One particle spectral function and analytic continuation for many-body implementation in the EMTO method

We investigate one of the most common analytic continuation techniques in condensed matter physics, namely the Pad\'{e} approximant. Aspects concerning its implementation in the exact muffin-tin orbitals (EMTO) method are scrutinized with special regard towards making it stable and free of artificial defects. The electronic structure calculations are performed for solid hydrogen, and the performance of the analytical continuation is assessed by monitoring the density of states constructed directly and via the Pad\'{e} approximation. We discuss the difference between the \textbf{k}-integrated and \textbf{k}-resolved analytical continuations, as well as describing the use of random numbers and pole residues to analyze the approximant. It is found that the analytic properties of the approximant can be controlled by appropriate modifications, making it a robust and reliable tool for electronic structure calculations. At the end, we propose a route to perform analytical continuation for the EMTO + dynamical mean field theory (DMFT) method.Comment: 20 pages, 7 figures. Revised version published in PR

Analytic continuation-free Green's function approach to correlated electronic structure calculations

We present a new charge self-consistent scheme combining Density Functional and Dynamical Mean Field Theory, which uses Green's function of multiple scattering-type. In this implementation the many-body effects are incorporated into the Kohn-Sham iterative scheme without the need for the numerically ill-posed analytic continuation of the Green's function and of the self-energy. This is achieved by producing the Kohn-Sham Hamiltonian in the sub-space of correlated partial waves and allows to formulate the Green's function directly on the Matsubara axis. The spectral moments of the Matsubara Green's function enable us to put together the real space charge density, therefore the charge self-consistency can be achieved. Our results for the spectral functions (density of states) and equation of state curves for transition metal elements, Fe, Ni and FeAl compound agree very well with those of Hamiltonian based LDA+DMFT implementations. The current implementation improves on numerical accuracy, requires a minimal effort besides the multiple scattering formulation and can be generalized in several ways that are interesting for applications to real materials

ERAWATCH Country Reports 2009: Romania. Analysis of policy mixes to foster R&D investment and to contribute to the ERA

The main objective of the ERAWATCH Policy Mix Country reports 2009 is to characterise and assess in a structured manner the evolution of the national policy mixes in the perspective of the Lisbon goals, with a particular focus on the national R&D investments targets and on the realisation and better governance of the European Research Area. The reports were produced for all EU Member State and five Associated States to support the mutual learning process and the monitoring of Member and Associated States' efforts by DG-RTD in the context of the Lisbon Strategy and the European Research Area. The country reports 2009 build and extend on the analysis provided by analytical country reports 2008 and on a synthesis of information from the ERAWATCH Research Inventory and other important available information sources.JRC.J.3-Knowledge for Growt

Mihai Gheorghiade, MD-Life and Concepts

How do you capture an idea, shape it, and then bring it into the world? Of his many talents, this ability was a fundamental characteristic of Mihai Gheorghiade. A quick glance through PubMed confirms his prodigious output, likely to overwhelm any novice or even expert scholar. His contribution to heart failure, especially acute heart failure (AHF), is profound, He authored several major concepts in acute heart failure, disseminated further by his students. Most concepts remained indelibly linked to his name: Digoxin trials research(1–3), AHFS (acute heart failure syndromes) definition(4), hemodynamic congestion(5), hospitalized heart failure (HHF) (6), the vulnerable phase(7,8), neutral hemodynamic agents(9), registries(10–12) and pre-trial registries(13), the “6-axis model”(14) and then the “8-axis model”(15). His work shaped the field of AHF