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Quéméner G, Bohn JL, Croft JFE. Electroassociation of Ultracold Dipolar Molecules into Tetramer Field-Linked States. PHYSICAL REVIEW LETTERS 2023; 131:043402. [PMID: 37566851 DOI: 10.1103/physrevlett.131.043402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 08/13/2023]
Abstract
The presence of electric or microwave fields can modify the long-range forces between ultracold dipolar molecules in such a way as to engineer weakly bound states of molecule pairs. These so-called field-linked states [A. V. Avdeenkov and J. L. Bohn, Phys. Rev. Lett. 90, 043006 (2003).PRLTAO0031-900710.1103/PhysRevLett.90.043006; L. Lassablière and G. Quéméner, Phys. Rev. Lett. 121, 163402 (2018).PRLTAO0031-900710.1103/PhysRevLett.121.163402], in which the separation between the two bound molecules can be orders of magnitude larger than the molecules themselves, have been observed as resonances in scattering experiments [X.-Y. Chen et al., Nature (London) 614, 59 (2023).NATUAS0028-083610.1038/s41586-022-05651-8]. Here, we propose to use them as tools for the assembly of weakly bound tetramer molecules, by means of ramping an electric field, the electric-field analog of magnetoassociation in atoms. This ability would present new possibilities for constructing ultracold polyatomic molecules.
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Affiliation(s)
- Goulven Quéméner
- Université Paris-Saclay, CNRS, Laboratoire Aimé Cotton, 91405 Orsay, France
| | - John L Bohn
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
| | - James F E Croft
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand and Department of Physics, University of Otago, Dunedin 9054, New Zealand
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2
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Devolder A, Tscherbul TV, Brumer P. Coherent Control of Ultracold Molecular Collisions: The Role of Resonances. J Phys Chem Lett 2023; 14:2171-2177. [PMID: 36808981 DOI: 10.1021/acs.jpclett.3c00146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We consider the coherent control of ultracold molecule-molecule scattering, impacted by a dense set of rovibrational resonances. To characterize the resonance spectrum, a rudimentary model based on multichannel quantum defect theory has been used to study the control of the scattering cross section and the reaction rate. Complete control around resonance energies is shown to be possible, but thermal averaging over a large number of resonances significantly reduces the extent of control of reaction rates related to the random distribution of optimal control parameters between resonances. We show that measuring the extent of coherent control could be used to extract meaningful information about the relative contribution of direct scattering versus collision complex formation, as well as about the statistical regime.
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Affiliation(s)
- Adrien Devolder
- Chemical Physics Theory Group, Department of Chemistry, and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, United States of America
| | - Paul Brumer
- Chemical Physics Theory Group, Department of Chemistry, and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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3
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Schindewolf A, Bause R, Chen XY, Duda M, Karman T, Bloch I, Luo XY. Evaporation of microwave-shielded polar molecules to quantum degeneracy. Nature 2022; 607:677-681. [PMID: 35896646 PMCID: PMC9329123 DOI: 10.1038/s41586-022-04900-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 05/24/2022] [Indexed: 11/11/2022]
Abstract
Ultracold polar molecules offer strong electric dipole moments and rich internal structure, which makes them ideal building blocks to explore exotic quantum matter1–9, implement quantum information schemes10–12 and test the fundamental symmetries of nature13. Realizing their full potential requires cooling interacting molecular gases deeply into the quantum-degenerate regime. However, the intrinsically unstable collisions between molecules at short range have so far prevented direct cooling through elastic collisions to quantum degeneracy in three dimensions. Here we demonstrate evaporative cooling of a three-dimensional gas of fermionic sodium–potassium molecules to well below the Fermi temperature using microwave shielding. The molecules are protected from reaching short range with a repulsive barrier engineered by coupling rotational states with a blue-detuned circularly polarized microwave. The microwave dressing induces strong tunable dipolar interactions between the molecules, leading to high elastic collision rates that can exceed the inelastic ones by at least a factor of 460. This large elastic-to-inelastic collision ratio allows us to cool the molecular gas to 21 nanokelvin, corresponding to 0.36 times the Fermi temperature. Such cold and dense samples of polar molecules open the path to the exploration of many-body phenomena with strong dipolar interactions. A general and efficient approach to evaporatively cool ultracold polar molecules through elastic collisions to create a degenerate quantum gas in three dimensions is demonstrated using microwave shielding.
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Affiliation(s)
- Andreas Schindewolf
- Max-Planck-Institut für Quantenoptik, Garching, Germany.,Munich Center for Quantum Science and Technology, Munich, Germany
| | - Roman Bause
- Max-Planck-Institut für Quantenoptik, Garching, Germany.,Munich Center for Quantum Science and Technology, Munich, Germany
| | - Xing-Yan Chen
- Max-Planck-Institut für Quantenoptik, Garching, Germany.,Munich Center for Quantum Science and Technology, Munich, Germany
| | - Marcel Duda
- Max-Planck-Institut für Quantenoptik, Garching, Germany.,Munich Center for Quantum Science and Technology, Munich, Germany
| | - Tijs Karman
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - Immanuel Bloch
- Max-Planck-Institut für Quantenoptik, Garching, Germany.,Munich Center for Quantum Science and Technology, Munich, Germany.,Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany
| | - Xin-Yu Luo
- Max-Planck-Institut für Quantenoptik, Garching, Germany. .,Munich Center for Quantum Science and Technology, Munich, Germany.
