1
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Arrowsmith-Kron G, Athanasakis-Kaklamanakis M, Au M, Ballof J, Berger R, Borschevsky A, Breier AA, Buchinger F, Budker D, Caldwell L, Charles C, Dattani N, de Groote RP, DeMille D, Dickel T, Dobaczewski J, Düllmann CE, Eliav E, Engel J, Fan M, Flambaum V, Flanagan KT, Gaiser AN, Garcia Ruiz RF, Gaul K, Giesen TF, Ginges JSM, Gottberg A, Gwinner G, Heinke R, Hoekstra S, Holt JD, Hutzler NR, Jayich A, Karthein J, Leach KG, Madison KW, Malbrunot-Ettenauer S, Miyagi T, Moore ID, Moroch S, Navratil P, Nazarewicz W, Neyens G, Norrgard EB, Nusgart N, Pašteka LF, N Petrov A, Plaß WR, Ready RA, Pascal Reiter M, Reponen M, Rothe S, Safronova MS, Scheidenerger C, Shindler A, Singh JT, Skripnikov LV, Titov AV, Udrescu SM, Wilkins SG, Yang X. Opportunities for fundamental physics research with radioactive molecules. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:084301. [PMID: 38215499 DOI: 10.1088/1361-6633/ad1e39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 01/12/2024] [Indexed: 01/14/2024]
Abstract
Molecules containing short-lived, radioactive nuclei are uniquely positioned to enable a wide range of scientific discoveries in the areas of fundamental symmetries, astrophysics, nuclear structure, and chemistry. Recent advances in the ability to create, cool, and control complex molecules down to the quantum level, along with recent and upcoming advances in radioactive species production at several facilities around the world, create a compelling opportunity to coordinate and combine these efforts to bring precision measurement and control to molecules containing extreme nuclei. In this manuscript, we review the scientific case for studying radioactive molecules, discuss recent atomic, molecular, nuclear, astrophysical, and chemical advances which provide the foundation for their study, describe the facilities where these species are and will be produced, and provide an outlook for the future of this nascent field.
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Affiliation(s)
- Gordon Arrowsmith-Kron
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
| | - Michail Athanasakis-Kaklamanakis
- Experimental Physics Department, CERN, CH-1211 Geneva 23, Switzerland
- KU Leuven, Department of Physics and Astronomy, Instituut voor Kern- en Stralingsfysica, B-3001 Leuven, Belgium
| | - Mia Au
- CERN, Geneva, Switzerland
- Johannes Gutenberg-Universität Mainz, Mainz, Germany
| | - Jochen Ballof
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
- Accelerator Systems Department, CERN, 1211 Geneva 23, Switzerland
| | - Robert Berger
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Anastasia Borschevsky
- Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen, The Netherlands
| | - Alexander A Breier
- Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | | | - Dmitry Budker
- Helmholtz-Institut, GSI Helmholtzzentrum fur Schwerionenforschung and Johannes Gutenberg University, Mainz 55128, Germany
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300, United States of America
| | - Luke Caldwell
- JILA, NIST and University of Colorado, Boulder, CO 80309, United States of America
- Department of Physics, University of Colorado, Boulder, CO 80309, United States of America
| | - Christopher Charles
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
- University of Western Ontario, 1151 Richmond St. N., London, Ontario N6A 5B7, Canada
| | - Nike Dattani
- HPQC Labs, Waterloo, Ontario, Canada
- HPQC College, Waterloo, Ontario, Canada
| | - Ruben P de Groote
- Instituut voor Kern- en Stralingsfysica, KU Leuven, Leuven, Belgium
- Department of Physics, University of Jyväskylä, Jyväskylä, Finland
| | - David DeMille
- University of Chicago, Chicago, IL, United States of America
- Argonne National Laboratory, Lemont, IL, United States of America
| | - Timo Dickel
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
- II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
| | - Jacek Dobaczewski
- School of Physics, Engineering and Technology, University of York, Heslington, York YO10 5DD, United Kingdom
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, PL-02-093 Warsaw, Poland
| | - Christoph E Düllmann
- Department of Chemistry-TRIGA Site, Johannes Gutenberg University, Fritz-Strassmann-Weg 2, 55128 Mainz, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt, Germany
- Helmholtz Institute Mainz, Staudingerweg 18, 55128 Mainz, Germany
| | - Ephraim Eliav
- School of Chemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Jonathan Engel
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255, United States of America
| | - Mingyu Fan
- Department of Physics, University of California, Santa Barbara, CA 93106, United States of America
| | | | - Kieran T Flanagan
- Photon Science Institute, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Alyssa N Gaiser
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
| | - Ronald F Garcia Ruiz
- Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
| | - Konstantin Gaul
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Thomas F Giesen
- Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Jacinda S M Ginges
