A new non-Fermi liquid fixed point

We study a new exchange interaction in which the conduction electrons with pseudo spin $S_c=3/2$ interact with the impurity spin $S_I=1/2$. Due to the overscreening of the impurity spin by higher conduction electron spin, a new non-trivial intermediate coupling strength fixed point is realized. Using the numerical renormalization group (NRG), we show that the low-energy spectra are described by a non-Fermi liquid excitation spectrum. A conformal field theory analysis is compared with NRG results and excellent agreement is obtained. Using the double fusion rule to generate the operator spectrum with the conformal theory, we find that the specific heat coefficient and magnetic susceptibility will diverge as $T^{-2/3}$, that the scaling dimension of an applied magnetic field is $5/6$, and that exchange anisotropy is always relevant. We discuss the possible relevance of our work to two-level system Kondo materials and dilute cerium alloys, and we point out a paradox in understanding the Bethe-Ansatz solutions to the multichannel Kondo model.Comment: Revised. 20 page

On the short-time thermal phase-stability of as-cast AlCoCrFeNi2.1 eutectic high entropy alloy

The authors would like to gratefully acknowledge the kind support of Clodualdo Aranas, who the NSERC Discovery Grant supported by the Natural Sciences and Engineering Research Council of Canada (RGPIN 04006). Also, JPO acknowledges Fundação para a Ciência e a Tecnologia (FCT – MCTES) for its financial support via the project UID/00667/2020 (UNIDEMI). JPO also acknowledges the funding of CENIMAT/i3N by national funds through the FCT-Fundação para a Ciência e a Tecnologia, I.P., within the scope of Multiannual Financing of R&D Units, reference UIDB/50025/2020–2023. JS acknowledges the China Scholarship Council for funding the Ph.D. grant (CSC No. 201808320394).The present work deals with the short-time thermal phase-stability of the as-cast eutectic AlCoCrFeNi2.1 high entropy alloy. Toward this end, the effect of different temperatures (800-1000 °C) and soaking times (15-60 min) on the stability of primary dendritic regions and formation of the ordered phases was explored. Microstructural characterization was supported by thermodynamic calculations and assessment of the subsequent mechanical properties. Upon the increase in annealing temperature and soaking time, the primary FCC dendritic areas grown and destabilized owing to elemental partitioning. This was followed by dendrite fragmentation and formation of needle shape B2 ordered phases within the primary FCC regions. Despite the unstable nature of the primary constituent phases, the material hardness increased considerably to a peak point corresponding to the moderate soaking time of 45 min. The variation of the subsequent mechanical properties was discussed relying on the characteristics of the ordered and primary phases.publishersversionpublishe

Four new coordination polymers involving transition metals with 1,2,4,5-benzenetetracarboxylate and pyridyl-donor ligand di(4-pyridyl) sulfide

AbstractFour new coordination polymers namely {[Mn2(BT)(DPS)2(H2O)6]·10H2O}n (MnBTDPS), {[Co2(BT)(DPS)2(H2O)6]·10H2O}n (CoBTDPS), {[Cu2(BT)(DPS)(H2O)4]·5H2O}n (CuBTDPS) and {[Zn2(BT)(DPS)2]·6H2O}n (ZnBTDPS), where BT=1,2,4,5-benzenetetracarboxylate and DPS=di(4-pyridyl) sulfide, were synthesized and characterized by thermal analysis, vibrational spectroscopy (Raman and infrared) and single crystal X-ray diffraction analysis. In all compounds, the DPS ligands are coordinated to metal sites in a bridging mode and the carboxylate moiety of BT ligands adopts a monodentate coordination mode, as indicated by the Raman spectra data through the Δν (νasym(COO)−ν sym(COO)) value. According to X-ray diffraction analysis, MnBTDPS and CoBTDPS are isostructural and in these cases, the metal centers exhibit a distorted octahedral geometry. In CuBTBPP, the Cu2+ centers geometries are best described as square-pyramids, according to the trigonality index τ=0.14 for Cu1 and τ=0.10 for Cu2. On the other hand, in ZnBTDPS, the Zn2+ sites adopt a tetrahedral geometry. Finally, the four compounds formed two-dimensional sheets that are connected to each other through hydrogen bonding giving rise to three-dimensional supramolecular arrays

Energy Resolution studies for NEXT

This work aims to present the current state of simulations of electroluminescence (EL) produced in gas-based detectors with special interest for NEXT --- Neutrino Experiment with a Xenon TPC. NEXT is a neutrinoless double beta decay experiment, thus needs outstanding energy resolution which can be achieved by using electroluminescence. The process of light production is reviewed and properties such as EL yield and associated fluctuations, excitation and electroluminescence efficiencies, and energy resolution, are calculated. An EL production region with a 5 mm width gap between two infinite parallel planes is considered, where a uniform electric field is produced. The pressure and temperature considered are 10 bar and 293 K, respectively. The results show that, even for low values of VUV photon detection efficiency, good energy resolution can be achieved: below 0.4 % (FWHM) at $Q_{\beta\beta}=$2.458 MeV

