A Numerical Perspective on Hartree-Fock-Bogoliubov Theory

The method of choice for describing attractive quantum systems is Hartree-Fock-Bogoliubov (HFB) theory. This is a nonlinear model which allows for the description of pairing effects, the main explanation for the superconductivity of certain materials at very low temperature. This paper is the first study of Hartree-Fock-Bogoliubov theory from the point of view of numerical analysis. We start by discussing its proper discretization and then analyze the convergence of the simple fixed point (Roothaan) algorithm. Following works by Canc\`es, Le Bris and Levitt for electrons in atoms and molecules, we show that this algorithm either converges to a solution of the equation, or oscillates between two states, none of them being a solution to the HFB equations. We also adapt the Optimal Damping Algorithm of Canc\`es and Le Bris to the HFB setting and we analyze it. The last part of the paper is devoted to numerical experiments. We consider a purely gravitational system and numerically discover that pairing always occurs. We then examine a simplified model for nucleons, with an effective interaction similar to what is often used in nuclear physics. In both cases we discuss the importance of using a damping algorithm

Identités plurielles : Couples mixtes et transmission du judaïsme

Quand on sait qu’aujourd’hui en France la moitié des mariages contractés par des personnes juives sont des mariages mixtes, la question « qu’est-ce qu’être juif? » revêt toute son importance. Que transmet-on lorsque l’on se sent juif, que l’on n’est pas pratiquant, que l’on partage sa vie et que l’on élève des enfants avec un conjoint non juif? L’enquête sociologique menée par l’auteure montre que les deux conjoints souhaitent transmettre un judaïsme qui ne soit pas uniquement religieux (voire non religieux), souvent qualifié de « culturel ». Il s’agit de réinventer des espaces, symboliques ou réels, pour donner corps à une identité plurielle et transmettre un judaïsme sécularisé. Ce désir de revendiquer une identité juive est intimement lié, on s’en doute, à la Shoah.Given that at present, more than half of the marriages contracted by Jew in France are mixed, the question “what does it mean to be Jewish?” is of particular importance. When individuals define themselves as Jewish but do not practice, and share their lives with a non-Jew, what do they transmit? My study shows that both partners, Jewish and non Jewish, want to transmit a Judaism that they often call a “cultural Judaism”. They seek to reinvent spaces, symbolic and real, that render their plural identity coherent and allow them to transmit a secularized Judaism to their children. This wish to claim a Jewish identity is often linked to the Shoah

Identités plurielles : Couples mixtes et transmission du judaïsme

Quand on sait qu’aujourd’hui en France la moitié des mariages contractés par des personnes juives sont des mariages mixtes, la question « qu’est-ce qu’être juif? » revêt toute son importance. Que transmet-on lorsque l’on se sent juif, que l’on n’est pas pratiquant, que l’on partage sa vie et que l’on élève des enfants avec un conjoint non juif? L’enquête sociologique menée par l’auteure montre que les deux conjoints souhaitent transmettre un judaïsme qui ne soit pas uniquement religieux (voire non religieux), souvent qualifié de « culturel ». Il s’agit de réinventer des espaces, symboliques ou réels, pour donner corps à une identité plurielle et transmettre un judaïsme sécularisé. Ce désir de revendiquer une identité juive est intimement lié, on s’en doute, à la Shoah.Given that at present, more than half of the marriages contracted by Jew in France are mixed, the question “what does it mean to be Jewish?” is of particular importance. When individuals define themselves as Jewish but do not practice, and share their lives with a non-Jew, what do they transmit? My study shows that both partners, Jewish and non Jewish, want to transmit a Judaism that they often call a “cultural Judaism”. They seek to reinvent spaces, symbolic and real, that render their plural identity coherent and allow them to transmit a secularized Judaism to their children. This wish to claim a Jewish identity is often linked to the Shoah

