Le labyrinthe dans les arts du XXe siècle. Les arts du XXe siècle dans le labyrinthe

La forme mythique du labyrinthe trouve de nombreuses résonnances dans les pratiques artistiques du XXe siècle. Elle est tout d’abord convoquée par les artistes qui cherchent à introduire une dimension participative dans la réception des oeuvres. Les créateurs de Dylaby, réalisation collective sous-titrée Un Labyrinthe dynamique (1962), métamorphosent par exemple un musée entier en dédale, bouleversant du même coup les habitudes perceptuelles et cognitives des visiteurs. Après avoir eux aussi créé des parcours labyrinthiques (Labyrinthe 1963, Labyrinthe II 1964) les membres du Groupe de Recherche d’Art Visuel poursuivent la remise en question du rapport traditionnel entre l’oeuvre et le spectateur en sortant du musée, invitant les citadins à considérer Paris comme un dédale hors échelle (Une Journée dans la rue, 1966). Le mythe du labyrinthe se rejoue ainsi à travers les oeuvres, ludiques ou inquiétantes, des plasticiens qui travaillent à même la ville. Endossant les rôles de Thésée à la recherche de son chemin (Stanley Brouwn), Minotaure aux aguets (Vito Acconci), Ariane tissant un fil à l’attention des citadins en proie à la monotonie et au somnambulisme (Francis Alÿs), ces artistes montrent que la fiction et la fable ne sont jamais loin derrière les sages apparences du réel.The mythical figure of the labyrinth is often echoed in twentieth century artistic practices. First, it is called upon by artits who wish to introduce a participative dimension in the way the work of art will be apprehended. The creators of Dylaby – a group creation subtitled « A Dynamic Labyrinth » - turn a full museum into a maze, whereby they upset the visitors’ habits of perception and cognition. After they, too, had created labyrinthic routes (Labyrinth, 1963 ; Labyrinth II, 1964), the members of the Groupe de Recherche d’Art Visuel (Research Group on Visual Art) carry on with the questioning of the traditional viewer-work-of-art relationship by going outside museums, inviting citizens to envision Paris as a beyond scale labyrinth (One Day in the Street, 1966). The myth of the labyrinth is thus reconsidered through works – whether playful or disturbing – of visual artists whose material is the very city. Posing as a Theseus groping for the way out (Stanley Brouwn) or a Minotaur on the alert (Vito Acconci) or again as an Ariadne weaving a thread destined to benumbed, sleep-walking and habit-ridden passers-by (Francis Alÿs), these artists show that fiction and fables can always be reachable behind the tame appearance of reality

Percolation with excluded small clusters and Coulomb blockade in a granular system

We consider dc-conductivity $\sigma$ of a mixture of small conducting and insulating grains slightly below the percolation threshold, where finite clusters of conducting grains are characterized by a wide spectrum of sizes. The charge transport is controlled by tunneling of carriers between neighboring conducting clusters via short ``links'' consisting of one insulating grain. Upon lowering temperature small clusters (up to some $T$-dependent size) become Coulomb blockaded, and are avoided, if possible, by relevant hopping paths. We introduce a relevant percolational problem of next-nearest-neighbors (NNN) conductivity with excluded small clusters and demonstrate (both numerically and analytically) that $\sigma$ decreases as power law of the size of excluded clusters. As a physical consequence, the conductivity is a power-law function of temperature in a wide intermediate temperature range. We express the corresponding index through known critical indices of the percolation theory and confirm this relation numerically.Comment: 7 pages, 6 figure

Transport properties and crystal field energy in CeTe

We report resistivity measurements of CeTe as a function of temperature above 4.2 K. The results are analysed in the framework of a model taking into account the inelastic scattering of the free carriers which can exchange the energy Δ with the Ce scattering centre. A very good agreement between theory and experiment is obtained The deduced value Δ ≃ 26 K is one order of magnitude smaller than predicted by the point charge model, which we attribute to the existence of a strong d-f hybridization.Nous avons mesure la résistivité électrique de CeTe en fonction de la température, audessus de 4,2 K. Les résultats sont analysés à l'aide d'un modèle prenant en compte la diffusion inélastique des porteurs libres par les ions cérium. Un bon accord entre la théorie et l'expérience est obtenu. La valeur déduite Δ ≃ 26 K est d'un ordre de grandeur plus faible que celle prédite par la théorie des charges ponctuelles ce que nous avons attribué à l'existence d'une forte hybridation f-d

Anisotropic magnetization, specific heat and resistivity of RFe2Ge2 single crystals

We have grown RFe2Ge2 single crystals for R = Y and ten members of the lanthanide series (Pr, Nd, Sm, Gd-Tm, Lu) using Sn flux as the solvent. The method yields clean, high quality crystal plates as evidenced by residual resistivities and RRR values in the range of 3-12 uOhm cm and 20-90 respectively. The crystals are also virtually free of magnetic impurities or secondary phases, allowing the study of the intrinsic anisotropic magnetic behavior of each compound. Characterization was made with X-Ray diffraction, and temperature and field dependent magnetization, specific heat and resistivity. Very strong anisotropies arising mostly from CEF effects were observed for all magnetic rare earths except Gd. Antiferromagnetic ordering occurred at temperatures between 16.5 K (Nd) and 1.1 K (Ho) that roughly scale with the de Gennes factor for the heavy rare earths. For some members there is also a lower temperature transition associated with changes in the magnetic structure. Tm did not order down to 0.4 K, and appears to be a van Vleck paramagnet. All members which ordered above 2 K showed a metamagnetic transition at 2 K for fields below 70 kOe. The calculated effective moments per rare earth atom are close to the expected free ion values of R^3+ except for Sm which displays anomalous behavior in the paramagnetic state. The non-magnetic members of this series (Y, Lu) are characterized by an unusually large electronic specific heat coefficient (gamma ~ 60 mJ/mol K^2) and temperature-independent susceptibility term (chi_0 ~ 0.003 emu/mol), indicative of a relatively large density of states at the Fermi surface.Comment: 34 pages, 13 figures, 1 table, submitted to J. Magn. Magn. Mate

EXCHANGE INTERACTIONS IN THE QUASI-LINEAR-CHAIN ANTIFERROMAGNET KFES2

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"Interventions artistiques dans l'espace public urbain : les femmes "apportent" leurs corps"

International audienc

"Les mots dans l'oeuvre d'Adrian Piper, ou l'adresse à un spectateur responsable"

International audienc

« Interventions "parasitiques" en milieu urbain : pour une redéfinition de la ville et de l’artiste »

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