A theoretical analysis of mid-mass neutron halos. What changes going from few- to many-body systems regarding neutron halos?

The present contribution summarizes the content and slightly updates the discussion of a recently proposed theoretical analysis of the halo phenomenon in many-fermion systems. We focus here on applications to potential neutron halos in mid-mass nuclei.Comment: 17 pages, 19 figures. arXiv admin note: substantial text overlap with arXiv:nucl-th/070205

Pairing in finite nuclei from low-momentum two- and three-nucleon interactions

The present contribution reviews recent advances made toward a microscopic understanding of superfluidity in nuclei using many-body methods based on the BCS ansatz and low-momentum inter-nucleon interactions, themselves based on chiral effective field theory and renormalization group techniques.Comment: 15 pages, contribution to "50 years of nuclear BCS", edited by R.A. Broglia and V. Zelevinsk

Treatment of the Intrinsic Hamiltonian in Particle-Number Nonconserving Theories

We discuss the implications of using an intrinsic Hamiltonian in theories without particle-number conservation, e.g., the Hartree-Fock-Bogoliubov approximation, where the Hamiltonian's particle-number dependence leads to discrepancies if one naively replaces the particle-number operator by its expectation value. We develop a systematic expansion that fixes this problem and leads to an a posteriori justification of the widely-used one- plus two-body form of the intrinsic kinetic energy in nuclear self-consistent field methods. The expansion's convergence properties as well as its practical applications are discussed for several sample nuclei.Comment: 6 pages, 5 figure

Innovation height, spillovers and TFP growth at the firm level: Evidence from French manufacturing

We examine the contribution of incremental and radical innovations to total factor productivity (TFP) growth at the firm level. The first part of our analysis is dedicated to the determinants of innovation and reveals two different innovation regimes. On the one hand, radical innovations rely strongly on firm-level spillovers, including property rights, and formal internal research while, on the other hand, incremental innovations rely mostly on the adoption of equipment goods accompanied by informal research. We find that radical innovations are the only significant contributors to TFP growth so that innovation height matters. We also find evidence that TFP growth is better represented by an upward shift of the production function than by a continuous innovation measure. Overall, the growth gains that we find are comparable to the ones of the previous studies.growth, innovation, total factor productivity, Solow residual, spillovers

Configuration mixing within the energy density functional formalism: pathologies and cures

Configuration mixing calculations performed in terms of the Skyrme/Gogny Energy Density Functional (EDF) rely on extending the Single-Reference energy functional into non-diagonal EDF kernels. The standard way to do so, based on an analogy with the pure Hamiltonian case and the use of the generalized Wick theorem, is responsible for the recently observed divergences and steps in Multi-Reference calculations. We summarize here the minimal solution to this problem recently proposed [Lacroix et al, arXiv:0809.2041] and applied with success to particle number restoration[Bender et al, arXiv:0809.2045]. Such a regularization method provides suitable corrections of pathologies for EDF depending on integer powers of the density. The specific case of fractional powers of the density[Duguet et al, arXiv:0809.2049] is also discussed.Comment: 5 pages, Proceedings of the French-Japanese Symposium, September 2008. To be published in Int. J. of Mod. Phys.

Are R&D subsidies a substitute or a complement to privately funded R&D? Evidence from France using propensity score methods for non- experimental data

This study examines the effect of research and development subsidies on the private funding of R&D in France. We address this issue from the annual R&D survey over 1985-1997, which provides information about the R&D subsidies given by all the ministries to the firms having at least one full-time person working on R&D. In order to determine whether the supported firms would have invested the same amount of private R&D without the subsidies, we use matching methods. We show that the use of these methods is important because the global evaluations, in this paper, more often give a potential effect among the non-supported firms than a real effect among the supported firms. We first study the probability to get a subsidy. We find that this probability is increasing with size, the debt ratio and the importance of privately funded R&D. In a second step, controlling for the past public support the firms benefited from, we find that, on average, public funds add to private funds, so that there would be no significant crowding out effect.propensity score, non-experimental data, policy evaluation, research and development, subsidies

HFB calculations with a microscopic pairing interaction

Hartree-Fock-Bogolyubov (HFB) calculations making use of a recently proposed microscopic effective pairing interaction are presented. The interaction was shown to reproduce the pairing properties provided by the realistic $AV18$ force very accurately in infinite matter. Although finite-ranged and non-local, it makes 3D HFB calculations in coordinate space tractable. As a first application, basic pairing properties of calcium isotopes in their ground-state are studied. By comparing the results with those obtained using a standard Density-Dependent Delta Interaction, the crucial isovector character of the microscopic interaction is highlighted.Comment: 6 pages, 6 figures. Proceedings of the Conference on Nuclei at the Limits, ANL, 2004. They will be published in the AIP Conference Proceedings Serie