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Xie X, Van de Graaff MJ, Chapurin R, Frye MD, Hutson JM, D'Incao JP, Julienne PS, Ye J, Cornell EA. Observation of Efimov Universality across a Nonuniversal Feshbach Resonance in ^{39}K. PHYSICAL REVIEW LETTERS 2020; 125:243401. [PMID: 33412063 DOI: 10.1103/physrevlett.125.243401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/19/2020] [Indexed: 06/12/2023]
Abstract
We study three-atom inelastic scattering in ultracold ^{39}K near a Feshbach resonance of intermediate coupling strength. The nonuniversal character of such resonance leads to an abnormally large Efimov absolute length scale and a relatively small effective range r_{e}, allowing the features of the ^{39}K Efimov spectrum to be better isolated from the short-range physics. Meticulous characterization of and correction for finite-temperature effects ensure high accuracy on the measurements of these features at large-magnitude scattering lengths. For a single Feshbach resonance, we unambiguously locate four distinct features in the Efimov structure. Three of these features form ratios that obey the Efimov universal scaling to within 10%, while the fourth feature, occurring at a value of scattering length closest to r_{e}, instead deviates from the universal value.
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Affiliation(s)
- Xin Xie
- JILA, National Institute of Standards and Technology and the University of Colorado, and Department of Physics, Boulder, Colorado 80309, USA
| | - Michael J Van de Graaff
- JILA, National Institute of Standards and Technology and the University of Colorado, and Department of Physics, Boulder, Colorado 80309, USA
| | - Roman Chapurin
- JILA, National Institute of Standards and Technology and the University of Colorado, and Department of Physics, Boulder, Colorado 80309, USA
| | - 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
| | - José P D'Incao
- JILA, National Institute of Standards and Technology and the University of Colorado, and Department of Physics, Boulder, Colorado 80309, USA
| | - Paul S Julienne
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, College Park, Maryland 20742, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and the University of Colorado, and Department of Physics, Boulder, Colorado 80309, USA
| | - Eric A Cornell
- JILA, National Institute of Standards and Technology and the University of Colorado, and Department of Physics, Boulder, Colorado 80309, USA
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2
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Blech A, Shagam Y, Hölsch N, Paliwal P, Skomorowski W, Rosenberg JW, Bibelnik N, Heber O, Reich DM, Narevicius E, Koch CP. Phase protection of Fano-Feshbach resonances. Nat Commun 2020; 11:999. [PMID: 32081896 PMCID: PMC7035365 DOI: 10.1038/s41467-020-14797-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 02/03/2020] [Indexed: 12/05/2022] Open
Abstract
Decay of bound states due to coupling with free particle states is a general phenomenon occurring at energy scales from MeV in nuclear physics to peV in ultracold atomic gases. Such a coupling gives rise to Fano-Feshbach resonances (FFR) that have become key to understanding and controlling interactions-in ultracold atomic gases, but also between quasiparticles, such as microcavity polaritons. Their energy positions were shown to follow quantum chaotic statistics. In contrast, their lifetimes have so far escaped a similarly comprehensive understanding. Here, we show that bound states, despite being resonantly coupled to a scattering state, become protected from decay whenever the relative phase is a multiple of π. We observe this phenomenon by measuring lifetimes spanning four orders of magnitude for FFR of spin-orbit excited molecular ions with merged beam and electrostatic trap experiments. Our results provide a blueprint for identifying naturally long-lived states in a decaying quantum system.
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Affiliation(s)
- Alexander Blech
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Yuval Shagam
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
- JILA, NIST and the Department of Physics, University of Colorado, Boulder, CO, 80309, USA
| | - Nicolas Hölsch
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093, Zürich, Switzerland
| | - Prerna Paliwal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Wojciech Skomorowski
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
- Department of Chemistry, University of Southern California, Los Angeles, CA, 90089, USA
| | - John W Rosenberg
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Natan Bibelnik
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Oded Heber
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Daniel M Reich
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Edvardas Narevicius
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Christiane P Koch
- Theoretische Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany.
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel.
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Klauss CE, Xie X, Lopez-Abadia C, D'Incao JP, Hadzibabic Z, Jin DS, Cornell EA. Observation of Efimov Molecules Created from a Resonantly Interacting Bose Gas. PHYSICAL REVIEW LETTERS 2017; 119:143401. [PMID: 29053296 DOI: 10.1103/physrevlett.119.143401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Indexed: 06/07/2023]
Abstract
We convert a strongly interacting ultracold Bose gas into a mixture of atoms and molecules by sweeping the interactions from resonant to weak. By analyzing the decay dynamics of the molecular gas, we show that in addition to Feshbach dimers it contains Efimov trimers. Typically around 8% of the total atomic population is bound into trimers, identified by their density-independent lifetime of about 100 μs. The lifetime of the Feshbach dimers shows a density dependence due to inelastic atom-dimer collisions, in agreement with theoretical calculations. We also vary the density of the gas across a factor of 250 and investigate the corresponding atom loss rate at the interaction resonance.