- School of Mathematics and Physics, The University of Queensland, Brisbane QLD 4072, Australia
| | | | - Gerald Gwinner
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 3M9, Canada
| | | | - Steven Hoekstra
- Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen, The Netherlands
- Nikhef, National Institute for Subatomic Physics, Amsterdam, The Netherlands
| | - Jason D Holt
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
- Department of Physics, McGill University, Montreal, QC H3A 2T8, Canada
| | - Nicholas R Hutzler
- California Institute of Technology, Pasadena, CA 91125, United States of America
| | - Andrew Jayich
- Department of Physics, University of California, Santa Barbara, CA 93106, United States of America
| | - Jonas Karthein
- Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
| | - Kyle G Leach
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
- Colorado School of Mines, Golden, CO 80401, United States of America
| | - Kirk W Madison
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T1Z1, Canada
| | - Stephan Malbrunot-Ettenauer
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
- Department of Physics, University of Toronto, 60 St. George St., Toronto, Ontario, Canada
| | | | - Iain D Moore
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Scott Moroch
- Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
| | - Petr Navratil
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
| | - Witold Nazarewicz
- Facility for Rare Isotope Beams and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, United States of America
| | - Gerda Neyens
- KU Leuven, Department of Physics and Astronomy, Instituut voor Kern- en Stralingsfysica, B-3001 Leuven, Belgium
| | - Eric B Norrgard
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States of America
| | - Nicholas Nusgart
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
| | - Lukáš F Pašteka
- Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen, The Netherlands
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Alexander N Petrov
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Center 'Kurchatov Institute' (NRC 'Kurchatov Institute'-PNPI), 1 Orlova roscha mcr., Gatchina 188300, Leningrad Region, Russia
- Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia
| | - Wolfgang R Plaß
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
- II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
| | - Roy A Ready
- Department of Physics, University of California, Santa Barbara, CA 93106, United States of America
| | - Moritz Pascal Reiter
- School of Physics & Astronomy, The University of Edinburgh, Peter Guthrie Tait Road, EH9 3FD Edinburgh, United Kingdom
| | - Mikael Reponen
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, Jyväskylä 40014, Finland
| | | | - Marianna S Safronova
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, United States of America
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, MD 20742, United States of America
| | - Christoph Scheidenerger
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
- II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
- Helmholtz Forschungsakademie Hessen für FAIR (HFHF), Campus Gießen, Gießen, Germany
| | - Andrea Shindler
- Facility for Rare Isotope Beams & Physics Department, Michigan State University, East Lansing, MI 48824, United States of America
| | - Jaideep T Singh
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI, United States of America
| | - Leonid V Skripnikov
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Center 'Kurchatov Institute' (NRC 'Kurchatov Institute'-PNPI), 1 Orlova roscha mcr., Gatchina 188300, Leningrad Region, Russia
- Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia
| | - Anatoly V Titov
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Center 'Kurchatov Institute' (NRC 'Kurchatov Institute'-PNPI), 1 Orlova roscha mcr., Gatchina 188300, Leningrad Region, Russia
- Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia
| | - Silviu-Marian Udrescu
- Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
| | - Shane G Wilkins
- Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
| | - Xiaofei Yang
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, People's Republic of China
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2
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Walraven EF, Tarbutt MR, Karman T. Scheme for Deterministic Loading of Laser-Cooled Molecules into Optical Tweezers. PHYSICAL REVIEW LETTERS 2024; 132:183401. [PMID: 38759201 DOI: 10.1103/physrevlett.132.183401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 03/27/2024] [Indexed: 05/19/2024]
Abstract
We propose to repeatedly load laser-cooled molecules into optical tweezers, and transfer them to storage states that are rotationally excited by two additional quanta. Collisional loss of molecules in these storage states is suppressed, and a dipolar blockade prevents the accumulation of more than one molecule. Applying three cycles loads tweezers with single molecules at an 80% success rate, limited by residual collisional loss. This improved loading efficiency reduces the time needed for rearrangement of tweezer arrays, which would otherwise limit the scalability of neutral molecule quantum computers.
