Bulletin of the American Physical Society
48th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 62, Number 8
Monday–Friday, June 5–9, 2017; Sacramento, California
Session P3: Rydberg Molecules and PolaronsFocus
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Chair: Tom Killian, Rice University Room: 308 |
Thursday, June 8, 2017 2:00PM - 2:30PM |
P3.00001: Macrodimers and Long-Range Rydberg Molecules Invited Speaker: Johannes Deiglmayr The large polarizability of atoms in highly excited states, so called Rydberg states, leads to strong and long-ranging interactions between such atoms. Interacting pairs of Rydberg atoms represent a very exotic molecular system, characterized by high internal excitation, high density of electronic states, internuclear separations exceeding one micrometer, and lifetimes beyond tens of microseconds. I will discuss the computational methods we have developed to determine the electronic structure of interacting Rydberg-atom pairs [1] and our spectroscopic approaches to verify these calculations.\\ Recently, we could observe the formation of “macrodimers”, vibrational bound states of two interacting Rydberg atoms, which were predicted in 2002 by Boisseau and coworkers [2,3]. I will discuss the employed sequential photoassociation scheme and the validity of the Born-Oppenheimer approximation for these states. \\ In an extended outlook, I will discuss our current and planned experiments towards determining electron-atom-scattering phase shifts from high-resolution spectroscopy of another class of exotic molecules, long-range Rydberg molecules where a Rydberg atom and a ground-state atom located inside the Rydberg orbit are bound to each other [4]. \\ {[1]} J. Deiglmayr, Phys. Scr. 91, 104007 (2016) \\ {[2]} H. Sa{\ss}mannshausen and J. Deiglmayr, Phys. Rev. Lett. 117, 83401 (2016) \\ {[3]} C. Boisseau, I. Simbotin, and R. C{\^o}t{\'e}, Phys. Rev. Lett. 88, 133004 (2002)\\ {[4]} C. H. Greene, A. S. Dickinson, and H. R. Sadeghpour, Phys. Rev. Lett. 85, 2458 (2000) [Preview Abstract] |
Thursday, June 8, 2017 2:30PM - 3:00PM |
P3.00002: Creation of Rydberg Polarons in a Bose Gas Invited Speaker: Richard Schmidt In this talk we review the theory of various types of Bose polarons that can be realized in ultracold atomic systems. We then report the spectroscopic observation of Rydberg polarons in a Bose gas which is in excellent agreement with theoretical predictions [1]. This novel type of polaron is created by excitation of Rydberg atoms in a strontium Bose-Einstein condensate and it is distinguished by the occupation of a large number bound molecular states [2]. The cross-over from few-body bound molecular oligomers to many-body polaron features is described with a functional determinant theory that solves an extended Froehlich Hamiltonian for an impurity in a Bose gas. The detailed analysis of the red-detuned tail of the excitation spectrum describes the contribution from the region of highest density in the condensate and provides a clear signature of Rydberg polarons. This work [1] has been performed in collaboration with groups at Rice University, Harvard University, and the TU Vienna.\\ \newline References:\\ [1] F. Camargo, R. Schmidt, J. D. Whalen, R. Ding, G. Woehl Jr., S. Yoshida, J. Burgd\"{o}rfer, F. B. Dunning, H. R. Sadeghpour, E. Demler, and T. C. Killian, in preparation (2017).\\ [2] R. Schmidt, H. R. Sadeghpour, and E. Demler, Phys. Rev. Lett. 116, 105302 (2016). [Preview Abstract] |
Thursday, June 8, 2017 3:00PM - 3:12PM |
P3.00003: Observation of spin-dependent relativistic effects in ultra-long-range Cs$_{\mathrm{2}}$ Rydberg molecules* Jin Yang, Samuel Markson, Seth Rittenhouse, Richard Schmidt, Hossein Sadeghpour, James Shaffer Recent research reveals spin-dependent relativistic effects play a significant role in the structure of ultra-long-range Rydberg molecules formed by the scattering of an electron from a ground state atom. Spin-dependent relativistic effects lead to striking features in the spectra of these molecules, like mixing between singlet and triplet states. To give a more precise prediction of the spectra, spin-orbit coupling and hyperfine interactions have to be considered. These effects are particularly important for Cs because several prominent, low energy p-wave resonances exist in the electron-ground state atom scattering and cause avoided crossings to occur. We use a Hamiltonian that includes spin-dependent interactions between the Rydberg electron and ground state atoms, to reproduce experimentally measured Cs ultra-long-range Rydberg molecule spectra correlating to the 31D$+$6S, 32D$+$6S, 38D$+$6S and 39D$+$6S asymptotes. Good agreement is found between theory and experiment. New, interesting features in the spectra can be related to the corresponding spin-dependent relativistic effects. [Preview Abstract] |
