9,390 research outputs found

    Fabrication of large ceramic electrolyte disks

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    Process for sintering compressed ceramic powders produces large ceramic disks for use as electrolytes in high-temperature electrolytic cells. Thin, strain-free uniformly dense disks as large as 30 cm squared have been fabricated by slicing ceramic slugs produced by this technique

    Superdeformations in Relativistic and Non-Relativistic Mean Field Theories

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    The applications of the extensions of relativistic mean field (RMF) theory to the rotating frame, such as cranked relativistic mean field (CRMF) theory and cranked relativistic Hartree-Bogoliubov (CRHB) theory, for the description of superdeformed bands in the A60A\sim 60, 140-150 and 190 mass regions are overviewed and compared briefly with the results obtained in non-relativistic mean field theories.Comment: 18 pages including 5 figures in PostScript, requires epsf.sty, invited talk presented at the International Conference on Achievements and Perspectives in Nuclear Structure, Crete, Greece, July 11-17, 1999, will be published in Physica Script

    Properties of superdeformed fission isomers in the cranked relativistic Hartree-Bogoliubov theory

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    The rotational and deformation properties of superdeformed fission isomers in the A240A\sim 240 mass region have been investigated within the framework of the cranked relativistic Hartree-Bogoliubov theory. The dependence of the results of the calculations on the parametrization of the RMF Lagrangian has been studied. The rotational properties are best described by the NL1 force.Comment: 5 pages, uses epsf.sty and hip-artc.sty, 1 PostScript figure, contribution to the Proceedings of the International Symposium on Exotic Nuclear Structures, May 15-20, 2000, Debrecen, Hungar

    Cranked relativistic Hartree-Bogoliubov theory: Superdeformation in the A190A\sim 190 mass region

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    A systematic investigation of the yrast superdeformed (SD) rotational bands in even-even nuclei of the A190A\sim 190 mass region has been performed within the framework of the cranked relativistic Hartree-Bogoliubov theory. The particle-hole channel of this theory is treated fully relativistically, while a finite range two-body force of Gogny type is used in the particle-particle (pairing) channel. Using the well established parameter sets NL1 for the Lagrangian and D1S for the Gogny force, very good description of experimental data is obtained with no adjustable parameters.Comment: 5 pages, 2 Postscript figures, uses sprocl.sty, contribution to the Proceedings of the International Conference ``Bologna 2000, Structure of the Nucleus at the Dawn of the Century'

    Quasiparticle-vibration coupling in relativistic framework: shell structure of Z=120 isotopes

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    For the first time, the shell structure of open-shell nuclei is described in a fully self-consistent extension of the covariant energy density functional theory. The approach implies quasiparticle-vibration coupling for superfluid systems. One-body Dyson equation formulated in the doubled quasiparticle space of Dirac spinors is solved for nucleonic propagators in tin isotopes which represent the reference case: the obtained energies of the single-quasiparticle levels and their spectroscopic amplitudes are in agreement with data. The model is applied to describe the shell evolution in a chain of superheavy isotopes 292,296,300,304^{292,296,300,304}120 and finds a rather stable proton spherical shell closure at Z = 120. An interplay of the pairing correlations and the quasiparticle-phonon coupling gives rise for a smooth evolution of the neutron shell gap between N = 172 and N = 184 neutron numbers. Vibrational corrections to the alpha decay energies reach several hundred keV and can be either positive and negative, thus also smearing the shell effects.Comment: 10 pages, 3 figure

    Squeezing as an irreducible resource

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    We show that squeezing is an irreducible resource which remains invariant under transformations by linear optical elements. In particular, we give a decomposition of any optical circuit with linear input-output relations into a linear multiport interferometer followed by a unique set of single mode squeezers and then another multiport interferometer. Using this decomposition we derive a no-go theorem for superpositions of macroscopically distinct states from single-photon detection. Further, we demonstrate the equivalence between several schemes for randomly creating polarization-entangled states. Finally, we derive minimal quantum optical circuits for ideal quantum non-demolition coupling of quadrature-phase amplitudes.Comment: 4 pages, 3 figures, new title, removed the fat
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