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Koller M, Jung F, Phrompao J, Zeppenfeld M, Rabey IM, Rempe G. Electric-Field-Controlled Cold Dipolar Collisions between Trapped CH_{3}F Molecules. PHYSICAL REVIEW LETTERS 2022; 128:203401. [PMID: 35657871 DOI: 10.1103/physrevlett.128.203401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/21/2022] [Indexed: 06/15/2023]
Abstract
Reaching high densities is a key step toward cold-collision experiments with polyatomic molecules. We use a cryofuge to load up to 2×10^{7} CH_{3}F molecules into a boxlike electric trap, achieving densities up to 10^{7}/cm^{3} at temperatures around 350 mK where the elastic dipolar cross section exceeds 7×10^{-12} cm^{2}. We measure inelastic rate constants below 4×10^{-8} cm^{3}/s and control these by tuning a homogeneous electric field that covers a large fraction of the trap volume. Comparison to ab initio calculations gives excellent agreement with dipolar relaxation. Our techniques and findings are generic and immediately relevant for other cold-molecule collision experiments.
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Affiliation(s)
- M Koller
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - F Jung
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - J Phrompao
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - M Zeppenfeld
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - I M Rabey
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - G Rempe
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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Devolder A, Brumer P, Tscherbul TV. Complete Quantum Coherent Control of Ultracold Molecular Collisions. PHYSICAL REVIEW LETTERS 2021; 126:153403. [PMID: 33929238 DOI: 10.1103/physrevlett.126.153403] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/09/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
We show that quantum interference-based coherent control is a highly efficient tool for tuning ultracold molecular collision dynamics that is free from the limitations of commonly used methods that rely on external electromagnetic fields. By varying the relative populations and phases of initial coherent superpositions of degenerate molecular states, we demonstrate complete coherent control over integral scattering cross sections in the ultracold s-wave regime of both the initial and final collision channels. The proposed control methodology is applied to ultracold O_{2}+O_{2} collisions, showing extensive control over s-wave spin-exchange cross sections and product branching ratios over many orders of magnitude.
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Affiliation(s)
- Adrien Devolder
- Chemical Physics Theory Group, Department of Chemistry, and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Paul Brumer
- Chemical Physics Theory Group, Department of Chemistry, and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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Matsuda K, De Marco L, Li JR, Tobias WG, Valtolina G, Quéméner G, Ye J. Resonant collisional shielding of reactive molecules using electric fields. Science 2021; 370:1324-1327. [PMID: 33303614 DOI: 10.1126/science.abe7370] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/09/2020] [Indexed: 11/03/2022]
Abstract
Full control of molecular interactions, including reactive losses, would open new frontiers in quantum science. We demonstrate extreme tunability of ultracold chemical reaction rates by inducing resonant dipolar interactions by means of an external electric field. We prepared fermionic potassium-rubidium molecules in their first excited rotational state and observed a modulation of the chemical reaction rate by three orders of magnitude as we tuned the electric field strength by a few percent across resonance. In a quasi-two-dimensional geometry, we accurately determined the contributions from the three dominant angular momentum projections of the collisions. Using the resonant features, we shielded the molecules from loss and suppressed the reaction rate by an order of magnitude below the background value, thereby realizing a long-lived sample of polar molecules in large electric fields.
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Affiliation(s)
- Kyle Matsuda
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.
| | - Luigi De Marco
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Jun-Ru Li
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - William G Tobias
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Giacomo Valtolina
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Goulven Quéméner
- Université Paris-Saclay, CNRS, Laboratoire Aimé Cotton, 91405 Orsay, France
| | - Jun Ye
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.
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González-Férez R, Shertzer J, Sadeghpour HR. Ultralong-Range Rydberg Bimolecules. PHYSICAL REVIEW LETTERS 2021; 126:043401. [PMID: 33576643 DOI: 10.1103/physrevlett.126.043401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
We predict that ultralong-range Rydberg bimolecules form in collisions between polar molecules in cold and ultracold settings. The interaction of Λ-doublet nitric oxide (NO) with long-lived Rydberg NO(nf, ng) molecules forms ultralong-range Rydberg bimolecules with GHz energies and kilo-Debye permanent electric dipole moments. The Hamiltonian includes both the anisotropic charge-molecular dipole interaction and the electron-NO scattering. The rotational constant for the Rydberg bimolecules is in the MHz range, allowing for microwave spectroscopy of rotational transitions in Rydberg bimolecules. Considerable orientation of NO dipole can be achieved. The Rydberg molecules described here hold promise for studies of a special class of long-range bimolecular interactions.
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Affiliation(s)
- Rosario González-Férez
- Instituto Carlos I de Física Teórica y Computacional, and Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada, Spain
- ITAMP, Center for Astrophysics, Harvard & Smithsonian, Cambridge, Massachusetts 02138 USA
| | - Janine Shertzer
- ITAMP, Center for Astrophysics, Harvard & Smithsonian, Cambridge, Massachusetts 02138 USA
- Department of Physics, College of the Holy Cross, Worcester, Massachusetts 01610, USA
| | - H R Sadeghpour
- ITAMP, Center for Astrophysics, Harvard & Smithsonian, Cambridge, Massachusetts 02138 USA
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