866 research outputs found
Collective states of the odd-mass nuclei within the framework of the Interacting Vector Boson Model
A supersymmetric extension of the dynamical symmetry group of
the Interacting Vector Boson Model (IVBM), to the orthosymplectic group
is developed in order to incorporate fermion degrees of
freedom into the nuclear dynamics and to encompass the treatment of odd mass
nuclei. The bosonic sector of the supergroup is used to describe the complex
collective spectra of the neighboring even-even nuclei and is considered as a
core structure of the odd nucleus. The fermionic sector is represented by the
fermion spin group .
The so obtained, new exactly solvable limiting case is applied for the
description of the nuclear collective spectra of odd mass nuclei. The
theoretical predictions for different collective bands in three odd mass
nuclei, namely , and from rare earth region are
compared with the experiment. The transition probabilities for the
and between the states of the ground band are also
studied. The important role of the symplectic structure of the model for the
proper reproduction of the behavior is revealed. The obtained results
reveal the applicability of the models extension.Comment: 18 pages, 8 figure
Analytic Formulae for the Matrix Elements of the Transition Operators in the Symplectic Extension of the Interacting Vector Boson Model
The tensor properties of all the generators of Sp(12,R) - the group of
dynamical symmetry of the Interacting Vector Boson Model (IVBM), are given with
respect to the reduction chain Sp(12,R) U(6) U(3) x U(2)
O(3) x U(1). Matrix elements of the basic building blocks of the
model are evaluated in symmetry adapted basis along the considered chain. As a
result of this, the analytic form of the matrix elements of any operator in the
enveloping algebra of the Sp(12,R), defining a certain transition operator, can
be calculated. The procedure allows further applications of the symplectic IVBM
for the description of transition probabilities between nuclear collective
states.Comment: 6 page
Energy Systematics of Low-lying Collective States within the Framework of the Interacting Vector Boson Model
In a new application of the algebraic Interacting Vector Boson Model (IVBM),
we exploit the reduction of its Sp(12,R) dynamical symmetry group to Sp(4,R) x
SO(3), which defines basis states with fixed values of the angular momentum L.
The relationship of the latter to $U(6) \subset U(3)x U(2), which is the
rotational limit of the model, means the energy distribution of collective
states with fixed angular momentum can be studied. Results for low-lying
spectra of rare-earth nuclei show that the energies of collective positive
parity states with L=0,2,4,6... lie on second order curves with respect to the
number of collective phonons n or vector bosons N=4n out of which the states
are built. The analysis of this behavior leads to insight regarding the common
nature of collective states, tracking vibrational as well as rotational
features.Comment: 8 pages, 5 figures, 4 table
Linear Invariant Systems Theory for Signal Enhancement
This paper discusses a linear time invariant (LTI) systems approach to signal enhancement via projective subspace techniques. It provides closed form expressions for the frequency response of data adaptive finite impulse response eigenfilters. An illustrative example using speech enhancement is also presented.Este artigo apresenta a aplicação da teoria de sistemas lineares invariantes no tempo (LTI) na anĂĄlise de tĂ©cnicas de sub-espaço. A resposta em frequĂȘncia dos filtros resultantes da decomposição em valores singulares Ă© obtida aplicando as propriedades dos sistemas LTI
q-Analogue of
A natural embedding for the
corresponding quantum algebras is constructed through the appropriate
comultiplication on the generators of each of the and
algebras. The above embedding is proved in their -boson realization by means
of the isomorphism between the (mn)(m)(n) algebras.Comment: 11 pages, no figures. In memory of professor R. P. Rousse
Unified dynamical symmetries in the symplectic extension of the interacting vector boson model
The algebraic Interacting Vector Boson Model (IVBM) is extended by exploiting three new subgroup chains in the reduction of its highest symplectic dynamical symmetry group Sp(12, R) to the physical angular momentum subgroup SO(3). The corresponding exactly solvable limiting cases are applied to achieve a description of complex nuclear collective spectra of even-even nuclei in the rare earth and actinide regions up to states of very high angular momentum. First we exploit two reductions in which collective modes can be mixed, and obtain successful descriptions of both positive and negative parity band conflgurations. The structure of band-head conflgurations, whose importance is established in the flrst two limits, is examined in a third reduction, that also provides important links between the subgroups of the other limits. © 2008 IOP Publishing Ltd
Staggering behavior of the low lying excited states of even-even nuclei in a Sp(4,R) classification scheme
We implement a high order discrete derivative analysis of the low lying
collective energies of even-even nuclei with respect to the total number of
valence nucleon pairs N in the framework of F- spin multiplets appearing in a
symplectic sp(4,R) classification scheme. We find that for the nuclei of any
given F- multiplet the respective experimental energies exhibit a Delta N=2
staggering behavior and for the nuclei of two united neighboring F- multiplets
well pronounced Delta N=1 staggering patterns are observed. Those effects have
been reproduced successfully through a generalized sp(4,R) model energy
expression and explained in terms of the step-like changes in collective modes
within the F- multiplets and the alternation of the F-spin projection in the
united neighboring multiplets. On this basis we suggest that the observed Delta
N=2 and Delta N=1 staggering effects carry detailed information about the
respective systematic manifestation of both high order alpha - particle like
quartetting of nucleons and proton (neutron) pairing interaction in nuclei.PACS
number(s):21.10.Re, 21.60.FwComment: 22 pages and 6 figures changes in the figure caption
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