7,957 research outputs found
Propagation of localized surface plasmons in sets of metallic nanocylinders at the exit of subwavelength slits
We analyze, by means of numerical simulations, transmission enhancements
through sub- wavelength slits due to the presence of sets of plasmonic
nanocylinders, placed near the exit of these apertures. Further, we extend this
study to photonic crystals of dipolar plasmonic particles in front of an array
of extraordinarily transmitting slits practiced in a metallic slab.Comment: 20 pages, 9 figures. Submitted to Journal of Nanophotonic
Importance of interlinguistic similarity and stable bilingualism when two languages compete
In order to analyze the dynamics of two languages in competition, one
approach is to fit historical data on their numbers of speakers with a
mathematical model in which the parameters are interpreted as the similarity
between those languages and their relative status. Within this approach, we
show here, on the basis of a detailed analysis and extensive calculations, the
outcomes that can emerge for given values of these parameters. Contrary to
previous results, it is possible that in the long term both languages coexist
and survive. This happens only when there is a stable bilingual group, and this
is possible only if the competing languages are sufficiently similar, in which
case its occurrence is favoured by both similarity and status symmetry.Comment: to appear in New Journal of Physic
Heisenberg-type higher order symmetries of superintegrable systems separable in cartesian coordinates
Heisenberg-type higher order symmetries are studied for both classical and
quantum mechanical systems separable in cartesian coordinates. A few particular
cases of this type of superintegrable systems were already considered in the
literature, but here they are characterized in full generality together with
their integrability properties. Some of these systems are defined only in a
region of , and in general they do not include bounded solutions.
The quantum symmetries and potentials are shown to reduce to their
superintegrable classical analogs in the limit.Comment: 23 Pages, 3 figures, To appear in Nonlinearit
Optical binding of cylinder photonic molecules in the near-field of partially coherent fluctuating Gaussian Schell model sources. A coherent mode representation
We present a theory and computation method of radiation pressure from
partially coherent light by establishing a coherent mode representation of the
radiation forces. This is illustrated with the near field emitted from a
Gaussian Schell model source, mechanically acting on a single cylinder with
magnetodielectric behavior, or on a photonic molecule constituted by a pair of
such cylinders. Thus after studying the force produced by a single particle, we
address the effects of the spatial coherence on the bonding and anti-bonding
states of two particles. The coherence length manifests the critical limitation
of the contribution of evanescent modes to the scattered fields, and hence to
the nature and strength of the electromagnetic fores, even when electric and/or
magnetic partial wave resonances are excited
Towards an Ashtekar formalism in eight dimensions
We investigate the possibility of extending the Ashtekar theory to eight
dimensions. Our approach relies on two notions: the octonionic structure and
the MacDowell-Mansouri formalism generalized to a spacetime of signature 1+7.
The key mathematical tool for our construction is the self-dual (antiself-dual)
four-rank fully antisymmetric octonionic tensor. Our results may be of
particular interest in connection with a possible formulation of M-theory via
matroid theory.Comment: 15 pages, Latex, minor changes, to appear in Class. Quantum Gra
Influence of the Ground-State Topology on the Domain-Wall Energy in the Edwards-Anderson +/- J Spin Glass Model
We study the phase stability of the Edwards-Anderson spin-glass model by
analyzing the domain-wall energy. For the bimodal distribution of bonds, a
topological analysis of the ground state allows us to separate the system into
two regions: the backbone and its environment. We find that the distributions
of domain-wall energies are very different in these two regions for the three
dimensional (3D) case. Although the backbone turns out to have a very high
phase stability, the combined effect of these excitations and correlations
produces the low global stability displayed by the system as a whole. On the
other hand, in two dimensions (2D) we find that the surface of the excitations
avoids the backbone. Our results confirm that a narrow connection exists
between the phase stability of the system and the internal structure of the
ground-state. In addition, for both 3D and 2D we are able to obtain the fractal
dimension of the domain wall by direct means.Comment: 4 pages, 3 figures. Accepted for publication in Rapid Communications
of Phys. Rev.
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