A functional renormalization group approach to electronic structure calculations for systems without translational symmetry

A formalism for electronic-structure calculations is presented that is based on the functional renormalization group (FRG). The traditional FRG has been formulated for systems that exhibit a translational symmetry with an associated Fermi surface, which can provide the organization principle for the renormalization group (RG) procedure. We here advance an alternative formulation, where the RG-flow is organized in the energy-domain rather than in k-space. This has the advantage that it can also be applied to inhomogeneous matter lacking a band-structure, such as disordered metals or molecules. The energy-domain FRG ({\epsilon}FRG) presented here accounts for Fermi-liquid corrections to quasi-particle energies and particle-hole excitations. It goes beyond the state of the art GW-BSE, because in {\epsilon}FRG the Bethe-Salpeter equation (BSE) is solved in a self-consistent manner. An efficient implementation of the approach that has been tested against exact diagonalization calculations and calculations based on the density matrix renormalization group is presented. Similar to the conventional FRG, also the {\epsilon}FRG is able to signalize the vicinity of an instability of the Fermi-liquid fixed point via runaway flow of the corresponding interaction vertex. Embarking upon this fact, in an application of {\epsilon}FRG to the spinless disordered Hubbard model we calculate its phase-boundary in the plane spanned by the interaction and disorder strength. Finally, an extension of the approach to finite temperatures and spin S = 1/2 is also given.Comment: 25 pages, 14 figure

Stress testing of real credit portfolios

Stress testing has become a crucial point on the Basel II agenda, mainly as Pillar I estimates do not explicitly take portfolio concentration into account. We start from the credit portfolio of the German pension insurer being a cross-sectional representation of the German economy and subsequently compose three bank portfolios corresponding to a small, medium and large bank. We apply univariate and multivariate stress tests both by using the Internal Rating based (IRB) model and by a model that additionally allows for variation of correlation. In a severe multivariate stress scenario based on historical data for Germany IRB capital requirements increase by more than 80% with little differences between the credit portfolios. If stress testing is additionally applied to correlation, the Value-at-Risk increases by up to 300% and portfolio differences materialize. --Credit Portfolio,Exposure concentration,Stress Testing,Basel II,Economic Capital

THE EFFECTS OF SALESPERSON TRAINING PROGRAM QUALITY ON SALESPERSON COMPETENCY AND MANAGEMENT OF THE DISTRIBUTION AREA TO INCREASE SALESPERSON PERFORMANCE (Differences Study on Distribution Pharmacy Company in Central Java, Indonesia)

A quality training program for sales persons will optimize sales persons’ performance through several variables, which are the competence of sales persons and the quality of distribution territory management. The problem of this research is how does the improvement of sales persons’ competence affecting the improvement of seller territory management quality is able to fill the gap between sales persons’ training program and sales persons’ performance. The samples were 166 respondents who are sales persons and have followed training program from various pharmaceutical distributor companies in Central Java. In addition, data was analyzed using the Structural Equation Modeling (SEM) of AMOS 23 program. To improving the performance of sales persons, their competence is significantly affected by sales persons training program, and the quality of distribution territory management is also significantly affected by sales persons' competence, while the performance of sales persons is significantly affected by the quality of distribution territory management. Meanwhile, the competence of sales persons provides neither major nor significant effect on the performance of sales persons

Totally odd depth-graded multiple zeta values and period polynomials

Inspired by a paper of Tasaka, we study the relations between totally odd, motivic depth-graded multiple zeta values. Our main objective is to determine the rank of the matrix $C_{N,r}$ defined by Brown. We will give new proofs for (conjecturally optimal) upper bounds on the rank of $C_{N,3}$ and $C_{N,4}$, which were first obtained by Tasaka. Finally, we present a recursive approach to the general problem, which reduces evaluating the rank of $C_{N,r}$ to an isomorphism conjecture.Comment: 14 page

