Derivative expansion and gauge independence of the false vacuum decay rate in various gauges

In theories with radiative symmetry breaking, the calculation of the false vacuum decay rate requires the inclusion of higher-order terms in the derivative expansion of the effective action. I show here that, in the case of covariant gauges, the presence of infrared singularities forbids the consistent calculation by keeping the lowest-order terms. The situation is remedied, however, in the case of $R_{\xi}$ gauges. Using the Nielsen identities I show that the final result is gauge independent for generic values of the gauge parameter $v$ that are not anomalously small.Comment: Some comments and references adde

Development of Improved Methods for Low Template DNA Analysis

We investigated on the crystallographic, morphological and magnetic characteristics of barium ferrite-SiO2/Si films prepared by sol-gel dip coating method. It is found that the sol obtained at 80°C for 90 min. is the most suitable for coating. The particles formed in the films prepared by heat treatment at 800°C for 3 hours exhibits needle-like particles placing parallel to substrate. The saturation magnetization increases as thickness increases, and its maximum value is 260 emu/cm3. The direction of easy-magnetization in the films has tendency to vary from perpendicular to parallel to substrate as thickness increases

One-loop corrections to the metastable vacuum decay

We evaluate the one-loop prefactor in the false vacuum decay rate in a theory of a self interacting scalar field in 3+1 dimensions. We use a numerical method, established some time ago, which is based on a well-known theorem on functional determinants. The proper handling of zero modes and of renormalization is discussed. The numerical results in particular show that quantum corrections become smaller away from the thin-wall case. In the thin-wall limit the numerical results are found to join into those obtained by a gradient expansion.Comment: 31 pages, 7 figure

The self-consistent bounce: an improved nucleation rate

We generalize the standard computation of homogeneous nucleation theory at zero temperature to a scenario in which the bubble shape is determined self-consistently with its quantum fluctuations. Studying two scalar models in 1+1 dimensions, we find the self-consistent bounce by employing a two-particle irreducible (2PI) effective action in imaginary time at the level of the Hartree approximation. We thus obtain an effective single bounce action which determines the rate exponent. We use collective coordinates to account for the translational invariance and the growth instability of the bubble and finally present a new nucleation rate prefactor. We compare the results with those obtained using the standard 1-loop approximation and show that the self-consistent rate can differ by several orders of magnitude.Comment: 28 pages, revtex, 7 eps figure

De betekenis van logos bij Herakleitos volgens de traditie en de fragmenten

Contains fulltext : mmubn000001_242395694.pdf (publisher's version ) (Open Access)Promotor : H.[=J.H.] RobbersVII, 219 p

Relation médecin-patient (étude qualitative des apports d'une formation clown pour les médecins, proposée par la Société de Formation Thérapeutique du Généraliste (SFTG))

La SFTG propose depuis 2007 une formation médicale continue à la relation médecin-patient en utilisant la pratique du clown comme outil de développement professionnel. A partir d'une étude qualitative sur la base d'entretiens individuels, nous nous sommes intéressés au ressenti des médecins sur les apports personnels et professionnels de cette formation. Sur les 64 participants aux séminaires depuis leur création, nous avons réalisés 21 entretiens. Cette étude permet de mettre en évidence des apports très variés en fonction des attentes et de la démarche de réflexion professionnelle des médecins. Sur le plan personnel, nous retrouvons une amélioration de l'estime de soi, des éléments pouvant prévenir le burn-out, ainsi qu'un apport psychothérapeutique. Sur le plan professionnel, certains médecins signalent une amélioration du vécu professionnel, de la relation avec le patient, un changement de place du médecin avec recentrage de la consultation sur le patient et ses attentes. Beaucoup signalent une amélioration de leurs compétences émotionnelles et de leur communication non verbale. La spécificité du clown réside sur la nécessaire authenticité du travail du clown, où le médecin n'est pas dans le travail d'un rôle, mais dans le travail de soi et d'appropriation de son corps. C'est aussi un terrain d'expérimentation bienveillant qui permet au médecin de se redécouvrir, d'expérimenter l'échec, de nouvelles émotions et manières d'être et de faire. En redéfinissant son rapport à soi-même, le médecin progresse dans son rapport à l'autre. En s'acceptant il s'engage davantage dans la rencontre avec l'autre et améliore sa relation au cabinet.Since 2007 the SFTG provides continuing medical training on doctor-patient relationship, using clown practices as a tool for professional development. For this qualitative study we carried out individual semi-structured interviews focusing on the doctors' feelings regarding personal and professional benefits of this training. We interviewed 21 of the 64 doctors having attended one or several courses. The study shows the variety of contributions according to the doctors' expectations and his approach to professional reflection. On a personal level, we identified an improved self-esteem, elements that help prevent burn-out, and psychotherapeutic contributions. On a professional level, some doctors highlight an improvement in the professional experience and the relationship with the patient, as well as a shifting of the doctor's position, the consultation then becoming patient-centered. Many doctors talk about an improvement of their emotional skills and their nonverbal communication. The clown s specificities lie in its demand for an authentic approach from the participant: the doctor is not working on a role but on himself, on the appropriation of his own body. This is also a benevolent testing ground, which enables the doctor to rediscover himself, to experience failure, new emotions, ways of being and acting. As the doctor redefines his relationship with himself, his relationship to others is evolving as well. Accepting himself, he commits to reaching out to the patient and his relationship with them is improved.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF