Bulletin of the American Physical Society
49th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting
Volume 63, Number 5
Monday–Friday, May 28–June 1 2018; Ft. Lauderdale, Florida
Session J08: Ultracold Mixtures |
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Chair: Frederic Chevy, Kastler Brossel Room: Grand F |
Wednesday, May 30, 2018 10:30AM - 10:42AM |
J08.00001: Towards the realization of Ba$+$ and Li quantum mixture Elia Perego, Amelia Detti, Lucia Duca, Massimo Inguscio, Carlo Sias Ultracold atoms and trapped ions are among the most studied physical systems in experimental quantum physics. On the one hand, ultracold neutral atoms form coherent ensembles of particles whose interactions, dimensionality and motion can be precisely controlled. On the other hand, trapped ions form cold crystals in which the Coulomb repulsion ensures a relatively large inter-particle separation, making it possible to address each single ion in a crystal. Quantum mixtures of ultracold atoms and trapped ions combine the advantages of the two techniques in a single experimental apparatus, and offer the possibility of using atom-ion interactions, which are approximately two orders of magnitude longer-ranged than atom-atom interactions, for the realization of new experiments in quantum simulation, quantum computation and controlled chemistry. We are currently setting up a novel apparatus for the realization of a quantum mixture of ultracold Lithium atoms and Barium ions. This setup, which aims at the realization of a coherent atom-ion mixture, is formed by a hybrid trap made of an ion trap within which ultracold atoms can be trapped either optically or magnetically. We will show the technological improvements and progress made so far in our experimental setup, which represent the first ion trapping experiment in Italy. Finally, we will give an overview of the experiments we will pursue with this setup. [Preview Abstract] |
Wednesday, May 30, 2018 10:42AM - 10:54AM |
J08.00002: Quantum Dynamics of the Ultracold LiNa + Li Chemical Reaction J. F. E. Croft, M. Li, H. Li, A. Petrov, B. K. Kendrick, N. Balakrishnan, S. Kotochigova Ultracold gases of polar molecules present an opportunity to examine chemical reactions with unprecedented control and precision. Chemical reactions involving KRb+KRb and K+KRb systems have been experimentally studied and their rates have been shown to be universal in nature. The LiNa molecule being the lightest heteronuclear polar molecule comprised of alkali metal atoms is of current experimental interest, in part because its chemical reaction with Li atom leading to Li$_2$+Na is expected to exhibit non-universal behavior. Here, we report explicit quantum dynamics of the Li+LiNa$\to$Li$_2$+Na reaction with full ro-vibrational product state resolution. We will discuss how three-body forces influence the reactivity and also explore non-adiabatic effects on the reaction dynamics. [Preview Abstract] |
Wednesday, May 30, 2018 10:54AM - 11:06AM |
J08.00003: Ultracold Triplet Ground State NaLi Molecules Hyungmok Son, Timur Rvachov, Juliana Park, Martin Zwierlein, Alan Jamison, Wolfgang Ketterle Ultracold heteronuclear molecules offer a unique platform for the study of many-body physics, quantum information processing, and chemistry at the quantum level. For this purpose, diatomic molecules in the absolute, singlet ground state have been created with various combinations of alkali atoms. Ultracold, fermionic NaLi molecules in the triplet ground have a long collisional lifetime and both electric and magnetic dipole moments. Therefore, by varying the strength and the relative orientation of the electric and magnetic fields applied to the molecules, we will be able to study novel spin lattice Hamiltonians and controlled molecular and atom-molecule collisions. We will report the results of our recent experiments with triplet ground state NaLi molecules, which are produced through STIRAP from magnetically-associated weakly-bound molecules. [Preview Abstract] |
Wednesday, May 30, 2018 11:06AM - 11:18AM |
J08.00004: Single and two photon spectroscopy of ultracold dipolar $^{\mathrm{6}}$Li-$^{\mathrm{40}}$K molecules Anbang Yang, Sofia Botsi, Sunil Kumar, Anbangkai Dieckmann, Mark Lam, Andrew Laugharn Ultracold heteronuclear dimers of $^{\mathrm{6}}$Li-$^{\mathrm{40}}$K, in their deeply-bound ro-vibronic states possess a large electric dipole moment. This makes them a suitable candidate for investigating long-range anisotropic dipole-dipole interactions. Starting from a sympathetically-cooled, quantum-degenerate mixture of $^{\mathrm{6}}$Li and $^{\mathrm{40}}$K, we create weakly-bound $^{\mathrm{6}}$Li-$^{\mathrm{40}}$K molecules via a magnetic-Feshbach association with a sole singlet admixture. High-resolution laser spectroscopy of the electronically-excited $B^{1}\Pi $ and $A{ }^{1}\Sigma $ potentials of $^{\mathrm{6}}$Li-$^{\mathrm{40}}$K Feshbach molecules is performed to identify intermediate vibrational states suitable for coherent Raman transfer to the electronic ground state. Subsequently, Autler-Townes spectroscopy is performed to investigate the deeply-bound ro-vibrational levels of the electronic ground state of $^{\mathrm{6}}$Li-$^{\mathrm{40}}$K molecules. Results of the single and two-photon molecular spectroscopy are presented in this talk. [Preview Abstract] |