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Affiliation(s)
- Etienne F Walraven
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - Michael R Tarbutt
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Tijs Karman
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
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3
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Jorapur V, Langin TK, Wang Q, Zheng G, DeMille D. High Density Loading and Collisional Loss of Laser-Cooled Molecules in an Optical Trap. PHYSICAL REVIEW LETTERS 2024; 132:163403. [PMID: 38701453 DOI: 10.1103/physrevlett.132.163403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 02/23/2024] [Accepted: 03/05/2024] [Indexed: 05/05/2024]
Abstract
We report optical trapping of laser-cooled molecules at sufficient density to observe molecule-molecule collisions for the first time in a bulk gas. SrF molecules from a red-detuned magneto-optical trap (MOT) are compressed and cooled in a blue-detuned MOT. Roughly 30% of these molecules are loaded into an optical dipole trap with peak number density n_{0}≈3×10^{10} cm^{-3} and temperature T≈40 μK. We observe two-body loss with rate coefficient β=2.7_{-0.8}^{+1.2}×10^{-10} cm^{3} s^{-1}. Achieving this density and temperature opens a path to evaporative cooling towards quantum degeneracy of laser-cooled molecules.
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Affiliation(s)
- Varun Jorapur
- Department of Physics, Yale University, New Haven, Connecticut 06511, USA
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Thomas K Langin
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Qian Wang
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - Geoffrey Zheng
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
| | - David DeMille
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
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4
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Zhang C, Rittenhouse ST, Tscherbul TV, Sadeghpour HR, Hutzler NR. Sympathetic Cooling and Slowing of Molecules with Rydberg Atoms. PHYSICAL REVIEW LETTERS 2024; 132:033001. [PMID: 38307061 DOI: 10.1103/physrevlett.132.033001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 12/05/2023] [Indexed: 02/04/2024]
Abstract
We propose to sympathetically slow and cool polar molecules in a cold, low-density beam using laser-cooled Rydberg atoms. The elastic collision cross sections between molecules and Rydberg atoms are large enough to efficiently thermalize the molecules even in a low-density environment. Molecules traveling at 100 m/s can be stopped in under 30 collisions with little inelastic loss. Our method does not require photon scattering from the molecules and can be generically applied to complex species for applications in precision measurement, quantum information science, and controlled chemistry.
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Affiliation(s)
- Chi Zhang
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - Seth T Rittenhouse
- Department of Physics, the United States Naval Academy, Annapolis, Maryland 21402, USA
- ITAMP, Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, USA
| | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - H R Sadeghpour
- ITAMP, Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, USA
| | - Nicholas R Hutzler
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
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5
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Ding YK, Zhang ZY, Liu JM. Simulation of quantum walks on a circle with polar molecules via optimal control. J Chem Phys 2023; 159:204303. [PMID: 38010330 DOI: 10.1063/5.0174472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/05/2023] [Indexed: 11/29/2023] Open
Abstract
Quantum walks are the quantum counterpart of classical random walks and have various applications in quantum information science. Polar molecules have rich internal energy structure and long coherence time and thus are considered as a promising candidate for quantum information processing. In this paper, we propose a theoretical scheme for implementing discrete-time quantum walks on a circle with dipole-dipole coupled SrO molecules. The states of the walker and the coin are encoded in the pendular states of polar molecules induced by an external electric field. We design the optimal microwave pulses for implementing quantum walks on a four-node circle and a three-node circle by multi-target optimal control theory. To reduce the accumulation of decoherence and improve the fidelity, we successfully realize a step of quantum walk with only one optimal pulse. Moreover, we also encode the walker into a three-level molecular qutrit and a four-level molecular ququart and design the corresponding optimal pulses for quantum walks, which can reduce the number of molecules used. It is found that all the quantum walks on a circle in our scheme can be achieved via optimal control fields with high fidelities. Our results could shed some light on the implementation of discrete-time quantum walks and high-dimensional quantum information processing with polar molecules.
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Affiliation(s)
- Yi-Kai Ding
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Zuo-Yuan Zhang
- School of Physical Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Jin-Ming Liu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
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6
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Zhang C, Hutzler NR, Cheng L. Intensity-Borrowing Mechanisms Pertinent to Laser Cooling of Linear Polyatomic Molecules. J Chem Theory Comput 2023. [PMID: 37384588 DOI: 10.1021/acs.jctc.3c00408] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
A study of the intensity-borrowing mechanisms important to optical cycling transitions in laser-coolable polyatomic molecules arising from non-adiabatic coupling, contributions beyond the Franck-Condon approximation, and Fermi resonances is reported. It has been shown to be necessary to include non-adiabatic coupling to obtain computational accuracy that is sufficient to be useful for laser cooling of molecules. The predicted vibronic branching ratios using perturbation theory based on the non-adiabatic mechanisms have been demonstrated to agree well with those obtained from variational discrete variable representation calculations for representative molecules including CaOH, SrOH, and YbOH. The electron-correlation and basis-set effects on the calculated transition properties, including the vibronic coupling constants, the spin-orbit coupling matrix elements, and the transition dipole moments, and on the calculated branching ratios have been thoroughly studied. The vibronic branching ratios predicted using the present methodologies demonstrate that RaOH is a promising radioactive molecule candidate for laser cooling.
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Nicholas R Hutzler
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, United States
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
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7
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Hallas C, Vilas NB, Anderegg L, Robichaud P, Winnicki A, Zhang C, Cheng L, Doyle JM. Optical Trapping of a Polyatomic Molecule in an ℓ-Type Parity Doublet State. PHYSICAL REVIEW LETTERS 2023; 130:153202. [PMID: 37115898 DOI: 10.1103/physrevlett.130.153202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 02/13/2023] [Indexed: 06/19/2023]
Abstract
We report optical trapping of a polyatomic molecule, calcium monohydroxide (CaOH). CaOH molecules from a magneto-optical trap are sub-Doppler laser cooled to 20(3) μK in free space and loaded into an optical dipole trap. We attain an in-trap molecule number density of 3(1)×10^{9} cm^{-3} at a temperature of 57(8) μK. Trapped CaOH molecules are optically pumped into an excited vibrational bending mode, whose ℓ-type parity doublet structure is a potential resource for a wide range of proposed quantum science applications with polyatomic molecules. We measure the spontaneous, radiative lifetime of this bending mode state to be ∼0.7 s.
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Affiliation(s)
- Christian Hallas
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Nathaniel B Vilas
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Loïc Anderegg
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Paige Robichaud
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Andrew Winnicki
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
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8
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Yang H, Cao J, Su Z, Rui J, Zhao B, Pan JW. Creation of an ultracold gas of triatomic molecules from an atom–diatomic molecule mixture. Science 2022; 378:1009-1013. [DOI: 10.1126/science.ade6307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In recent years, there has been notable progress in the preparation and control of ultracold gases of diatomic molecules. The next experimental challenge is the production of ultracold polyatomic molecular gases. Here, we report the creation of an ultracold gas of
23
Na
40
K
2
triatomic molecules from a mixture of ground-state sodium-23–potassium-40 (
23
Na
40
K) molecules and potassium-40 (
40
K) atoms. The triatomic molecules were created by adiabatic magneto-association through an atom–diatomic molecule Feshbach resonance. We obtained clear evidence for the creation of triatomic molecules by directly detecting them using radio-frequency dissociation. Approximately 4000 triatomic molecules with a high-peak phase-space density of 0.05 could be created. The ultracold triatomic molecules can serve as a launchpad to probe the three-body potential energy surface and may be used to prepare quantum degenerate triatomic molecular gases.
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Affiliation(s)
- Huan Yang
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Jin Cao
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Zhen Su
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
| | - Jun Rui
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Bo Zhao
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Jian-Wei Pan
- Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
- Shanghai Research Center for Quantum Science and CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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9
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Vilas NB, Hallas C, Anderegg L, Robichaud P, Winnicki A, Mitra D, Doyle JM. Magneto-optical trapping and sub-Doppler cooling of a polyatomic molecule. Nature 2022; 606:70-74. [PMID: 35650357 DOI: 10.1038/s41586-022-04620-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/04/2022] [Indexed: 11/09/2022]
Abstract
Laser cooling and trapping1,2, and magneto-optical trapping methods in particular2, have enabled groundbreaking advances in science, including Bose-Einstein condensation3-5, quantum computation with neutral atoms6,7 and high-precision optical clocks8. Recently, magneto-optical traps (MOTs) of diatomic molecules have been demonstrated9-12, providing access to research in quantum simulation13 and searches for physics beyond the standard model14. Compared with diatomic molecules, polyatomic molecules have distinct rotational and vibrational degrees of freedom that promise a variety of transformational possibilities. For example, ultracold polyatomic molecules would be uniquely suited to applications in quantum computation and simulation15-17, ultracold collisions18, quantum chemistry19 and beyond-the-standard-model searches20,21. However, the complexity of these molecules has so far precluded the realization of MOTs for polyatomic species. Here we demonstrate magneto-optical trapping of a polyatomic molecule, calcium monohydroxide (CaOH). After trapping, the molecules are laser cooled in a blue-detuned optical molasses to a temperature of 110 μK, which is below the Doppler cooling limit. The temperatures and densities achieved here make CaOH a viable candidate for a wide variety of quantum science applications, including quantum simulation and computation using optical tweezer arrays15,17,22,23. This work also suggests that laser cooling and magneto-optical trapping of many other polyatomic species24-27 will be both feasible and practical.