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Affiliation(s)
- Catherine E Klauss
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, Boulder, Colorado 80309-0440, USA
| | - Xin Xie
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, Boulder, Colorado 80309-0440, USA
| | - Carlos Lopez-Abadia
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, Boulder, Colorado 80309-0440, USA
| | - José P D'Incao
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, Boulder, Colorado 80309-0440, USA
| | - Zoran Hadzibabic
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Deborah S Jin
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, Boulder, Colorado 80309-0440, USA
| | - Eric A Cornell
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, Boulder, Colorado 80309-0440, USA
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4
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Smith DH. Inducing Resonant Interactions in Ultracold Atoms with a Modulated Magnetic Field. PHYSICAL REVIEW LETTERS 2015; 115:193002. [PMID: 26588376 DOI: 10.1103/physrevlett.115.193002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Indexed: 06/05/2023]
Abstract
In systems of ultracold atoms, pairwise interactions can be resonantly enhanced by a new mechanism that does not rely upon a magnetic Feshbach resonance. In this mechanism, interactions are controlled by tuning the frequency of an oscillating parallel component of the magnetic field close to the transition frequency between the scattering atoms and a two-atom bound state. The real part of the resulting s-wave scattering length a is resonantly enhanced when the oscillation frequency is close to the transition frequency. The resonance parameters can be controlled by varying the amplitude of the oscillating field. The amplitude also controls the imaginary part of a, which arises because the oscillating field converts atom pairs into molecules. The real part of a can be made much larger than the background scattering length without introducing catastrophic atom losses from the imaginary part. For the case of a shallow bound state in the scattering channel, the dimensionless resonance parameters are universal functions of the dimensionless oscillation amplitude.
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Affiliation(s)
- D Hudson Smith
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
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Abstract
Two-atom systems in small traps are of fundamental interest for understanding the role of interactions in degenerate cold gases and for the creation of quantum gates in quantum information processing with single-atom traps. One of the key quantities is the inelastic relaxation (decay) time when one of the atoms or both are in a higher hyperfine state. Here we measure this quantity in a heteronuclear system of 87Rb and 85Rb in a micro optical trap and demonstrate experimentally and theoretically the presence of both fast and slow relaxation processes, depending on the choice of the initial hyperfine states. This experimental method allows us to single out a particular relaxation process thus provides an extremely clean platform for collisional physics studies. Our results have also implications for engineering of quantum states via controlled collisions and creation of two-qubit quantum gates. Understanding the behaviour of trapped two-atom systems is interesting for engineering quantum gases, and one of the key quantities to determine is the inelastic relaxation time from hyperfine states. Here, the authors measure this quantity for heteronuclear systems of 87Rb and 85Rb in a micro optical trap.
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Affiliation(s)
- Jeremy M. Hutson
- a Department of Chemistry , University of Durham , South Road, Durham , DH1 3LE , England
| | - Pavel Soldán
- b Faculty of Nuclear Sciences and Physical Engineering , Department of Physics , Doppler Institute , Czech Technical University , Břehová 7 , 115 19 Praha 1 , Czech Republic
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7
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Ferlaino F, Knoop S, Mark M, Berninger M, Schöbel H, Nägerl HC, Grimm R. Collisions between tunable halo dimers: exploring an elementary four-body process with identical bosons. PHYSICAL REVIEW LETTERS 2008; 101:023201. [PMID: 18764179 DOI: 10.1103/physrevlett.101.023201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Indexed: 05/26/2023]
Abstract
We study inelastic collisions in a pure, trapped sample of Feshbach molecules made of bosonic cesium atoms in the quantum halo regime. We measure the relaxation rate coefficient for decay to lower-lying molecular states and study the dependence on scattering length and temperature. We identify a pronounced loss minimum with varying scattering length along with a further suppression of loss with decreasing temperature. Our observations provide insight into the physics of a few-body quantum system that consists of four identical bosons at large values of the two-body scattering length.
