Ground-state properties of bosons in three- and two-dimensional traps

We study trapped systems of bosons at zero temperature in three and two dimensions. Conditions are fulfilled for the application of Gross-Pitaevskii theory with a positive scattering length. Series expansions for ground-state properties are obtained in both the noninteracting and the strong-coupling (Thomas-Fermi) limits. From these expansions, analytic estimates are presented in the form of two-point Pad\'e approximants. We explicitly show the approximants for the total energy per particle and the chemical potential.Comment: LaTeX, 4 pages, 3 ps figure

Renormalised perturbative series for the impurity levels in a quantum well

The energy levels of an impurity center in a deep quantum well of width L and depth g are studied analytically . Renormalised perturbative series are constructed in the regions g L^ > 1. Maximal binding energy and wave function deformation to a quasi-twodimensional function are found to occur at a certain L_c satisfying sqrt{g} L_c ~ 1. Similar results may be obtained for the impurity in a quantum wire, in a dot or in a multiwell structure.Comment: 11 pages. LaTeX. 3 figures not include

The NIST compilation of ionization potentials revisited (I): From He-like to Xe-like ions

The National Institute of Standards and Technology (NIST) database on ionization potentials for neutral atoms and ions is examined. For each isoelectronic sequence, we construct a regularized perturbative series that exactly matches the large-$Z$ and $Z\approx N-1$ regions. Comparison of the NIST data with this series allows the identification of problematic values in the reported data.Comment: 19 pages, 43 figure