Laser Cooling of Molecular Anions

We propose a scheme for laser cooling of negatively charged molecules. We briefly summarise the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C$\_2^-$, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photo-detachment process is present, as well as Doppler laser cooling of trapped C$\_2^-$, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources and antimatter physics

Negative-index media for matter-wave optics

We consider the extension of optical meta-materials to matter waves. We show that the generic property of pulsed comoving magnetic fields allows us to fashion the wave-number dependence of the atomic phase shift. It can be used to produce a transient negative group velocity of an atomic wave packet, which results into a negative refraction of the matter wave. Application to slow metastable argon atoms Ar*(3P2) shows that the device is able to operate either as an efficient beam splitter or an atomic meta-lens. Implications of "meta-media" in atom optics are considered.Comment: 4 pages, 4 figures, submitted at PRL 4 November 200

Knowledge, attitudes, and practices of community pharmacists toward the management of acne vulgaris in Palestine: a cross-sectional study

Background Acne vulgaris (AV) is a common dermatological disease affecting almost 85% of teenagers. Patients with AV usually present at community pharmacies during the early stages of their disease. Aim The aim of this study was to assess community pharmacists’ knowledge, attitudes, and practice toward AV management in West Bank in Palestine. Methods This study was a cross-sectional questionnaire-based study. The questionnaire included four sections: 1) demographic, 2) knowledge, 3) attitude and practice items related causes, and 4) treatment options and counseling during management of patients with AV. A convenience sampling method was implemented in this study. Parametric and non-parametric tests were used to compare different issues as appropriate. P < 0.05 were considered significant. Result A total of 270 community pharmacists were interviewed, and more than half (54.1%) were males. The study revealed that community pharmacists had an inadequate level of knowledge on management of AV; only 7.7% had high levels of knowledge. Pharmacists have positive attitude regarding AV management, but inadequate knowledge was reflected on their treatment practices; only 10% of participants independently dealt with AV without referral. Pharmacists with a low level of knowledge showed five times more referrals than those with a high level of knowledge (OR: 5.3; P < 0.001), and those with a bachelor degree showed three times more referrals than postgraduates (OR: 3.3; P < 0.001). Conclusion There is a demand to update dermatological knowledge of community pharmacists and encourage them to attend structured training programs about the management of AV.Funding source: None

Dynamics of evanescent matter waves in negative-index media

International audiencenumbers: 03.75.-b Matter Waves 03.75.Be Atom and Neutron Optics 37.10.Gh Atom Traps and Guides 42.25.-p Wave Optics ABSTRACT Semi-evanescent and evanescent matter-waves produced by an atom wave packet impinging a repulsive barrier can be back-refracted and reconstructed by the application of negative-index " comoving " potential pulses. One shows that those collapses and revivals generate a matter wave confined on both sides of the barrier border (" surface matter wave ") and should be observable via the retardation of atom reflection from the barrier interface. This property, joined to the possibility recently demonstrated of inducing negative refraction of atom waves, makes such potentials a matter-wave counterpart of negative-index materials or " meta materials " well-known in light optics

Perspectives nouvelles pour l'optique atomique en jets : Interaction de van der Waals-Zeeman et milieux d'indice négatif pour les ondes de matière

In the first part of this thesis, we develop both theoretical and experimental studies of a type of short range atom-surface interaction (less than 10nm) called van der Waals-Zeeman transitions. To perform this study, we first use a supersonic beam of various metastable gaz rare atoms (Ne*, Ar*, Kr*), then we use a metastable argon beam Ar*(3P2) decelerated using a standard Zeeman slower. In the first case, we observe an increase of the range of the van der Waals-Zeeman interaction with respect to the raise of the anisotropy constant n. In the second case, the increase of the range is observed as a function of the velocity decrease of a metastable argon atom from 560 to 170m/s. The combination of these two methods allows us to measure the range of the interaction (the yield of which is of a few 10^(-4)) with a spatial resolution between 2 and 3 nm. In the second part of this work, we introduce the new field of negative index media for atom optics. These media consist of potentials called comoving potentials acting in vacuum. The two major demonstrated effects produced by this type of media are: the negative refraction effect for atomic waves and the spatial narrowing of the atomic wave-packet. Finally, the application of the negative index media to evanescent waves (produced by a static magnetic potential barrier) allows a localization of these waves within a few micrometers thick zone on both sides of the potential barrier.Dans la première partie de cette thèse, nous développons l'étude expérimentale et théorique d'un type d'interactions à très courte portée (moins de 10nm), dites de van der Waals-Zeeman, entre un atome de gaz rare et une surface métallique. Il s'agit d'utiliser d'une part un jet supersonique d'atomes métastables pour diverse espèces (Ne*, Ar*, Kr*) et, d'autre part, un jet d'argon métastable Ar*(3P2) décéléré par un ralentisseur Zeeman standard. Dans le premier cas, on observe un accroissement de la portée de l'interaction de van der Waals-Zeeman en fonction de l'augmentation de la constante d'anisotropie n. Dans le second cas, l'augmentation de la portée est observée lors d'une diminution de la vitesse d'un atome d'argon métastable de 560 à 170m/s. La combinaison de ces méthodes nous a permis de mesurer la portée de l'interaction (dont l'efficacité est de quelques 10^(-4)) avec une résolution spatiale de 2 à 3nm. Dans la seconde partie de ce travail, nous introduisons la thématique nouvelle des milieux d'indice négatif pour l'optique atomique. Ces milieux consistent en des potentiels dits comobiles agissant dans le vide. Deux effets majeurs de ces milieux d'indice négatif sont démontrés : la réfraction négative pour des ondes de matière et le rétrécissement du paquet d'onde atomique. Enfin, nous montrons que l'application de milieux d'indice négatif aux ondes évanescentes de matière (créées à l'aide d'une barrière de potentiel magnétique statique) permet de les localiser sur une épaisseur de quelques micromètres de part et d'autre du bord de la barrière de potentiel