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A vector field coming from spontaneous Lorentz violation mechanism, namely Bumblebee model is analysed in a topological framework in a $(1+2)D$ Minkowski space-time. Taking a $(1+2)D$ nonlinear Bumblebee vector matter field dynamics where we include topological like Chern-Simons type terms, a vector version of a soliton state, or vortex was found. The Nielsen-Olesen procedure was used in order to derive a Lorentz-violation vector parameter which characterizes, via Spontaneous Symmetry Breaking mechanism, the non-trivial vacuum. We verify the stability of the model as much as the magnetic vortex, and noticed that the soliton modes with polarized direction generated can be associated with local anisotropy of vacuum energy. The vortex equations of motion and the asymptotic behaviour is presented. We have obtained that the effect of the Lorentz symmetry violation expressed by the a time-like Bumblebee vector field vacuum could be shown as kind of pulse at a fixed point $r_0$ in a limitless universe, or as a barrier at $r_0$ which can represent a boundary in the universe, if the Bumblebee vector field vacuum has space-like characteristic. We also analyse the spectrum via propagators where we note that the topological mass contributes as well to the dynamical mass poles. We obtain that the Chern-Simons type terms, in fact, indicates the "speed" of the field to saturate the asymptotic limit and that the vortex core can not be dimension zero., Comment: 12 pages, 6 figures

The Kardar-Parisi-Zhang (KPZ) equation has been connected to a large number of important stochastic processes in physics, chemistry and growth phenomena, ranging from classical to quantum physics. The central quest in this field is the search for ever more precise universal growth exponents. Notably, exact growth exponents are only known for $1+1$ dimensions. In this work, we present physical and geometric analytical methods that directly associate these exponents to the fractal dimension of the rough interface. Based on this, we determine the growth exponents for the $2+1$ dimensions, which are in agreement with the results of thin films experiments and precise simulations. We also make a first step towards a solution in $d+1$ dimensions, where our results suggest the inexistence of an upper critical dimension.

We present new results from the Parallaxes of Southern Extremely Cool dwarfs program to measure parallaxes, proper motions and multi-epoch photometry of L and early T dwarfs. The observations were made on 108 nights over the course of 8 years using the Wide Field Imager on the ESO 2.2m telescope. We present 118 new parallaxes of L \& T dwarfs of which 52 have no published values and 24 of the 66 published values are preliminary estimates from this program. The parallax precision varies from 1.0 to 15.5 mas with a median of 3.8 mas. We find evidence for 2 objects with long term photometric variation and 24 new moving group candidates. We cross-match our sample to published photometric catalogues and find standard magnitudes in up to 16 pass-bands from which we build spectral energy distributions and H-R diagrams. This allows us to confirm the theoretically anticipated minimum in radius between stars and brown dwarfs across the hydrogen burning minimum mass. We find the minimum occurs between L2 and L6 and verify the predicted steep dependence of radius in the hydrogen burning regime and the gentle rise into the degenerate brown dwarf regime. We find a relatively young age of 2 Gyr from the kinematics of our sample., Comment: In press MNRAS

In this article, we present a systematic study of the critical behavior of phase oscillators with multiplicative noise from a thermodynamic equilibrium approach. We have already presented the thermodynamics of phase noise oscillators and mapped out in detail the behavior of free energy, entropy, and specific heat in a previous work [P. D. Pinto, F.A. Oliveira, A.L.A. Penna, Phys. Rev. E 93, 052220 (2016)], in which we also introduced the concept of synchronization field. This proved to be important in order to understand the effect of multiplicative noise in the synchronization of the system. Using this approach, our aim is now to study analytically the critical behavior of this system from which we derive a fluctuation-dissipation relation as well as the critical exponents associated with the order parameter, specific heat, and susceptibility. We show that the exponents obey the Rushbrooke and Widom scaling laws.

In this work, we study the pattern solutions of doubly nonlocal logistic map that include spatial kernels in both growth and competition terms. We show that this map includes as a particular case the nonlocal Fisher-Kolmogorov equation, and we demonstrate the existence of three kinds of stationary nonlinear solutions: one uniform, one cosine type that we refer to as wavelike solution, and another in the form of Gaussian. We also obtain analytical expressions that describe the nonlinear pattern behavior in the system, and we establish the stability criterion. We define thermodynamics grandeurs such as entropy and the order parameter. Based on this, the pattern-no-pattern and pattern-pattern transitions are properly analyzed. We show that these pattern solutions may be related to the recently observed peak adding phenomenon in nonlinear optics.

