SCOAP3 Repository
https://repo.scoap3.org
SCOAP3 Repository latest documentsenSat, 25 May 2019 04:51:31 GMTInvenio 1.1.4.1330-44020repo.admin@scoap3.org36020125https://repo.scoap3.org/img/site_logo_rss.pngSCOAP3 Repository
https://repo.scoap3.org
Search Search this site:p
https://repo.scoap3.org/search
The Heisenberg spinor field classification and its interplay with the Lounesto’s classification
https://repo.scoap3.org/record/31729
Dirac linear spinor fields were obtained from non-linear Heisenberg spinors, in the literature. Here we extend that idea by considering not only Dirac spinor fields but spinor fields in any of the Lounesto’s classes. When one starts considering all these classes of fields, the question of providing a classification for the Heisenberg spinor naturally arises. In this work the classification of Heisenberg spinor fields is derived and scrutinized, in its interplay with the Lounesto’s spinor field classification.Arcodía, Marcos R. A.Sat, 23 Mar 2019 09:05:53 GMThttps://repo.scoap3.org/record/31729urn:ISSN:1434-6052Springer/Società Italiana di Fisica2019-3-21Thermal dissociation of heavy mesons and configurational entropy
https://repo.scoap3.org/record/28722
We study the dissociation of heavy vector mesons in a thermal medium from the point of view of the configurational entropy. Bottomonium and charmonium vector mesons in a plasma are represented using a holographic AdS/QCD model. The quasinormal modes, describing the quasiparticle states, are determined for a representative range of temperature and their corresponding CE is then computed. The main result indicates that the CE is an important contrivance to investigate the stability of the heavy mesons against dissociation in the thermal medium.Braga, Nelson R.F.Tue, 23 Oct 2018 03:32:55 GMThttps://repo.scoap3.org/record/28722urn:ISSN:0370-2693Elsevier2018-12-10Non-existence of rest-frame spin-eigenstate spinors in their own electrodynamics
https://repo.scoap3.org/record/25367
We assume a physical situation where gravity with torsion is neglected for an electrodynamically self-interacting spinor that will be taken in its rest-frame and spin-eigenstate: we demonstrate that under this circumstance no solution exists for the system of field equations. Despite such a situation might look artificial nevertheless it represents the instance that is commonly taken as the basis for all computations of quantum electrodynamics.Fabbri, LucaTue, 08 May 2018 17:53:15 GMThttps://repo.scoap3.org/record/25367urn:ISSN:1434-6052Springer/Società Italiana di Fisica2018-5-8Unveiling a spinor field classification with non-Abelian gauge symmetries
https://repo.scoap3.org/record/24355
A spinor fields classification with non-Abelian gauge symmetries is introduced, generalizing the U(1) gauge symmetries-based Lounesto's classification. Here, a more general classification, contrary to the Lounesto's one, encompasses spinor multiplets, corresponding to non-Abelian gauge fields. The particular case of SU(2) gauge symmetry, encompassing electroweak and electromagnetic conserved charges, is then implemented by a non-Abelian spinor classification, now involving 14 mixed classes of spinor doublets. A richer flagpole, dipole, and flag-dipole structure naturally descends from this general classification. The Lounesto's classification of spinors is shown to arise as a Pauli's singlet, into this more general classification.Fabbri, LucaThu, 15 Mar 2018 08:25:21 GMThttps://repo.scoap3.org/record/24355urn:ISSN:0370-2693Elsevier2018-04-10Torsion axial vector and Yvon-Takabayashi angle: zitterbewegung, chirality and all that
https://repo.scoap3.org/record/24308
We consider propagating torsion as a completion of gravitation in order to describe the dynamics of curved-twisted space-times filled with Dirac spinorial fields; we discuss interesting relationships of the torsion axial vector and the curvature tensor with the Yvon-Takabayashi angle and the module of the spinor field, that is the two degrees of freedom of the spinor field itself: in particular, we shall discuss in what way the torsion axial vector could be seen as the potential of a specific interaction of the Yvon-Takabayashi angle, and therefore as a force between the two chiral projections of the spinor field itself. Chiral interactions of the components of a spinor may render effects of zitterbewegung, as well as effective mass terms and other related features: we shall briefly sketch some of the analogies and differences with the similar but not identical situation given by the Yukawa interaction occurring in the Higgs sector of the standard model. We will provide some overall considerations about general consequences for contemporary physics, consequences that have never been discussed before, so far as we are aware, in the present physics literature.Fabbri, LucaTue, 13 Mar 2018 10:52:00 GMThttps://repo.scoap3.org/record/24308urn:ISSN:1434-6052Springer/Società Italiana di Fisica2018-3-13AdS/QCD duality and the quarkonia holographic information entropy
