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  • 1
    Electronic Resource
    Electronic Resource
    Statistical Spectroscopy (1982)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Nuclear and Particle Science 32 (1982), S. 35-64 
    Details
    ISSN: 0163-8998
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ns.32.120182.000343
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  • 2
    Electronic Resource
    Electronic Resource
    Group theoretical aspects of the extended interacting boson model (1987)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 28 (1987), S. 1644-1652 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: Group theoretical aspects of the extended interacting boson model (gIBM) with s, d, and g bosons are discussed. The basis states and branching rules are given for the seven dynamical symmetries. Casimir operators and their eigenvalues are obtained and enable one to write down energy formulas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.527471
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  • 3
    Electronic Resource
    Electronic Resource
    Transformation brackets between U(N)⊃SO(N)⊃SO(Na)⊕SO(Nb) and U(N)⊃U(Na)⊕U(Nb)⊃SO(Na)⊕SO(Nb) (1997)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 38 (1997), S. 6639-6647 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: Transformation brackets between U(N)⊃SO(N)⊃SO(Na)⊕SO(Nb) and U(N)⊃U(Na)⊕U(Nb)⊃SO(Na)⊕SO(Nb) for symmetric U(N) irreducible representations are derived for Na, Nb≥2 by using bispherical coordinates in N=Na+Nb dimensions and a convolution identity for generalized Laguerre polynomials. The formula derived for the transformation brackets also applies to the special cases with Na≥2, Nb=1 and Na=1, Nb≥2. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.532229
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  • 4
    Electronic Resource
    Electronic Resource
    Energy dependence of the strengths of pairing and quadrupole-quadrupole components of the nuclear effective interactions (1982)
    Springer
    The European physical journal 309 (1982), S. 159-162 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A prescription is given for obtaining the energy dependence of the strengths of pairing and quadrupole-quadrupole interaction operators when a given effective nuclear Hamiltonian is approximated by a linear combination of these two operators. For 2s−1d shell interactions it is found that simple estimates of the strengths, based on averaging over the whole spectrum, are misleading for the pairing interaction which, in the ground state domain, increases strongly with particle number, in contrast to the quadrupole strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01414977
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  • 5
    Electronic Resource
    Electronic Resource
    Bivariate distributions in statistical spectroscopy studies: Fixed-J level densities, fixed-J averages and spin cut-off factors (1984)
    Springer
    The European physical journal 315 (1984), S. 91-98 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Analytical studies with the TBRE ensemble, supplemented by numerical calculations with realistic interactions show that for large particle numbers, the bivariate cumulants (k rs ) defined for the Hamiltonian operator (H) and theJ z operator, are very small; ∥k rs ∥≲0.3 for 3≦r+s≦6. As a result the expansions around a bivariate normal density are meaningful for the fixed-M densities (ρ(E,M)). We adopt a bivariate Edgeworth expansion forρ(E,M) and give a compact form for the same. Finally using thisρ(E,M) (which also define fixed-J densities uniquely), new series expansions are given for fixed-M (and hence for fixed-J) averages of the powers ofH and also for the spin cut-off factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01436213
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  • 6
    Electronic Resource
    Electronic Resource
    Geometric shapes withg- bosons in the interacting boson model (1990)
    Springer
    The European physical journal 337 (1990), S. 15-22 
    Details
    ISSN: 1434-601X
    Keywords: 21.60.Ev ; 21.60.FW ; 02.40.+m
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Geometric aspects of the extended interacting boson model (gIBM) withs, d andg bosons are studied using coherent states. Algebraic expressions for the coherent state expectation values of various terms in the general gIBM Hamiltonian are derived in terms of the quadrupole and hexadecupole deformation variablesβ 2 andβ 4 and the asymmetry angleγ. These in turn are used to determine the equilibrium shape parameters (β 2 0 ,β 4 0 ,γ 0) in the seven dynamical symmetry limits of gIBM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01283933
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  • 7
    Electronic Resource
    Electronic Resource
    Bivariate distributions in statistical spectroscopy studies (1985)
    Springer
    The European physical journal 322 (1985), S. 129-136 
    Details
    ISSN: 1434-601X
    Keywords: 21.10.Cs ; 02.50.+s
