86 research outputs found
Origin of the anomalous Hall Effect in overdoped n-type cuprates: current vertex corrections due to antiferromagnetic fluctuations
The anomalous magneto-transport properties in electron doped (n-type)
cuprates were investigated using Hall measurements at THz frequencies. The
complex Hall angle was measured in overdoped PrCeCuO samples (x=0.17 and 0.18) as a continuous function of
temperature above at excitation energies 5.24 and 10.5 meV. The results,
extrapolated to low temperatures, show that inelastic scattering introduces
electron-like contributions to the Hall response. First principle calculations
of the Hall angle that include current vertex corrections (CVC) induced by
electron interactions mediated by magnetic fluctuations in the Hall
conductivity reproduce the temperature, frequency, and doping dependence of the
experimental data. These results show that CVC effects are the source of the
anomalous Hall transport properties in overdoped ntype cuprates.Comment: 5 pages, 3 figure
Scaling and commensurate-incommensurate crossover for the d=2, z=2 quantum critical point of itinerant antiferromagnets
Quantum critical points exist at zero temperature, yet, experimentally their
influence seems to extend over a large part of the phase diagram of systems
such as heavy-fermion compounds and high-temperature superconductors.
Theoretically, however, it is generally not known over what range of parameters
the physics is governed by the quantum critical point. We answer this question
for the spin-density wave to fermi-liquid quantum critical point in the
two-dimensional Hubbard model. This problem is in the universality
class. We use the Two-Particle Self-Consistent approach, which is accurate from
weak to intermediate coupling, and whose critical behavior is the same as for
the self-consistent-renormalized approach of Moriya. Despite the presence of
logarithmic corrections, numerical results demonstrate that quantum critical
scaling for the static magnetic susceptibility can extend up to very high
temperatures but that the commensurate to incommensurate crossover leads to
deviations to scaling.Comment: Unchanged numerical results. It is now shown analytically that the
approach includes logarithmic corrections and that the critical behavior is
equivalent to the theory of Moriya. 6 pages, 3 figures, Late
The hidden world within plants: ecological and evolutionary considerations for defining functioning of microbial endophytes
All plants are inhabited internally by diverse microbial communities comprising bacterial, archaeal, fungal, and protistic taxa. These microorganisms showing endophytic lifestyles play crucial roles in plant development, growth, fitness, and diversification. The increasing awareness of and information on endophytes provide insight into the complexity of the plant microbiome. The nature of plant-endophyte interactions ranges from mutualism to pathogenicity. This depends on a set of abiotic and biotic factors, including the genotypes of plants and microbes, environmental conditions, and the dynamic network of interactions within the plant biome. In this review, we address the concept of endophytism, considering the latest insights into evolution, plant ecosystem functioning, and multipartite interactions.EU Cost Action [FA1103, 312117]; FWF (Austrian Science Foundation) [P26203-B22, P24569-B25]; Portuguese FCT (Foundation for Science and Technology) [SFRH/BPD/78931/2011]info:eu-repo/semantics/publishedVersio
Points fixes d'opérateurs non linéaires dans un espace de Banach ordonné
Ce mémoire a pour but de présenter certains résultats récemment obtenus en théorie du point fixe dans le cadre des espaces de Banach ordonnés, ainsi que d'illustrer les techniques utilisées pour l'obtention de ces résultats dans un tel contexte. Une partie du travail vise à obtenir une généralisation aux applications y-contractantes deux résultats classiques pour les opérateurs complètement continus qui laissent le cône des éléments positifs invariant. L'autre partie est consacrée à une branche élémentaire de la théorie du point fixe dans les espaces de Banach ordonnés, soit l'étude de points fixes pour les opérateurs qui sont monotones par rapport à la relation d'ordre de l'espace et qui laissent un intervalle invariant
Points fixes d'opérateurs non linéaires dans un espace de Banach ordonné
Ce mémoire a pour but de présenter certains résultats récemment obtenus en théorie du point fixe dans le cadre des espaces de Banach ordonnés, ainsi que d'illustrer les techniques utilisées pour l'obtention de ces résultats dans un tel contexte. Une partie du travail vise à obtenir une généralisation aux applications y-contractantes deux résultats classiques pour les opérateurs complètement continus qui laissent le cône des éléments positifs invariant. L'autre partie est consacrée à une branche élémentaire de la théorie du point fixe dans les espaces de Banach ordonnés, soit l'étude de points fixes pour les opérateurs qui sont monotones par rapport à la relation d'ordre de l'espace et qui laissent un intervalle invariant
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