Information-entropic analysis of Korteweg--de Vries solitons in the quark-gluon plasma

Solitary waves propagation of baryonic density perturbations, ruled by the Korteweg--de Vries equation in a mean-field quark-gluon plasma model, are investigated from the point of view of the theory of information. A recently proposed continuous logarithmic measure of information, called configurational entropy, is used to derive the soliton width, defining the pulse, for which the informational content of the soliton spatial profile is more compressed, in the Shannon's sense.Comment: 6 pages, 1 figur

Strategies for building pathology reports in an urban rehabilitation process: Project of the Old City Centre of Coimbra

The increasing interest on architectural heritage associated to the recognised building value, at economic, social and cultural levels have stimulated, in the recent decades, the urban rehabilitation and renovation o several cities in Europe. Despite the strategy or method adopted in a city renovation process, its efficiency depends mainly on: type of buildings (structural systems, construction techniques and materials); intervention level (singular buildings, groups of buildings, urban zones, etc.); and, project objective (risk assessment, decision making to support future rehabilitation projects, definition of council maintenance policies, etc.). In what concerns large renovation programs of old city centres, choosing the most adequate approach for inspection, appraisal and diagnosis is a complex task that can determine the success or failure of the project purpose. This paper describes the preparation phase of the inspection of 700 buildings located in the old city centre of Coimbra (Portugal), where a global renovation process is planned for the forthcoming years. In the scope of the renovation and rehabilitation process, the city council contract a complete identification and inspection survey of the buildings, directed on three different domains: (a) architectural typologies, (b) constructive and pathological condition of buildings, and (c) socio-demographic characterisation, of this part of the city. It will be present the check-lists developed and some of the obtained results on point (b), related to roofing systems, and exterior façades. This diagnosis procedure shows that the inspection results quality is quite dependent on the items surveyed for each construction element (roof, façade, internal members, installation efficiency), as well as on the possibility of their correlation for a single building. The adopted method has been applied on 70% of the buildings inspected within the project perimeter. Further treatment of the inspection and appraisal data will allow the developing pathology reports and list repair actions, and estimating rehabilitation costs. It will also help to produce defect level diagrams and seismic building risk maps, but, most important, to improve and guide a renewal strategy and intervention methodology for old buildings

The extended minimal geometric deformation of SU(NN) dark glueball condensates

The extended minimal geometric deformation (EMGD) procedure, in the holographic membrane paradigm, is employed to model stellar distributions that arise upon self-interacting scalar glueball dark matter condensation. Such scalar glueballs are SU($N$) Yang-Mills hidden sectors beyond the Standard Model. Then, corrections to the gravitational wave radiation, emitted by SU($N$) EMGD dark glueball stars mergers, are derived, and their respective spectra are studied in the EMGD framework, due to a phenomenological brane tension with finite value. The bulk Weyl fluid that drives the EMGD is then proposed to be experimentally detected by enhanced windows at the eLISA and LIGO.Comment: 9 pages, 7 figure

Extended quantum portrait of MGD black holes and information entropy

The extended minimal geometric deformation (EMGD) is employed on the fluid membrane paradigm, to describe compact stellar objects as Bose--Einstein condensates (BEC) consisting of gravitons. The black hole quantum portrait, besides deriving a preciser phenomenological bound for the fluid brane tension, is then scrutinized from the point of view of the configurational entropy. It yields a range for the critical density of the EMGD BEC, whose configurational entropy has global minima suggesting the configurational stability of the EMGD BEC.Comment: 9 pages, 7 figures, matches the published versio

Oxygen clamps in gold nanowires

We investigate how the insertion of an oxygen atom in an atomically thin gold nanowire can affect its rupture. We find, using ab initio total energy density functional theory calculations, that O atoms when inserted in gold nanowires form not only stable but also very strong bonds, in such a way that they can extract atoms from a stable tip, serving in this way as a clamp that could be used to pull a string of gold atoms.Comment: 4 pages; 4 figure

Dynamical Evolution of an Unstable Gravastar with Zero Mass

Using the conventional gravastar model, that is, an object constituted by two components where one of them is a massive infinitely thin shell and the other one is a de Sitter interior spacetime, we physically interpret a solution characterized by a zero Schwarzschild mass. No stable gravastar is formed and it collapses without forming an event horizon, originating what we call a massive non-gravitational object. The most surprise here is that the collapse occurs with an exterior de Sitter vacuum spacetime. This creates an object which does not interact gravitationally with an outside test particle and it may evolve to a point-like topological defect.Comment: 8 pages, 10 figures, to appear in Astrophysics and Space Scienc