1
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Lara M, Jambrina PG, Aoiz FJ. Universal behavior in complex-mediated reactions: Dynamics of S(1D) + o-D2 → D + SD at low collision energies. J Chem Phys 2023; 158:2889001. [PMID: 37154275 DOI: 10.1063/5.0147182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/18/2023] [Indexed: 05/10/2023] Open
Abstract
Reactive and elastic cross sections and rate coefficients have been calculated for the S(1D) + D2(v = 0, j = 0) reaction using a modified hyperspherical quantum reactive scattering method. The considered collision energy ranges from the ultracold regime, where only one partial wave is open, up to the Langevin regime, where many of them contribute. This work presents the extension of the quantum calculations, which in a previous study were compared with the experimental results, down to energies in the cold and ultracold domains. Results are analyzed and compared with the universal case of the quantum defect theory by Jachymski et al. [Phys. Rev. Lett. 110, 213202 (2013)]. State-to-state integral and differential cross sections are also shown covering the ranges of low-thermal, cold, and ultracold collision energy regimes. It is found that at E/kB < 1 K, there are substantial departures from the expected statistical behavior and that dynamical features become increasingly important with decreasing collision energy, leading to vibrational excitation.
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Affiliation(s)
- Manuel Lara
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - P G Jambrina
- Departamento de Química Física, Facultad de Farmacia, Universidad de Salamanca, 37008 Salamanca, Spain
| | - F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
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2
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Collisional cooling of ultracold molecules. Nature 2020; 580:197-200. [DOI: 10.1038/s41586-020-2141-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 01/27/2020] [Indexed: 11/09/2022]
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3
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Tobias WG, Matsuda K, Valtolina G, De Marco L, Li JR, Ye J. Thermalization and Sub-Poissonian Density Fluctuations in a Degenerate Molecular Fermi Gas. PHYSICAL REVIEW LETTERS 2020; 124:033401. [PMID: 32031827 DOI: 10.1103/physrevlett.124.033401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Indexed: 06/10/2023]
Abstract
We observe thermalization in the production of a degenerate Fermi gas of polar ^{40}K^{87}Rb molecules. By measuring the atom-dimer elastic scattering cross section near the Feshbach resonance, we show that Feshbach molecules rapidly reach thermal equilibrium with both parent atomic species. Equilibrium is essentially maintained through coherent transfer to the ground state. Sub-Poissonian density fluctuations in Feshbach and ground-state molecules are measured, giving an independent characterization of degeneracy and directly probing the molecular Fermi-Dirac distribution.
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Affiliation(s)
- William G Tobias
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Kyle Matsuda
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Giacomo Valtolina
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Luigi De Marco
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Jun-Ru Li
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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4
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Reaction kinetics of ultracold molecule-molecule collisions. Nat Commun 2018; 9:5244. [PMID: 30531934 PMCID: PMC6286306 DOI: 10.1038/s41467-018-07576-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 11/09/2018] [Indexed: 11/08/2022] Open
Abstract
Studying chemical reactions on a state-to-state level tests and improves our fundamental understanding of chemical processes. For such investigations it is convenient to make use of ultracold atomic and molecular reactants as they can be prepared in well defined internal and external quantum states. Here, we investigate a single-channel reaction of two Li2-Feshbach molecules where one of the molecules dissociates into two atoms 2AB ⇒ AB + A + B. The process is a prototype for a class of four-body collisions where two reactants produce three product particles. We measure the collisional dissociation rate constant of this process as a function of collision energy/temperature and scattering length. We confirm an Arrhenius-law dependence on the collision energy, an a4 power-law dependence on the scattering length a and determine a universal four body reaction constant.
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5
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Wolf J, Deiß M, Krükow A, Tiemann E, Ruzic BP, Wang Y, D’Incao JP, Julienne PS, Denschlag JH. State-to-state chemistry for three-body recombination in an ultracold rubidium gas. Science 2017; 358:921-924. [DOI: 10.1126/science.aan8721] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 10/10/2017] [Indexed: 11/02/2022]
Affiliation(s)
- Joschka Wolf
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
| | - Markus Deiß
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
| | - Artjom Krükow
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
| | - Eberhard Tiemann
- Institut für Quantenoptik, Leibniz Universität Hannover, 30167 Hannover, Germany
| | - Brandon P. Ruzic
- Joint Quantum Institute, University of Maryland, and the National Institute of Standards and Technology (NIST), College Park, MD 20742, USA
| | - Yujun Wang
- American Physical Society, Ridge, NY 11961, USA
| | - José P. D’Incao
- JILA, NIST, and the Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Paul S. Julienne
- Joint Quantum Institute, University of Maryland, and the National Institute of Standards and Technology (NIST), College Park, MD 20742, USA
| | - Johannes Hecker Denschlag
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
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6
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Rvachov TM, Son H, Sommer AT, Ebadi S, Park JJ, Zwierlein MW, Ketterle W, Jamison AO. Long-Lived Ultracold Molecules with Electric and Magnetic Dipole Moments. PHYSICAL REVIEW LETTERS 2017; 119:143001. [PMID: 29053331 DOI: 10.1103/physrevlett.119.143001] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Indexed: 06/07/2023]
Abstract
We create fermionic dipolar ^{23}Na^{6}Li molecules in their triplet ground state from an ultracold mixture of ^{23}Na and ^{6}Li. Using magnetoassociation across a narrow Feshbach resonance followed by a two-photon stimulated Raman adiabatic passage to the triplet ground state, we produce 3×10^{4} ground state molecules in a spin-polarized state. We observe a lifetime of 4.6 s in an isolated molecular sample, approaching the p-wave universal rate limit. Electron spin resonance spectroscopy of the triplet state was used to determine the hyperfine structure of this previously unobserved molecular state.
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Affiliation(s)
- Timur M Rvachov
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Hyungmok Son
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Ariel T Sommer
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Sepehr Ebadi
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
| | - Juliana J Park
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Martin W Zwierlein
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Wolfgang Ketterle
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Alan O Jamison
- Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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7
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Above-threshold scattering about a Feshbach resonance for ultracold atoms in an optical collider. Nat Commun 2017; 8:452. [PMID: 28878374 PMCID: PMC5587761 DOI: 10.1038/s41467-017-00458-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/29/2017] [Indexed: 11/13/2022] Open
Abstract
Ultracold atomic gases have realized numerous paradigms of condensed matter physics, where control over interactions has crucially been afforded by tunable Feshbach resonances. So far, the characterization of these Feshbach resonances has almost exclusively relied on experiments in the threshold regime near zero energy. Here, we use a laser-based collider to probe a narrow magnetic Feshbach resonance of rubidium above threshold. By measuring the overall atomic loss from colliding clouds as a function of magnetic field, we track the energy-dependent resonance position. At higher energy, our collider scheme broadens the loss feature, making the identification of the narrow resonance challenging. However, we observe that the collisions give rise to shifts in the center-of-mass positions of outgoing clouds. The shifts cross zero at the resonance and this allows us to accurately determine its location well above threshold. Our inferred resonance positions are in excellent agreement with theory. Studies on energy-dependent scattering of ultracold atoms were previously carried out near zero collision energies. Here, the authors observe a magnetic Feshbach resonance in ultracold Rb collisions for above-threshold energies and their method can also be used to detect higher partial wave resonances.
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8
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Inelastic collisions of ultracold triplet Rb 2 molecules in the rovibrational ground state. Nat Commun 2017; 8:14854. [PMID: 28332492 PMCID: PMC5376650 DOI: 10.1038/ncomms14854] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 02/07/2017] [Indexed: 11/08/2022] Open
Abstract
Exploring and controlling inelastic and reactive collisions on the quantum level is a main goal of the developing field of ultracold chemistry. For this, the preparation of precisely defined initial atomic and molecular states in tailored environments is necessary. Here we present experimental studies of inelastic collisions of metastable ultracold Rb2 molecules in an array of quasi-1D potential tubes. In particular, we investigate collisions of molecules in the absolute lowest triplet energy level where any inelastic process requires a change of the electronic state. Remarkably, we find similar decay rates as for collisions between rotationally or vibrationally excited triplet molecules where other decay paths are also available. The decay rates are close to the ones for universal reactions but vary considerably when confinement and collision energy are changed. This might be exploited to control the collisional properties of molecules. Investigating the collisional behaviour of molecules on the quantum level is the key in understanding and controlling chemical reactions. Here the authors measure inelastic collision rates for ultracold Rb2 dimers in precisely defined quantum states and show that the rates can be tuned via external parameters.
