SU(3) quasidynamical symmetry underlying the Alhassid--Whelan arc of regularity (2009)
Bonatsos, Dennis, McCutchan, E. A., Casten, R. F.
The first example of an empirically manifested quasi dynamical symmetry trajectory in the interior of the symmetry triangle of the Interacting Boson Approximation model is identified for large boson...
Bohr Hamiltonian with deformation-dependent mass term (2009)
Bonatsos, Dennis, Georgoudis, P., Lenis, D., Minkov, N., Quesne, C.
The Bohr Hamiltonian describing the collective motion of atomic nuclei is modified by allowing the mass to depend on the nuclear deformation. Exact analytical expressions are derived for spectra and...
Regularities and symmetries of subsets of collective 0+ states (2009)
Bonatsos, Dennis, McCutchan, E. A., Casten, R. F., Casperson, R. J., Werner, V., Williams, E.
The energies of subsets of excited 0+ states in geometric collective models are investigated and found to exhibit intriguing regularities. In models with an infinite square well potential, it is...
0+ states in the large boson number limit of the Interacting Boson Approximation model (2008)
Bonatsos, Dennis, McCutchan, E. A., Casten, R. F.
Studies of the Interacting Boson Approximation (IBA) model for large boson numbers have been triggered by the discovery of shape/phase transitions between different limiting symmetries of the model....
Simple, empirical order parameter for a first order quantum phase transition in atomic nuclei (2008)
Bonatsos, Dennis, McCutchan, E. A., Casten, R. F., Casperson, R. J.
A simple, empirical signature of a first order phase transition in atomic nuclei is presented, the ratio of the energy of the 6+ level of the ground state band to the energy of the first excited 0+...
Unified description of 0+ states in a large class of nuclear collective models (2008)
Bonatsos, Dennis, McCutchan, E. A., Casten, R. F.
A remarkably simple regularity in the energies of 0+ states in a broad class of collective models is discussed. A single formula for all 0+ states in flat-bottomed infinite potentials that depends...
Exactly separable version of the Bohr Hamiltonian with the Davidson potential (2008)
Bonatsos, Dennis, McCutchan, E. A., Minkov, N., Casten, R. F., Yotov, P., Lenis, D., ...
An exactly separable version of the Bohr Hamiltonian is developed using a potential of the form u(beta)+u(gamma)/beta^2, with the Davidson potential u(beta)= beta^2 + beta_0^4/beta^2 (where beta_0 is...
What can we learn from the Interacting Boson Model in the limit of large boson numbers? (2008)
Bonatsos, Dennis, McCutchan, E. A., Casten, R. F.
Over the years, studies of collective properties of medium and heavy mass nuclei in the framework of the Interacting Boson Approximation (IBA) model have focused on finite boson numbers,...
Shape/Phase Transitions and Critical Point Symmetries in Atomic Nuclei (2008)
Shape/phase transitions in atomic nuclei have first been discovered in the framework of the Interacting Boson Approximation (IBA) model. Critical point symmetries appropriate for nuclei at the...
Complementary descriptions of shape/phase transitions in atomic nuclei (2008)
Bonatsos, Dennis, McCutchan, E. A., Zamfir, N. V.
Shape/phase transitions in atomic nuclei have first been discovered in the framework of the Interacting Boson Approximation (IBA) model. Critical point symmetries appropriate for nuclei at the...
Special Solutions of the Bohr Hamiltonian Related to Shape Phase Transitions in Nuclei (2007)
Bonatsos, Dennis, Lenis, D., Petrellis, D.
Nuclei exhibit quantum phase transitions (earlier called ground state phase transitions) between different shapes as the number of nucleons is modified, resulting in changes in the ground and low...
Dennis Bonatsos, D. Lenis, D. Petrellis, P. A. Terziev, I. Yigitoglu
An exact, parameter free (up to overall scale factors) solution of the Bohr Hamiltonian is obtained by freezing the � degree of freedom at � = 30�. A structural similarity between the spectrum...
McCutchan, E. A., Bonatsos, Dennis, Zamfir, N. V.
The parameter independent (up to overall scale factors) predictions of the X(5)-$\beta^2$, X(5)-$\beta^4$, and X(3) models, which are variants of the X(5) critical point symmetry developed within the...
