16,103 research outputs found
Monochromatic Clique Decompositions of Graphs
Let be a graph whose edges are coloured with colours, and be a -tuple of graphs. A monochromatic -decomposition of is a partition of the edge set of such that each
part is either a single edge or forms a monochromatic copy of in colour
, for some . Let be the smallest
number , such that, for every order- graph and every
-edge-colouring, there is a monochromatic -decomposition with at
most elements. Extending the previous results of Liu and Sousa
["Monochromatic -decompositions of graphs", Journal of Graph Theory},
76:89--100, 2014], we solve this problem when each graph in is a
clique and is sufficiently large.Comment: 14 pages; to appear in J Graph Theor
Graviton resonances on two-field thick branes
This work presents new results about the graviton massive spectrum in
two-field thick branes. Analyzing the massive spectra with a relative
probability method we have firstly showed the presence of resonance structures
and obtained a connection between the thickness of the defect and the lifetimes
of such resonances. We obtain another interesting results considering the
degenerate Bloch brane solutions. In these thick brane models, we have the
emergence of a splitting effect controlled by a degeneracy parameter. When the
degeneracy constant tends to a critical value, we have found massive resonances
to the gravitational field indicating the existence of modes highly coupled to
the brane. We also discussed the influence of the brane splitting effect over
the resonance lifetimes.Comment: 15 pages, 8 figure
Dielectric mismatch and shallow donor impurities in GaN/HfO2 quantum wells
In this work we investigate electron-impurity binding energy in GaN/HfO
quantum wells. The calculation considers simultaneously all energy
contributions caused by the dielectric mismatch: (i) image self-energy (i.e.,
interaction between electron and its image charge), (ii) the direct Coulomb
interaction between the electron-impurity and (iii) the interactions among
electron and impurity image charges. The theoretical model account for the
solution of the time-dependent Schr\"odinger equation and the results shows how
the magnitude of the electron-impurity binding energy depends on the position
of impurity in the well-barrier system. The role of the large dielectric
constant in the barrier region is exposed with the comparison of the results
for GaN/HfO with those of a more typical GaN/AlN system, for two different
confinement regimes: narrow and wide quantum wells.Comment: 6 Pages, 7 figure
Meta-pipeline: A new execution mechanism for distributed pipeline processing
The Caravela platform has been proposed by the authors of this paper to perform distributed stream-based computing on general purpose computation. This platform uses a secured execution unit called flow-model that prevents remote users to touch local information in a computer. The flow-model is assigned to local or remote processing units that execute its program. This paper is focused on a new execution mechanism that defines a pipeline composed by flow-models, called meta-pipeline, and is designed as a set of additional functions of the Caravela platform. The pipeline is executed automatically by the meta-pipeline runtime environment. This paper describes the execution mechanism and also presents an application example.info:eu-repo/semantics/acceptedVersio
Pauli-Lubanski scalar in the Polygon Approach to 2+1-Dimensional Gravity
In this paper we derive an expression for the conserved Pauli-Lubanski scalar
in 't Hooft's polygon approach to 2+1-dimensional gravity coupled to point
particles. We find that it is represented by an extra spatial shift in
addition to the usual identification rule (being a rotation over the cut). For
two particles this invariant is expressed in terms of 't Hooft's phase-space
variables and we check its classical limit.Comment: Some errors are corrected and a new introduction and discussion are
added. 6 pages Latex, 4 eps-figure
- …