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Affiliation(s)
- Nathaniel B Vilas
- Department of Physics, Harvard University, Cambridge, MA, USA. .,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.
| | - Christian Hallas
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Loïc Anderegg
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Paige Robichaud
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Andrew Winnicki
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Debayan Mitra
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.,Department of Physics, Columbia University, New York, NY, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
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10
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Lu Y, Holland CM, Cheuk LW. Molecular Laser Cooling in a Dynamically Tunable Repulsive Optical Trap. PHYSICAL REVIEW LETTERS 2022; 128:213201. [PMID: 35687464 DOI: 10.1103/physrevlett.128.213201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 03/31/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Recent work with laser-cooled molecules in attractive optical traps has shown that the differential ac Stark shifts arising from the trap light itself can become problematic, limiting collisional shielding efficiencies, rotational coherence times, and laser-cooling temperatures. In this Letter, we explore trapping and laser cooling of CaF molecules in a ring-shaped repulsive optical trap. The observed dependences of loss rates on temperature and barrier height show characteristic behavior of repulsive traps and indicate strongly suppressed average ac Stark shifts. Within the trap, we find that Λ-enhanced gray molasses cooling is effective, producing similar minimum temperatures as those obtained in free space. By combining in-trap laser cooling with dynamical reshaping of the trap, we also present a method that allows highly efficient and rapid transfer from molecular magneto-optical traps into conventional attractive optical traps, which has been an outstanding challenge for experiments to date. Notably, our method could allow nearly lossless transfer over millisecond timescales.
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Affiliation(s)
- Yukai Lu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Connor M Holland
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Lawrence W Cheuk
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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11
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Zhao B, Pan JW. Quantum control of reactions and collisions at ultralow temperatures. Chem Soc Rev 2022; 51:1685-1701. [PMID: 35169822 DOI: 10.1039/d1cs01040a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
At temperatures close to absolute zero, the molecular reactions and collisions are dominantly governed by quantum mechanics. Remarkable quantum phenomena such as quantum tunneling, quantum threshold behavior, quantum resonances, quantum interference, and quantum statistics are expected to be the main features in ultracold reactions and collisions. Ultracold molecules offer great opportunities and challenges in the study of these intriguing quantum phenomena in molecular processes. In this article, we review the recent progress in the preparation of ultracold molecules and the study of ultracold reactions and collisions using ultracold molecules. We focus on the controlled ultracold chemistry and the scattering resonances at ultralow temperatures. The challenges in understanding the complex ultracold reactions and collisions are also discussed.
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Affiliation(s)
- Bo Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China.,Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China.,Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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12
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Yang H, Wang XY, Su Z, Cao J, Zhang DC, Rui J, Zhao B, Bai CL, Pan JW. Evidence for the association of triatomic molecules in ultracold 23Na 40K + 40K mixtures. Nature 2022; 602:229-233. [PMID: 35140383 DOI: 10.1038/s41586-021-04297-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 11/29/2021] [Indexed: 11/09/2022]
Abstract
Ultracold assembly of diatomic molecules has enabled great advances in controlled chemistry, ultracold chemical physics and quantum simulation with molecules1-3. Extending the ultracold association to triatomic molecules will offer many new research opportunities and challenges in these fields. A possible approach is to form triatomic molecules in a mixture of ultracold atoms and diatomic molecules by using a Feshbach resonance between them4,5. Although ultracold atom-diatomic-molecule Feshbach resonances have been observed recently6,7, using these resonances to form triatomic molecules remains challenging. Here we report on evidence of the association of triatomic molecules near the Feshbach resonance between 23Na40K molecules in the rovibrational ground state and 40K atoms. We apply a radio-frequency pulse to drive the free-bound transition in ultracold mixtures of 23Na40K and 40K and monitor the loss of 23Na40K molecules. The association of triatomic molecules manifests itself as an additional loss feature in the radio-frequency spectra, which can be distinguished from the atomic loss feature. The observation that the distance between the association feature and the atomic transition changes with the magnetic field provides strong evidence for the formation of triatomic molecules. The binding energy of the triatomic molecules is estimated from the measurements. Our work contributes to the understanding of the complex ultracold atom-molecule Feshbach resonances and may open up an avenue towards the preparation and control of ultracold triatomic molecules.