Parameter-Free Solution of the Bohr Hamiltonian for Actinides Critical in the Octupole Mode (2005)
An analytic, parameter-free (up to overall scale factors) solution of the Bohr Hamiltonian involving axially symmetric quadrupole and octupole deformations, as well as an infinite well potential, is...
X(3): An Exactly Separable Gamma-Rigid Version of the X(5) Critical Point Symmetry (2005)
Bonatsos, Dennis, Lenis, D., Petrellis, D., Terziev, P. A., Yigitoglu, I.
A gamma-rigid version (with gamma=0) of the X(5) critical point symmetry is constructed. The model, to be called X(3) since it is proved to contain three degrees of freedom, utilizes an infinite well...
Critical Point Symmetries in Nuclei (2005)
Bonatsos, Dennis, Lenis, D., Petrellis, D., Terziev, P. A., Yigitoglu, I.
Critical Point Symmetries (CPS) appear in regions of the nuclear chart where a rapid change from one symmetry to another is observed. The first CPSs, introduced by F. Iachello, were E(5), which...
Bonatsos, Dennis, Lenis, D., Petrellis, D., Terziev, P. A., Yigitoglu, I.
A gamma-rigid solution of the Bohr Hamiltonian for gamma = 30 degrees is derived, its ground state band being related to the second order Casimir operator of the Euclidean algebra E(4)....
Bonatsos, Dennis, Lenis, D., Minkov, N., Petrellis, D., Yotov, P.
An analytic collective model in which the relative presence of the quadrupole and octupole deformations is determined by a parameter (phi_0), while axial symmetry is obeyed, is developed. The model...
W(5): Wobbling Mode in the Framework of the X(5) Model (2004)
Bonatsos, Dennis, Lenis, D., Petrellis, D., Terziev, P. A.
Using in the Bohr Hamiltonian the approximations leading to the Bohr and Mottelson description of wobbling motion in even nuclei, a W(5) model for wobbling bands, coexisting with a X(5) ground state...
Z(5): Critical point symmetry for the prolate to oblate nuclear shape phase transition (2004)
Bonatsos, Dennis, Lenis, D., Petrellis, D., Terziev, P. A.
A critical point symmetry for the prolate to oblate shape phase transition is introduced, starting from the Bohr Hamiltonian and approximately separating variables for $\gamma=30^{\rm o}$....
Bonatsos, Dennis, Lenis, D., Minkov, N., Petrellis, D., Raychev, P. P., Terziev, P. A.
Davidson potentials of the form $\beta^2 +\beta_0^4/\beta^2$, when used in the E(5) framework, bridge the U(5) and O(6) symmetries, while they bridge the U(5) and SU(3) symmetries when used in the...
Sequence of Potentials Interpolating between the U(5) and E(5) Symmetries (2003)
Bonatsos, Dennis, Lenis, D., Minkov, N., Raychev, P. P., Terziev, P. A.
It is proved that the potentials of the form $\beta^{2n}$ (with $n$ being integer) provide a ``bridge'' between the U(5) symmetry of the Bohr Hamiltonian with a harmonic oscillator potential...
Bonatsos, Dennis, Lenis, D., Minkov, N., Petrellis, D., Raychev, P. P., Terziev, P. A.
Davidson potentials of the form $\beta^2 +\beta_0^4/\beta^2$, when used in the original Bohr Hamiltonian for $\gamma$-independent potentials bridge the U(5) and O(6) symmetries. Using a variational...
Rotationally Invariant Hamiltonians for Nuclear Spectra Based on Quantum Algebras (2003)
Bonatsos, Dennis, Kotsos, B. A., Raychev, P. P., Terziev, P. A.
The rotational invariance under the usual physical angular momentum of the SUq(2) Hamiltonian for the description of rotational nuclear spectra is explicitly proved and a connection of this...
Bonatsos, Dennis, Kotsos, B. A., Raychev, P. P., Terziev, P. A.
The rotational invariance under the usual physical angular momentum of the SUq(2) Hamiltonian for the description of rotational molecular spectra is explicitly proved and a connection of this...
Deformed Harmonic Oscillators for Metal Clusters and Balian-Bloch Theory (2003)
Bonatsos, Dennis, Lenis, D., Raychev, P. P., Terziev, P. A.