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9
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Lara M, Jambrina PG, Aoiz FJ, Launay JM. Cold and ultracold dynamics of the barrierless D+ + H2 reaction: Quantum reactive calculations for ∼R−4 long range interaction potentials. J Chem Phys 2015; 143:204305. [DOI: 10.1063/1.4936144] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Manuel Lara
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - P. G. Jambrina
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - F. J. Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - J.-M. Launay
- Institut de Physique de Rennes, UMR CNRS 6251, Université de Rennes I, F-35042 Rennes, France
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10
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Wang TT, Heo MS, Rvachov TM, Cotta DA, Ketterle W. Deviation from universality in collisions of ultracold 6Li2 molecules. PHYSICAL REVIEW LETTERS 2013; 110:173203. [PMID: 23679724 DOI: 10.1103/physrevlett.110.173203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Indexed: 06/02/2023]
Abstract
Collisions of 6Li2 molecules with free 6Li atoms reveal a striking deviation from universal predictions based on long-range van der Waals interactions. Li2 closed-channel molecules are formed in the highest vibrational state near a narrow Feshbach resonance and decay via two-body collisions with Li2, Li, and Na. For Li2 + Li2 and Li2 + Na, the decay rates agree with the universal predictions of the quantum Langevin model. In contrast, the rate for Li2 + Li is exceptionally small, with an upper bound 10 times smaller than the universal prediction. This can be explained by the low density of available decay states in systems of light atoms [G. Quéméner, J.-M. Launay, and P. Honvault, Phys. Rev. A 75, 050701 (2007)], for which such collisions have not been studied before.
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Affiliation(s)
- Tout T Wang
- MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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11
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Affiliation(s)
- Goulven Quéméner
- JILA, University of Colorado,
Boulder, CO 80309-0440, United States
| | - Paul S. Julienne
- Joint Quantum Institute, NIST
and the University of Maryland, Gaithersburg, Maryland 20899-8423,
United States
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12
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Lara M, Dayou F, Launay JM. Reaching the cold regime: S(1D) + H2 and the role of long-range interactions in open shell reactive collisions. Phys Chem Chem Phys 2011; 13:8359-70. [DOI: 10.1039/c0cp02091e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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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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14
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Knoop S, Ferlaino F, Berninger M, Mark M, Nägerl HC, Grimm R, D'Incao JP, Esry BD. Magnetically controlled exchange process in an ultracold atom-dimer mixture. PHYSICAL REVIEW LETTERS 2010; 104:053201. [PMID: 20366759 DOI: 10.1103/physrevlett.104.053201] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Indexed: 05/29/2023]
Abstract
We report on the observation of an elementary exchange process in an optically trapped ultracold sample of atoms and Feshbach molecules. We can magnetically control the energetic nature of the process and tune it from endoergic to exoergic, enabling the observation of a pronounced threshold behavior. In contrast to relaxation to more deeply bound molecular states, the exchange process does not lead to trap loss. We find excellent agreement between our experimental observations and calculations based on the solutions of three-body Schrödinger equation in the adiabatic hyperspherical representation. The high efficiency of the exchange process is explained by the halo character of both the initial and final molecular states.