In this article, we present an approach for the thermodynamics of phase oscillators induced by an internal multiplicative noise. We analytically derive the free energy, entropy, internal energy, and specific heat. In this framework, the formulation of the first law of thermodynamics requires the definition of a synchronization field acting on the phase oscillators. By introducing the synchronization field, we have consistently obtained the susceptibility and analyzed its behavior. This allows us to characterize distinct phases in the system, which we have denoted as synchronized and parasynchronized phases, in analogy with magnetism. The system also shows a rich complex behavior, exhibiting ideal gas characteristics for low temperatures and susceptibility anomalies that are similar to those present in complex fluids such as water.

Several group in the World followed the solar diameter with dedicated instruments, namely solar astrolabes, since 1974. Their data have been gathered in several observing stations connected in the R2S3 (Reseau de Suivi au Sol du Rayon Solaire) network and through reciprocal visits and exchanges: Nice/Calern Observatory, Rio de Janeiro Observatorio Nacional/Brazil, IAG/Universidade de Sao Paulo/Brazil, Antalya Observatory/Turkey, San Fernando/Spain. The tradition of these observational efforts is here briefly sketched with the aim to evidence the possibility to analyze against the solar activity all these 42 years data at once by overcoming the problem of the shift between the different series. Each instrument has its own density filter with a prismatic effect responsible of that shift. The overall change of the solar radius during the last century is evident by comparing the Auwers' radius of 959.63" (1891, present IAU standard) with 959.94" (2015, from eclipses and Venus transit data, the latter either observed from space) and the role of ground-based daily measurements has been and it is crucial nowadays with Picard-sol and the Reflecting Heliometer of Rio de Janeiro, to ensure an homogeneus and continuous monitor of the solar diameter without the lifetime limitation of the satellites., Comment: 4 pages, one double figure, IAU General Assembly 2015 focus meeting 29 no. 2236038

Started its regular, daily operational phase in 2011 and installed in 2009 by the occasion of the Symp264 in the XXVII IAU GA at Rio de Janeiro, the results so far obtained show that the Heliometer of the Observatorio Nacional fulfilled its planed performance of single measurement to the level of few tens of milli-arcsecond, freely pivoting around the heliolatitudes without systematic deviations or error enhancement. We present and discuss the astrometric additions required on ground based astronomic programs. We also discuss instrumental and observations terms, namely the constancy of the basic heliometric angle, against which the measurements are made, and the independence to meteorological and pointing conditions., Comment: 3 pages 2 double figures, proc. of IAU GA 2015 meeting no. 29, no. 2243377

We present near-infrared spectroscopy for 52 ultracool dwarfs, including two newly discovered late-M dwarfs, one new late-M subdwarf candidate, three new L and four new T dwarfs. We also present parallaxes and proper motions for 21 of them. Four of the targets presented here have previous parallax measurements, while all the others are new values. This allow us to populate further the spectral sequence at early types (L0-L4). Combining the astrometric parameters with the new near-infrared spectroscopy presented here, we are able to investigate further the nature of some of the objects. In particular, we find that the peculiar blue L1 dwarf SDSS J133148.92-011651.4 is a metal-poor object, likely a member of the galactic thick disk. We discover a new M subdwarf candidate, 2MASS J20115649-6201127. We confirm the low-gravity nature of EROS-MP J0032-4405, DENIS-P J035726.9-441730, and 2MASS J22134491-2136079. We present two new metal-poor dwarfs: the L4pec 2MASS J19285196-4356256 and the M7pec SIPS2346-5928. We also determine the effective temperature and bolometric luminosity of the 21 targets with astrometric measurements, and we obtain a new polynomial relation between effective temperature and near-infrared spectral type. The new fit suggests a flattening of the sequence at the transition between M and L spectral types. This could be an effect of dust formation, that causes a more rapid evolution of the spectral features as a function of the effective temperature., Comment: Accepted for publication in AJ. 37 pages, 17 figures, 6 tables

