797 research outputs found
Perturbative treatment of the multichannel interacting resonant level model in steady state non-equilibrium
We consider the steady state non-equilibrium physics of the multichannel
interacting resonant level model in the weak coupling regime. By using the
scattering state method we show in agreement with the rate equations that the
negative differential conductance at large enough voltages is due to the
renormalization of the hopping amplitude thus of the vertex.Comment: 3+ pages, 4 figure
Periodicity of high-order functions in the CNS Final progress report, year ending 30 Jun. 1971
Analysis of cerebral slow potentials underlying human attentive processes in central nervous syste
Serious Games and Participatory Research in Public Health
This survey study considers the state of the art of participatory research approaches using serious games to improve public health. It provides perspectives on existing research and future directions
Towards a microscopic description of dimer adsorbates on metallic surfaces
Despite the experimental successes of Scanning Tunneling Microscopy (STM) and
the interest in more complex magnetic nanostructures, our present understanding
and theoretical description of STM spectra of magnetic adatoms is mainly
phenomenological and most often ignores many-body effects. Here, we propose a
theory which includes a microscopic description of the wave functions of the
substrate and magnetic adatoms together with quantum many-body effects. To test
our theory, we have computed the STM spectra of magnetic Cobalt monomers and
dimers adsorbed on metallic Copper surfaces and succesfully compared our
results to recent available experimental data.Comment: 4 pages, 2 figures, discussion of calculation of RKKY interaction and
connection to NRG included. Extended discussion on calculations of the
one-electron parameters of Anderson model. Typos correcte
A renormalization-group analysis of the interacting resonant level model at finite bias: Generic analytic study of static properties and quench dynamics
Using a real-time renormalization group method we study the minimal model of
a quantum dot dominated by charge fluctuations, the two-lead interacting
resonant level model, at finite bias voltage. We develop a set of RG equations
to treat the case of weak and strong charge fluctuations, together with the
determination of power-law exponents up to second order in the Coulomb
interaction. We derive analytic expressions for the charge susceptibility, the
steady-state current and the conductance in the situation of arbitrary system
parameters, in particular away from the particle-hole symmetric point and for
asymmetric Coulomb interactions. In the generic asymmetric situation we find
that power laws can be observed for the current only as function of the level
position (gate voltage) but not as function of the voltage. Furthermore, we
study the quench dynamics after a sudden switch-on of the level-lead couplings.
The time evolution of the dot occupation and current is governed by exponential
relaxation accompanied by voltage-dependent oscillations and characteristic
algebraic decay.Comment: 24 pages, 13 figures; revised versio
SU(4) Fermi Liquid State and Spin Filtering in a Double Quantum Dot System
We study a symmetrical double quantum dot (DD) system with strong capacitive
inter-dot coupling using renormalization group methods. The dots are attached
to separate leads, and there can be a weak tunneling between them. In the
regime where there is a single electron on the DD the low-energy behavior is
characterized by an SU(4)-symmetric Fermi liquid theory with entangled spin and
charge Kondo correlations and a phase shift . Application of an external
magnetic field gives rise to a large magneto-conductance and a crossover to a
purely charge Kondo state in the charge sector with SU(2) symmetry. In a four
lead setup we find perfectly spin polarized transmission.Comment: 4 pages, 4 figures, ReVTe
Knowledge co-creation in participatory policy and practice: Building community through data-driven direct democracy
Engaging citizens with digital technology to co-create data, information and knowledge has widely become an important strategy for informing the policy response to COVID-19 and the ‘infodemic’ of misinformation in cyberspace. This move towards digital citizen participation aligns well with the United Nations’ agenda to encourage the use of digital tools to enable data-driven, direct democracy. From data capture to information generation, and knowledge co-creation, every stage of the data lifecycle bears important considerations to inform policy and practice. Drawing on evidence of participatory policy and practice during COVID-19, we outline a framework for citizen ‘e-participation’ in knowledge co-creation across every stage of the policy cycle. We explore how coupling the generation of information with that of social capital can provide opportunities to collectively build trust in institutions, accelerate recovery and facilitate the ‘e-society’. We outline the key aspects of realising this vision of data-driven direct democracy by discussing several examples. Sustaining participatory knowledge co-creation beyond COVID-19 requires that local organisations and institutions (e.g. academia, health and welfare, government, business) incorporate adaptive learning mechanisms into their operational and governance structures, their integrated service models, as well as employing emerging social innovations
Absorption, distribution and accumulation of nitrogen applied at different phenological stages in southern highbush blueberry (Vaccinium corymbosum interspecific hybrid)
Southern highbush blueberry has an early harvesting and then a long period of vegetative growth until dormancy, compared to highbush and rabbiteye blueberries. Nitrogen requirements could be different because of this specific early harvesting. Absorption of 15N enriched ammonium sulfate was compared at five phenological stages from bud swell to pre-dormancy in two years old plants of the cultivars Star and ÓNeal. Plants grown in pots were irrigated with ammonium sulfate solution (15N). Five plants for each application date were excavated and separated in parts (roots, canes, leaves, flowers, fruits or floral buds). Samples were taken three weeks after application from bud swell to pre-harvest treatment, and three month after for post-harvest and pre-dormancy treatment. Each tissue were dried and weighed before and after, and analyzed for 15N content, N content and N %….N%, and in leaves were also determined macro and micro nutrients. Nitrogen fertilization at bud swell is effective, even for the ÓNeal cultivarthat present floral bud break in absence of leaves. Post-harvest fertilization contribute N for summer vegetativegrowth which would influence the floral buds development next year, Nitrogenstorage at this time would led to the improved floral behavior next year. Nitrogen losses risk is lower at post-harvestfertilization.Fil: Pescie, María A.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Borda, Marcela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Ortiz, Daniela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Landriscini, María Rosa. Universidad Nacional del Sur. Departamento de Agronomía. Área Suelos y Aguas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Lavado, Raul Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin
Energy-resolved inelastic electron scattering off a magnetic impurity
We study inelastic scattering of energetic electrons off a Kondo impurity. If
the energy E of the incoming electron (measured from the Fermi level) exceeds
significantly the Kondo temperature T_K, then the differential inelastic
cross-section \sigma (E,w), i.e., the cross-section characterizing scattering
of an electron with a given energy transfer w, is well-defined. We show that
\sigma (E,w) factorizes into two parts. The E-dependence of \sigma (E,w) is
logarithmically weak and is due to the Kondo renormalization of the effective
coupling. We are able to relate the w-dependence to the spin-spin correlation
function of the magnetic impurity. Using this relation, we demonstrate that in
the absence of magnetic field the dynamics of the impurity spin causes the
electron scattering to be inelastic at any temperature. Quenching of the spin
dynamics by an applied magnetic field results in a finite elastic component of
the electron scattering cross-section. The differential scattering
cross-section may be extracted from the measurements of relaxation of hot
electrons injected in conductors containing localized spins.Comment: 15 pages, 9 figures; final version as published, minor changes,
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