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Affiliation(s)
- S Knoop
- Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria
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15
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Gneiting C, Hornberger K. Bell test for the free motion of material particles. PHYSICAL REVIEW LETTERS 2008; 101:260503. [PMID: 19113762 DOI: 10.1103/physrevlett.101.260503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Indexed: 05/27/2023]
Abstract
We present a scheme to establish nonclassical correlations in the motion of two macroscopically separated massive particles without resorting to entanglement in their internal degrees of freedom. It is based on the dissociation of a diatomic molecule with two temporally separated Feshbach pulses generating a motional state of two counterpropagating atoms that is capable of violating a Bell inequality by means of correlated single-particle interferometry. We evaluate the influence of dispersion on the Bell correlation, showing it to be important but manageable in a proposed experimental setup. The latter employs Bose-Einstein condensation of fermionic lithium atoms, uses laser-guided atom interferometry, and seems to be within the reach of present-day technology.
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Affiliation(s)
- Clemens Gneiting
- Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, 80333 Munich, Germany
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16
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Inada Y, Horikoshi M, Nakajima S, Kuwata-Gonokami M, Ueda M, Mukaiyama T. Collisional properties of p-wave Feshbach molecules. PHYSICAL REVIEW LETTERS 2008; 101:100401. [PMID: 18851195 DOI: 10.1103/physrevlett.101.100401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Indexed: 05/26/2023]
Abstract
We have observed p-wave Feshbach molecules for all three combinations of the two lowest hyperfine spin states of 6Li. By creating a pure molecular sample in an optical trap, we measured the inelastic collision rates of p-wave molecules. We have also measured the elastic collision rate from the thermalization rate of a breathing mode which was excited spontaneously upon molecular formation.
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Affiliation(s)
- Yasuhisa Inada
- ERATO Macroscopic Quantum Control Project, JST, Yayoi, Bunkyo-Ku, Tokyo 113-8656, Japan
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17
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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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18
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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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19
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Cvitas MT, Soldán P, Hutson JM, Honvault P, Launay JM. Interactions and dynamics in Li+Li2 ultracold collisions. J Chem Phys 2007; 127:074302. [PMID: 17718608 DOI: 10.1063/1.2752162] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A potential energy surface for the lowest quartet electronic state ((4)A(')) of lithium trimer is developed and used to study spin-polarized Li+Li(2) collisions at ultralow kinetic energies. The potential energy surface allows barrierless atom exchange reactions. Elastic and inelastic cross sections are calculated for collisions involving a variety of rovibrational states of Li(2). Inelastic collisions are responsible for trap loss in molecule production experiments. Isotope effects and the sensitivity of the results to details of the potential energy surface are investigated. It is found that for vibrationally excited states, the cross sections are only quite weakly dependent on details of the potential energy surface.
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Affiliation(s)
- Marko T Cvitas
- Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, United Kingdom
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20
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Driben R, Oz Y, Malomed BA, Gubeskys A, Yurovsky VA. Mismatch management for optical and matter-wave quadratic solitons. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 75:026612. [PMID: 17358441 DOI: 10.1103/physreve.75.026612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2006] [Indexed: 05/14/2023]
Abstract
We propose a way to control solitons in chi(2) (quadratically nonlinear) systems by means of periodic modulation imposed on the phase-mismatch parameter ("mismatch management," MM). It may be realized in the cotransmission of fundamental-frequency (FF) and second-harmonic (SH) waves in a planar optical waveguide via a long-period modulation of the usual quasi-phase-matching pattern of ferroelectric domains. In an altogether different physical setting, the MM may also be implemented by dint of the Feshbach resonance in a harmonically modulated magnetic field in a hybrid atomic-molecular Bose-Einstein condensate (BEC), with the atomic and molecular mean fields (MFs) playing the roles of the FF and SH, respectively. Accordingly, the problem is analyzed in two different ways. First, in the optical model, we identify stability regions for spatial solitons in the MM system, in terms of the MM amplitude and period, using the MF equations for spatially inhomogeneous configurations. In particular, an instability enclave is found inside the stability area. The robustness of the solitons is also tested against variation of the shape of the input pulse, and a threshold for the formation of stable solitons is found in terms of the power. Interactions between stable solitons are virtually unaffected by the MM. The second method (parametric approximation), going beyond the MF description, is developed for spatially homogeneous states in the BEC model. It demonstrates that the MF description is valid for large modulation periods, while, at smaller periods, non-MF components acquire gain, which implies destruction of the MF under the action of the high-frequency MM.