https://repo.scoap3.org/record/22392
Bottomonium and charmonium, representing quarkonia states, are scrutinized under the point of view of the information theory, in the AdS/QCD holographic setup. A logarithmic measure of information, comprised by the configurational entropy, is here employed to quantitatively study quarkonia radially excited S -wave states. The configurational entropy provides data regarding the relative dominance and the abundance of the bottomonium and charmonium states, whose underlying information is more compressed, in the Shannon's theory meaning. The derived configurational entropy, therefore, identifies the lower phenomenological prevalence of higher S -wave resonances and higher masses quarkonia in Nature.Braga, Nelson R.F.Tue, 21 Nov 2017 15:16:57 GMThttps://repo.scoap3.org/record/22392urn:ISSN:0370-2693Elsevier2017-12-08Information-entropic analysis of Korteweg–de Vries solitons in the quark–gluon plasma
https://repo.scoap3.org/record/21569
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.Goncalves da Silva, A.Wed, 20 Sep 2017 11:51:12 GMThttps://repo.scoap3.org/record/21569urn:ISSN:0370-2693Elsevier2017-10-28On the spinor representation
https://repo.scoap3.org/record/20864
A systematic study of the spinor representation by means of the fermionic physical space is accomplished and implemented. The spinor representation space is shown to be constrained by the Fierz–Pauli–Kofink identities among the spinor bilinear covariants. A robust geometric and topological structure can be manifested from the spinor space, wherein the first and second homotopy groups play prominent roles on the underlying physical properties, associated to fermionic fields. The mapping that changes spinor fields classes is then exemplified, in an Einstein–Dirac system that provides the spacetime generated by a fermion.Hoff da Silva, J. M.Fri, 21 Jul 2017 06:20:46 GMThttps://repo.scoap3.org/record/20864urn:ISSN:1434-6052Springer/Società Italiana di Fisica2017-7-21Black hole acoustics in the minimal geometric deformation of a de Laval nozzle
https://repo.scoap3.org/record/20294
The correspondence between sound waves, in a de Laval propelling nozzle, and quasinormal modes emitted by brane-world black holes deformed by a 5D bulk Weyl fluid are here explored and scrutinized. The analysis of sound waves patterns in a de Laval nozzle in the laboratory, reciprocally, is here shown to provide relevant data about the 5D bulk Weyl fluid and its on-brane projection, comprised by the minimal geometrically deformed compact stellar distribution on the brane. Acoustic perturbations of the gas fluid flow in the de Laval nozzle are proved to coincide with the quasinormal modes of black holes solutions deformed by the 5D Weyl fluid, in the geometric deformation procedure. Hence, in a phenomenological Eötvös–Friedmann fluid brane-world model, the realistic shape of a de Laval nozzle is derived and its consequences studied.da Rocha, RoldãoWed, 31 May 2017 09:16:51 GMThttps://repo.scoap3.org/record/20294urn:ISSN:1434-6052Springer/Società Italiana di Fisica2017-5-29Configurational entropy of anti-de Sitter black holes
https://repo.scoap3.org/record/19021
Recent studies indicate that the configurational entropy is an useful tool to investigate the stability and (or) the relative dominance of states for diverse physical systems. Recent examples comprise the connection between the variation of this quantity and the relative fraction of light mesons and glueballs observed in hadronic processes. Here we develop a technique for defining a configurational entropy for an AdS-Schwarzschild black hole. The achieved result corroborates consistency with the Hawking–Page phase transition. Namely, the dominance of the black hole configurational entropy will be shown to increase with the temperature. In order to verify the consistency of the new procedure developed here, we also consider the case of black holes in flat space-time. For such a black hole, it is known that evaporation leads to instability. The configurational entropy obtained for the flat space case is thoroughly consistent with the physical expectation. In fact, we show that the smaller the black holes, the more unstable they are. So, the configurational entropy furnishes a reliable measure for stability of black holes.Braga, Nelson R.F.Thu, 16 Feb 2017 10:27:58 GMThttps://repo.scoap3.org/record/19021urn:ISSN:0370-2693Elsevier2017-03-07Configurational entropy of glueball states
https://repo.scoap3.org/record/18221