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Affiliation(s)
- Huan Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Xin-Yao Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China.,Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhen Su
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Jin Cao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - De-Chao Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Jun Rui
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China.,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China.,Shanghai Research Center for Quantum Sciences, Shanghai, China
| | - Bo Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China. .,Shanghai Research Center for Quantum Sciences, Shanghai, China.
| | - Chun-Li Bai
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China. .,University of Chinese Academy of Sciences, Beijing, China.
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai, China. .,Shanghai Research Center for Quantum Sciences, Shanghai, China.
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13
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Wu Y, Burau JJ, Mehling K, Ye J, Ding S. High Phase-Space Density of Laser-Cooled Molecules in an Optical Lattice. PHYSICAL REVIEW LETTERS 2021; 127:263201. [PMID: 35029467 DOI: 10.1103/physrevlett.127.263201] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 10/26/2021] [Indexed: 06/14/2023]
Abstract
We report laser cooling and trapping of yttrium monoxide molecules in an optical lattice. We show that gray molasses cooling remains exceptionally efficient for yttrium monoxide molecules inside the lattice with a molecule temperature as low as 6.1(6) μK. This approach has produced a trapped sample of 1200 molecules, with a peak spatial density of ∼1.2×10^{10} cm^{-3}, and a peak phase-space density of ∼3.1×10^{-6}. By ramping down the lattice depth, we cool the molecules further to 1.0(2) μK, 20 times colder than previously reported for laser-cooled molecules in a trap.
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Affiliation(s)
- Yewei Wu
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Justin J Burau
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Kameron Mehling
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Shiqian Ding
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
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14
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Siercke M, Ospelkaus S. A New Way to Slow Down Complex Molecules. PHYSICS 2021. [DOI: 10.1103/physics.14.180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Langin TK, Jorapur V, Zhu Y, Wang Q, DeMille D. Polarization Enhanced Deep Optical Dipole Trapping of Λ-Cooled Polar Molecules. PHYSICAL REVIEW LETTERS 2021; 127:163201. [PMID: 34723596 DOI: 10.1103/physrevlett.127.163201] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/12/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate loading of SrF molecules into an optical dipole trap (ODT) via in-trap Λ-enhanced gray molasses cooling. We find that this cooling can be optimized by a proper choice of relative ODT and cooling beam polarizations. In this optimized configuration, we observe molecules with temperatures as low as 14(1) μK in traps with depths up to 570 μK. With optimized parameters, we transfer ∼5% of molecules from our radio-frequency magneto-optical trap into the ODT, at a density of ∼2×10^{9} cm^{-3}, a phase space density of ∼2×10^{-7}, and with a trap lifetime of ∼1 s.
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Affiliation(s)
- Thomas K Langin
- Department of Physics, Yale University, New Haven, Connecticut, Connecticut 06520, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - Varun Jorapur
- Department of Physics, Yale University, New Haven, Connecticut, Connecticut 06520, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - Yuqi Zhu
- Department of Physics, Yale University, New Haven, Connecticut, Connecticut 06520, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - Qian Wang
- Department of Physics, Yale University, New Haven, Connecticut, Connecticut 06520, USA
- Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA
| | - David DeMille
- Department of Physics, University of Chicago, Chicago, Illinois 60637, USA
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16
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Jurgilas S, Chakraborty A, Rich CJH, Caldwell L, Williams HJ, Fitch NJ, Sauer BE, Frye MD, Hutson JM, Tarbutt MR. Collisions between Ultracold Molecules and Atoms in a Magnetic Trap. PHYSICAL REVIEW LETTERS 2021; 126:153401. [PMID: 33929220 DOI: 10.1103/physrevlett.126.153401] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/19/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
We prepare mixtures of ultracold CaF molecules and Rb atoms in a magnetic trap and study their inelastic collisions. When the atoms are prepared in the spin-stretched state and the molecules in the spin-stretched component of the first rotationally excited state, they collide inelastically with a rate coefficient k_{2}=(6.6±1.5)×10^{-11} cm^{3}/s at temperatures near 100 μK. We attribute this to rotation-changing collisions. When the molecules are in the ground rotational state we see no inelastic loss and set an upper bound on the spin-relaxation rate coefficient of k_{2}<5.8×10^{-12} cm^{3}/s with 95% confidence. We compare these measurements to the results of a single-channel loss model based on quantum defect theory. The comparison suggests a short-range loss parameter close to unity for rotationally excited molecules, but below 0.04 for molecules in the rotational ground state.
