Sovereign Bonds and Socially Responsible Investment

While the literature on Socially Responsible Investment (SRI) is mainly focused on the stock market, little attention has been paid to SRI in sovereign bonds. This paper investigates the effect of taking into account socially responsible indicators for countries, the Vigeo Sustainability Ratings (VSR), on the efficient frontier formed with the sovereign bonds of twenty developed countries. It shows that it is possible to increase the portfolios’ VSR rating without significantly harming the risk/return relationship. The analysis then focuses on specific ratings relating to a) the environment, b) social concerns, and c) public governance. The results suggest that socially responsible portfolios of sovereign bonds can be built without a significant diversification cost.Socially Responsible Investment, Sovereign Bonds, Portfolio Selection, Rating, Spanning Tests, Mean-variance efficiency, Portfolio Choice

Critical exponents of the semimetal-insulator transition in graphene: A Monte Carlo study

The low-energy theory of graphene exhibits spontaneous chiral symmetry breaking due to pairing of quasiparticles and holes, corresponding to a semimetal-insulator transition at strong Coulomb coupling. We report a Lattice Monte Carlo study of the critical exponents of this transition as a function of the number of Dirac flavors $N_f^{}$, finding $\delta = 1.25 \pm 0.05$ for $N_f^{} = 0$, $\delta = 2.26 \pm 0.06$ for $N_f^{} = 2$ and $\delta = 2.62 \pm 0.11$ for $N_f^{} = 4$, with $\gamma \simeq 1$ throughout. We compare our results with recent analytical work for graphene and closely related systems, and discuss scenarios for the fate of the chiral transition at finite temperature and carrier density, an issue of relevance for upcoming experiments with suspended graphene samples.Comment: 5 pages, 5 figures. Published versio

Who will go down this year ? The Determinants of Promotion and Relegation in European Soccer Leagues

Contributing to the lively debate on closed leagues (North American model) versus open leagues (European model) in professional sport league, this paper aims at determining the drivers of promotion and relegation in the major European soccer leagues. Using a large and original dataset (for example: club’s link with a billionaire, club listed in the stock market, etc.) and logistic regressions, our results show that institutional factors matter to settle in the elite. It also indicates that open leagues system in European soccer championships is de facto very similar to closed leagues system. Furthermore, our forecasting model can be of interest for soccer investors or bookmakers.Economics of Sport, Organization of Sports Leagues, Soccer, Promotion and Relegation, Economic Forecasting, Regional Economy, Billionaires, Stock Market.

Lattice methods for strongly interacting many-body systems

Lattice field theory methods, usually associated with non-perturbative studies of quantum chromodynamics, are becoming increasingly common in the calculation of ground-state and thermal properties of strongly interacting non-relativistic few- and many-body systems, blurring the interfaces between condensed matter, atomic and low-energy nuclear physics. While some of these techniques have been in use in the area of condensed matter physics for a long time, others, such as hybrid Monte Carlo and improved effective actions, have only recently found their way across areas. With this topical review, we aim to provide a modest overview and a status update on a few notable recent developments. For the sake of brevity we focus on zero-temperature, non-relativistic problems. After a short introduction, we lay out some general considerations and proceed to discuss sampling algorithms, observables, and systematic effects. We show selected results on ground- and excited-state properties of fermions in the limit of unitarity. The appendix contains details on group theory on the lattice.Comment: 64 pages, 32 figures; topical review for J. Phys. G; replaced with published versio

Pressure, compressibility, and contact of the two-dimensional attractive Fermi gas

Using ab initio lattice methods, we calculate the finite temperature thermodynamics of homogeneous two-dimensional spin-1/2 fermions with attractive short-range interactions. We present results for the density, pressure, compressibility, and quantum anomaly (i.e. Tan's contact) for a wide range of temperatures and coupling strengths, focusing on the unpolarized case. Within our statistical and systematic uncertainties, our prediction for the density equation of state differs quantitatively from the prediction by Luttinger-Ward theory in the strongly coupled region of parameter space, but otherwise agrees well with it. We also compare our calculations with the second- and third-order virial expansion, with which they are in excellent agreement in the low-fugacity regime.Comment: 7 pages, 8 figures, including supplemental material