The configurational entropy of glueball states is calculated using a holographic description. Glueball states are represented by a supergravity dual picture, consisting of a 5-dimensional graviton–dilaton action of a dynamical holographic AdS/QCD model. The configurational entropy is studied as a function of the glueball spin and of the mass, providing information about the stability of the glueball states.Bernardini, Alex E.Thu, 08 Dec 2016 15:57:07 GMThttps://repo.scoap3.org/record/18221urn:ISSN:0370-2693Elsevier2016-12-31Stability of the graviton Bose–Einstein condensate in the brane-world
https://repo.scoap3.org/record/17729
We consider a solution of the effective four-dimensional Einstein equations, obtained from the general relativistic Schwarzschild metric through the principle of Minimal Geometric Deformation (MGD). Since the brane tension can, in general, introduce new singularities on a relativistic Eötvös brane model in the MGD framework, we require the absence of observed singularities, in order to constrain the brane tension. We then study the corresponding Bose–Einstein condensate (BEC) gravitational system and determine the critical stability region of BEC MGD stellar configurations. Finally, the critical stellar densities are shown to be related with critical points of the information entropy.Casadio, RobertoWed, 02 Nov 2016 15:50:31 GMThttps://repo.scoap3.org/record/17729urn:ISSN:0370-2693Elsevier2017-10-23Fluid/gravity correspondence and the CFM black brane solutions
https://repo.scoap3.org/record/17496
We consider the lower bound for the shear viscosity-to-entropy density ratio, obtained from the fluid/gravity correspondence, in order to constrain the post-Newtonian parameter of brane-world metrics. In particular, we analyse the Casadio–Fabbri–Mazzacurati (CFM) effective solutions for the gravity side of the correspondence and argue that including higher-order terms in the hydrodynamic expansion can lead to a full agreement with the experimental bounds, for the Eddington–Robertson–Schiff post-Newtonian parameter in the CFM metrics. This lends further support to the physical relevance of the viscosity-to-entropy ratio lower bound and fluid/gravity correspondence. Hence we show that CFM black branes are, effectively, Schwarzschild black branes.Casadio, R.Mon, 17 Oct 2016 15:37:12 GMThttps://repo.scoap3.org/record/17496urn:ISSN:1434-6052Springer/Società Italiana di Fisica2016-10-17Entropic information of dynamical AdS/QCD holographic models
https://repo.scoap3.org/record/17182
The Shannon based conditional entropy that underlies five-dimensional Einstein–Hilbert gravity coupled to a dilaton field is investigated in the context of dynamical holographic AdS/QCD models. Considering the UV and IR dominance limits of such AdS/QCD models, the conditional entropy is shown to shed some light onto the meson classification schemes, which corroborate with the existence of light-flavor mesons of lower spins in Nature. Our analysis is supported by a correspondence between statistical mechanics and information entropy which establishes the physical grounds to the Shannon information entropy, also in the context of statistical mechanics, and provides some specificities for accurately extending the entropic discussion to continuous modes of physical systems. From entropic informational grounds, the conditional entropy allows one to identify the lower experimental/phenomenological occurrence of higher spin mesons in Nature. Moreover, it introduces a quantitative theoretical apparatus for studying the instability of high spin light-flavor mesons.Bernardini, Alex E.Fri, 16 Sep 2016 13:27:15 GMThttps://repo.scoap3.org/record/17182urn:ISSN:0370-2693Elsevier2018-04-19Matter Localization on Brane-Worlds Generated by Deformed Defects
https://repo.scoap3.org/record/16714
Localization and mass spectrum of bosonic and fermionic matter fields of some novel families of asymmetric thick brane configurations generated by deformed defects are investigated. The localization profiles of spin 0, spin 1/2, and spin 1 bulk fields are identified for novel matter field potentials supported by thick branes with internal structures. The condition for localization is constrained by the brane thickness of each model such that thickest branes strongly induce matter localization. The bulk mass terms for both fermion and boson fields are included in the global action as to produce some imprints on mass-independent potentials of the Kaluza-Klein modes associated with the corresponding Schrödinger equations. In particular, for spin 1/2 fermions, a complete analytical profile of localization is obtained for the four classes of superpotentials here discussed. Regarding the localization of fermion fields, our overall conclusion indicates that thick branes produce a left-right asymmetric chiral localization of spin 1/2 particles.da Rocha, RoldãoSun, 07 Aug 2016 12:16:02 GMThttps://repo.scoap3.org/record/16714urn:ISSN:1687-7365Hindawi Publishing Corporation2016-08-07Bounds on topological Abelian string-vortex and string-cigar from information-entropic measure
https://repo.scoap3.org/record/14430