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Affiliation(s)
- S Jurgilas
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - A Chakraborty
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - C J H Rich
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - L Caldwell
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - H J Williams
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - N J Fitch
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - B E Sauer
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Matthew D Frye
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Jeremy M Hutson
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - M R Tarbutt
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
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17
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Caldwell L, Tarbutt MR. Enhancing Dipolar Interactions between Molecules Using State-Dependent Optical Tweezer Traps. PHYSICAL REVIEW LETTERS 2020; 125:243201. [PMID: 33412074 DOI: 10.1103/physrevlett.125.243201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/02/2020] [Indexed: 06/12/2023]
Abstract
We show how state-dependent optical potentials can be used to trap a pair of molecules in different internal states at a separation much smaller than the wavelength of the trapping light. This close spacing greatly enhances the dipole-dipole interaction and we show how it can be used to implement two-qubit gates between molecules that are 100 times faster than existing protocols and than rotational coherence times already demonstrated. We analyze complications due to hyperfine structure, tensor light shifts, photon scattering, and collisional loss, and conclude that none is a barrier to implementing the scheme.
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Affiliation(s)
- L Caldwell
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - M R Tarbutt
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
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18
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Najafian K, Meir Z, Willitsch S. From megahertz to terahertz qubits encoded in molecular ions: theoretical analysis of dipole-forbidden spectroscopic transitions in N 2. Phys Chem Chem Phys 2020; 22:23083-23098. [PMID: 33048077 DOI: 10.1039/d0cp03906c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent advances in quantum technologies have enabled the precise control of single trapped molecules on the quantum level. Exploring the scope of these new technologies, we studied theoretically the implementation of qubits and clock transitions in the spin, rotational, and vibrational degrees of freedom of molecular nitrogen ions including the effects of magnetic fields. The relevant spectroscopic transitions span six orders of magnitude in frequency, illustrating the versatility of the molecular spectrum for encoding quantum information. We identified two types of magnetically insensitive qubits with very low ("stretched"-state qubits) or even zero ("magic" magnetic-field qubits) linear Zeeman shifts. The corresponding spectroscopic transitions are predicted to shift by as little as a few mHz for an amplitude of magnetic-field fluctuations on the order of a few mG, translating into Zeeman-limited coherence times of tens of minutes encoded in the rotations and vibrations of the molecule. We also found that the Q(0) line of the fundamental vibrational transition is magnetic-dipole allowed by interaction with the first excited electronic state of the molecule. The Q(0) transitions, which benefit from small systematic shifts for clock operation and is thus well suited for testing a possible variation in the proton-to-electron mass ratio, were so far not considered in single-photon spectra. Finally, we explored possibilities to coherently control the nuclear-spin configuration of N2+ through the magnetically enhanced mixing of nuclear-spin states.
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Affiliation(s)
- Kaveh Najafian
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland.
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19
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Mitra D, Vilas NB, Hallas C, Anderegg L, Augenbraun BL, Baum L, Miller C, Raval S, Doyle JM. Direct laser cooling of a symmetric top molecule. Science 2020; 369:1366-1369. [DOI: 10.1126/science.abc5357] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/10/2020] [Indexed: 11/02/2022]
Abstract
Ultracold polyatomic molecules have potentially wide-ranging applications in quantum simulation and computation, particle physics, and quantum chemistry. For atoms and small molecules, direct laser cooling has proven to be a powerful tool for quantum science in the ultracold regime. However, the feasibility of laser-cooling larger, nonlinear polyatomic molecules has remained unknown because of their complex structure. We laser-cooled the symmetric top molecule calcium monomethoxide (CaOCH3), reducing the temperature of ~104 molecules from 22 ± 1 millikelvin to 1.8 ± 0.7 millikelvin in one dimension and state-selectively cooling two nuclear spin isomers. These results demonstrate that the use of proper ro-vibronic transitions enables laser cooling of nonlinear molecules, thereby opening a path to efficient cooling of chiral molecules and, eventually, optical tweezer arrays of complex polyatomic species.
