Unresolved sideband photon recoil spectroscopy of molecular ions

We reflect on the prospect of exploiting the recoil associated with absorption and emission of photons to perform spectroscopy of a single molecular ion. For this recoil to be detectable, the molecular ion is sympathetically cooled by a laser-cooled atomic ion to near the quantum mechanical ground state of a common trapping potential. More specifically, we present a general framework for simulating the expected photon recoil spectra in regimes where either the natural transition linewidth $\Gamma_t$ of the molecular ion or the spectral width $\Gamma_L$ of the exciting light source exceeds the motional angular frequencies (typically $\sim 2\pi\times 0.1 - 1$ MHz) of the two-ion system. To exemplify the framework, we present two complementary cases: spectroscopy of the broad 3s $^2$S$_{1/2}$ - 3p $^2$P$_{3/2}$ electronic transition ($\Gamma_t/2\pi = 41.8$ MHz) of a single $^{24}$Mg$^+$ ion at $\lambda=279.6$ nm by a narrow laser source ($\Gamma_L/2\pi \lesssim 1$ MHz) and mid-infrared vibrational spectroscopy of the very narrow $|v=0,J=1\rangle$ - $|v'=1,J'=0\rangle$ transition ($\Gamma_t/2\pi = 2.50$ Hz) at $\lambda=6.17$ $\mu$m in the $^1\Sigma^+$ electronic ground state of $^{24}$MgH$^+$ by a broadband laser source ($\Gamma_L/2\pi \gtrsim$ 10 MHz). The atomic ion $^{24}$Mg$^+$ has been picked to introduce a simple system to make comparisons with experimental results while still capturing most of the physics involved in electronic excitations of molecular ions.Comment: 28 pages, 15 figure

Sideband cooling of small ion Coulomb crystals in a Penning trap

We have recently demonstrated the laser cooling of a single 40 Ca + ion to the motional ground state in a Penning trap using the resolved-sideband cooling technique on the electric quadrupole transition S 1/2 ↔ D 5/2 . Here we report on the extension of this technique to small ion Coulomb crystals made of two or three 40 Ca + ions. Efficient cooling of the axial motion is achieved outside the Lamb-Dicke regime on a two-ion string along the magnetic field axis as well as on two- and three-ion planar crystals. Complex sideband cooling sequences are required in order to cool both axial degrees of freedom simultaneously. We measure a mean excitation after cooling of n COM for the centre of mass (COM) mode and n B for the breathing mode of the two-ion string with corresponding heating rates of 11(2)s -1 and 1(1)s -1 at a trap frequency of 162 kHz. The occupation of the ground state of the axial modes (n tilt = n COM = 0) is above 75% for the two-ion planar crystal and the associated heating rates 0.8(5)s -1 at a trap frequency of 355 kHz

Sideband cooling of the radial modes of motion of a single ion in a Penning trap

Doppler and sideband cooling are long-standing techniques that have been used together to prepare trapped atomic ions in their ground state of motion. In this paper we study how these techniques can be extended to cool both radial modes of motion of a single ion in a Penning trap. We numerically explore the prerequisite experimental parameters for efficient Doppler cooling in the presence of an additional oscillating electric field to resonantly couple the radial modes. The simulations are supported by experimental data for a single 40 Ca + ion Doppler cooled to ∼ 100 phonons in both radial modes at a magnetron frequency of 52 kHz and a modified cyclotron frequency of 677 kHz. For these frequencies, we then show that mean phonon numbers of 0.35(5) for the modified cyclotron and 1.7(2) for the magnetron motions are achieved after 68 ms of sideband cooling

Le patient hypocondriaque en médecine générale (étude qualitative sur le vécu et le ressenti du praticien)

