We have used the convergent close-coupling method and a unitarized firstorder many-body theory to calculate integral cross sections for elastic scattering and momentum transfer, for excitation of the 5d2 1S, 6s6p P1, 6s7p P1, 6s8p P1, 6s5d D2, 5d2 D2, 6s6d D2, 6p5d F3, 6s4f F3, 6p5d D2, 6s6p P0,1,2, 6s5d D1,2,3, and 6p5d D2 states, for ionization and for total scattering by electron impact on t...

The binding of polarons, or its absence, is an old and subtle topic. Here we prove two things rigorously. First, the transition from many-body collapse to the existence of a thermodynamic limit for N polarons occurs precisely at U = 2α, where U is the electronic Coulomb repulsion and α is the polaron coupling constant. Second, if U is large enough, there is no multi-polaron binding of any kind....

The nonadditive many-body interactions are significant for structural and thermodynamic properties of condensed phase systems. In this work we examined the many-body interaction energy of a large number of common organic/biochemical molecular clusters, which consist of 18 chemical species and cover nine common organic elements, using the Møller-Plesset perturbation theory to the second order (M...

We study the excited energy of the isoscalar giant quadrupole resonance with the scaling method in the relativistic many-body framework. In this calculation we introduce the momentum-dependent parts of the Dirac self-energies arising from the one-pion exchange on the assumption of the pseudo-vector coupling with nucleon field. It is shown that this momentumdependence enhances the Landau mass si...

Isotopic and isotonic chains of superheavy nuclei are analyzed to search for spherical double shell closures beyond Z=82 and N=126 within the new effective field theory model of Furnstahl, Serot, and Tang for the relativistic nuclear many-body problem. We take into account several indicators to identify the occurrence of possible shell closures, such as two-nucleon separation energies, two-nucl...

Isotopic and isotonic chains of superheavy nuclei are analyzed to search for spherical double shell closures beyond Z = 82 and N = 126 within the new effective field theory model of Furnstahl, Serot, and Tang for the relativistic nuclear many-body problem. We take into account several indicators to identify the occurrence of possible shell closures, such as two-nucleon separation energies, two-...

Microscopic nuclear structure calculations have been performed within the framework of the unitary-model-operator approach. Ground-state and single-particle energies are calculated for nuclei around C, O and Ca with modern nucleon-nucleon interactions.

We show the exponential decay of eigenfunctions of second-order geometric many-body type Hamiltonians at non-threshold energies. Moreover, in the case of first order and small second order perturbations we show that there are no eigenfunctions with positive energy.