Even Galois Representations and the Fontaine--Mazur conjecture II

We prove, under mild hypotheses, that there are no irreducible two-dimensional_even_ Galois representations of \Gal(\Qbar/\Q) which are de Rham with distinct Hodge--Tate weights. This removes the "ordinary" hypothesis required in previous work of the author. We construct examples of irreducible two-dimensional residual representations that have no characteristic zero geometric (= de Rham) deformations.Comment: Updated to take into account suggestions of the referee; the main theorems remain unchange

Completed cohomology of Shimura curves and a p-adic Jacquet-Langlands correspondence

We study indefinite quaternion algebras over totally real fields F, and give an example of a cohomological construction of p-adic Jacquet-Langlands functoriality using completed cohomology. We also study the (tame) levels of p-adic automorphic forms on these quaternion algebras and give an analogue of Mazur's `level lowering' principle.Comment: Updated version. Contains some minor corrections compared to the published versio

Strain mapping at the nanoscale using precession electron diffraction in transmission electron microscope with off axis camera

International audiencePrecession electron diffraction is an efficient technique to measure strain in nanostructures by precessing the electron beam, while maintaining a few nanometre probe size. Here, we show that an advanced diffraction pattern treatment allows reproducible and precise strain measurements to be obtained using a default 512 x 512 DigiSTAR off-axis camera both in advanced or non-corrected transmission electron microscopes. This treatment consists in both projective geometry correction of diffraction pattern distortions and strain Delaunay triangulation based analysis. Precision in the strain measurement is improved and reached 2.7 x 10(-4) with a probe size approaching 4.2 nm in diameter. This method is applied to the study of the strain state in InGaAs quantum-well (QW) devices elaborated on Si substrate. Results show that the GaAs/Si mismatch does not induce in-plane strain fluctuations in the InGaAs QW region. (C) 2014 AIP Publishing LLC

Long-range attraction between particles in dusty plasma and partial surface tension of dusty phase boundary

Effective potential of a charged dusty particle moving in homogeneous plasma has a negative part that provides attraction between similarly charged dusty particles. A depth of this potential well is great enough to ensure both stability of crystal structure of dusty plasma and sizable value of surface tension of a boundary surface of dusty region. The latter depends on the orientation of the surface relative to the counter-ion flow, namely, it is maximal and positive for the surface normal to the flow and minimal and negative for the surface along the flow. For the most cases of dusty plasma in a gas discharge, a value of the first of them is more than sufficient to ensure stability of lenticular dusty phase void oriented across the counter-ion flow.Comment: LATEX, REVTEX4, 7 pages, 6 figure

ÉTUDE SPECTROSCOPIQUE PAR BOMBARDEMENT ÉLECTRONIQUE DES NIVEAUX EXCITÉS D'ÉLÉMENTS PEU VOLATILS ET DE GAZ RARES

Nous avons utilisé une excitation électronique pour faire quelques mesures sur des niveaux excités atomiques. Des éléments peu volatils baryum et argent ont été étudiés sous forme de jets atomiques par effet Hanle. Des expériences de résonance magnétique du type Brossel ont été réalisées sur des gaz rares (Ne, Ar, Xe). L'observation de ces resonances a été permise grâce à l'emploi d'une technique d'accumulation de données améliorant nettement le rapport signal sur bruit.Electronic bombardment excitation has been used for measurements on atomic excited states. The « involatile » elements barium and silver have been studied in atomic beams by the Hanle effect. Magnetic-resonance Brossel-type experiments have been performed on rare gases (Ne, Ar, Xe). The observation of these resonances was made possible by a data storage technique which greatly increased the signal to noise ratio