Semigroups of valuations on local rings

In this paper the question of which semigroups are realizable as the semigroup of values attained on a Noetherian local ring which is dominated by a valuation is considered. We give some striking examples, indicating that there may be no constraints on the semigroup beyond those known classically.Comment: 19 page

Toric Geometry and the Semple-Nash modification

This paper proposes some material towards a theory of general toric varieties without the assumption of normality. Their combinatorial description involves a fan to which is attached a set of semigroups subjected to gluing-up conditions. In particular it contains a combinatorial construction of the blowing up of a sheaf of monomial ideals on a toric variety. In the second part it is shown that over an algebraically closed base field of zero characteristic the Semple-Nash modification of a general toric variety is isomorphic to the blowing up of the sheaf of logarithmic jacobian ideals and that in any characteristic this blowing-up is an isomorphism if and only if the toric variety is non singular. In the second part we prove that orders on the lattice of monomials (toric valuations) of maximal rank are uniformized by iterated Sempla-Nash modifications.Comment: New version. Appeared in "Revista de la Real Academia de Ciencias Exactas, Fisicas y Naturales, Serie A Matematicas", October 2012 (Electronic

Hybrid continuous dynamical decoupling: a photon-phonon doubly dressed spin

We study the parametric interaction between a single Nitrogen-Vacancy electronic spin and a diamond mechanical resonator in which the spin is embedded. Coupling between spin and oscillator is achieved by crystal strain, which is generated upon actuation of the oscillator and which parametrically modulates the spins' energy splitting. Under coherent microwave driving of the spin, this parametric drive leads to a locking of the spin Rabi frequency to the oscillator mode in the megahertz range. Both the Rabi oscillation decay time and the inhomogeneous spin dephasing time increase by two orders of magnitude under this spin-locking condition. We present routes to prolong the dephasing times even further, potentially to the relaxation time limit. The remarkable coherence protection that our hybrid spin-oscillator system offers is reminiscent of recently proposed concatenated continuous dynamical decoupling schemes and results from our robust, drift-free strain-coupling mechanism and the narrow linewidth of the high-quality diamond mechanical oscillator employed. Our findings suggest feasible applications in quantum information processing and sensing.Comment: 6 pages, 4 figure

Les effets phonostylistiques caractéristiques des chanteuses de musique populaire anglophone

La version intégrale de ce mémoire est disponible uniquement pour consultation individuelle à la Bibliothèque de musique de l’Université de Montréal (www.bib.umontreal.ca/MU).La voix est un instrument si complexe dans ses possibilités de phrasés, d’intentions et d’inflexions, qu’elle est unique à chaque interprète. En musique populaire, ces styles vocaux ou phonostyles se traduisent par l’utilisation de timbres et d’effets vocaux distinctifs (souffle sur la voix, coup de glotte, voix de fausset, etc.) qui s’appliquent de façon globale et constante ou, le plus souvent, de façon très localisée, sur l’attaque de certains mots par exemple. Dans ce mémoire, sont définis et illustrés un ensemble d’effets phonostylistiques caractéristiques des chanteuses po- pulaires anglophones des années 1980 à nos jours, du point de vue de différentes disciplines (physiologie, acoustique, paralinguistique, phonos- tylistique). Pour finir, il est présenté une application du sujet à l’étude des techniques vocales de 3 chanteuses.The voice is a complex instrument. Phrasing, inflexions and intentions are different with every musician. In popular music, those acoustic signa- tures or phonostyles (LEON, 1993) exist through the use of timbre and different vocal effects (breathy voice, glottal stop, falsetto voice, etc.). Those can be applied constantly to the voice or on a very discrete basis (as the attack of a sound for example). In this dissertation, we will define and illustrate a certain number of phonostylistic caracteristics through a research among popular music and female singers from year 1980 to our days, from different fields’point of view (physiology, acoustic, par- alinguistic, phonostylistic). In the end, the subject will be applied to the study of three singers’vocal technique

Le laboratoire de Robert Collongues (1950-2000): Une école de recherche aux débuts de la chimie du solide

This text deals with the origins, the foundation and the evolution of the research school founded by Robert Collongues that has partly led to the birth of Solid State Chemistry in France since the fifties. Through its institutional and thematic evolutions, this laboratory exemplifies a typical science research school. The two annex diagrams portray two different faces of this research school through temporal evolution. The transmission and the construction of knowledge (scientific and technical) from one generation of researchers to the following one will be stressed upon so as to enlighten the main features of the Collongues' method on the techno-scientific, institutional and human levels in a moving economic world. The new production of knowledge will thus be shown through the evolution of this branch of the French Solid State Chemistry.Cet article décrit la genèse puis l'évolution de l'école de recherche fondée par Robert Collongues, qui a contribué à l'émergence de la chimie du solide en France à partir des années 1950. Nous montrerons que ce laboratoire constitue un cas exemplaire d'une école de recherche en science en décrivant ses évolutions, que ce soit au niveau des thèmes de recherche ou des institutions. Les deux schémas fournis en annexe offrent deux portraits dynamiques de cette école de recherche au cours du temps. Nous insisterons sur la transmission et la construction des connaissances (savoirs et savoir-faire) d'une génération de chercheurs à la suivante afin de mettre en lumière les traits principaux de la méthode Collongues sur les plans techno-scientifique, institutionnel et humain, dans un environnement économique mouvant. Nous chercherons ainsi à montrer l'évolution des modes de production des savoirs au sein de cette branche de la chimie du solide française