Thursday, June 8, 2017 3:12PM - 3:24PM |
P3.00004: Anisotropic blockade using pendular Rydberg butterfly molecules Matthew Eiles, Jesus Perez-Rios, Hyunwoo Lee, Chris Greene The photoassociation spectrum of ''butterfly" Rydberg molecules in a weak electric field has been recently observed, revealing that these molecules are, due to their dipole moments and bond lengths, deep in the pendular regime even at small field strengths (~1V/cm) \footnote{ T. Niederpruem, et al. Nat. Commun. 10, 1038 (2016)}. Their properties -- excellent field alignment and orientation, extended charge distributions, and the parameter tunability determined by the Rydberg state -- make these molecules ideal candidates for exploring many-body physics in dipolar gases. We have calculated the long-range interaction between molecules prepared in a quasi-one-dimensional trap; this interaction is dominated at long range by the anisotropic dipole-dipole force. By varying the angle between the applied field and the trap axis, this contribution can be tuned to zero at the magic angle, which presents a clear experimental signature in the density of Rydberg molecules which rises sharply near the magic angle due to the anisotropic excitation ''blockade" mechanism. Verification of these interactions through this straightforward experimental scheme will encourage the use of these molecules to study polaron physics in a mixed system, angulon/pendulon interactions, or crystal phase formation. [Preview Abstract] |
Thursday, June 8, 2017 3:24PM - 3:36PM |
P3.00005: Progress towards long-range Rydberg molecules with \textsuperscript{87}Sr Roger Ding, Joseph Whalen, Francisco Camargo, F. Barry Dunning, Thomas Killian Many recent experiments have probed the interactions between highly-excited Rydberg atoms and nearby ground state atoms, allowing the study of a wide range of phenomena such as few-body, long-range Rydberg molecules in thermal gases\footnote{V. Bendkowsky \textit{et al.}, Nature (London) \textbf{458}, 1005 (2008).}\textsuperscript{,}\footnote{B. J. DeSalvo \textit{et al.}, Phys. Rev. A \textbf{92}, 031403 (2015).} ($\sim 10^{13}\text{cm}^{-3}$) and many-body effects in Bose-Einstein condensates\footnote{M. Schlagmüller \textit{et al.}, Phys. Rev. Lett. \textbf{116}, 053001 (2016).} ($\sim 10^{14}\text{cm}^{-3}$). These experiments have exclusively been performed with bosons. We report our results working with the fermionic isotope \textsuperscript{87}Sr ($I=9/2$) with which one can hope to see modified molecular structure and suppression of short-range collisional loss due to the Pauli exclusion principle. We will describe the spectra for two-photon excitation to the $5sns\,\textsuperscript{3}S\textsubscript{1}$ Rydberg state from a spin-polarized sample and our progress towards obtaining Rydberg molecular spectra. [Preview Abstract] |
Thursday, June 8, 2017 3:36PM - 3:48PM |
P3.00006: ABSTRACT WITHDRAWN |
Thursday, June 8, 2017 3:48PM - 4:00PM |
P3.00007: Free-space microwave-to-optical conversion via six-wave mixing in Rydberg atoms Jingshan Han, Thibault Vogt, Christian Gross, Dieter Jaksch, Martin Kiffner, Wenhui Li The interconversion of millimeter waves and optical fields is an important and highly topical subject for classical and quantum technologies. In this talk, we report an experimental demonstration of coherent and efficient microwave-to-optical conversion in free space via six-wave mixing in Rydberg atoms \footnote{J. Han, T. Vogt, Ch. Gross, D. Jaksch, M. Kiffner, and W. Li, arXiv:1701.07969.}. Our scheme utilizes the strong coupling of millimeter waves to Rydberg atoms as well as the frequency mixing based on electromagnetically induced transparency (EIT) that greatly enhances the nonlinearity for the conversion process. We achieve a free-space conversion efficiency of 0.25\% with a bandwidth of about 4 MHz in our experiment. Optimized geometry and energy level configurations should enable the broadband interconversion of microwave and optical fields with near-unity efficiency. These results indicate the tremendous potential of Rydberg atoms for the efficient conversion between microwave and optical fields, and thus paves the way to many applications. [Preview Abstract] |
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