Anti-de Sitter branes with Neveu-Schwarz and Ramond-Ramond backgrounds

We review some facts about AdS2xS2 branes in AdS3xS3 with a Neveu-Schwarz background, and consider the case of Ramond-Ramond backgrounds. We compute the spectrum of quadratic fluctuations in the low-energy approximation and discuss the open-string geometry.Comment: 8 pages, uses JHEP3.cl

Orientifolds of the 3-sphere

We study the geometry of orientifolds in the SU(2) WZW model. They correspond to the two inequivalent, orientation-reversing involutions of $S^3$, whose fixed-point sets are: the north and south poles (O0), or the equator two-sphere (O2). We show how the geometric action of these involutions leads unambiguously to the previously obtained algebraic results for the Klein bottle and Moebius amplitudes. We give a semiclassical derivation of the selection rules and signs in the crosscap couplings, paying particular attention to discrete B-fluxes. A novel observation, which does not follow from consistency of the one-loop vacuum diagrams, is that in the case of the O0 orientifolds only integer- or only half-integer-spin Cardy states may coexist.Comment: Latex file, 19 pages, one figure, uses JHEP.cls. One reference added, final version as it appeared in JHE

D-branes and orientifolds of SO(3)

We study branes and orientifolds on the group manifold of SO(3). We consider particularly the case of the equatorial branes, which are projective planes. We show that a Dirac-Born-Infeld action can be defined on them, although they are not orientable. We find that there are two orientifold projections with the same spacetime action, which differ by their action on equatorial branes.Comment: 11 pages, no figure, uses JHEP3.cls. V2 : minor correction

Quantum Matrix Models for Simple Current Orbifolds

An algebraic formulation of the stringy geometry on simple current orbifolds of the WZW models of type A_N is developed within the framework of Reflection Equation Algebras, REA_q(A_N). It is demonstrated that REA_q(A_N) has the same set of outer automorphisms as the corresponding current algebra A^{(1)}_N which is crucial for the orbifold construction. The CFT monodromy charge is naturally identified within the algebraic framework. The ensuing orbifold matrix models are shown to yield results on brane tensions and the algebra of functions in agreement with the exact BCFT data.Comment: 31 pages, LaTeX; typos corrected, new elements added, the contents restructure

D-brane charges on non-simply connected groups

The maximally symmetric D-branes of string theory on the non-simply connected Lie group SU(n)/Z_d are analysed using conformal field theory methods, and their charges are determined. Unlike the well understood case for simply connected groups, the charge equations do not determine the charges uniquely, and the charge group associated to these D-branes is therefore in general not cyclic. The precise structure of the charge group depends on some number theoretic properties of n, d, and the level of the underlying affine algebra k. The examples of SO(3)=SU(2)/Z_2 and SU(3)/Z_3 are worked out in detail, and the charge groups for SU(n)/Z_d at most levels k are determined explicitly.Comment: 31 pages, 1 figure. 2 refs added. Added the observation: the charge group for each su(2) theory equals the centre of corresponding A-D-E grou

Probing Orientifold Behavior Near NS Branes

The effect of NS 5 branes on an orientifold is studied. The orientifold is allowed to pass through a pile of k NS branes forming a regularized CHS geometry. Its effect on open strings in its vicinity is used to study the change in the orientifold charge induced by the NS branes.Comment: Important references added, 30 pages, 8 figure

D-brane charges on SO(3)

In this letter we discuss charges of D-branes on the group manifold SO(3). Our discussion will be based on a conformal field theory analysis of boundary states in a Z_2-orbifold of SU(2). This orbifold differs from the one recently discussed by Gaberdiel and Gannon in its action on the fermions and leads to a drastically different charge group. We shall consider maximally symmetric branes as well as branes with less symmetry, and find perfect agreement with a recent computation of the corresponding K-theory groups.Comment: 11 pages, 1 figure. Some comments adde

La grotte de Gargas (Aventignan, Hautes-Pyrénées) : nouvelles perspectives de recherche et premiers résultats sur les occupations gravettiennes.

