46 research outputs found
Rotationally Invariant Hamiltonians for Nuclear Spectra Based on Quantum Algebras
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 Hamiltonian to the formalisms of
Amal'sky and Harris is provided. In addition, a new Hamiltonian for rotational
spectra is introduced, based on the construction of irreducible tensor
operators (ITO) under SUq(2) and use of q-deformed tensor products and
q-deformed Clebsch-Gordan coefficients. The rotational invariance of this
SUq(2) ITO Hamiltonian under the usual physical angular momentum is explicitly
proved, a simple closed expression for its energy spectrum (the ``hyperbolic
tangent formula'') is introduced, and its connection to the Harris formalism is
established. Numerical tests in a series of Th isotopes are provided.Comment: 34 pages, LaTe
Ground- band coupling in heavy deformed nuclei and SU(3) contraction limit
We derive analytic expressions for the energies and -transition
probabilities in the states of the ground and bands of heavy deformed
nuclei within a collective Vector-Boson Model with SU(3) dynamical symmetry. On
this basis we examine the analytic behavior of the SU(3) energy splitting and
the B(E2) interband transition ratios in the SU(3) contraction limits of the
model. The theoretical analyses outline physically reasonable ways in which the
ground- band coupling vanishes. The experimental data on the lowest
collective states of even-even rare earth nuclei and actinides strongly support
the theoretical results. They suggest that a transition from the
ground- band coupling scheme to a scheme in which the ground band is
situated in a separate irreducible representation of SU(3) should be realized
towards the midshell regions. We propose that generally the SU(3) group
contraction process should play an important role for such a kind of
transitions in any collective band coupling scheme in heavy deformed nuclei.Comment: 24 pages (LaTeX), 7 figures (12 postscript files
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