The predictions for the shell structure of metal clusters of the three-dimensional q-deformed harmonic oscillator (3D q-HO), utilizing techniques of quantum groups and having the symmetry...
Sequence of Potentials Lying Between the U(5) and X(5) Symmetries (2003)
Bonatsos, Dennis, Lenis, D., Minkov, N., Raychev, P. P., Terziev, P. A.
Starting from the original collective Hamiltonian of Bohr and separating the beta and gamma variables as in the X(5) model of Iachello, an exactly soluble model corresponding to a harmonic oscillator...
Deformed Harmonic Oscillators for Metal Clusters: Analytic Properties and Supershells (2002)
Bonatsos, Dennis, Lenis, D., Raychev, P. P., Terziev, P. A.
The analytic properties of Nilsson's Modified Oscillator (MO), which was first introduced in nuclear structure, and of the recently introduced, based on quantum algebraic techniques, 3-dimensional...
Bonatsos, Dennis, Daskaloyannis, C., Drenska, S. B., Fotiades, N., Minkov, N., Raychev, P. P., ...
``Beat'' patterns are shown to appear in the octupole bands of several actinides and rare earths, their appearance being independent from the formula used in order to isolate and demonstrate them. It...
Ground-gamma band mixing and odd-even staggering in heavy deformed nuclei (2000)
Minkov, Nikolay, Drenska, S. B., Raychev, P. P., Roussev, R. P., Bonatsos, Dennis
It is proposed that the odd-even staggering (OES) in the $\gamma$- bands of heavy deformed nuclei can be reasonably characterized by a discrete approximation of the fourth derivative of the odd-even...
Ground-$\gamma$ band coupling in heavy deformed nuclei and SU(3) contraction limit (2000)
Minkov, Nikolay, Drenska, S. B., Raychev, P. P., Roussev, R. P., Bonatsos, Dennis
We derive analytic expressions for the energies and $B(E2)$-transition probabilities in the states of the ground and $\gamma$ bands of heavy deformed nuclei within a collective Vector-Boson Model...
Staggering effects in nuclear and molecular spectra (2000)
Bonatsos, Dennis, Daskaloyannis, C, Drenska, S B, Karoussos, N, Maruani, J, Minkov, N, ...
Ground-$\gamma$ band coupling in a collective scheme with a broken $SU(3)$ symmetry (2000)
Minkov, N, Drenska, S B, Raychev, P P, Roussev, R P, Bonatsos, Dennis
$\Delta J = 2$ staggering in rotational bands of diatomic molecules (2000)
Bonatsos, Dennis, Daskaloyannis, C, Drenska, S B, Lalazissis, G A, Minkov, N, Raychev, P P, ...
Broken SU(3) symmetry and ground-$\gamma$ band coupling in deformed even-even nuclei (2000)
Minkov, N, Drenska, S B, Raychev, P P, Roussev, R P, Bonatsos, Dennis
Parafermions and generalized parafermions in physical systems (1999)
Bonatsos, Dennis, Daskaloyannis, C, Kanakoglou, K, Petsos, G
$Ground-\gamma$ band coupling in heavy deformed nuclei and SU(3) contraction limit (1999)
Minkov, N, Drenska, S B, Raychev, P P, Roussev, R P, Bonatsos, Dennis
Parafermionic and Generalized Parafermionic Algebras (1999)
Bonatsos, Dennis, Daskaloyannis, C., Kanakoglou, K.
The general properties of the ordinary and generalized parafermionic algebras are discussed. The generalized parafermionic algebras are proved to be polynomial algebras. The ordinary parafermionic...
Quantum Groups and Their Applications in Nuclear Physics (1999)
Bonatsos, Dennis, Daskaloyannis, C.
Quantum algebras are a mathematical tool which provides us with a class of symmetries wider than that of Lie algebras, which are contained in the former as a special case. After a self-contained...
Quantum Algebraic Symmetries in Nuclei, Molecules and Atomic Clusters (1999)
Bonatsos, Dennis, Daskaloyannis, C.
Various applications of quantum algebraic techniques in nuclear structure physics and in molecular physics are briefly reviewed and a recent application of these techniques to the structure of atomic...
The 3-Dimensional q-Deformed Harmonic Oscillator and Magic Numbers of Alkali Metal Clusters (1999)
Bonatsos, Dennis, Karoussos, N., Raychev, P. P., Roussev, R. P., Terziev, P. A.
Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator with Uq(3) > SOq(3) symmetry are compared to experimental data for alkali metal clusters, as well as to theoretical...
Generalized deformed oscillator for vortices in superfluid films (1997)
Bonatsos, Dennis, Daskaloyannis, C.
The algebra of observables of a system of two identical vortices in a superfluid thin film is described as a generalized deformed oscillator with a structure function containing a linear (harmonic...
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
The concept of bisection of a harmonic oscillator or hydrogen atom, used in the past in establishing the connection between U(3) and O(4), is generalized into multisection (trisection, tetrasection,...
Symmetries in nuclei and molecules (1997)
Bonatsos, Dennis, Kolokotronis, P., Lenis, D., Daskaloyannis, C., Lalazissis, G. A., Drenska, S. B., ...
Recent progress in two different fronts is reported. First, the concept of bisection of a harmonic oscillator (HO) or hydrogen atom (HA), used in the past in establishing the connection between U(3)...
Investigations of the broken SU(3) symmetry in deformed even-even nuclei (1997)
Minkov, N., Drenska, S., Raychev, P., Roussev, R., Bonatsos, Dennis
A collective vector-boson model with broken SU(3) symmetry is applied to several deformed even-even nuclei. The model description of ground and $\gamma$ bands together with the corresponding B(E2)...
Coupled Q-oscillators as a model for vibrations of polyatomic molecules (1997)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P.
The system of two $Q$-deformed oscillators coupled so that the total Hamiltonian has the su$_Q$(2) symmetry is proved to be equivalent, to lowest order approximation, to a system of two identical...
Coupled Q-oscillators as a model for vibrations of polyatomic molecules (1996)
Bonatsos, Dennis, Daskaloyannis, C, Kolokotronis, P
The system of two $Q$-deformed oscillators coupled so that the total Hamiltonian has the su$_Q$(2) symmetry is proved to be equivalent, to lowest order approximation, to a system of two identical...
Generalized deformed oscillator for vortices in superfluid films (1996)
Bonatsos, Dennis, Daskaloyannis, C
The algebra of observables of a system of two identical vortices in a superfluid thin film is described as a generalized deformed oscillator with a structure function containing a linear (harmonic...
Investigations of the broken SU(3) symmetry in deformed even-even nuclei (1996)
Minkov, N, Drenska, S B, Raychev, P P, Roussev, R P, Bonatsos, Dennis
A collective vector-boson model with broken SU(3) symmetry is applied to several deformed even-even nuclei. The model description of ground and $\gamma$ bands together with the corresponding B(E2)...
Symmetries in nuclei and molecules (1996)
Bonatsos, Dennis, Kolokotronis, P, Lenis, D, Daskaloyannis, C, Lalazissis, G A, Drenska, S B, ...
Recent progress in two different fronts is reported. First, the concept of bisection of a harmonic oscillator (HO) or hydrogen atom (HA), used in the past in establishing the connection between U(3)...
$\Delta I=4$ and $\Delta I=8$ bifurcations in rotational bands of diatomic molecules (1996)
Bonatsos, Dennis, Daskaloyannis, C, Lalazissis, G A, Drenska, S B, Minkov, N, Raychev, P P, ...
It is shown that the recently observed $\Delta I=4$ bifurcation seen in superdeformed nuclear bands is also occurring in rotational bands of diatomic molecules. In addition, signs of a $\Delta I=8$...
Nonlinear deformed su(2) algebras involving two deforming functions (1996)
Bonatsos, Dennis, Kolokotronis, P, Daskaloyannis, C, Ludu, A, Quesne, C
The most common nonlinear deformations of the su(2) Lie algebra, introduced by Polychronakos and Ro\v cek, involve a single arbitrary function of J_0 and include the quantum algebra su_q(2) as a...
A nonlinear deformed su(2) algebra with a two-colour quasitriangular Hopf structure (1996)
Bonatsos, Dennis, Daskaloyannis, C, Kolokotronis, P, Ludu, A, Quesne, C
Nonlinear deformations of the enveloping algebra of su(2), involving two arbitrary functions of J_0 and generalizing the Witten algebra, were introduced some time ago by Delbecq and Quesne. In the...
