17,625 research outputs found
Confined magneto-optical waves in graphene
The electromagnetic mode spectrum of single-layer graphene subjected to a
quantizing magnetic field is computed taking into account intraband and
interband contributions to the magneto-optical conductivity. We find that a
sequence of weakly decaying quasi-transverse-electric modes, separated by
magnetoplasmon polariton modes, emerge due to the quantizing magnetic field.
The characteristics of these modes are tuneable, by changing the magnetic field
or the Fermi energy.Comment: 9 pages, 7 figures. published version: text and figures revised and
updated + new references and one figure adde
Fundamental Oscillation Periods of the Interlayer Exchange Coupling beyond the RKKY Approximation
A general method for obtaining the oscillation periods of the interlayer
exchange coupling is presented. It is shown that it is possible for the
coupling to oscillate with additional periods beyond the ones predicted by the
RKKY theory. The relation between the oscillation periods and the spacer Fermi
surface is clarified, showing that non-RKKY periods do not bear a direct
correspondence with the Fermi surface. The interesting case of a FCC(110)
structure is investigated, unmistakably proving the existence and relevance of
non-RKKY oscillations. The general conditions for the occurrence of non-RKKY
oscillations are also presented.Comment: 34 pages, 10 figures ; to appear in J. Phys.: Condens. Mat
The Nature and Validity of the RKKY limit of exchange coupling in magnetic trilayers
The effects on the exchange coupling in magnetic trilayers due to the
presence of a spin-independent potential well are investigated. It is shown
that within the RKKY theory no bias nor extra periods of oscillation associated
with the depth of the well are found, contrary to what has been claimed in
recent works. The range of validity of the RKKY theory is also discussed.Comment: 10, RevTe
Exchange coupling between magnetic layers across non-magnetic superlattices
The oscillation periods of the interlayer exchange coupling are investigated
when two magnetic layers are separated by a metallic superlattice of two
distinct non-magnetic materials. In spite of the conventional behaviour of the
coupling as a function of the spacer thickness, new periods arise when the
coupling is looked upon as a function of the number of cells of the
superlattice. The new periodicity results from the deformation of the
corresponding Fermi surface, which is explicitly related to a few controllable
parameters, allowing the oscillation periods to be tuned.Comment: 13 pages; 5 figures; To appear in J. Phys.: Cond. Matte
NeuralREG: An end-to-end approach to referring expression generation
Traditionally, Referring Expression Generation (REG) models first decide on
the form and then on the content of references to discourse entities in text,
typically relying on features such as salience and grammatical function. In
this paper, we present a new approach (NeuralREG), relying on deep neural
networks, which makes decisions about form and content in one go without
explicit feature extraction. Using a delexicalized version of the WebNLG
corpus, we show that the neural model substantially improves over two strong
baselines. Data and models are publicly available.Comment: Accepted for presentation at ACL 201
Muitas Palavras à Procura de Silêncio: A Caminho do Ciberespaço
Homenagem a Yvette Centeno a partir de análise do que publicou na blogosesfera
Shane Meadows’ country: «This is England» (2006)
This Is England is social realist film portraying racism and poverty in 1980s Britain through the eyes of Shaun, a 12 year old boy, who has lost his father in the Falklands war and as to come to terms with his own identity, the difficult transition from childhood to adolescence and the need to fit in a determined group/tribe/gang. The following article aims at analysing relevant aspects depicted from the film emphasizing the so much debated reality of life during 80s. In This is England Shane Meadows manages to rediscover his own self geography, by revisiting his adolescent years. It is a biographical film about the importance of peer pressure and the results of an excess of nationalism, at the same time it typifies some issues related to the 80s youth culture.This is England é um filme social e realista que descreve o racismo e a pobreza na Grã-Bretanha dos anos 80 através do olhar de Shaun, um rapaz de 12 anos, que perdeu o pai a Guerra das Maldivas e tem de gerir a busca pela sua identidade, a transição da infância para adolescência e a necessidade de pertencer a um determinado grupo/tribo/gang. O presente artigo visa analisar aspectos relevantes extraídos do filme enfatizando a tão debatida realidade da vida nos anos 80. Em This is England Shane Meadows reencontra a geografia do ser, através do revisitar dos seus anos enquanto adolescente. É um filme biográfico acerca da importância da pressão exercida pelos pares e o resultado de um nacionalismo excessivo, ao mesmo tempo que tipifica alguns aspectos relacionados com a cultura dos anos 80
- …