Connection between charge transfer and alloying core-level shifts based on density-functional calculations

The measurement of alloying core-level binding energy (CLBE) shifts has been used to give a precise meaning to the fundamental concept of charge transfer. Here, ab-initio density-functional calculations for the intermetallic compound MgAu are used to investigate models which try to make a connection between the core levels shifts and charge transfer. The calculated CLBE shifts agree well with experiment, and permit an unambiguous separation into initial-state and screening contributions. Interestingly, the screening contribution is large and cannot be neglected in any reasonable description. Comparison of the calculated results with the predictions of simple models show that these models are not adequate to describe the realistic situation. On the positive side, the accuracy of the density-functional calculations indicates that the combination of experiments with such calculations is a powerful tool to investigate unknown systems.Comment: RevTeX 10 pages incl 8 figure

Which radius for the Sun?

The high accuracy reached by solar limb observations, by helioseismic measurements and by Standard Solar Models (SSMs) calculations suggests that general relativity corrections are included when discussing the solar radius. The Allen value (R$_{\odot}$ = 695.99 $\pm$ 0.07 Mm) has to be reduced by 1.5 Km. This correction, which is small as compared with present accuracy, should be kept in mind for future more precise measurements and/or calculations.Comment: Latex, 3 page

Beauveria bassiana strain ATCC 74040 (Naturalis®), a valuable tool for the control of the cherry fruit fly (Rhagoletis cerasi)

Naturalis® is a bioinsecticide based on living conidiospores of the naturally occuring Beauveria bassiana strain ATCC 74040. The entomopathogenic fungus acts primarily by contact: once attached to the insect’s cuticle, the conidiospores germinate producing penetration hyphae, which enter and proliferate inside the insect’s body. The fungus invades and feeds on its host, causing its death due to dehydration and/or depletion of nutrients. Several years of laboratory, semi-field and field studies showed that also Tephritid flies (Ceratitis capitata, Rhagoletis cerasi, Bactrocera oleae) are susceptible to infection by B. bassiana strain ATCC 74040. The results of efficacy trials conducted in 2004-05 are reported. Naturalis was tested both alone and in an integrated pest management strategy. The product showed high efficacy in controlling R. cerasi, comparable to or higher than that of the chemical reference treatment. The B. bassiana-based product Naturalis can thus be considered an efficient tool for the control of the cherry fruit fly

Bounds on hep neutrinos

The excess of highest energy solar-neutrino events recently observed by Superkamiokande can be in principle explained by anomalously high $hep$-neutrino flux $\Phi_{\nu}(hep)$. Without using SSM calculations, from the solar luminosity constraint we derive that $\Phi_\nu(hep)/S_{13}$ cannot exceed the SSM estimate by more than a factor three. If one makes the additional hypothesis that $hep$ neutrino production occurs where the $^3$He concentration is at equilibrium, helioseismology gives an upper bound which is (less then) two times the SSM prediction. We argue that the anomalous $hep$-neutrino flux of order of that observed by Superkamiokande cannot be explained by astrophysics, but rather by a large production cross-section.Comment: 7 pages, RevTeX fil

Gribov horizon and non-perturbative BRST symmetry in the maximal Abelian gauge

The non-perturbative nilpotent exact BRST symmetry of the Gribov-Zwanziger action in the Landau gauge constructed in [ arXiv:1506.06995 [hep-th]] is generalized to the case of Euclidean Yang-Mills theories quantized in the maximal Abelian gauge. The resulting diagonal gluon propagator is evaluating in dimensions D=4,3,2. In D=4,3 a decoupling type behavior is found in the infrared region, while in D=2 a scaling type behavior emerges.Comment: Reviewed version with a new section and new references adde

Extracting convergent surface energies from slab calculations

The formation energy of a solid surface can be extracted from slab calculations if the bulk energy per atom is known. It has been pointed out previously that the resulting surface energy will diverge with slab thickness if the bulk energy is in error, in the context of calculations which used different methods to study the bulk and slab systems. We show here that this result is equally relevant for state-of-the-art computational methods which carefully treat bulk and slab systems in the same way. Here we compare different approaches, and present a solution to the problem that eliminates the divergence and leads to rapidly convergent and accurate surface energies.Comment: 3 revtex pages, 1 figure, in print on J. Phys. Cond. Mat

A non-perturbative study of matter field propagators in Euclidean Yang-Mills theory in linear covariant, Curci-Ferrari and maximal Abelian gauges

In this work, we study the propagators of matter fields within the framework of the Refined Gribov-Zwanziger theory, which takes into account the effects of the Gribov copies in the gauge-fixing quantization procedure of Yang-Mills theory. In full analogy with the pure gluon sector of the Refined Gribov-Zwanziger action, a non-local long-range term in the inverse of the Faddeev-Popov operator is added in the matter sector. Making use of the recent BRST invariant formulation of the Gribov-Zwanziger framework achieved in [Capri et al 2016], the propagators of scalar and quark fields in the adjoint and fundamental representations of the gauge group are worked out explicitly in the linear covariant, Curci-Ferrari and maximal Abelian gauges. Whenever lattice data are available, our results exhibit good qualitative agreement.Comment: 27 pages, no figures; V2, minor modifications, to appear in EPJ