BAREA , J.

The observed preponderance of ground states with angular momentum L=0 in many-body quantum systems with random two-body interactions is analyzed in terms of correlation coefficients (covariances) among different eigenstates. It is shown that the geometric analysis of Chau can be interpreted in terms of correlations (covariances) between energy...

Transfer reactions constitute a stringent test for nuclear supersymmetry, a theory that simultaneously describes neighboring nuclei with bosonic and fermionic character. We construct and analytically evaluate one-nucleon transfer matrix elements between supersymmetric partners with the U( 6/4) case as an example, and stress the...

The appropriate use of the interacting boson-fermion model one nucleon transfer operator in connection with nuclear supersymmetries is discussed. We emphasize that care must be taken in using the same coupling order, either l-s or s-l, in the odd particle creation operator appearing in the one nucleon transfer ...

The boson-conserving one-nucleon transfer operator in the interacting boson model (IBM) is reanalyzed. Extra terms are added to the usual form used for that operator. These new terms change generalized seniority by one unit, as the ones considered up to now. The results obtained using the new form for the transfer operator are...

Low-lying energy states of the 147 -153Pm isotopic chain are studied within the framework of the neutron-proton interacting boson-fermion model (IBFM-2). The spectra of these isotopes show a transition from a particle coupled to a vibrational core to a particle coupled to a deformed one. The calculation reproduces this behavior. In addition,...

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 in the γ degree of freedom, and the interacting boson model (IBM) are explored. This work is the natural extension of the...

The mapping of the single fermion creation operator (ci†) onto the Interacting Boson-Fermion space (IBFM) is revisited within the Generalized Seniority scheme. In the original work the Number Operator Approximation (NOA) was used. Here the exact evaluation of the relevant terms using exact values for the fermion matrix elements in the...

The photovoltaic cells (PV) are commonly used as global radiation measurement device, even though when it has been proved that there are significant differences with respect to using pyranometers. The dirt deposited on the surface of the PV is one of the most influential factors in the measurement of the solar radiation. In this work we have...

A systematic study of isotope chains in the rare-earth region is presented. For chains 60 144 2 154Nd, 62 146 2 160Sm, 64 148 2 162Gd, and 66 150 2 166 Dy, energy levels, E2 transition rates, and two-neutron separation energies are described by using the most general ~ up to two-body terms interacting boson model ~ IBM Hamiltonian. For...

β -decay rates of 121–131 Cs have been calculated in the framework of the neutron-proton interacting boson- fermion model (IBFM-2). For odd- A nuclei, the decay operator can be written in a relatively simple form in terms of the one-nucleon transfer operator. Previous studies of β decay in IBFM-2 were based on a transfer operator obtained by...

A new procedure is presented that combines well-known nuclear models with image reconstruction techniques. A color-coded image is built by taking the differences between measured masses and the predictions given by the different theoretical models. This image is viewed as part of a larger array in the (N,Z) plane, where unknown nuclear masses...

We present evidence for a new supersymmetric quartet in the A~190 region of the nuclear mass table. New experimental information on transfer and neutron capture reactions to the odd-odd nucleus 194Ir strongly suggests the existence of a new supersymmetric quartet, consisting of the 192,193Os and 193,194Ir nuclei. We make explicit predictions...