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Orthogonal polynomials in two variables, defined by a bivariate density function, are used to derive series expansions for expectation values with respect to the two variables. The convergence of the resulting polynomial expansion is due to the action of a central limit theorem. The shell model results for fixedE, J occupancies in (ds) m=5T=1/2 space are compared with the polynomial expansion results and the agreement is good.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01412025
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  • 8
    Electronic Resource
    Electronic Resource
    B(IS4; 0 GS + →4 γ + ) systematics in rare-earth nuclei: SUsdg (3) description (1993)
    Springer
    The European physical journal 346 (1993), S. 261-264 
    Details
    ISSN: 1434-601X
    Keywords: 21.10.Ky ; 21.60.Fw ; 23.20.Js ; 27.70.+ q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The observed variation of B(IS4; 0 GS + → γ + ) with mass number A, that gives information about hexadecupole component inγ-vibration, in rare-earth nuclei is studied in the SUsdg (3) limit of sdg interacting boson model employing IBM-2 to IBM-1 projected hexadecupole transition operator with effective charges determined using a multi-j shell mapping procedure. The SUsdg (3) limit provides a reasonably good description of the data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01292514
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  • 9
    Electronic Resource
    Electronic Resource
    Bivariate distributions in statistical spectroscopy studies: III. Non interacting particle strength densities for one-body transition operators (1995)
    Springer
    The European physical journal 351 (1995), S. 365-376 
    Details
    ISSN: 1434-601X
    Keywords: 21.10.Pc ; 21.60.Cs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In statistical spectroscopy, it was shown by French et al. (Ann. Phys., N.Y. 181, 235 (1988)) that the bivariate strength densities take a convolution form with the non interacting particle (NIP) strength density being convoluted with a spreading bivariate Gaussian due to interactions. Leaving aside the question of determining the parameters of the spreading bivariate Gaussian, one needs good methods for constructing the NIP bivariate strength densitiesI O h (E,E′) (h is a one-body hamiltonian andO is a transition operator) in large shell model spaces. A formalism for constructingI O h is developed for one-body transition operators by using spherical orbits and spherical configurations. For rapid construction and also for applying the statistical theory in large shell model spacesI O h is decomposed into partial densities defined by unitary orbit configurations (unitary orbit is a set of spherical orbits). Trace propagation formulas for the bivariate momentsM rs with r+s ≤2 of the partial NIP strength densities, which will determine the Gaussian representation, are derived. In a large space numerical example with Gamow-Tellerβ − transition operator, the superposition of unitary orbit partial bivariate Gaussian densities is shown to give a good representation of the exact NIP strength densities. Trace propagation formulas forM rs with r+〈—4 are also derived inm-particle scalar spaces which are useful for many purposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01291141
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  • 10
    Electronic Resource
    Electronic Resource
    Bivariate distributions in statistical spectroscopy studies: IV. Interacting particle Gamow-Teller strength densities and β-decay rates offp-shell nuclei for presupernova stars (1995)
    Springer
    The European physical journal 351 (1995), S. 377-383 
    Details
    ISSN: 1434-601X
    Keywords: 21.10.Pc ; 21.60.Cs ; 23.40.Hc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A method to calculate temperature dependentβ-decay rates is developed by writing the expression for the rates explicitly in terms of bivariateGT strength densities (I O H (GT)) for a given hamiltonianH=h+V and state densities of the parent nucleus besides having the usual phase space factors. The theory developed in the preceding paper (III) for constructing NIP strength densities is applied for generatingI O h (GT) and thenI O H (GT) is constructed using the bivariate convolution formI O H (GT)=Σ S I O(GT) h,S ⊗ρ O(GT) V,S ; BIV-G . The spreading bivariate Gaussian ρ O(GT) V ;BIV-G, forfp-shell nuclei, is constructed by assuming that the marginal centroids are zero, the marginal variances are same as the corresponding state density variances and fixing the bivariate correlation coefficient $$\bar \zeta $$ using experimentalβ-decay half lifes. With the deduced values of $$\bar \zeta $$ $$\bar \zeta $$ ∼ 0.67,β-S-decay rates for61,62Fe and62–64Co isotopes are calculated at presupernova matter densitiesρ=107–109 gm/cc, temperaturesT=(3–5)×109 ∘K and electron fractions Ye=0.43–0.5. The convolution form forI O(GT) H led to a simple expression for calculatingGT non-energy weighted sum rule strength and it describes (within 10%) the shell model results offp-shell nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01291142
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