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Affiliation(s)
- R Driben
- Department of Interdisciplinary Studies, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
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21
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22
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Bodo E, Gianturco FA. Collisional quenching of molecular ro-vibrational energy by He buffer loading at ultralow energies. INT REV PHYS CHEM 2006. [DOI: 10.1080/01442350600772928] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Kheruntsyan KV. Quantum atom optics with fermions from molecular dissociation. PHYSICAL REVIEW LETTERS 2006; 96:110401. [PMID: 16605799 DOI: 10.1103/physrevlett.96.110401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Indexed: 05/08/2023]
Abstract
We study a fermionic atom optics counterpart of parametric down-conversion with photons. This can be realized through dissociation of a Bose-Einstein condensate of molecular dimers consisting of fermionic atoms. We present a theoretical model describing the quantum dynamics of dissociation and find analytic solutions for mode occupancies and atomic pair correlations, valid in the short time limit. The solutions are used to identify upper bounds for the correlation functions, which are applicable to any fermionic system and correspond to ideal particle number-difference squeezing.
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Affiliation(s)
- K V Kheruntsyan
- ARC Centre of Excellence for Quantum-Atom Optics, School of Physical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
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24
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Thalhammer G, Winkler K, Lang F, Schmid S, Grimm R, Denschlag JH. Long-lived Feshbach molecules in a three-dimensional optical lattice. PHYSICAL REVIEW LETTERS 2006; 96:050402. [PMID: 16486906 DOI: 10.1103/physrevlett.96.050402] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Indexed: 05/06/2023]
Abstract
We have created and trapped a pure sample of Feshbach molecules in a three-dimensional optical lattice. Compared to previous experiments without a lattice, we find dramatic improvements such as long lifetimes of up to 700 ms and a near unit efficiency for converting tightly confined atom pairs into molecules. The lattice shields the trapped molecules from collisions and, thus, overcomes the problem of inelastic decay by vibrational quenching. Furthermore, we have developed an advanced purification scheme that removes residual atoms, resulting in a lattice in which individual sites are either empty or filled with a single molecule in the vibrational ground state of the lattice.
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Affiliation(s)
- G Thalhammer
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
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Zahzam N, Vogt T, Mudrich M, Comparat D, Pillet P. Atom-molecule collisions in an optically trapped gas. PHYSICAL REVIEW LETTERS 2006; 96:023202. [PMID: 16486571 DOI: 10.1103/physrevlett.96.023202] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Indexed: 05/06/2023]
Abstract
Cold inelastic collisions between confined cesium (Cs) atoms and Cs2 molecules are investigated inside a CO2 laser dipole trap. Inelastic atom-molecule collisions can be observed and measured with a rate coefficient of approximately 2.6 x 10(-11) cm3 s(-1), mainly independent of the molecular rovibrational state populated. Lifetimes of purely atomic and molecular samples are essentially limited by rest gas collisions. The pure molecular trap lifetime ranges 0.3-1 s, 4 times smaller than the atomic one, as is also observed in a pure magnetic trap. We give an estimation of the inelastic molecule-molecule collision rate to be approximately 10(-11) cm3 s(-1).
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Affiliation(s)
- N Zahzam
- Laboratoire Aimé Cotton, CNRS, Campus d'Orsay Bâtiment 505, 91405 Orsay, France
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26
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Staanum P, Kraft SD, Lange J, Wester R, Weidemüller M. Experimental investigation of ultracold atom-molecule collisions. PHYSICAL REVIEW LETTERS 2006; 96:023201. [PMID: 16486570 DOI: 10.1103/physrevlett.96.023201] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Indexed: 05/06/2023]
Abstract
Ultracold collisions between Cs atoms and Cs2 dimers in the electronic ground state are observed in an optically trapped gas of atoms and molecules. The Cs2 molecules are formed in the triplet ground state by cw photoassociation through the outer well of the 0-(g) (P3/2) excited electronic state. Inelastic atom-molecule collisions converting internal excitation into kinetic energy lead to a loss of Cs2 molecules from the dipole trap. Rate coefficients are determined for collisions involving Cs atoms in either the F=3 or F=4 hyperfine ground state, and Cs2 molecules in either highly vibrationally excited states (nu'=32-47) or in low vibrational states (nu'=4-6) of the a3 summation(u)+ triplet ground state. The rate coefficients beta approximately 10(-10) cm3/s are found to be largely independent of the vibrational and rotational excitation indicating unitary limited cross sections.
