Bulletin of the American Physical Society
2013 Joint Meeting of the APS Division of Atomic, Molecular & Optical Physics and the CAP Division of Atomic, Molecular & Optical Physics, Canada
Volume 58, Number 6
Monday–Friday, June 3–7, 2013; Quebec City, Canada
Session U1: Hot Topics |
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Chair: Linda Young, Argonne National Laboratory Room: 200A |
Friday, June 7, 2013 10:30AM - 11:00AM |
U1.00001: Using the Earth as a Polarized Electron Source to Search for Long-Range Spin-Spin Interactions Invited Speaker: Larry Hunter Many extensions of the standard model of particle physics predict the existence of long-range spin-spin interactions. We have developed an approach which uses the Earth as a polarized spin source to investigate these interactions. We combine recent deep-Earth geophysics and geochemistry results with precise tabulations of the geomagnetic field to create a comprehensive map of electron polarization within the Earth. We examine possible long-range interactions between these spin-polarized geoelectrons and the spin-polarized electrons and nucleons in three laboratory experiments. By combining our model and the results from these experiments we establish new stringent bounds on torsion gravity and possible long-range spin-spin forces associated with the virtual exchange of either spin-one axial bosons or unparticles. The resulting bound on the spin-spin force between an electron and a neutron is one million times smaller than their gravitational attraction. [Preview Abstract] |
Friday, June 7, 2013 11:00AM - 11:30AM |
U1.00002: All-optical switch and transistor gated by one photon Invited Speaker: Vladan Vuletic The realization of an all-optical transistor where one `gate' photon controls a `source' light beam, is a long-standing goal in optical science. By slowing and stopping a light pulse in an atomic ensemble contained inside an optical resonator, we realize a device in which one stored gate photon controls the resonator transmission and reflection of subsequently applied source photons. More than 1000 source photons can be switched by just one stored gate photon. If retrieval of the stored gate photon is required, more than two source photons can be switched. [Preview Abstract] |
Friday, June 7, 2013 11:30AM - 12:00PM |
U1.00003: Direct measurement of the van der Waals interaction between two Rydberg atoms Invited Speaker: Thierry Lahaye This talk will report on the direct measurement of the van der Waals interaction between two isolated, single Rydberg atoms separated by a controlled distance of a few micrometers. By working in a regime where the single-atom Rabi frequency of the laser used for excitation to the Rydberg state is comparable to the interaction energy, we observe a partial Rydberg blockade, whereby the time-dependent populations of the various two-atom states exhibit coherent oscillations with several frequencies. A quantitative comparison of the data with a simple model based on the optical Bloch equations allows us to extract the van der Waals energy, and to observe its characteristic C6 /R6 dependence. The magnitude of the measured C6 coefficient agrees well with ab-initio calculations, and we observe its dramatic increase with the principal quantum number n of the Rydberg state. Our results demonstrate a good degree of experimental control, which opens interesting perspectives in quantum information processing and quantum simulation using long-range interactions between atoms. [Preview Abstract] |
Friday, June 7, 2013 12:00PM - 12:30PM |
U1.00004: Laser cooling to quantum degeneracy1 Invited Speaker: Florian Schreck We have created Bose-Einstein condensates (BECs) of strontium using laser cooling as the only cooling method [1]. Our scheme is based on the combination of three techniques, favored by the properties of this element. Using a narrow intercombination transition, we prepare a laser cooled sample of 107 84Sr atoms in a large “reservoir” dipole trap at a phase-space density of ~0.1. Further increase of the phase-space density has formerly been hindered by detrimental effects of the laser cooling photons, such as an effective repulsion between atoms by multiple scattering. To avoid these effects, we render atoms transparent for these photons in a small spatial region within the laser cooled cloud. Transparency is induced by a light shift on the optically excited state of the laser cooling transition. In the region of transparency, we are able to increase the density of the gas by accumulating atoms in a small “dimple” dipole trap. Atoms in the dimple thermalize with the reservoir of laser-cooled atoms by elastic collisions and form a BEC. Condensates of up to 105 atoms can be repeatedly formed on a timescale of 100 ms. Our method opens new prospects for the generation of a continuous atom laser. [1] Stellmer et al., arXiv:1301.4776 (2013). 1This work was supported by the Austrian Science Fund (FWF Project No. Y507-N20) and the European Commission (FET-Open Grant No. 250072). 2In collaboration with Simon Stellmer, Benjamin Pasquiou, and Rudolf Grimm (IQOQI, OEAW and Institute for Experimental Physics & Center for Quantum Physics, University of Innsbruck). [Preview Abstract] |
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