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RPA calculations with Gaussian expansion method  [PDF]
H. Nakada,K. Mizuyama,M. Yamagami,M. Matsuo
Physics , 2009, DOI: 10.1016/j.nuclphysa.2009.07.010
Abstract: The Gaussian expansion method (GEM) is extensively applied to the calculations in the random-phase approximation (RPA). We adopt the mass-independent basis-set that has been tested in the mean-field calculations. By comparing the RPA results with those obtained by several other available methods for Ca isotopes, using a density-dependent contact interaction and the Woods-Saxon single-particle states, we confirm that energies, transition strengths and widths of their distribution are described by the GEM bases to good precision, for the $1^-$, $2^+$ and $3^-$ collective states. The GEM is then applied to the self-consistent RPA calculations with the finite-range Gogny D1S interaction. The spurious center-of-mass motion is well separated from the physical states in the $E1$ response, and the energy-weighted sum rules for the isoscalar transitions are fulfilled reasonably well. Properties of low-energy transitions in $^{60}$Ca are argued in some detail.
Hartree-Fock-Bogolyubov calculations with Gaussian expansion method  [PDF]
H. Nakada
Physics , 2005, DOI: 10.1016/j.nuclphysa.2007.12.011
Abstract: We extensively develop an algorithm of implementing the Hartree-Fock-Bogolyubov calculations, in which the Gaussian expansion method is employed. This algorithm is advantageous in describing the energy-dependent exponential and oscillatory asymptotics of the quasiparticle wave functions at large $r$, and in handling various effective interactions including those with finite ranges. We apply the present method to the oxygen isotopes with the Gogny interaction, keeping the spherical symmetry. In respect to the new magic numbers, effects of the pair correlation on the N=16 and 32 nuclei are investigated.
Assessing the accuracy of Hartree-Fock-Bogoliubov calculations by use of mass relations  [PDF]
D. Hove,D. V. Fedorov,A. S. Jensen,K. Riisager,N. T. Zinner
Physics , 2014, DOI: 10.1140/epja/i2014-14181-y
Abstract: The accuracy of three different sets of Hartree-Fock-Bogoliubov calculations of nuclear binding energies is systematically evaluated. To emphasize minor fluctuations, a second order, four-point mass relation, which almost completely eliminates smooth aspects of the binding energy, is introduced. Applying this mass relation yields more scattered results for the calculated binding energies. By examining the Gaussian distributions of the non-smooth aspects which remain, structural differences can be detected between measured and calculated binding energies. Substructures in regions of rapidly changing deformation, specifically around $(N,Z)=(60,40)$ and $(90,60)$, are clearly seen for the measured values, but are missing from the calculations. A similar three-point mass relation is used to emphasize odd-even effects. A clear decrease with neutron excess is seen continuing outside the experimentally known region for the calculations.
Nuclear electric dipole moment of light nuclei in the gaussian expansion method  [PDF]
Nodoka Yamanaka,Emiko Hiyama
Physics , 2015,
Abstract: The nuclear electric dipole moment is a very sensitive probe of CP violation beyond the standard model, and for light nuclei, it can be evaluated accurately using few-body calculational methods. In this talk, we present the result of the calculation of the electric dipole moment of the deuteron, $^3$He, $^3$H, $^6$Li, and $^9$Be in the Gaussian expansion method with the realistic nuclear force, and assuming the one-meson exchange model for the P, CP-odd nuclear force. We then give future prospects for models beyond standard model such as the supersymmetry.