Introduction: Dans sa pratique quotidienne~ le médecin généraliste est amené à voir des patients envahissants, très demandeurs et peu gratifiants: les patients hypoconpnaques. Ces derniers consultent régulièrement les cabinets des praticiens sans pathologies sévères ou chroniques. Ds sont sources de difficultés pour le médecin à la fois en termes de diagnostic mais aussi de prise en charge. Matériel et méthodes: Nous avons réalisé une étude qualitative, à raide de la technique du focus group , en interrogeant 15 médecins du Gard et de l'Hérault Nous nous sommes intéressés à leur vécu et à leur ressenti face au patient hypocondriaque, à la façon dont ils les prennent en charge et enfin à la relation ainsi établie. L'analyse des différents verbatims a permis de connaitre les sentiments du médecin, ses principales difficultés et son mode de défense face à ces patients. Résultats: Le diagnostic d'hypocondrie est un diagnostic long et difficile. Les consultations sont la plupart du temps chronophages et énergivores ; le médecin ressent alors de la méfiance, du stress, de rinsatisfactÏon face à ce patient qui réussit à le mettre en situation d'échec, d'impuissance, à le faire douter quant à ses capacités médicales. Le praticien perd alors son rôle primaire, il devient simple prescripteur, manipulé par les dires de son patient. La prise en charge de l'hypocondriaque doit passer par une écoute active, un surinvestissement de la consultation, un examen succinct mais nécessaire pour établir une relation de confiance basée sur la fidélité, la complicité et r empathie. Conclusion: Le travail ainsi réalisé auprès du patient hypocondriaque nécessite du temps et une approche psychosomatique à raide de la thérapie cognitivo-comportementale que peu de médecins pratiquent. Elle permet de diminuer l'anxiété du patient, de redonner satisfaction au médecin et d'aboutir à une relation médecin/malade de bonne qualité.MONTPELLIER-BU Médecine UPM (341722108) / SudocSudocFranceF

Sideband cooling of ion coulomb crystals in a Penning trap

This thesis reports on the progress of resolved sideband cooling on the S1/2 D5\2 transition of 40Ca+ ions in a Penning trap. We demonstrate cooling of the axial motion of a single ion to the ground state over a wide range of trapping frequencies (67 kHz to 420 kHz) with a mean motional state ranging from nz = 0.07(1) to nz = 0.015(18). We are also able to cool the radial motion of the ion close to the ground state with mean motional states below one for both the modified cyclotron and magnetron modes. In order to carry out sideband cooling of the radial mode, the ion is initially cooled with Doppler cooling in the presence of an axialisation field. Efficient sideband cooling outside the Lamb-Dicke regime is performed using complex cooling sequences featuring laser pulses at different frequencies. The sideband cooling technique is extended to one- and two- dimensional ion Coulomb crystals. For a two-ion chain, aligned with the magnetic field, we measure for the centre of mass mode a final mean motional state nc = 0.25(6) and for the breathing mode nb = 0.07(4) with respective heating rates of 11(2) s-1 and 1(1) s-1. Near ground state cooling of the transverse (axial) modes of two-dimensional planar crystals made of up to 10 ions is achieved. A coherent drive of the cold ions is demonstrated by the observation of Rabi oscillations. Ramsey experiments are performed on a single ion to study the coherence of the system. We find a 1/e coherence time of the optical transition S1/2 D5/2 equal to 1.76(7) ms. This was increased to 13.2(6) ms using Uhrig dynamical decoupling. By creating superpositions of the motional states of the ion, we measure the coherence time of the axial motion. A maximum of 565(21) ms is found at 420 kHz.Open Acces

Chiens et chats à l'officine

On compte en France plus de 8,1 millions de chiens et 8,7 millions de chats. Sur les 4 millions de clients des officines françaises, plus de la moitié possède un chat ou un chien et sollicitera donc son pharmacien à ce sujet. C'est pourquoi l'officinal se doit d'être compétent dans le domaine vétérinaire afin de répondre aux questions les plus couramment posées. Cette thèse aborde en trois parties : la physiologie des chiens et des chats ; les pathologies pouvant être prises en charge à l'officine ; les zoonoses transmises à l'homme. Le pharmacien se doit d'associer le conseil à la délivrance du médicament vétérinaire par une connaissance minimale des pathologies les plus fréquentes. Il constitue également un maillon important dans la prévention et les conseils associés aux zoonoses.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Coherence properties of highly-excited motional states of a trapped ion

We present a study of the coherence properties of a variety of motional states of a single ion confined in a Penning ion trap. We demonstrate that the motion of the ion has a coherence time of the order of 1 s, using Ramsey interferometry. We introduce a technique for preparing the ion in an incoherent superposition of highly-excited motional states using a simple modification of optical sideband cooling. Coherent manipulation of these states allows measurements of optical and motional coherence to be carried out. We show that these highly-excited motional state superpositions have long coherence times despite the incoherent preparation of the states. Such states can be useful for sensitive motional dephasing measurements