In this paper we construct and study a formulation of a chargeless complex vector matter field in a supersymmetric framework. To this aim we combine two no-chiral scalar superfields in order to take the vector component field to build the chargeless complex vector superpartner where the respective field strength transforms as matter fields by a global $U(1)$ gauge symmetry. To the aim to deal with consistent terms without breaking the global $U(1)$ symmetry it imposes a choice to the complex combination revealing a kind of symmetry between the choices and eliminate the extra degrees of freedom consistently with the supersymmetry. As the usual case the mass supersymmetric sector contributes as a complement to dynamics of the model. We obtain the equations of motion of the Proca's type field, for the chiral spinor fields and for the scalar field on the mass-shell which show the same mass as expected. This work establishes the firsts steps to extend the analysis of charged massive vector field in a supersymmetric scenario., Comment: 8 pages

The discovery and subsequent detailed study of T dwarfs has provided many surprises and pushed the physics and modeling of cool atmospheres in unpredicted directions. Distance is a critical parameter for studies of these objects to determine intrinsic luminosities, test binarity and measure their motion in the Galaxy. We describe a new observational program to determine distances across the full range of T dwarf sub-types using the NTT/SOFI telescope/instrument combination. We present preliminary results for ten objects, five of which represent new distances., Comment: 11 pages, 6 figrues, accepted by MNRAS

Recent research on global climate changes points to three distinct sources of climate disturbance: anthropogenic; natural changes in the oceans and atmosphere; and irregularities in the solar cycles. One of the most direct ways to survey an exogenous component of the climatic variability is through the measurement of variations in the diameter and shape of the solar disk. At Observatorio Nacional/MCTI, Rio de Janeiro, after several years of diameter observation using a CCD Solar Astrolabe, these measurements are now performed by a state-of-the-art Solar Heliometer. The heliometric method is one of the most successful techniques to measure small variations of angles. Its principle has been used for the latest space borne astrometric missions, aiming to milli-arcsecond precision. The success of this method relies in the fact that it minimizes the dependence of angular measurements to the thermal and mechanical stability of the instrument. However in the classic heliometer the objective is split into two halves to which is applied a linear displacement along the cut, thus still leaving room for a residual dependence with the focus, due to non-concentricity of the beams of the two images. The focus variation, as well as the effects brought by the large temperature variations during solar observations, was tackled in the Solar Heliometer by having all optical elements and their niches made on CCZ, and the telescope tube on carbon fiber, both materials of negligible thermal coefficient. Additionally, the measures are made perpendicular to the separation direction and the plate scale can be known at every time from the solar motion itself. We present the results from the first year of measurements, in special exploring the upheaval of solar activity on late 2011., Comment: 2 pages, 2 figures, in Solar and Astrophysical Dynamos and Magnetic Activity (A.G. Kosovichev, E.M. de Gouveia Dal Pino and Y. Yan, editors) Proceedings IAU Symposium No. 294 (2013)

In this communication we propose a most general equation to study pattern formation for one-species population and their limit domains in systems of length L. To accomplish this we include non-locality in the growth and competition terms where the integral kernels are now depend on characteristic length parameters alpha and beta. Therefore, we derived a parameter space (alpha,beta) where it is possible to analyze a coexistence curve alpha*=alpha*(\beta) which delimits domains for the existence (or not) of pattern formation in population dynamics systems. We show that this curve has an analogy with coexistence curve in classical thermodynamics and critical phenomena physics. We have successfully compared this model with experimental data for diffusion of Escherichia coli populations.

We present results from the PARallaxes of Southern Extremely Cool objects (PARSEC) program, an observational program begun in April 2007 to determine parallaxes for 122 L and 28 T southern hemisphere dwarfs using the Wide Field Imager on the ESO 2.2m telescope. The results presented here include parallaxes of 10 targets from observations over 18 months and a first version proper motion catalog. The proper motions were obtained by combining PARSEC observations astrometrically reduced with respect to the UCAC2 Catalog, and the 2MASS Catalog. The resulting median proper motion precision is 5mas/yr for 195,700 sources. The 140 0.3deg2 fields sample the southern hemisphere in an unbiased fashion with the exception of the galactic plane due to the small number of targets in that region. We present preliminary parallaxes with a 4.2 mas median precision for 10 brown dwarfs, 2 of which are within 10pc. These increase by 20% the present number of L dwarfs with published parallaxes. Of the 10 targets, 7 have been previously discussed in the literature: two were thought to be binary but the PARSEC observations show them to be single, one has been confirmed as a binary companion and another has been found to be part of a binary system, both of which will make good benchmark systems. Observations for the PARSEC program will end in early 2011 providing 3-4 years of coverage for all targets. The main expected outputs are: more than a 100% increase of the number of L dwarfs with parallaxes; to increment - in conjuction with published results - to at least 10 the number of objects per spectral subclass up to L9, and; to put sensible limits on the general binary fraction of brown dwarfs. We aim to contribute significantly to the understanding of the faint end of the H-R diagram and of the L/T transition region., Comment: Subnmitted to Astronomical Journal

