Experiential learning in virtues ethics through a case study: The 'St. Albans Family Enterprises'

Teaching business ethics effectively may prepare future leaders and managers to better deal with delicate situations that they might face in the workplace. However, such an aim is one of the biggest challenges that educators at universities are called on to solve. An increasing number of scholars are invoking the role of prudence in the virtue ethics context as a viable approach to teach students how to manage ethical dilemmas. In this regard, this paper presents the ‘St. Albans Family Enterprise’ case study that can serve as an instrument to help students and practitioners develop their ethical decision-making ability and to foster a disposition towards applying sound judgment or what can be called in classical terms, prudence. The paper also offers guidance to educators about how the case can be used for teaching purposes, and explains the implications of exercising practical wisdom (prudence) within a virtue ethics framework

Impact of electronic correlations on the equation of state and transport in ϵ\epsilon-Fe

We have obtained the equilibrium volumes, bulk moduli, equations of state of the ferromagnetic cubic $\alpha$ and paramagnetic hexagonal $\epsilon$ phases of iron in close agreement with experiment using an ab initio dynamical mean-field theory approach. The local dynamical correlations are shown to be crucial for a successful description of the ground-state properties of paramagnetic $\epsilon$-Fe. Moreover, they enhance the effective mass of the quasiparticles and reduce their lifetimes across the $\alpha \to \epsilon$ transition leading to a step-wise increase of the resistivity, as observed in experiment. The calculated magnitude of the jump is significantly underestimated, which points to non-local correlations. The implications of our results for the superconductivity and non-Fermi-liquid behavior of $\epsilon$-Fe are discussed.Comment: 6 pages, 3 figure

Electronic correlations in vanadium chalcogenides: BaVSe3 versus BaVS3

Albeit structurally and electronically very similar, at low temperature the quasi-one-dimensional vanadium sulfide BaVS3 shows a metal-to-insulator transition via the appearance of a charge-density-wave state, while BaVSe3 apparently remains metallic down to zero temperature. This different behavior upon cooling is studied by means of density functional theory and its combination with the dynamical mean-field theory and the rotationally-invariant slave-boson method. We reveal several subtle differences between these chalcogenides that provide indications for the deviant behavior of BaVSe3 at low temperature. In this regard, a smaller Hubbard U in line with an increased relevance of the Hund's exchange J plays a vital role.Comment: 16 pages, 11 figures, published versio

Orthogonal Polynomial Representation of Imaginary-Time Green's Functions

We study the expansion of single-particle and two-particle imaginary-time Matsubara Green's functions of quantum impurity models in the basis of Legendre orthogonal polynomials. We discuss various applications within the dynamical mean-field theory (DMFT) framework. The method provides a more compact representation of the Green's functions than standard Matsubara frequencies and therefore significantly reduces the memory-storage size of these quantities. Moreover, it can be used as an efficient noise filter for various physical quantities within the continuous-time quantum Monte Carlo impurity solvers recently developed for DMFT and its extensions. In particular, we show how to use it for the computation of energies in the context of realistic DMFT calculations in combination with the local density approximation to the density functional theory (LDA+DMFT) and for the calculation of lattice susceptibilities from the local irreducible vertex function.Comment: 14 pages, 11 figure

On infrared divergences in spin glasses

By studying the structure of infrared divergences in a toy propagator in the replica approach to the Ising spin glass below $T_c$, we suggest a possible cancellation mechanism which could decrease the degree of singularity in the loop expansion.Comment: 13 pages, Latex , revised versio

Síndrome del túnel radial: Epicondilitis resistente

Desde 1996 al 2003, fueron intervenidos 25 pacientes (26 extremidades) de síndrome del túnel radial. Todos los procedimientos fueron realizados por el mismo cirujano y en el mismo hospital con un abordaje postero-externo del túnel radial. Se realizó un seguimiento de todos los pacientes en el tiempo después de la cirugía de 4 meses a 6 años y 4 meses (tiempo medio de 22 meses). Los resultados fueron evaluados según los criterios de Roles y Mausdley; 12 pacientes tuvieron resultados excelentes (46.15%), 9 pacientes buenos (34.61%) y 5 pacientes regulares (19.23%). Once pacientes fueron tratados previamente de epicondilitis lateral (entesitis). La mayoría de los pacientes están satisfechos con la cirugía refiriendo un alivio de la sintomatología y una mejora de la funcionalidad tras la cirugía.Between 1996 and 2003, 25 patients (26 extremities) underwent decompression of the radial tunnel. All procedures were performed at the same surgeon and the same institution using posterior approach. The total 25 patients were available for follow-up evaluation alter surgery (range 4 months - 6 years and 4 months) with average of 22 months. The outcomes was determined using the original criteria of Roles and Mausdley, 12 patients were rated as excellent (46.15%), 9 patients has good results (34.61%) and 5 patients had fair results. Eleven patients were treated previously of tennis elbow. Most of the patients were satisfied and felt subjectively improved by the surgery. They obtained pain relief and better functional status after surgery

Strong Correlations in a nutshell

We present the phase diagram of clusters made of two, three and four coupled Anderson impurities. All three clusters share qualitatively similar phase diagrams that include Kondo screened and unscreened regimes separated by almost critical crossover regions reflecting the proximity to barely avoided critical points. This suggests the emergence of universal paradigms that apply to clusters of arbitrary size. We discuss how these crossover regions of the impurity models might affect the approach to the Mott transition within a cluster extension of dynamical mean field theory.Comment: 45 pages, 14 figures. To appear in Journal of Physics: Condensed Matte

Universal transport signatures in two-electron molecular quantum dots: gate-tunable Hund's rule, underscreened Kondo effect and quantum phase transitions

We review here some universal aspects of the physics of two-electron molecular transistors in the absence of strong spin-orbit effects. Several recent quantum dots experiments have shown that an electrostatic backgate could be used to control the energy dispersion of magnetic levels. We discuss how the generically asymmetric coupling of the metallic contacts to two different molecular orbitals can indeed lead to a gate-tunable Hund's rule in the presence of singlet and triplet states in the quantum dot. For gate voltages such that the singlet constitutes the (non-magnetic) ground state, one generally observes a suppression of low voltage transport, which can yet be restored in the form of enhanced cotunneling features at finite bias. More interestingly, when the gate voltage is controlled to obtain the triplet configuration, spin S=1 Kondo anomalies appear at zero-bias, with non-Fermi liquid features related to the underscreening of a spin larger than 1/2. Finally, the small bare singlet-triplet splitting in our device allows to fine-tune with the gate between these two magnetic configurations, leading to an unscreening quantum phase transition. This transition occurs between the non-magnetic singlet phase, where a two-stage Kondo effect occurs, and the triplet phase, where the partially compensated (underscreened) moment is akin to a magnetically "ordered" state. These observations are put theoretically into a consistent global picture by using new Numerical Renormalization Group simulations, taylored to capture sharp finie-voltage cotunneling features within the Coulomb diamonds, together with complementary out-of-equilibrium diagrammatic calculations on the two-orbital Anderson model. This work should shed further light on the complicated puzzle still raised by multi-orbital extensions of the classic Kondo problem.Comment: Review article. 16 pages, 17 figures. Minor corrections and extra references added in V