Restrictions over two-dimensional gauge models with Thirring-like interaction

Some years ago, it was shown how fermion self-interacting terms of the Thirring-type impact the usual structure of massless two-dimensional gauge theories [1]. In that work only the cases of pure vector and pure chiral gauge couplings have been considered and the corresponding Thirring term was also pure vector and pure chiral respectively, such that the vector (or chiral) Schwinger model should not lose its chirality structure due to the addition of the quartic interaction term. Here we extend this analysis to a generalized vector and axial coupling both for the gauge interaction and the quartic fermionic interactions. The idea is to perform quantization without losing the original structure of the gauge coupling. In order to do that we make use of an arbitrariness in the definition of the Thirring-like interaction.Comment: 9 pages, no figure

Anderson localization on the Falicov-Kimball model with Coulomb disorder

The role of Coulomb disorder is analysed in the Anderson-Falicov-Kimball model. Phase diagrams of correlated and disordered electron systems are calculated within dynamical mean-field theory applied to the Bethe lattice, in which metal-insulator transitions led by structural and Coulomb disorders and correlation can be identified. Metallic, Mott insulator, and Anderson insulator phases, as well as the crossover between them are studied in this perspective. We show that Coulomb disorder has a relevant role in the phase-transition behavior as the system is led towards the insulator regime

Differential interferometric phases at high spectral resolution as a sensitive physical diagnostic of circumstellar disks

Context. The circumstellar disks ejected by many rapidly rotating B stars (so-called Be stars) offer the rare opportunity of studying the structure and dynamics of gaseous disks at high spectral as well as angular resolution. Aims. This paper explores a newly identified effect in spectro-interferometric phase that can be used for probing the inner regions of gaseous edge-on disks on a scale of a few stellar radii. Methods. The origin of this effect (dubbed central quasi-emission phase signature, CQE-PS) lies in the velocity-dependent line absorption of photospheric radiation by the circumstellar disk. At high spectral and marginal interferometric resolution, photocenter displacements between star and isovelocity regions in the Keplerian disk reveal themselves through small interferometric phase shifts. To investigate the diagnostic potential of this effect, a series of models are presented, based on detailed radiative transfer calculations in a viscous decretion disk. Results. Amplitude and detailed shape of the CQE-PS depend sensitively on disk density and size and on the radial distribution of the material with characteristic shapes in differential phase diagrams. In addition, useful lower limits to the angular size of the central stars can be derived even when the system is almost unresolved. Conclusions. The full power of this diagnostic tool can be expected if it can be applied to observations over a full life-cycle of a disk from first ejection through final dispersal, over a full cycle of disk oscillations, or over a full orbital period in a binary system

Capital Accumulation Process and Resilience: urban planning and redevelopment of port areas, a case study of Santos (Brazil)

The present work aims at outlining a current urban scenario of the urban planning implemented in the city of Santos (Brazil), especially the policies of urban and port requalification through the analysis of the actions of Alegra Centro Program. Alegra Centro is the name of the Revitalization and Development Program of the Historical Central Region of Santos. The program was created by the city government in February of 2003 and the analysis is focused on the last decade. The program is based on strategic actions and goals for development of the central area of Santos and its port. It also stimulates the resumption of economic development through actions in the following areas: improvement of the urban landscape; preservation and restoration of historical sites, artistic and landscape heritage; integration between the pier and the central area among others. Based on Harvey (2002) and others authors this paper identifies the process of capital accumulation and reproduction in the local space through the analysis of the developing urban requalification policy, therefore the resilience of the urban space (THACKARA, 2009), and its historical relationship in the process of the city urban planning. This work also deals with the transformations of the urban space of the city of Santos, from the physical and social point of view. It discusses the realized actions in the process of urban requalification and compares them with the ones taken towards housing policy. The proposal of the present work verifies that the project of requalification of Santos is indeed one that privileges the allocation of public resources in a strategic site of the city. Furthermore, would not the implementation of the urban requalification model be the adoption of “displaced ideas” (SCHWARZ, 1999) therefore the importation of models without considering the specificities, local reality and social fragilities? It discusses and concludes the following hypotheses: the proposal of requalification is more of an ideological rhetoric, which perpetuates the accumulation of capital, therefore the resilience of the urban space; the studied demonstrates the impact of the proposals in the urban dynamics and reality and its social issue. It confirms the thesis that the ongoing redevelopment project in the city of Santos is an urban policy that favors the allocation of public resources in strategic areas of the city, especially in the central area, for the benefit of private entrepreneurs. And finally it demonstrates the city plan or scheme that is being implemented in Santos, which is the allocation of public resources in the city central area as a public strategic that has been deepened the social issues without considering the local residents