Couples mixtes et circoncision

En matière de transmission, la circoncision est la première question concrète à laquelle sont confrontés les couples mixtes juif/non juif lorsqu'ils attendent un enfant et a fortiori lorsqu'un fils naît. Elle est loin d'être anodine et fait ressurgir toutes sortes de conflits, de questionnements et de négociations. C'est à partir d'une enquête qualitative auprès de couples mixtes que cette question est abordée. Lorsqu'ils font circoncire leur fils, ces couples perpétuent un lien avec le judaïsme. Dans des discours qui mettent à l'écart certaines questions, ce geste est rationalisé, sécularisé et s'appuie sur la médecine. C'est un acte biographique, identitaire et de mémoire. Ceux qui ne font pas circoncire leur fils n'interrompent pas pour autant la chaîne de la transmission d'un judaïsme sécularisé en choisissant d'autres ressources identitaires.In matter of transmission, Jewish/non-Jewish mixed couples, when they expect a child and especially when a son was born, have to deal with circumcision. The decision to practice or not this ritual is taken after several discussions, conflicts and negociations. This question is analyzed from a qualitative survey among mixed couples. When their son is circumcised, this ritual is rationalized, secularized and refers to medicine. Circumcision is then a biographical, identity and a memory act. For those who do not make their son circumcized, they find other identity ressources to transmit a secularized Judaism.En lo referente a la cuestión de la transmisión, la circuncisión es la primera cuestión concreta a la que se enfrentan las parejas mixtas judío/ no judío cuando esperan un hijo y luego, cuando el niño nace. Lejos de ser anodina, plantea todo tipo de conflictos, de cuestionamientos y de negociaciones. Este tema es aquí abordado a partir de una investigación cualitativa con parejas mixtas. En tanto hacen circuncidar a su hijo, estas parejas perpetúan un lazo con el judaísmo. En los discursos que distinguen algunas cuestiones, este gesto es racionalizado, secularizado y se apoya en la medicina. Es un acto biográfico, identitario y de memoria. Aquellos que no hacen circuncidar a su hijo no interrumpen sin embargo, necesariamente, la cadena de transmisión de un judaísmo secularizado, eligiendo otros recursos identitarios

Mobilisations religieuses et États généraux de la bioéthique

En 2018-2019, le séminaire qui s’intéresse aux liens entre religion, éthique, biotechnologies et parenté, a poursuivi les travaux initiés l’année précédente en se concentrant sur les États généraux de la bioéthique qui se sont déroulés à l’hiver et au printemps 2018, préludant à la révision des lois de bioéthique. Il s’agit de saisir comment le religieux perçoit les biotechnologies et en retour, comment ces dernières travaillent les univers religieux de l’intérieur : les autorités religieuses comme les fidèles

Acculturating human experimentation: an empirical survey in France

International audiencePreliminary results of an empirical study of human experimentation practices are presented and contrasted with those of a survey conducted a hundred years ago when clinical research, although tolerated, was culturally deviant. Now that biomedical research is both authorized and controlled, its actors (sponsors, committees, investigators, subjects) come out with heterogeneous rationalities, and they appear to be engaged in a transactional process of negotiating their rationales with one another. In the European context "protective" of subjects, surprisingly the subjects we interviewed (and especially patient-subjects) were creative and revealed an aptitude for integrating experimental medicine into common culture

Laïcité, famille et santé

Programme de l’année 2006-2007 : Médecine, mort et sécularisation : premiers éléments de réflexio

A new optical set-up for on-line following up the crystallization of polymers at high cooling rates

International audienceA new experimental procedure, named " Polymer High Cooling - Optics " and whose performance has been improved, is presented. It allows us to monitor on-line the quiescent crystallization of a polymer film under high and constant cooling rates. With such a set-up, two cooling control modes are available resulting into a range of relatively moderate (from 30 to 500°C/min) and a range of high (from 500 to 1600°C/min) constant cooling rates. The crystallization experiments are observed by polarized light microscopy. Preliminary results are presented. They are obtained on the α-modification of one industrial grade of isotactic polypropylene, under relatively moderate constant cooling rates. Two relevant crystallization parameters are captured, the temperature of crystallization together with the spherulitic growth kinetics versus cooling rate. Accurate data are obtained. As well, they are in good agreement with comparable literature results compiled by Janeschitz-Kriegl [Macromolecules, 2006]. The obtained results seem to match the Hoffman and Lauritzen theory. These discussions validate our " Polymer High Cooling - Optics " set-up in relatively moderate constant cooling rates. Next step is to demonstrate the suitability of this first generation set-up for higher constant cooling rates

Glycerol as a cheap, safe and sustainable solvent for the catalytic and regioselective β,β-diarylation of acrylates over palladium nanoparticles

Herein we show that glycerol can be considered as a promising cheap and green solvent for the regioselective β,β-diarylation of alkenes. Whereas this reaction is generally catalyzed under an inert atmosphere by expensive phosphine or carbene-palladium complexes, we show here that the diarylation of alkenes can be conveniently achieved in glycerol in the presence of air-stable palladium nanoparticles. These palladium nanoparticles were stabilized over a sugar-based surfactant derived from biomass. By an adjustment of the reaction temperature, we were able to control the mono- and diarylation step of alkenes, thus offering a convenient route to unsymmetrical diarylated alkenes. At the end of the reaction, the diarylated alkenes were cleanly and selectively extracted from the glycerol-palladium catalytic phase using supercritical carbon dioxide, thus affording a convenient purification work-up. Within the framework of green chemistry, this work combines (i) catalysis in a cheap, safe and sustainable medium, (ii) easily made and air-stable palladium nanoparticles as the catalyst, and (iii) a clean and selective extraction of the reaction products with supercritical carbon dioxide