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Affiliation(s)
- F Ferlaino
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria
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8
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Orlandini S, Baccarelli I, Gianturco F. Searching for many-body effects and Efimov states in very weakly bound triatomics: HeNeH− and HeNeH. Mol Phys 2008. [DOI: 10.1080/00268970801939001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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9
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Knoop S, Mark M, Ferlaino F, Danzl JG, Kraemer T, Nägerl HC, Grimm R. Metastable feshbach molecules in high rotational states. PHYSICAL REVIEW LETTERS 2008; 100:083002. [PMID: 18352621 DOI: 10.1103/physrevlett.100.083002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Indexed: 05/26/2023]
Abstract
We experimentally demonstrate Cs2 Feshbach molecules well above the dissociation threshold, which are stable against spontaneous decay on the time scale of 1 s. An optically trapped sample of ultracold dimers is prepared in a high rotational state and magnetically tuned into a region with a negative binding energy. The metastable character of these molecules arises from the large centrifugal barrier in combination with negligible coupling to states with low rotational angular momentum. A sharp onset of dissociation with increasing magnetic field is mediated by a crossing with a lower rotational dimer state and facilitates dissociation on demand with a well-defined energy.
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Affiliation(s)
- S Knoop
- Institut für Experimentalphysik and Forschungszentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria
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Papp SB, Wieman CE. Observation of heteronuclear Feshbach molecules from a 85Rb-87Rb gas. PHYSICAL REVIEW LETTERS 2006; 97:180404. [PMID: 17155521 DOI: 10.1103/physrevlett.97.180404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Indexed: 05/12/2023]
Abstract
We report on the observation of ultracold heteronuclear Feshbach molecules. Starting with a 87Rb Bose-Einstein condensate and a cold atomic gas of 85Rb, we utilize previously unobserved interspecies Feshbach resonances to create up to 25,000 molecules. Even though the 85Rb gas is nondegenerate, we observe a large molecular conversion efficiency due to the presence of a quantum degenerate 87Rb gas; this represents a key feature of our system. We compare the molecule creation at two different Feshbach resonances with different magnetic-field widths. The two Feshbach resonances are located at 265.44+/-0.15 G and 372.4+/-1.3 G. We also directly measure the small binding energy of the molecules through resonant magnetic-field association.
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Affiliation(s)
- S B Papp
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA.
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12
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Thompson ST, Hodby E, Wieman CE. Ultracold molecule production via a resonant oscillating magnetic field. PHYSICAL REVIEW LETTERS 2005; 95:190404. [PMID: 16383963 DOI: 10.1103/physrevlett.95.190404] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Indexed: 05/05/2023]
Abstract
A novel atom-molecule conversion technique has been investigated. Ultracold 85Rb atoms sitting in a dc magnetic field near the 155 G Feshbach resonance are associated by applying a small sinusoidal oscillation to the magnetic field. There is resonant atom to molecule conversion when the modulation frequency closely matches the molecular binding energy. We observe that the atom to molecule conversion efficiency depends strongly on the frequency, amplitude, and duration of the applied modulation and on the phase space density of the sample. This technique offers high conversion efficiencies without the necessity of crossing or closely approaching the Feshbach resonance and allows precise spectroscopic measurements. Efficiencies of 55% have been observed for pure Bose-Einstein condensates.
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Affiliation(s)
- S T Thompson
- JILA, National Institute of Standards and Technology and The University of Colorado, and the Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA
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13
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Hodby E, Thompson ST, Regal CA, Greiner M, Wilson AC, Jin DS, Cornell EA, Wieman CE. Production efficiency of ultracold feshbach molecules in bosonic and fermionic systems. PHYSICAL REVIEW LETTERS 2005; 94:120402. [PMID: 15903898 DOI: 10.1103/physrevlett.94.120402] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Indexed: 05/02/2023]
Abstract
We investigate the production efficiency of ultracold molecules in bosonic 85Rb and fermionic 40K when the magnetic field is swept across a Feshbach resonance. For adiabatic sweeps of the magnetic field, our novel model shows that the conversion efficiency of both species is solely determined by the phase space density of the atomic cloud, in contrast with a number of theoretical predictions. In the nonadiabatic regime our measurements of the 85Rb molecule conversion efficiency follow a Landau-Zener model.
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Affiliation(s)
- E Hodby
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA
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14
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Köhler T, Tiesinga E, Julienne PS. Spontaneous dissociation of long-range Feshbach molecules. PHYSICAL REVIEW LETTERS 2005; 94:020402. [PMID: 15698151 DOI: 10.1103/physrevlett.94.020402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Indexed: 05/24/2023]
Abstract
We study the spontaneous dissociation of diatomic molecules produced in cold atomic gases via magnetically tunable Feshbach resonances. We provide a universal formula for the lifetime of these molecules that relates their decay to the scattering length and the loss rate constant for inelastic spin relaxation. Our universal treatment as well as our exact coupled channels calculations for 85Rb dimers predict a suppression of the decay over several orders of magnitude when the scattering length is increased. Our predictions are in good agreement with recent measurements of the lifetime of 85Rb(2).
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Affiliation(s)
- Thorsten Köhler
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
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