Bulletin of the American Physical Society
51st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 65, Number 4
Monday–Friday, June 1–5, 2020; Portland, Oregon
Session G06: Formation and Cooling of MoleculesLive
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Chair: Daniel McCarron, University of Connecticut Room: E141-142 |
Wednesday, June 3, 2020 8:00AM - 8:12AM Live |
G06.00001: Developing a quantum gas microscope for NaRb molecules Lysander Christakis, Jason Rosenberg, Geoffrey Zheng, Waseem Bakr The study of many-body physics with ultracold gases has benefited greatly in recent years from quantum gas microscopy, which allows for single particle detection and manipulation of individual atoms within an optical lattice. In parallel, numerous research groups have achieved rapid progress in creating and probing ultracold gases of polar molecules. Here we present our progress towards synthesizing these two research areas via a quantum gas microscope of bosonic NaRb molecules. We currently perform fluorescence imaging of a degenerate rubidium gas in a 2D optical lattice with single site resolution. We are working towards realizing Na/Rb mixtures in our apparatus and preparing NaRb molecules. We will detect the molecules in the lattice by dissociating them and imaging the constituent atoms. Our apparatus also features in-vacuum electrodes for tuning the interactions between the molecules via electric fields which should enable evaporating the molecules to degeneracy and open the door to microscopic studies of strongly dipolar Bose gases. [Preview Abstract] |
Wednesday, June 3, 2020 8:12AM - 8:24AM Live |
G06.00002: Improving the formation of $^{23}$Na$^{40}$K molecules towards degeneracy Andreas Schindewolf, Marcel Duda, Roman Bause, Xing-Yan Chen, Akira Kamijo, Renhao Tao, Immanuel Bloch, Xin-Yu Luo Recently L. De Marco et al. demonstrated the formation of degenerate samples of dipolar KRb molecules [1]. Inspired by this achievement we investigated molecule formation in a double-degenerate mixture of $^{23}$Na and $^{40}$K atoms. By switching from RF association to a magnetic-field sweep over a Feshbach resonance, we can now convert 50% of our Na atoms into NaK molecules and produce samples of up to $5 \times 10^4$ molecules. [1] L. De Marco et al., Science 363, 853 (2019). [Preview Abstract] |
Wednesday, June 3, 2020 8:24AM - 8:36AM Live |
G06.00003: Progress toward ultracold sodium-cesium molecules Aden Lam, Niccolo` Bigagli, Claire Warner, Ian Stevenson, Sebastian Will We present work toward a dipolar quantum gas of sodium-cesium molecules in their ground state. Sodium-cesium has the largest dipole moment of the non-reactive bi-alkali molecules, 4.6 Debye, which promises to enable strongly correlated many-body quantum states. So far, sodium and cesium have not been simultaneously cooled to quantum degeneracy. We present our progress toward overlapping ultracold ensembles of sodium and cesium atoms, which includes the creation of overlapping magneto-optical traps and the development of a simultaneous cooling strategy. Additionally, we report on preliminary studies of interspecies Feshbach resonances between ultracold sodium and cesium atoms which is a key step in creating a molecular quantum gas, including the exploration of a loosely bound molecular state in the closed channel of a Feshbach resonance. [Preview Abstract] |
Wednesday, June 3, 2020 8:36AM - 8:48AM Live |
G06.00004: Towards Direct Laser Cooling of Barium Monofluoride Ralf Albrecht, Marian Rockenhaeuser, Tim Langen We report on the progress of our experiment for the direct laser cooling and trapping of barium monofluoride molecules. Laser cooling of molecules had long been considered impossible due to their complex vibrational and rotational level structure. However, beneficial Franck-Condon factors and selection rules allow for optical cycling in many molecular species, including barium monofluoride. Hot molecules are generated through laser ablation of a pressed pellet inside a cold cell and precooled by collisions with a cold buffer gas of helium atoms. The thermalized gas mixture exits the cell through a few-millimeter-sized aperture and enters a high vacuum region as a cold and intense beam. A careful characterization of this beam and demonstration of optical cycling is presented in [1], which paves the way for the implementation of transversal laser cooling of the beam. The current status of this effort will be presented.\newline [1] R. Albrecht et. al., Phys. Rev. A 101, 013413 (2020) [Preview Abstract] |
Wednesday, June 3, 2020 8:48AM - 9:00AM Live |
G06.00005: Toward efficient YbLi molecule production in a 3d optical lattice Katherine McCormick, Alaina Green, Jun Hui See Toh, Xinxin Tang, Subhadeep Gupta Owing to their potential for tunable, long-range interactions and rich energy-level structure, ultracold molecules are promising platforms for quantum computing, simulation, and metrology. In contrast to many cold molecule experiments, which use bi-alkali systems where the ground state is $^1\Sigma$, the YbLi molecule has a $^2\Sigma$ ground state; this introduces an electronic spin degree of freedom, which could prove useful for quantum information applications or for studies of spin-controlled chemistry. After a comprehensive study of magnetic Feshbach resonances between Yb and Li [1], including their spin and temperature dependence, we are now well positioned to produce YbLi molecules through magnetoassociation. I will describe ongoing efforts to this end, including integrating a three-dimensional optical lattice and stabilizing the magnetic field. \newline [1] A. Green, et al., arXiv:1912.04874 [Preview Abstract] |