In this work we obtain bounds on the topological Abelian string-vortex and on the string-cigar, by using a new measure of configurational complexity, known as configurational entropy. In this way, the information-theoretical measure of six-dimensional braneworlds scenarios is capable to probe situations where the parameters responsible for the brane thickness are arbitrary. The so-called configurational entropy (CE) selects the best value of the parameter in the model. This is accomplished by minimizing the CE, namely, by selecting the most appropriate parameters in the model that correspond to the most organized system, based upon the Shannon information theory. This information-theoretical measure of complexity provides a complementary perspective to situations where strictly energy-based arguments are inconclusive. We show that the higher the energy the higher the CE, what shows an important correlation between the energy of the a localized field configuration and its associated entropic measure.Correa, R.A.C.Mon, 22 Feb 2016 19:19:50 GMThttps://repo.scoap3.org/record/14430urn:ISSN:0370-2693Elsevier2018-04-18Dark Spinors Hawking Radiation in String Theory Black Holes
https://repo.scoap3.org/record/13457
The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, which are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard model matter and gauge fields are suppressed by at least one power of unification scale, being restricted just to the Higgs field and to the graviton likewise. The tunnelling method for the emission and absorption of mass dimension one particles across the event horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further evidence for the universality of black hole radiation, further encompassing particles beyond the standard model.da Rocha, RoldãoMon, 18 Jan 2016 16:58:08 GMThttps://repo.scoap3.org/record/13457urn:ISSN:1687-7365Hindawi Publishing Corporation2016-01-10Configurational entropy in brane-world models
https://repo.scoap3.org/record/12504
In this work we investigate the entropic information on thick brane-world scenarios and its consequences. The brane-world entropic information is studied for the sine-Gordon model and hence the brane-world entropic information measure is shown to be an accurate way for providing the most suitable range for the bulk AdS curvature, in particular from the informational content of physical solutions. Besides, the brane-world configurational entropy is employed to demonstrate a high organisational degree in the structure of the configuration of the system, for large values of a parameter of the sine-Gordon model but the one related to the AdS curvature. The Gleiser and Stamatopoulos procedure is finally applied in order to achieve a precise correlation between the energy of the system and the brane-world configurational entropy.Correa, R. A. C.Mon, 02 Nov 2015 20:34:30 GMThttps://repo.scoap3.org/record/12504urn:ISSN:1434-6052Springer/Società Italiana di Fisica2015-11-2Holographic dark energy models and higher order generalizations in dynamical Chern–Simons modified gravity
https://repo.scoap3.org/record/9006
Dark energy models are here investigated and studied in the framework of the Chern–Simons modified gravity model. We bring into focus the holographic dark energy model with Granda–Oliveros cut-off, the modified holographic Ricci dark energy model and a model with higher derivatives of the Hubble parameter. The relevant expressions of the scale factor a(t) for a Friedmann–Robertson–Walker Universe are derived and studied, and, in this context, the evolution of the scale factor is shown to be similar to the one displayed by the modified Chaplygin gas in two of the above models.Pasqua, AntonioMon, 02 Feb 2015 16:31:57 GMThttps://repo.scoap3.org/record/9006urn:ISSN:1434-6052Springer/Società Italiana di Fisica2015-2-3Regular Bulk Solutions in Brane-Worlds with Inhomogeneous Dust and Generalized Dark Radiation
https://repo.scoap3.org/record/8981
From the dynamics of a brane-world with matter fields present in the bulk, the bulk metric and the black string solution near the brane are generalized, when both the dynamics of inhomogeneous dust/generalized dark radiation on the brane-world and inhomogeneous dark radiation in the bulk as well are considered as exact dynamical collapse solutions. Based on the analysis on the inhomogeneous static exterior of a collapsing sphere of homogeneous dark radiation on the brane, the associated black string warped horizon is studied, as well as the 5D bulk metric near the brane. Moreover, the black string and the bulk are shown to be more regular upon time evolution, for suitable values for the dark radiation parameter in the model, by analyzing the soft physical singularities.da Rocha, RoldãoThu, 29 Jan 2015 20:30:00 GMThttps://repo.scoap3.org/record/8981urn:ISSN:1687-7365Hindawi Publishing Corporation2015-01-29