Fresh inflation and decoherence of super Hubble fluctuations

I study a stochastic approach to the recently introduced fresh inflation model for super Hubble scales. I find that the state loses its coherence at the end of the fresh inflationary period as a consequence of the damping of the interference function in the reduced density matrix. This fact should be a consequence of a) the relative evolutions of both the scale factor and the horizon and b) the additional thermal and dissipative effects. This implies a relevant difference with respect to supercooled inflationary scenarios which require a very rapid expansion of the scale factor to give the decoherence of super Hubble fluctuations.Comment: version with minor changes. To appear in Phys. Rev.

FITOREGULADORES E GERMINAÇÃO DE SEMENTES DE MARACUJÁ DOCE EM CONDIÇÕES DE LABORATÓRIO

The experiment was carried out in Seed Analyze Laboratory of Department of Crop Science of São Paulo State University (UNESP) Botucatu, Brasil. The objective of the experiment was to study the influence of phytoregulators on the germination of Passiflora alata Curtis seeds. Completely randomized blocks, with four replications, 14 treatments of 50 seeds per plot was the experimental design used in the assay. The treatments was composed by applications of GA3, phenylmethil-tetrahydro-pyranil-aminopurine, and ethephon phytoregulators on dosages of 75 and 150 mg L-1 and in combinations of couples of thoses. In the treatments were used two controls, being one with seeds only soaked in distilled water and, the other seeds that did not receive any treatment. The evaluations of initial root emission, percentage of normal seedling, and percentage of hard seeds were avaluated by germination test under 25 °C temperature, during 35 days and after the seeds were remained more 35 days under 20-30 °C temperature. GA3, N-phenylmethyl-9- tetra-hydro-2H-2 pyranil 9H-6 aminopurine, and ethephon phytoregulators, on the 75 and 150 mg L-1 dosages did not favor the process of P.alata seed germinations.O experimento conduzido no Laboratório de Análise de Sementes do Departamento de Produção Vegetal - Setor Agricultura da Faculdade de Ciências Agronômicas do campus de Botucatu - UNESP, teve como objetivo avaliar a influência de fitorreguladores na germinação de sementes de Passiflora alata Curtis. Foram avaliados 14 tratamentos sob o delineamento experimental inteiramente casualizado com 4 repetições de 50 sementes cada. Os tratamentos constaram da aplicação dos fitorreguladores GA3, fenilmetiltetrahidro- piranil-aminopurina e ethephon nas concentrações de 75 e 150 mg.L-1, isolados e combinados com as mesmas dosagens, das sementes embebidas somente em água destilada e das sementes sem qualquer tratamento (testemunha). As avaliações de emissão de radícula, porcentagem de plântulas normais e porcentagem de sementes duras foram avaliadas pelo teste de germinação sob temperatura constante de 25 ºC, por 35 dias e temperatura de 20-30 ºC, por mais 35 dias. Os fitorreguladores GA3, N-fenilmetil-9- Tetra-Hidro-2H-2 piranil 9H-6 amino purina e ethephon, isolados ou em misturas, nas dosagens de 75 e 150 mg.L-1 não favoreceram o processo germinativo de sementes de P. alata

Enhanced pressure drop, planar contraction flows and continuous spectrum models

This study addresses a rheological problem that has been outstanding now for the past few decades, raised by the experimental findings of Binding and Walters [1]. There, it was established experimentally that planar contraction flows for some Boger fluids could display enhanced pressure-drops above Newtonian flows, as was the case for their tubular counterparts. Nevertheless, flow-structures to achieve this result were reported to be markedly different, planar to circular. In this article, it is shown how predictive differential-viscoelastic solutions with continuum models can replicate these observations. Key to this success has been the derivation of a new definition for the third-invariant of the rate-of-deformation tensor in planar flows, mimicking that of the circular case [2], [3]. This provides a mechanism to successfully incorporate dissipation within planar flows, as performed earlier for tubular flows. Still, to reach the necessary large deformation-rates to achieve planar enhanced pressure-drops, and whilst maintaining steady flow-conditions, it has been found crucial to invoke a continuous-spectrum relaxation-time model [3]. The rheological power and flexibility of such a model is clearly demonstrated, over its counterpart Maxwellian single-averaged relaxation-time approximation; the latter transcending the boundaries of steady-to-unsteady flow to manifest equivalent levels of enhanced pressure-drops. Then, the role of extensional viscosity and first normal-stress difference, each play their part to achieve such planar enhanced pressure-drops. As a by-product, the distinctive planar ‘bulb-flow’ structures discovered by Binding and Walters [1], absent in tubular flows, are also predicted under the associated regime of high deformation-rates where enhanced pressure-drop arise

The Fluorescence Detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section