The large number and all-sky distribution of quasars from different surveys, along with their presence in large, deep astrometric catalogs,enables the building of an optical materialization of the ICRS following its defining principles. Namely: that it is kinematically non-rotating with respect to the ensemble of distant extragalactic objects; aligned with the mean equator and dynamical equinox of J2000; and realized by a list of adopted coordinates of extragalatic sources. Starting from the updated and presumably complete LQAC list of QSOs, the initial optical positions of those quasars are found in the USNO B1.0 and GSC2.3 catalogs, and from the SDSS DR5. The initial positions are next placed onto UCAC2-based reference frames, following by an alignment with the ICRF, to which were added the most precise sources from the VLBA calibrator list and the VLA calibrator list - when reliable optical counterparts exist. Finally, the LQRF axes are inspected through spherical harmonics, contemplating to define right ascension, declination and magnitude terms. The LQRF contains J2000 referred equatorial coordinates for 100,165 quasars, well represented across the sky, from -83.5 to +88.5 degrees in declination, and with 10 arcmin being the average distance between adjacent elements. The global alignment with the ICRF is 1.5 mas, and the individual position accuracies are represented by a Poisson distribution that peaks at 139 mas in right ascension and 130 mas in declination. It is complemented by redshift and photometry information from the LQAC. The LQRF is designed to be an astrometric frame, but it is also the basis for the GAIA mission initial quasars' list, and can be used as a test bench for quasars' space distribution and luminosity function studies., Comment: 23 pages, 23 figures, 6 tables Accepted for publication by Astronomy & Astrophysics, on 25 May 2009

Taking a full 3D nonlinear vector matter field dynamics, a vector version of a soliton state was found. The Nielsen-Olesen procedure was used in order to derive a Lorentz-violation vector parameter which characterizes, via Spontaneous Symmetry Breaking mechanism, the non-trivial vacuum. A stable vortex configuration is obtained, and although the Chern-Simons-type terms do not contribute to the value of the vortex core, the propagator analysis suggests us the possibility of a contribution to the size of the vortex core and to the growth of the field to achieve the asymptotic limit value with the distance., Comment: 9 pages, 1 figure, Revtex4 format

In this paper we study the nonlocal effects of noncommutative spacetime on simple physical systems. Our main point is the assumption that the noncommutative effects are consequences of a background field which generates a local spin structure. So, we reformulate some simple electrostatic models in the presence of a spin-deformation contribution to the geometry of the motion, and we obtain an interesting correlation amongst the deformed area vector, the 3D noncommutative effects and the usual spin vector given in quantum mechanics framework. Remarkably we can observe that a spin-orbit coupling term comes to light on the spatial sector of a potential wrote in terms of noncommutative coordinates what indicates that bound states are particular cases in this procedure. Concerning to confined or bounded particles in this noncommutative domain we verify that the kinetic energy is modified by a deformation factor. Finally, we discuss about perspectives., Comment: 14 pages, 1 figure

We consider a model with a charged vector field along with a Cremmer-Scherk-Kalb-Ramond (CSKR) matter field coupled to a U(1) gauge potential. We obtain a natural Lorentz symmetry violation due to the local U(1) spontaneous symmetry breaking mechanism triggered by the imaginary part of the vector matter. The choice of the unitary gauge leads to the decoupling of the gauge-KR sector from the Higgs-KR sector. The excitation spectrum is carefully analyzed and the physical modes are identified. We propose an identification of the neutral massive spin-1 Higgs-like field with the massive Z' boson of the so-called mirror matter models., Comment: 10 pages, no figures, revtex4, Preprint CBPF-NF-037/03

We introduce a basis for a bi-dimensional finite matrix calculus and a bi-dimensional finite matrix action principle. As an application, we analyze scalar and spinorial fields in $D=4n+2$ in this approach. We verify that to establish a bi-dimensional matrix action principle we have to define a Dirac-algebra-modified Lebniz rule. From the bi-dimensional equations of motion, we obtain a matrix holomorphic feature for massless matrix scalar and spinorial fields., Comment: 9 pages, LaTex, revised version