Fermion dynamical symmetry model

A Fermion dynamical symmetry model which can account for both the low as well as high spin nuclear collective phenomena is presented. 

Motivated by these considerations, we have recently proposed a multi-chain fermionic dynamical symmetry model (FDSM) which was developed to specifically address the above raised questions. Our starting point is the Ginocchio SO(8) model 10(since from now on only fermion groups will be mentioned, we shall drop the use of the F superscript to denote them). In our opinion, Ginocchio was the first person to seriously pursue the concept of multi-chain dynamical symmetries from a fermionic viewpoint. The main ingredients of the Ginocchio model can be summarized as follows. If one were to take the fermion pair (i.e. a+a+ type of operators) with =0 S) and 2(D) and certain multipole operators (i.e. a+a type of operators), both types are constructed from... 

The model which we have developed is called the Fermion Dynamical Symmetry Model (FDSM)11 which is the subject matter of two recent preprints. The FDSM begins with a shell model Hamiltonian in one major valence shell. 

In conclusion, just as the IBM, the FDSM contains, for each low energy collective mode, a dynamical symmetry. For no broken pairs, some of the FDSM symmetries correspond to those experimentally known and studied previouly by the IBM. Thus all the IBM dynamical symmetries are recovered. In addition, as a natural consequence of the Hamiltonian, the model describes also the coupling of unpaired particles to such modes. Furthermore, since the model is fully microscopic, its parameters are calculable from effective nucleon-nucleon interactions. The uncanny resemblance of these preliminary results to well-established phenomenology leads us to speculate that fermion dynamical symmetries in nuclear structure may be far more pervasive than has commonly been supposed. 

L = 2 Fermion Pairs in Nuclear Dynamic Symmetry Models... 

Comprehensive reviews of different versions of the interacting boson and interacting boson-fermion models, as well as surveys of transitions between dynamical symmetries have been published, e.g., by lachello and Arima (1987), lachello and Van Isacker (1991), and Fenyes (2002). 

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