21 research outputs found

    Zeeman Relaxation of Cold Atomic Iron and Nickel in Collisions with 3He

    Get PDF
    We have measured the ratio of the diffusion cross-section to the angular momentum reorientation cross-section in the colliding Fe-3He and Ni-3He systems. Nickel (Ni) and iron (Fe) atoms are introduced via laser ablation into a cryogenically cooled experimental cell containing cold (< 1 K) 3He buffer gas. Elastic collisions rapidly cool the translational temperature of the ablated atoms to the helium temperature. The cross-section ratio is extracted by measuring the decays of the atomic Zeeman sublevels. For our experimental conditions, thermal energy is comparable to the Zeeman splitting. As a result, thermal excitations between Zeeman sublevels significantly impact the observed decay. To determine the cross-section ratio accurately, we introduce a model of Zeeman state dynamics that includes thermal excitations. We find the cross-section ratio for Ni-3He = 5 x 10^3 and Fe-3He <= 3 x 10^3 at 0.75 K in a 0.8 T magnetic field. These measurements are interpreted in the context of submerged shell suppression of spin relaxation as studied previously in transition metals and rare earth atoms.Comment: 10 pages, 5 figures; submitted to Phys. Rev.

    Ponderomotive light squeezing with atomic cavity optomechanics

    Full text link
    Accessing distinctly quantum aspects of the interaction between light and the position of a mechanical object has been an outstanding challenge to cavity-optomechanical systems. Only cold-atom implementations of cavity optomechanics have indicated effects of the quantum fluctuations in the optical radiation pressure force. Here we use such a system, in which quantum photon-number fluctuations significantly drive the center of mass of an atomic ensemble inside a Fabry-Perot cavity. We show that the optomechanical response both amplifies and ponderomotively squeezes the quantum light field. We also demonstrate that classical optical fluctuations can be attenuated by 26 dB or amplified by 20 dB with a weak input pump power of < 40 pW, and characterize the optomechanical amplifier's frequency-dependent gain and phase response in both the amplitude and phase-modulation quadratures

    Formation and dynamics of van der Waals molecules in buffer-gas traps

    Full text link
    We show that weakly bound He-containing van der Waals molecules can be produced and magnetically trapped in buffer-gas cooling experiments, and provide a general model for the formation and dynamics of these molecules. Our analysis shows that, at typical experimental parameters, thermodynamics favors the formation of van der Waals complexes composed of a helium atom bound to most open-shell atoms and molecules, and that complex formation occurs quickly enough to ensure chemical equilibrium. For molecular pairs composed of a He atom and an S-state atom, the molecular spin is stable during formation, dissociation, and collisions, and thus these molecules can be magnetically trapped. Collisional spin relaxations are too slow to affect trap lifetimes. However, helium-3-containing complexes can change spin due to adiabatic crossings between trapped and untrapped Zeeman states, mediated by the anisotropic hyperfine interaction, causing trap loss. We provide a detailed model for Ag3He molecules, using ab initio calculation of Ag-He interaction potentials and spin interactions, quantum scattering theory, and direct Monte Carlo simulations to describe formation and spin relaxation in this system. The calculated rate of spin-change agrees quantitatively with experimental observations, providing indirect evidence for molecular formation in buffer-gas-cooled magnetic traps.Comment: 20 pages, 13 figure

    Nathan Ukalović, klarinet : drugi dio diplomskog ispita

    No full text
    Drugi dio diplomskog ispita Nathana Ukalovića (klarinet), studenta Muzičke akademije u Zagrebu. Ispit je održan na Muzičkoj akademiji u dvorani "Stančić" 30.9.2021. Klavirska pratnja: Marina Matolić; mentor: Davor Reba. Program: 1. Gioacchino Rossini: Introdukcija, tema i varijacije za klarinet i orkestar; 2. Jörg Widmann: Fantasie; 3. Johannes Brahms: Sonata za klarinet op. 120, br. 2

    Concerto en ré majeur : pour violon et orchestre Op. 77 / Johannes Brahms ; Nathan Milstein et The Pittsburgh Symphony; Orchestra dir. William Steinberg

    No full text
    Titre uniforme : [Concertos. Violon, orchestre. Op. 77. Ré majeur]BnF-Partenariats, Collection sonore - BelieveContient une table des matière
    corecore