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Cet article se propose d’interroger le témoignage politique de Salvador Allende Gossens 50 ans après sa mort. Sa question est basiquement : Quelle pourrait aujourd’hui la signification de la figure de Allende dans notre manière « d’agir, de penser et d’inventer un avenir » après la révolte sociale au Chili de l’octobre 2019 ? Cette réponse passe par la saisie des effets historiques et symboliques de la crise hégémonique des Etats-Unis et du coup d’Etat de 1973, ainsi que l’assomption de l’incapacité des mouvements progressistes à indiquer une alternative crédible au « réalisme capitaliste » tout au long des cinquante dernières années… This paper aims at inquiring Salvador Allende political testimony 50 years after his death. Its question is basically: What could be the meaning of Allende’s figure today in our way of “acting, thinking and inventing a future” after the Chilian social revolt of October 2019? This answer passes by the seizure of the historical and symbolic effects of the hegemonic crisis of the United States and the Golpe of 1973, and the assumption of the incapacity of the progressive movements to indicate a credible alternative to the “capitalist realism” throughout the last fifty years...

Con la publicación de este decimonoveno Cahier, dedicado a los “espectros del poder popular”, ofrecemos a los lectores los primeros resultados de un proyecto de investigación en curso, que se llevó a cabo durante un año y medio, en forma de un seminario virtual, reuniéndose periódicamente. Este proyecto colectivo surgió de los debates que acompañaron y siguieron a la conferencia Teoría y práctica entre universidades y movimientos, organizada por Anna Pia Ruoppo, Fabrizio Carlino y Marco Morra...

This paper reconsiders critically current manners of writing the history of protest movements. Its focus is the notion of “counter public sphere” (Gegen-Öffentlichkeit) that Oskar Negt and Alexander Kluge forged in Public Sphere and Experience (1972) within the framework of Critical Theory and of Antiauthoritarian movement. This paper is composed of a conceptual analysis of Counter-Public-Sphere, an historical-critical enlightenment of the political context of its emergence, a critical reconsideration of current manner of writing the history of German student movement and an attempt of a description from within of Berliner Antiauthoritarian mobilization (1966-68). Este artículo cuestiona la manera corriente de escribir la historia de los movimientos de protesta de los años Sesenta. Su enfoque es desde la categoría de “esfera pública de oposición” (Gegen-Öffentlichkeit) que Oskar Negt y Alexander Kluge forjan en Öffentlichkeit und Erfahrung (1972) en el marco de la Teoría Critica y del Movimiento Antiautoritario. El artículo se compone de un análisis de la noción de esfera pública de oposición (Gegenöffentlichkeit), elaborando un esclarecimiento histórico-crítico del contexto político de su surgimiento, una problematización de la manera de escribir la historia de las luchas estudiantiles de los años 60 y una descripción desde dentro de la movilización antiautoritaria berlinesa (1966-68).

Squeezed states of light contribute to the reduction of quantum noise in gravitational-wave interferometers. This result, predicted by Caves in 1981, has been demonstrated by the main gravitational-wave detectors. The injection of phase-squeezed light only decreases quantum shot noise fluctuations, improving the detector sensitivity in high-frequency band; the corresponding anti-squeezing, indeed, induces radiation pressure noise, increasing quantum noise in low-frequency band. This becomes important for near detector generation, where current low frequency noises, that cover the radiation pressure noise, will be reduced. To face this problem, the use of frequency dependent squeezing, obtained using a long external filter cavity, is planned. An alternative method, based on EPR experiment, can be used for the same purpose. It has the advantage to avoid further complex infrastructures required for the filter cavity. We propose a table-top experiment to test the broadband quantum noise reduction that can be obtained injecting entangled beams through the interferometer dark port. The conceptual design and the possible implementation in a small-scale suspended interferometer will be presented.

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International audience; Transmission Raman spectroscopy experiments were performed as function of time on iron doped congruent lithium niobate crystals within two –in principle equivalent symmetric- configurations, namely Y(zx)Y and Y(xz)Y according to Raman selection rules. Whereas only the lines corresponding to E[TO] phonons are detected at any time as expected in the Y(zx)Y configuration, the spectra in the Y(xz)Y configuration shows a large evolution with time. Just at the beginning of illumination, the spectrum in the transmission geometry is very similar to the corresponding spectrum in back-scattering, but rapidly new lines appear and increase in intensity with time. After one minute of illumination, the spectrum completely differs from expected E[TO]. These new lines in fact arise from another mode symmetry and are clearly assigned as due to A1[TO] phonons.This activation with time of forbidden A1[TO] Raman lines for this configuration result from photorefractive internal field which causes the polarization conversion from ordinary to extraordinary polarization and is originated by photorefractivity of the crystal.

International audience; Different concentration of Ho3+ions doped lithium niobate powders andalkoxides were synthesized by solid and wet reactions respectively. Obtainedpowders and fired alkoxides were investigated by means of X-ray diffractionanalyses and corresponding lattice parameters were calculated. Thin films ofLiNbO3:Ho3+ were grown by Sol-Gel method on a sapphire substrate of (001)orientation.Structural modifications of obtained thin films were investigated by highresolutionx-ray reciprocal space mapping. The reciprocal space maps werecollected in the proximity of the symmetric (006) and asymmetric (018) Braggreflections of the sapphire substrate. By comparing the maps obtained fromdifferent independent Bragg reflections, the deformation matrix was solved andlattice parameters of thin films were calculated.

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