Parallelizing Gaussian Process Calculations in R  [PDF]
Christopher J. Paciorek,Benjamin Lipshitz,Wei Zhuo,Prabhat,Cari G. Kaufman,Rollin C. Thomas
Computer Science , 2013, DOI: 10.18637/jss.v063.i10
Abstract: We consider parallel computation for Gaussian process calculations to overcome computational and memory constraints on the size of datasets that can be analyzed. Using a hybrid parallelization approach that uses both threading (shared memory) and message-passing (distributed memory), we implement the core linear algebra operations used in spatial statistics and Gaussian process regression in an R package called bigGP that relies on C and MPI. The approach divides the matrix into blocks such that the computational load is balanced across processes while communication between processes is limited. The package provides an API enabling R programmers to implement Gaussian process-based methods by using the distributed linear algebra operations without any C or MPI coding. We illustrate the approach and software by analyzing an astrophysics dataset with n=67,275 observations.
Hartree Fock Calculations in the Density Matrix Expansion Approach  [PDF]
F. Hofmann,H. Lenske
Physics , 1997, DOI: 10.1103/PhysRevC.57.2281
Abstract: The density matrix expansion is used to derive a local energy density functional for finite range interactions with a realistic meson exchange structure. Exchange contributions are treated in a local momentum approximation. A generalized Slater approximation is used for the density matrix where an effective local Fermi momentum is chosen such that the next to leading order off-diagonal term is canceled. Hartree-Fock equations are derived incorporating the momentum structure of the underlying finite range interaction. For applications a density dependent effective interaction is determined from a G-matrix which is renormalized such that the saturation properties of symmetric nuclear matter are reproduced. Intending applications to systems far off stability special attention is paid to the low density regime and asymmetric nuclear matter. Results are compared to predictions obtained from Skyrme interactions. The ground state properties of stable nuclei are well reproduced without further adjustments of parameters. The potential of the approach is further exemplified in calculations for A=100...140 tin isotopes. Rather extended neutron skins are found beyond 130Sn corresponding to solid layers of neutron matter surrounding a core of normal composition.
Deformation quantization of Poisson manifolds in the derivative expansion  [PDF]
A. V. Bratchikov
Mathematics , 2005,
Abstract: Deformation quantization of Poisson manifolds is studied within the framework of an expansion in powers of derivatives of Poisson structures. We construct the Lie group associated with a Poisson bracket algebra which defines a second order deformation in the derivative expansion.
Gaussian expansion approach to Coulomb breakup  [PDF]
T. Egami,K. Ogata,T. Matsumoto,Y. Iseri,M. Kamimura,M. Yahiro
Physics , 2004, DOI: 10.1103/PhysRevC.70.047604
Abstract: An accurate treatment of Coulomb breakup reactions is presented by using both the Gaussian expansion method and the method of continuum discretized coupled channels. As $L^2$-type basis functions for describing bound- and continuum-states of a projectile, we take complex-range Gaussian functions, which form in good approximation a complete set in a large configuration space being important for Coulomb-breakup processes. Accuracy of the method is tested quantitatively for $^{8}{\rm B}+^{58}$Ni scattering at 25.8 MeV.
Deformation of Brody curves and mean dimension  [PDF]
Masaki Tsukamoto
Mathematics , 2007,
Abstract: The main purpose of this paper is to show that ideas of deformation theory can be applied to "infinite dimensional geometry". We develop the deformation theory of Brody curves. Brody curve is a kind of holomorphic map from the complex plane to the projective space. Since the complex plane is not compact, the parameter space of the deformation can be infinite dimensional. As an application we prove a lower bound on the mean dimension of the space of Brody curves.
Relativistic Mean Field Calculations of $Λ$ and $Σ$ Hypernuclei  [PDF]
N. K. Glendenning,D. Von-Eiff,M. Haft,H. Lenske,M. K. Weigel
Physics , 1992, DOI: 10.1103/PhysRevC.48.889
Abstract: Single--particle spectra of $\Lambda $ and $\Sigma $ hypernuclei are calculated within a relativistic mean--field theory. The hyperon couplings used are compatible with the $\Lambda $ binding in saturated nuclear matter, neutron-star masses and experimental data on $\Lambda $ levels in hypernuclei. Special attention is devoted to the spin-orbit potential for the hyperons and the influence of the $\rho $-meson field (isospin dependent interaction).
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