Mutual information and the F-theorem

Mutual information is used as a purely geometrical regularization of entanglement entropy applicable to any QFT. A coefficient in the mutual information between concentric circular entangling surfaces gives a precise universal prescription for the monotonous quantity in the c-theorem for d=3. This is in principle computable using any regularization for the entropy, and in particular is a definition suitable for lattice models. We rederive the proof of the c-theorem for d=3 in terms of mutual information, and check our arguments with holographic entanglement entropy, a free scalar field, and an extensive mutual information model.Comment: 80 pages, 16 figure

Gravitinos Tunneling from Black Holes

Black hole radiation of gravitinos is investigated as the classically forbidden tunneling of spin-3/2 fermions through an event horizon. We show that all four spin states of the gravitino yield the same emission temperature, and retrieve the Unruh temperature in a Rindler spacetime as well as the Hawking temperature for a Kerr-Newman charged rotating black hole.Comment: 10 pages, late

Structure of Lanczos-Lovelock Lagrangians in Critical Dimensions

The Lanczos-Lovelock models of gravity constitute the most general theories of gravity in D dimensions which satisfy (a) the principle of of equivalence, (b) the principle of general co-variance, and (c) have field equations involving derivatives of the metric tensor only up to second order. The mth order Lanczos-Lovelock Lagrangian is a polynomial of degree m in the curvature tensor. The field equations resulting from it become trivial in the critical dimension $D = 2m$ and the action itself can be written as the integral of an exterior derivative of an expression involving the vierbeins, in the differential form language. While these results are well known, there is some controversy in the literature as to whether the Lanczos-Lovelock Lagrangian itself can be expressed as a total divergence of quantities built only from the metric and its derivatives (without using the vierbeins) in $D = 2m$. We settle this issue by showing that this is indeed possible and provide an algorithm for its construction. In particular, we demonstrate that, in two dimensions, $R \sqrt{-g} = \partial_j R^j$ for a doublet of functions $R^j = (R^0,R^1)$ which depends only on the metric and its first derivatives. We explicitly construct families of such R^j -s in two dimensions. We also address related questions regarding the Gauss-Bonnet Lagrangian in $D = 4$. Finally, we demonstrate the relation between the Chern-Simons form and the mth order Lanczos-Lovelock Lagrangian.Comment: 15 pages, no figure

Working Conditions and Organization of Teachers of Public Schools

This paper aims at analysing working conditions and organization of public basic school teachers in João Pessoa (PB). To do so we departed from a multidiciplinary approach: activity ergonomy and psycho-dynamics of working under a gender social relations viewpoint. Alongside this research we made use of activity observation and formed communities expanded search. In regard to the research participants, a group of forty professionals from three different schools collaborated with the investigation. When it comes to the analysis of the produced data, we observed that the main reason why theses professionals chose the educational workfield is deeply rooted in gender social relations and socio-economic conditions. We also verified certain discrepancies between the job description and the work actually done by theses professionals. However, it was noticed that despite the difficulties encountered in work situations, the teachers through the use of their sensitivity and creativity, develop various forms of regulation of the activity, giving new ways to work and inventing different ways to link to it

Implicações das políticas educacionais nas vivências subjetivas de professoras de escolas públicas

The educational policies implemented in Brazil since the 1990s have been producing significant effects on the restructuring of the teaching job. The carried out study aimed to analyze the implications of these educational policies in the subjective experiences of teachers from public schools in the municipality of João Pessoa. For that, we have used observations of the activities and of the constitution of amplified communities researched. The analysis of the materials produced was carried out following the dialogic perspective of the discourse. We have verified that the educational programs, in general, are seen by the teachers as immediate and palliative measures, which do not effectively solve education and teaching quality problems. They report that these programs, instead of favoring their job, have generated overload, making it difficult the accomplishment of their activity, and also causing implications to their health. We have observed, however, that, despite the difficulties found in the work situations, the teachers, through their creative mobilization, carry out several ways of activity regulation, giving new shapes to the work and developing different ways of articulating themselves to it.As políticas educacionais implementadas no Brasil desde a década de 1990 têm produzido efeitos significativos na reestruturação do trabalho docente. O estudo realizado teve como objetivo analisar as implicações dessas políticas nas vivências subjetivas de professoras de escolas públicas do município de João Pessoa. Para tanto, fizemos uso de observações da atividade e da constituição de comunidades ampliadas de pesquisa. A análise dos materiais produzidos foi realizada seguindo a perspectiva dialógica do discurso. Constatamos que, em geral, os programas educacionais são vistos pelas professoras como medidas imediatas e paliativas, que não resolvem efetivamente os problemas da educação e da qualidade do ensino. As professoras relatam que esses programas, ao invés de favorecer seu trabalho, têm gerado sobrecarga, dificultando a realização de sua atividade, e, inclusive, acarretando implicações na sua saúde. Entretanto, observamos que, apesar das dificuldades encontradas pelas professoras nas situações de trabalho, elas realizam, por intermédio de sua mobilização criativa, diversos modos de regulação da atividade, dando novas formas ao trabalho e desenvolvendo diferentes maneiras de articular-se em relação a ele

Exact Hawking Radiation of Scalars, Fermions, and Bosons Using the Tunneling Method Without Back-Reaction

Hawking radiation is studied for arbitrary scalars, fermions, and spin-1 bosons, using a tunneling approach, to every order in $\hbar$ but ignoring back-reaction effects. It is shown that the additional quantum terms yield no new contribution to the Hawking temperature. Indeed, it is found that the limit of small $\hbar$ in the standard quantum WKB approximation is replaced by the near-horizon limit in the gravitational WKB approach.Comment: 8 pages, no figures. v3: Introduction updated. Version to appear in PL