9,180 research outputs found

    Controlling the pair momentum of the FFLO state in a 3D Fermi gas through a 1D periodic potential

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    The question whether a spin-imbalanced Fermi gas can accommodate the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state has been the subject of intense study. This state, in which Cooper pairs obtain a nonzero momentum, has hitherto eluded experimental observation. Recently, we demonstrated that the FFLO state can be stabilized in a 3D Fermi gas, by adding a 1D periodic potential. Until now it was assumed that the FFLO wave vector always lies parallel to this periodic potential (FFLO-P). In this contribution we show that, surprisingly, the FFLO wave vector can also lie skewed with respect to the potential (FFLO-S). Starting from the partition sum, the saddle-point free energy of the system is derived within the path-integral formalism. Minimizing this free energy allows us to study the different competing ground states of the system. To qualitatively understand the underlying pairing mechanism, we visualize the Fermi surfaces of the spin up and spin down particles. From this visualization, we find that tilting the FFLO wave vector with respect to the direction of the periodic potential, can result in a larger overlap between the pairing bands of both spin species. This skewed FFLO state can provide an additional experimental signature for observing FFLO superfluidity in a 3D Fermi gas.Comment: 19 pages, 3 figure

    Macroscopic and Microscopic Properties of a Cloned Glutamate Transporter/Chloride Channel

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    The behavior of a Cl− channel associated with a glutamate transporter was studied using intracellular and patch recording techniques in Xenopus oocytes injected with human EAAT1 cRNA. Channels could be activated by application of glutamate to either face of excised membrane patches. The channel exhibited strong selectivity for amphipathic anions and had a minimum pore diameter of ∌5Å. Glutamate flux exhibited a much greater temperature dependence than Cl− flux. Stationary and nonstationary noise analysis was consistent with a sub-femtosiemen Cl− conductance and a maximum channelPo â‰Ș 1. The glutamate binding rate was similar to estimates for receptor binding. After glutamate binding, channels activated rapidly followed by a relaxation phase. Differences in the macroscopic kinetics of channels activated by concentration jumps of l-glutamate or d-aspartate were correlated with differences in uptake kinetics, indicating a close correspondence of channel gating to state transitions in the transporter cycle

    TMD PDF's: gauge invariance, RG properties and Wilson lines

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    The UV divergences associated with transverse-momentum dependent (TMD) parton distribution functions (PDF) are calculated together with the ensuing one-loop anomalous dimensions in the light-cone gauge. Time-reversal-odd effects in the anomalous dimensions are observed and the role of Glauber gluons is discussed. A generalized renormalization procedure of TMD PDFs is proposed, relying upon the renormalization of contour-dependent operators with obstructions.Comment: 4 pages, 1 figure. Talk presented at the International Workshop on Diffraction in High Energy and Nuclear Physics, La Londe-les-Maures, France, 9-14 Sept 2008. v2: 5 pages, preprint number and e-mail addresses adde

    Burning and Management Alternatives on Forage Accumulation and Floristic Composition of a Native Pasture

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    The forage accumulation and floristic composition of native pasture, submitted to burning and alternative management practices, was evaluated during one year. The experimental design was a completely randomized, with five treatments and three replications. The forage accumulation was evaluated in a grazing exclusion cage, and the floristic composition was estimated with Botanal method. The systems without burning were more productive and, among these, the forage accumulation was similar between the one without burning and without mowing and the improve treatments, and the annual accumulation was greater than 9,000 Kg/ha of green forage dry matter. The species Paspalum notatum, P. paniculatum and Desmodium incanum had greater contribution in the improved and mowed treatments. The biennial burning stimulated species of Andropogon and Schizachyrium genus and also opportunistic species. The alternative management showed to be more sustainable, promoted greater floristic diversity, and allowed increase of species with good nutritive value

    Effect of Burning and Management Alternatives on Forage Litter Composition of a Native Pasture

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    The content and quantities of nutrients in forage and litter was evaluated in native pasture under grazing, submitted to burning and alternatives practices. The experimental design was a completely randomized, with three replications. The biennial burning has no effect in nutrients contents of the forage, but in the case of litter plus senescent material the concentration of Ca and Mg decreased as compared to the systems without burning. The sod-seeding treatment increased the nutrient contents in the alive and dead tissues. Nutrient accumulation on forage tissue and litter plus senescent material, was highest in the systems without burning

    New Neurons Don’t Talk Back

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    GABAergic interneurons enforce highly sparse activity patterns in principal neurons of the dentate gyrus. In this issue of Neuron, Temprana et al. (2015) show that immature adult-born neurons largely function independently of inhibitory feedback circuits, neither receiving nor generating feedback inhibition

    The contribution of the computer science as well as the information and communication science approaches for the editorial function of the territorial information systems.

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    International audienceThis collaboration focuses on the data-processing software evolution which implements an editorial function in territorial information systems in various using contexts. It results from collaboration between humanities, social sciences, computer science and information and communication science researchers, and which has been established since 2000 within the ISTI21 and the MSH LEDOUX22 framework. In a previous paper, we summed up the research activities about territorial intelligence since the seventies'. Essentially, it was a friendly data processing solutions development: PRAGMA for quantitative data analysis; ANACONDA and NUAGE for qualitative data analysis. Thanks to computer science researchers collaboration, the SITRA23 research action allowed the completing of statistical analysis data by spatial analysis and cartography tools. Then the ICASIT24 started updating and making the statistical data and spatial analysis software, previously developed to evolve within the networks and Internet framework. Progressively, we became aware of the editorial function importance of this analytical chain, directed towards an online results edition. This paper deepens the specific added value of computer science as well as information and communication sciences to the design and the territorial intelligence systems modelling
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