Empirical risk analysis of pension insurance: the case of Germany

With this paper we seek to contribute to the literature on pension insurance systems. The financial literature tends to focus exclusively on the US pension insurance system. This is the first major empirical study to address the German occupational pension insurance (PSVaG) plan in Germany. The study is based on a Merton-type one-factor model, in which we determine the credit portfolio risk profile of the occupational pension insurance plan and compare two alternative pricing plans. We find that there is a low, yet non-negligible risk of very high losses that may threaten the existence of the occupational pension insurance plan (PSVaG). While relating risk premiums to firms' default probabilities would cause them to diverge widely, a marginal risk contribution method would produce less pronounced differences compared to the current, uniform pricing plan. --Pension insurance,Risk-adjusted premiums,Credit portfolio risk

Study of the CAC mechanisms for telecommunications systems with adaptive links according to propagation conditions

This paper presents the framework and the activities of a PhD research work in progress supported by Alcatel Alenia Space in collaboration with TeSA and SUPAERO. It deals with Connection Admission Control (CAC) for Telecommunications Systems with adaptive links according to propagation conditions. Indeed, in high frequency bands communications, deep fadings may occur because of atmospheric propagation losses. The mitigation techniques used to counteract fades impacts the system capacity, therefore the CAC mechanism. The CAC which only uses current capacity information may lead to intolerable dropping of admitted connection, and thus breaches the QoS guarantees made upon connection acceptance. New CAC mechanisms shall be studied to take into account the capacity variation and the mitigation techniques (IFMT) developed to compensate the attenuation in Ka and above frequency range

The Structure–Agency Relation of Growth Imperative Hypotheses in a Credit Economy

Growth dynamics are often explained by insatiable wants or anthropological constants, modelled as preferences and behavioural axioms. By contrast, structural perspectives postulate a growth imperative due to macroeconomic or monetary system-inherent properties. Reconciling both perspectives, we develop a relational structure–agency framework to evaluate growth imperative hypotheses. We analytically separate the credit structure (including balance-sheet mechanics and nominal uncertainty) from institutional structure, and describe decision norms for households, entrepreneurs, commercial banks, central bank, and the state. Our framework suggests that the interplay of credit principles, income-dependent saving and portfolio saving rationales prevent the interest rate from adjusting downwards and thereby cause mature credit economies to stagnate. Underemployment results in growth policies becoming the dominant norm – seeking, under budget constraints, to overcome declining growth rates. Our method helps identifying agency to resolve this imperative. Preventing real asset inflation to relieve monetary policy at the effective lower bound appears essential

Verifying non-functional real-time properties by static analysis

International audienceStatic analyzers based on abstract interpretation are tools aiming at the automatic detection of run-time properties by analyzing the source, assembly or binary code of a program. From Airbus' point of view, the first interesting properties covered by static analyzers available on the market, or as prototypes coming from research, are absence of run-time errors, maximum stack usage and Worst-Case Execution Time (WCET). This paper will focus on the two latter

Interdependence of Angiogenesis and Arteriogenesis in Development and Disease

The structure of arterial networks is optimized to allow efficient flow delivery to metabolically active tissues. Optimization of flow delivery is a continuous process involving synchronization of the structure and function of the microcirculation with the upstream arterial network. Risk factors for ischemic cardiovascular diseases, such as diabetes mellitus and hyperlipidemia, adversely affect endothelial function, induce capillary regression, and disrupt the micro- to macrocirculation cross-talk. We provide evidence showing that this loss of synchronization reduces arterial collateral network recruitment upon arterial stenosis, and the long-term clinical outcome of current revascularization strategies in these patient cohorts. We describe mechanisms and signals contributing to synchronized growth of micro- and macrocirculation in development and upon ischemic challenges in the adult organism and identify potential therapeutic targets. We conclude that a long-term successful revascularization strategy should aim at both removing obstructions in the proximal part of the arterial tree and restoring “bottom-up” vascular communication