Bulletin of the American Physical Society
42nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 56, Number 5
Monday–Friday, June 13–17, 2011; Atlanta, Georgia
Session P6: Few-body Ultracold Systems |
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Chair: Doerte Blume, Washington State University Room: A706 |
Thursday, June 16, 2011 2:00PM - 2:30PM |
P6.00001: New results on Efimov physics and the creation of RbCs molecules Invited Speaker: I will present new results from two different experiments on ultracold gases, both based on scattering length tunability near Feshbach resonances. In a first experiment, we investigate universal few-body physics with ultracold cesium atoms. We detect various Efimov states in a magnetic field range up to 1000G by measuring loss resonances in three-body recombination processes [1]. We find in total five distinct Efimov resonances in the same spin channel, all resulting from different Feshbach resonances. Surprisingly, all Efimov resonances occur at the same value of the scattering length, which points to universality across all Feshbach resonances and rules out a significant variation of the three-body parameter. In a second experiment, we produce a degenerate or near-degenerate ultracold mixture of $^{87}$Rb and $^{133}$Cs atoms [2]. We investigate the interspecies scattering properties by Feshbach spectroscopy and we determine the background inter-species scattering length to be unusually large and positive. Starting with magneto-associated Feshbach molecules, we perform spectroscopic measurements on the two-photon optical transition that will serve to transfer RbCs molecules to the rovibronic ground state via a STIRAP transfer scheme [3]. This work constitutes a first step towards the production of a quantum gas of ground-state polar molecules. \\[4pt] [1] M. Berninger, A. Zenesini, B. Huang, H.-C. N\"agerl, F. Ferlaino, R. Grimm, P. Julienne, J. Hutson, to be published.\\[0pt] [2] A. D. Lercher, T. Takekoshi, M. Debatin, B. Schuster, R. Rameshan, F. Ferlaino, R. Grimm, H.-C. N\"agerl, arXiv:1101.1409.\\[0pt] [3] M. Debatin, T. Takekoshi, R. Rameshan, L. Reichs\"ollner, F. Ferlaino, R. Grimm, H.-C. N\"agerl, to be published. [Preview Abstract] |
Thursday, June 16, 2011 2:30PM - 3:00PM |
P6.00002: Coherent Transfer of Photoassociated Molecules into the Rovibrational Ground State Invited Speaker: Recently, there have been impressive advances in methods of creating ultracold molecules from ultracold atomic gases. One of the key technologies used there is Stimulated Raman Adiabatic Passage (STIRAP), which has been successfully used for transferring Feshbach molecules into the rovibrational ground state. Since STIRAP relies on quantum coherence, it is unclear if STIRAP is also useful for non-polarized sample, like photo-associated molecules in a magneto-optical trap. Here we report on the SITRAP transfer of weakly bound molecules produced by photoassociation (PA). Laser cooled 41K and 87Rb atoms were first photo-associated into loosely-bound molecules in the X$^{1}\Sigma $ potential. Using v=41, J=1 level in the (3)$^{1}\Sigma $ potential as an intermediate level, we succeeded in transferring molecules in the v=91, J=0 level into the absolute ground state (X$^{1}\Sigma $, v=0, N=0). High-resolution spectroscopy based on the coherent transfer revealed the hyperfine structure of both weakly-bound and tightly-bound molecules. Our results show that a pure sample of ultracold ground-state molecules is achieved via the all-optical association of laser-cooled atoms, opening possibilities to coherently manipulate a wide variety of molecules.\\[4pt] In collaboration with Kiyotaka Aikawa, Kohei Oasa, University of Tokyo; Masahito Ueda, University of Tokyo, JST, ERATO; Jun Kobayashi, University of Tokyo; and Tetsuo Kishimoto, University of Electro-Communications. [Preview Abstract] |
Thursday, June 16, 2011 3:00PM - 3:30PM |
P6.00003: Probing universal few-body dynamics Invited Speaker: Almost 40 years ago, Vitaly Efimov predicted a much debated set of universal weakly-bound three-body states. In recent years, many of his predictions have been confirmed and expanded upon including the first measurements of geometric scaling in three-body systems and the prediction and observation of associated four-body states. In this talk I will discuss recent theoretical developments in three-body dynamics that can be used to probe Efimov trimers. First, the dependence of the three-body recombination rate constant on the binding energy of deeply-bound dimer states will be presented. This dependence can modify the width of resonances associated with Efimov trimers. Alternatively, measurement of losses due to three-body recombination can be used to probe the behavior of deeply bound dimers. New theoretical results in RF association of universal trimers will also be presented. The simple golden rule based methods used can easily be extended to describe the association rates observed in new experiments in three-component fermionic gases. [Preview Abstract] |
Thursday, June 16, 2011 3:30PM - 4:00PM |
P6.00004: Efimov physics and more: the ultracold few-body problem Invited Speaker: Few-body physics has seen a few rather dramatic experimental realizations of long-predicted Efimov physics in the last five years. These successes have come thanks to the unprecedented control that ultracold atomic gases afford for few-body systems. We have made considerable progress in understanding the universal aspects of these ultracold few-body collisions. The experiments, however, have not yet been carried out in a fully universal regime. I will discuss some of my group's efforts to understand how the usual universal inelastic rate constant expressions must be modified in this case. We have also begun to look in new directions for signatures of the Efimov effect and find it quite pervasive --- appearing, for instance, in the four-body problem and in optical lattices. Moreover, we have identified surprising new few-body effects beyond Efimov's that might also be accessible in ultracold experiments. [Preview Abstract] |
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