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Affiliation(s)
- Debayan Mitra
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Nathaniel B. Vilas
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Christian Hallas
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Loïc Anderegg
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Benjamin L. Augenbraun
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Louis Baum
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Calder Miller
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Shivam Raval
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - John M. Doyle
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
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20
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Baum L, Vilas NB, Hallas C, Augenbraun BL, Raval S, Mitra D, Doyle JM. 1D Magneto-Optical Trap of Polyatomic Molecules. PHYSICAL REVIEW LETTERS 2020; 124:133201. [PMID: 32302203 DOI: 10.1103/physrevlett.124.133201] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/09/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate a 1D magneto-optical trap of the polar free radical calcium monohydroxide (CaOH). A quasiclosed cycling transition is established to scatter ∼10^{3} photons per molecule, predominantly limited by interaction time. This enables radiative laser cooling of CaOH while compressing the molecular beam, leading to a significant increase in on axis beam brightness and reduction in temperature from 8.4 to 1.4 mK.
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Affiliation(s)
- Louis Baum
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Nathaniel B Vilas
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Christian Hallas
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Benjamin L Augenbraun
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Shivam Raval
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Debayan Mitra
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - John M Doyle
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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21
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Caldwell L, Williams HJ, Fitch NJ, Aldegunde J, Hutson JM, Sauer BE, Tarbutt MR. Long Rotational Coherence Times of Molecules in a Magnetic Trap. PHYSICAL REVIEW LETTERS 2020; 124:063001. [PMID: 32109098 DOI: 10.1103/physrevlett.124.063001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/17/2019] [Indexed: 06/10/2023]
Abstract
Polar molecules in superpositions of rotational states exhibit long-range dipolar interactions, but maintaining their coherence in a trapped sample is a challenge. We present calculations that show many laser-coolable molecules have convenient rotational transitions that are exceptionally insensitive to magnetic fields. We verify this experimentally for CaF where we find a transition with sensitivity below 5 Hz G^{-1} and use it to demonstrate a rotational coherence time of 6.4(8) ms in a magnetic trap. Simulations suggest it is feasible to extend this to more than 1 s using a smaller cloud in a biased magnetic trap.
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Affiliation(s)
- L Caldwell
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - H J Williams
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - N J Fitch
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - J Aldegunde
- Departamento de Quimica Fisica, Universidad de Salamanca, E-37008 Salamanca, Spain
| | - Jeremy M Hutson
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - B E Sauer
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - M R Tarbutt
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
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22
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Ding S, Wu Y, Finneran IA, Burau JJ, Ye J. Sub-Doppler Cooling and Compressed Trapping of YO Molecules at μK Temperatures. PHYSICAL REVIEW. X 2020; 10:10.1103/physrevx.10.021049. [PMID: 33643688 PMCID: PMC7909871 DOI: 10.1103/physrevx.10.021049] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Complex molecular structure demands customized solutions to laser cooling by extending its general set of principles and practices. Compared with other laser-cooled molecules, yttrium monoxide (YO) exhibits a large electron-nucleus interaction, resulting in a dominant hyperfine interaction over the electron spin-rotation coupling. The YO ground state is thus comprised of two manifolds of closely spaced states, with one of them possessing a negligible Landé g factor. This unique energy level structure favors dual-frequency dc magneto-optical trapping (MOT) and gray molasses cooling (GMC). We report exceptionally robust cooling of YO at 4 μK over a wide range of laser intensity, detunings (one- and two-photon), and magnetic field. The magnetic insensitivity enables the spatial compression of the molecular cloud by alternating GMC and MOT under the continuous operation of the quadrupole magnetic field. A combination of these techniques produces a laser-cooled molecular sample with the highest phase space density in free space.
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Affiliation(s)
- Shiqian Ding
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Yewei Wu
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Ian A. Finneran
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Justin J. Burau
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
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