International audienceIn this paper, we present the first results of new excavations of Gargas Cave from 2004 to 2005. These excavations were undertaken 90 years after the interruption of archaeological research by É. Cartailhac and H. Breuil (1911 and 1913). The current excavation concerns a zone that corresponds to a debris cone that naturally closed the cave. It contains two loci, separated by 20 metres. The first one (GES) is at the base of the cone near the former Cartailhac-Breuil excavations. The second one (GPO), which has not yet been excavated, is at the top of the cone near the prehistoric entrance. In the GES sector, we have identified the upper part of the stratigraphic sequence described during the Cartailhac-Breuil excavations and which corresponds to the Gravettian occupations. In the GPO sector, the deposit shows some sedimentological differences, but the Gravettian ensemble is also represented there. Our study of the newly excavated materials integrates information contributed by the old collections. According to the results of C14 dating, the Gravettian occupations occurred between 27,000 and 25,000 BP. The lithic industry is attributed to the Middle Gravettian with Noailles burins and shows a clear microlithic trend. The bone industry is principally composed of “mattocks” made on herbivore ribs, smoothers, awls and retouchers. The antler waste products show that longitudinal grooving was used for the fabrication of tools. Though no Isturitz Points have yet been found during the new excavations, this characteristic Gravettian point type is present in the old collections. The personal ornaments consist mainly of pierced Atlantic shells and perforated Cervid, Bovin, Izard and Carnivore teeth. In terms of their meat diet, the Gravettian groups at this site consumed mostly Reindeer, Bovinae and Izard. A zooarchaeological analysis has also demonstrated that the cave was occupied during all seasons and that butchery and consumption activities were performed there.Nous présentons ici les premiers résultats obtenus au cours de la reprise des fouilles dans la grotte de Gargas (campagnes 2004-2005). Celles-ci interviennent 90 ans après l'interruption des recherches archéologiques d'É. Cartailhac et H. Breuil (1911 et 1913). La fouille actuelle concerne la zone correspondant au cône d'éboulis qui a fermé naturellement la grotte. Elle se déroule sur deux locus distant d'une vingtaine de mètres : le premier (GES) à la base du cône, à proximité des anciennes fouilles Cartailhac- Breuil, le second (GPO) en amont du cône, proche de l'entrée préhistorique ; cette dernière zone n'avait pas été fouillée jusqu'à ce jour. Dans le secteur GES, nous avons retrouvé la partie supérieure du profil stratigraphique, décrit lors des fouilles Cartailhac-Breuil et qui correspond aux occupations gravettiennes. Dans le secteur GPO, le remplissage présente quelques différences sédimentologiques, mais l'ensemble gravettien est également présent. L'étude du matériel récent est réalisée en intégrant l'apport documentaire des anciennes collections. D'après les résultats des datations14C, les occupations gravettiennes s'échelonnent entre 27 000 et 25 000 BP. L'industrie lithique se rapporte au Gravettien moyen à burins de Noailles, avec une nette tendance à la microlithisation. L'industrie en matières dures d'origine animale se compose principalement de côtes d'herbivores utilisées, de lissoirs, de poinçons et de retouchoirs. Les déchets de débitage en bois de Cervidés témoignent de l'utilisation du rainurage longitudinal pour la fabrication de l'outillage. Si aucune « sagaie d'Isturitz » n'a été découverte au cours des campagnes récentes, ce type caractéristique du Gravettien fait néanmoins partie des anciennes collections. Les éléments de parure sont principalement constitués de coquillages perforés de provenance atlantique et de dents percées de Cervidés, de Bovinés et de Carnivores. Le régime carné des Gravettiens était principalement basé sur le Renne, les Bovinés et l'Isard. L'analyse archéozoologique a également permis d'établir que la grotte a été fréquentée à toutes les périodes de l'année et qu'elle fut le lieu d'activités de boucherie et de consommation

Seeking cyclonic activity records in speleothems from central Pacific: preliminary sample screening

PosterInternational audienceIdeal cyclone-sensitive speleothems would have the following properties: active at the time of sampling and recording the past few millenia, with fast growth rate, made of clean primary calcite, precipitated without kinetic fractionation, and fed by water with a short residence time allowing for the isotopic signal of short events like cyclones to be transferred but long enough for the drip water to be supersaturated. The screening for this type of speleothem is still in progress and the results presented here are very preliminary. U-Th dating: low U concentration (9-40ng/g; host rock is reef limestone) ; significant detrital content, involving large corrections and large final age uncertainties. Growth rate is highly variable, from ~0.12 mm/yr to ~0.03mm/yr. Tau12A: δ 18 O profile shows some quite large variations (~3‰), with several abrupt events that we will try to identify in other archives. δ 13 C signal amplitude is very large (~-4 to ~-14‰) suggesting the effect of prior calcite precipitation. The δ 18 O signal gets heavier when the δ 13 C does, which could reflect the rainfall amount in this context. Var12C: δ 18 O profile shows values between-3.1 and-6.3‰, with decadal or centennial fluctuations, superimposed on a general trend which is consistent with the one of the δ 13 C profile without being correlated, which implies that calcite precipitation could occur in conditions close to isotopic equilibrium. Once properly dated, this record should provide interesting information about past rainfall regimes on the island

Boundary States of c=1 and 3/2 Rational Conformal Field Theories

We study the boundary states for the rational points in the moduli spaces of c=1 conformal and c=3/2 superconformal field theories, including the isolated Ginsparg points. We use the orbifold and simple-current techniques to relate the boundary states of different theories and to obtain symmetry-breaking, non-Cardy boundary states. We show some interesting examples of fractional and twisted branes on orbifold spaces.Comment: Latex, 46 pages, 1 figur