Wednesday, May 30, 2018 11:18AM - 11:30AM |
J08.00005: Orientation-resolved imaging of rotational superposition states in ultracold LiRb Ian Stevenson, Dan Elliott We present work toward coherent detection and imaging of rotational superposition states in ultracold lithium-rubidium. Starting from $X \ ^1\Sigma^+ v = 43$, $J = 0$, populated by photoassociation in a dual species MOT, we apply a RF pulse to form a $J = 0/J = 1$ superposition state. The molecules are ionized by a frequency comb source whose repetition rate is phase coherent with the RF field. We present spectra highlighting a 3-photon doubly-resonant ionizing transition starting from $X \ ^1\Sigma^+ v = 43$, $J = 0$ and $X \ ^1\Sigma^+ v = 43$, $J = 1$ as well as preliminary results toward orientation-resolved imaging of the superposition state. [Preview Abstract] |
Wednesday, May 30, 2018 11:30AM - 11:42AM |
J08.00006: Towards quantum-state-resolved ultracold chemical reactions of KRb molecules Ming-Guang Hu, Yu Liu, Andrei Gheorghe, Yen-Wei Lin, David Grimes, Kang-Kuen Ni Ultracold atoms and molecules provide a new platform to explore chemical reactions at ultralow temperatures. In this regime, reactions that are unlikely to happen classically could proceed surprisingly efficiently due to their quantum mechanical nature. We are investigating a likely~4-center reaction, 2KRb-\textgreater K2$+$Rb2$+$KE(1.24 meV), in the temperature regime below 1 micro-Kelvin. Towards this goal, we have built an apparatus that combines AMO techniques for ultracold reagent preparation and physical chemistry techniques for reaction product detection through resonance enhanced multiphoton ionization (REMPI) and velocity-map imaging (VMI). The micro-eV sensitivity of our VMI also provides a new tool to study ultracold Rydberg chemical reactions and few-body collisions. [Preview Abstract] |
Wednesday, May 30, 2018 11:42AM - 11:54AM |
J08.00007: Enhancing the trap density of hydroxyl radicals with skimmer cooling Hao Wu, Dave Reens, Tim Langen, Yuval Shagam, Daniela Fontecha, Jun Ye The large density and low temperature offered by supersonic expansions of molecular beams have enabled groundbreaking development in precision spectroscopy, chemical reaction kinetics, molecular dynamics, and so on. However, beam attenuation due to skimmer interference generally limits the beam density that can be realized. It was recently shown that skimmer cryocooling could suppress shockwaves involved in skimmer interference (Segev et al, Sci. Adv. 2017,\textbf{3}, e1602258). We have applied the skimmer cooling technique to hydroxyl radicals and perform for the first time a direct comparison between a cold skimmer and a state of the art room temperature skimmer. Our comparison reveals a 30-fold density enhancement for hydroxyl radicals. By combining the cooled skimmer with a downstream stark decelerator and quadrupole magnetic trap, we will be able to increase the trapping density to further study collisional effects between radicals. [Preview Abstract] |
Wednesday, May 30, 2018 11:54AM - 12:06PM |
J08.00008: Isotopic effects in Rb$_2$ molecules formed by Rydberg- and ground-state atoms Jamie MacLennan, Yun-Jhih Chen, Georg Raithel The scattering interaction of a Rydberg electron with a ground-state atom can form bound molecular states. Measurement of these binding energies may help refine calculations of electron-atom scattering phase shifts. We report spectroscopic measurements of the molecular binding energies of Rb(24D$_J$ + 5S$_{1/2}$). Dense samples of cold atoms are prepared in a high-intensity optical lattice formed in an in-vacuum near-concentric optical cavity. The molecules are excited via a two-step laser excitation, and analyzed via counting of ions generated by photoionization and molecular decay. We observe molecular states with binding energies up to 430 MHz, with sub-percent relative uncertainty. We show and discuss binding-energy variance by isotope and hyperfine level of the ground-state atom, and by the J-value of the Rydberg level. Isotopic hyperfine-coupling effects on the molecular vibrational energy arise from the different I-values and the different masses of the Rb isotopes. [Preview Abstract] |
Wednesday, May 30, 2018 12:06PM - 12:18PM |
J08.00009: Cold chemistry of a single ion in highly dense media: from three-body recombination to molecular photodissociation Jes\'{u}s P\'{e}rez-R\'{i}os, Amir Mohammadi, Artjom Kr\"{u}kow, Johannes Hecker Denschlag, Humberto da Silva Jr., Olivier Dulieu A single laser cooled Ba$^{+}$ ion is brought in contact with a dense ultracold cloud of Rb atoms held by a dipole trap, leading to molecular formation through three-body recombination. However, the presence of light opens up new and intriguing reaction pathways rendering unexpected reaction products. These novel products are theoretically explained as a consequence of a very efficient vibrational quenching mechanism followed by photodissociation of the molecular ion by the light coming from the atomic dipole trap. Our findings, both theoretical and experimental will help to understand the role of light in cold chemistry experiments and how it limits sympathetic cooling of molecular ions. [Preview Abstract] |
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