The $SU_q$(2) rotator model in excited collective bands of even deformed nuclei (1996)
Minkov, N, Drenska, S B, Raychev, P P, Roussev, R P, Bonatsos, Dennis
$\Delta I=4$ and $\Delta I=8$ bifurcations in rotational bands of diatomic molecules (1996)
Bonatsos, Dennis, Daskaloyannis, C., Lalazissis, G. A., Drenska, S. B., Minkov, N., Raychev, P. P., ...
It is shown that the recently observed $\Delta I=4$ bifurcation seen in superdeformed nuclear bands is also occurring in rotational bands of diatomic molecules. In addition, signs of a $\Delta I=8$...
Quasi-Exactly Soluble Potentials and Deformed Oscillators (1996)
Bonatsos, Dennis, Daskaloyannis, C., Mavromatis, H. A.
It is proved that quasi-exactly soluble potentials corresponding to an oscillator with harmonic, quartic and sextic terms, for which the $n+1$ lowest levels of a given parity can be determined...
Representations of the deformed U(su(2)) and U(osp(1,2)) algebras (1996)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
The polynomial deformations of the Witten extensions of the U(su(2)) and U(osp(1,2)) algebras are three generator algebras with normal ordering, admitting a two generator subalgebra. The modules and...
Generalized Deformed Oscillators and Algebras (1995)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P.
The generalized deformed oscillator schemes introduced as unified frameworks of various deformed oscillators are proved to be equivalent, their unified representation leading to a correspondence...
Quantum Algebraic Symmetries in Nuclear and Molecular Physics (1995)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
Various applications of quantum algebraic techniques in nuclear structure physics and molecular physics are briefly reviewed. Contains 81 references.
Quantum Algebras in Nuclear Structure (1995)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
Quantum algebras are a mathematical tool which provides us with a class of symmetries wider than that of Lie algebras, which are contained in the former as a special case. After a self-contained...
Generalized Deformed su(2) Algebras, Deformed Parafermionic Oscillators and Finite W Algebras (1995)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P.
Several physical systems (two identical particles in two dimensions, isotropic oscillator and Kepler system in a 2-dim curved space) and mathematical structures (quadratic algebra QH(3), finite W...
Quantum Algebraic Symmetries in Nuclei and Molecules (1995)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
Various applications of quantum algebraic techniques in nuclear and molecular physics are briefly reviewed. Emphasis is put in the study of the symmetries of the anisotropic quantum harmonic...
Quantum Algebraic Symmetries in Nuclear Structure (1995)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
Various applications of quantum algebraic techniques in nuclear structure physics, such as the su$_q$(2) rotator model and its extensions, the use of deformed bosons in the description of pairing...
The Use of Quantum Groups in Nuclear Structure Problems (1995)
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
Various applications of quantum algebraic techniques in nuclear structure physics, such as the su$_q$(2) rotator model and its extensions, the use of deformed bosons in the description of pairing...
Connection Between q-Deformed Anharmonic Oscillators and Quasi-Exactly Soluble Potentials (1995)
Bonatsos, Dennis, Daskaloyannis, C., Mavromatis, Harry A.
It is proved that quasi-exactly soluble potentials (QESPs) corresponding to an oscillator with harmonic, quartic and sextic terms, for which the $n+1$ lowest levels of a given parity can be...
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
The symmetry algebra of the two-dimensional anisotropic quantum harmonic oscillator with rational ratio of frequencies, which is characterizing ``pancake'' nuclei, is identified as a non-linear...
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
The symmetry algebra of the N-dimensional anisotropic quantum harmonic oscillator with rational ratios of frequencies is constructed by a method of general applicability to quantum superintegrable...
Bonatsos, Dennis, Daskaloyannis, C., Kolokotronis, P., Lenis, D.
The symmetry algebra of the two-dimensional quantum harmonic oscillator with rational ratio of frequencies is identified as a non-linear extension of the u(2) algebra. The finite dimensional...
Deformed oscillator algebras for two dimensional quantum superintegrable systems (1993)
Bonatsos, Dennis, Daskaloyannis, C., Kokkotas, K.
Quantum superintegrable systems in two dimensions are obtained from their classical counterparts, the quantum integrals of motion being obtained from the corresponding classical integrals by a...