Wednesday, June 3, 2020 9:00AM - 9:12AM Live |
G06.00006: Extension of opto-electric Sisyphus cooling to diatomic and polyatomic radicals Manuel Koller, Isabel M. Rabey, Martin Zeppenfeld, Gerhard Rempe Opto-electric Sisyphus cooling is a powerful technique which allows direct cooling of polyatomic molecules to the ultracold regime [1,2]. Taking advantage of the strong interaction between a molecule's dipole moment and an external field allows cooling over several orders of magnitude in temperature by cycling only a few dozen photons. In this talk we demonstrate the possibility to extend this cooling scheme to a broad range of molecular radicals. This includes diatomic radicals with Lambda doubling in the ground state and linear molecules in an excited vibrational bending mode. We will present details of the cooling scheme for individual molecules such as CH, possible with only three lasers. [1] Zeppenfeld et al., Nature 91, 570--573 (2012) [2] Prehn et al., PRL 116, 063005 (2016) [Preview Abstract] |
Wednesday, June 3, 2020 9:12AM - 9:24AM Live |
G06.00007: Progress towards a 3D MOT of CaOH Debayan Mitra, Louis Baum, Nathanial Vilas, Christian Hallas, Shivam Raval, John Doyle Laser cooling and evaporative cooling are the workhorse techniques that have revolutionized the control of atomic systems. In recent years the magneto-optical trap (MOT) has been successfully adapted to several diatomic molecules. We now seek to broaden these successes by extending the MOT to polyatomic molecules. The vibrational and rotational structure of polyatomic molecules generically gives rise to complexities in optical cycling, but also to useful closely spaced opposite parity levels in low lying excited states with orbital angular momentum along the internuclear axis. These parity doublets allow full polarization at low electric fields, a significant advantage for a range of applications such as precision measurement [1], quantum computation [2] and quantum simulation [3]. With calcium monohydroxide molecules (CaOH) we have very recently demonstrated an optical cycling scheme efficient enough for optical cooling and a one-dimensional MOT. Data from that work allowed us to quantitatively predict for CaOH the capture velocity $v_{\mathrm{CaOH}}$ \textasciitilde 7 m/s for a 3D MOT [4]. Here we present our progress with CaOH towards achieving $v_{\mathrm{CaOH}}$ in a cryogenic buffer-gas beam [5] and the loading of a 3D MOT. [1] Kozyryev and Hutzler, PRL 119, 133002 (2017) [2] Yu et. al, New J. Phys. 21, 093049 (2019) [3] Wall et. al, New J. Phys. 17, 025001 (2015) [4] Baum et. al, arXiv 2001.10525 [5] Hutzler et. al. Chem. Rev. 112, \textbf{9} 4803 (2012) [Preview Abstract] |
Wednesday, June 3, 2020 9:24AM - 9:36AM Live |
G06.00008: Laser-Coolable Asymmetric Top Molecules Benjamin Augenbraun, Ivan Kozyryev, Timothy Steimle, Tanya Zelevinsky, John Doyle We present a practical roadmap to laser cool asymmetric top molecules, including chiral species [1]. We analyze how the complex rotational and vibrational structure, and the generally relaxed selection rules, affect optical cycling in these species. A diverse class of asymmetric top molecules is identified which can be laser cooled effectively with reasonable experimental complexity. We present vibrational branching ratio measurements for CaSH and CaNH2, two prototypical members of this class of molecules. In addition, calculations of vibrational branching ratios show that over a dozen isoelectronic species are highly favorable for laser cooling. As part of this analysis, we describe methods to achieve rotationally closed optical cycles in these molecules. Potential scientific impacts of these species span frontiers in controlled chemistry, quantum simulation, and searches for physics beyond the Standard Model. [1] B. L. Augenbraun, J. M. Doyle, T. Zelevinsky, and I. Kozyryev, arXiV:2001.11020 (2020) [Preview Abstract] |
Wednesday, June 3, 2020 9:36AM - 9:48AM On Demand |
G06.00009: Singlet Pathway to the Ground State of Ultracold Polar Molecules Sofia Botsi, Anbang Yang, Sunil Kumar, Sambit B. Pal, Mark M. Lam, Ieva Cepaite, Andrew Laugharn, Kai Dieckmann We demonstrate a two-photon pathway to the ground state of $^{\mathrm{6}}$Li$^{\mathrm{40}}$K molecules that involves only singlet-to-singlet optical transitions. We start from a molecular state which contains a significant admixture from the singlet ground state potential by selecting the Feshbach resonance for molecule association. With the only contributing singlet state to the molecular state being fully stretched and with control over the lasers polarization we address a sole hyperfine component of the excited A$^{\mathrm{1}}\Sigma^{\mathrm{+}}$ potential without resolving its hyperfine structure. This scheme ensures access to only one ground state hyperfine component with sufficient Franck-Condon factors and moderate laser powers for both coupling transitions. Its implementation results in large and balanced Rabi frequencies, a favorable condition for the coherent transfer to the ground state. We perform dark resonance spectroscopy to precisely determine the transition frequencies of the states involved. The strong dipolar nature of $^{\mathrm{6}}$Li$^{\mathrm{40}}$K is revealed by Stark spectroscopy, as it is necessary for the study of dipolar interactions in an optical lattice. [Preview Abstract] |
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