3), and O(6) symmetries of the Interacting Boson Model (IBM) have been traditionally placed at the vertices of the symmetry triangle, while an O(5) symmetry is known to hold along the U(5)–O(6) side of the triangle. We construct [1] for the first time a symmetry line in the interior of the triangle, along which the SU(3) symmetry is preserved. This is achieved by using the contraction of the SU(3) algebra to the algebra of the rigid rotator in the large boson number limit of the IBM. The line extends from the SU(3) vertex to near the critical line of the first order shape/phase transition separating the spherical and prolate deformed phases. It lies within the Alhassid–Whelan arc of regularity, the unique valley of regularity connecting the SU(3) and U(5) vertices amidst chaotic regions, thus providing an explanation for its existence.

scholarly journals Connecting the X(5)-β2, X(5)-β4, and X(3) models to the shape/phase transition region of the Interacting Boson Model

2020 ◽  
Vol 15 ◽  
pp. 118
Author(s):  
E. A. McCutchan ◽  
D. Bonatsos ◽  
R. F. Casten
Keyword(s):  
Phase Transition ◽  
Transition Region ◽  
Interacting Boson Model ◽  
Shape Transition ◽  
Scale Factors ◽  
Phase Transition Region ◽  
Boson Model ◽  
Shape Phase Transition ◽  
Two Parameter ◽  
Boson Approximation

The parameter independent (up to overall scale factors) predictions of the X(5)-β2, X(5)-β4, and X(3) models, which are variants of the X(5) critical point symmetry developed within the framework of the geometric collective model, are compared to two- parameter calculations in the framework of the interacting boson approximation (IBA) model. The results show that these geometric models coincide with IBA parameters consistent with the phase/shape transition region of the IBA for boson numbers of physical interest (close to 10). 186Pt and 172Os are identified as good examples of X(3), while 146Ce, 174Os and 158Er, 176Os are identified as good examples of X(5)-β2 and X(5)-β4 behavior respectively.

Simultaneous description of low-lying positive and negative parity states in spd, sdf and spdf interacting boson model

2016 ◽  
Vol 25 (11) ◽  
pp. 1650089 ◽  
Author(s):  
M. A. Jafarizadeh ◽  
A. Jalili Majarshin ◽  
N. Fouladi
Keyword(s):  
Phase Transition ◽  
Lie Algebra ◽  
Degrees Of Freedom ◽  
Energy Levels ◽  
Negative Parity ◽  
Interacting Boson Model ◽  
Algebraic Solution ◽  
Transitional Region ◽  
Boson Model ◽  
Usual Formula

In order to investigate negative parity states, it is necessary to consider negative parity-bosons additionally to the usual [Formula: see text]- and [Formula: see text]-bosons. The dipole and octupole degrees of freedom are essential to describe the observed low-lying collective states with negative parity. An extended interacting boson model (IBM) that describes pairing interactions among s, p, d and f-boson based on affine [Formula: see text] Lie algebra in the quantum phase transition (QPT) field, such as spd-IBM, sdf-IBM and spdf-IBM, is composed based on algebraic structure. In this paper, a solvable extended transitional Hamiltonian based on affine [Formula: see text] Lie algebra is proposed to describe low-lying positive and negative parity states between the spherical and deformed gamma-unstable shape. Three model of new algebraic solution for even–even nuclei are introduced. Numerical extraction to low-lying energy levels and transition rates within the control parameters of this evaluated Hamiltonian are presented for various [Formula: see text] values. We reproduced the positive and negative parity states and our calculations suggest that the results of spdf-IBM are better than spd-IBM and sdf-IBM in this literature. By reproducing the experimental results, the method based on signature of the phase transition such as level crossing in the lowest excited states is used to provide a better description of Ru isotopes in this transitional region.

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