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Affiliation(s)
- Peter Staanum
- Physikalisches Institut, Universität Freiburg, Hermann-Herder-Strassee 3, 79104 Freiburg, Germany
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27
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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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28
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Kheruntsyan KV, Olsen MK, Drummond PD. Einstein-Podolsky-Rosen correlations via dissociation of a molecular Bose-Einstein condensate. PHYSICAL REVIEW LETTERS 2005; 95:150405. [PMID: 16241704 DOI: 10.1103/physrevlett.95.150405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Indexed: 05/05/2023]
Abstract
Recent experimental measurements of atomic intensity correlations through atom shot noise suggest that atomic quadrature phase correlations may soon be measured with a similar precision. We propose a test of local realism with mesoscopic numbers of massive particles based on such measurements. Using dissociation of a Bose-Einstein condensate of diatomic molecules into bosonic atoms, we demonstrate that strongly entangled atomic beams may be produced which possess Einstein-Podolsky-Rosen (EPR) correlations in field quadratures in direct analogy to the position and momentum correlations originally considered by EPR.
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Affiliation(s)
- K V Kheruntsyan
- ARC Centre of Excellence for Quantum-Atom Optics, School of Physical Sciences, University of Queensland, Brisbane, Qld 4072, Australia
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29
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Sage JM, Sainis S, Bergeman T, DeMille D. Optical production of ultracold polar molecules. PHYSICAL REVIEW LETTERS 2005; 94:203001. [PMID: 16090241 DOI: 10.1103/physrevlett.94.203001] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2004] [Indexed: 05/03/2023]
Abstract
We demonstrate the production of ultracold polar RbCs molecules in their vibronic ground state, via photoassociation of laser-cooled atoms followed by a laser-stimulated state transfer process. The resulting sample of X1Sigma+ (nu = 0) molecules has a translational temperature of approximately 100 microK and a narrow distribution of rotational states. With the method described here it should be possible to produce samples even colder in all degrees of freedom, as well as other bialkali species.
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Affiliation(s)
- Jeremy M Sage
- Department of Physics, Yale University, New Haven, Connecticut 06520, USA
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30
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Chin C, Kraemer T, Mark M, Herbig J, Waldburger P, Nägerl HC, Grimm R. Observation of Feshbach-like resonances in collisions between ultracold molecules. PHYSICAL REVIEW LETTERS 2005; 94:123201. [PMID: 15903917 DOI: 10.1103/physrevlett.94.123201] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Indexed: 05/02/2023]
Abstract
We observe magnetically tuned collision resonances for ultracold Cs2 molecules stored in a CO2-laser trap. By magnetically levitating the molecules against gravity, we precisely measure their magnetic moment. We find an avoided level crossing which allows us to transfer the molecules into another state. In the new state, two Feshbach-like collision resonances show up as strong inelastic loss features. We interpret these resonances as being induced by Cs4 bound states near the molecular scattering continuum. The tunability of the interactions between molecules opens up novel applications such as controlled chemical reactions and synthesis of ultracold complex molecules.
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Affiliation(s)
- C Chin
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
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31
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Abo-Shaeer JR, Miller DE, Chin JK, Xu K, Mukaiyama T, Ketterle W. Coherent molecular optics using ultracold sodium dimers. PHYSICAL REVIEW LETTERS 2005; 94:040405. [PMID: 15783537 DOI: 10.1103/physrevlett.94.040405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Indexed: 05/24/2023]
Abstract
Coherent molecular optics is performed using two-photon Bragg scattering. Molecules were produced by sweeping an atomic Bose-Einstein condensate through a Feshbach resonance. The spectral width of the molecular Bragg resonance corresponded to an instantaneous temperature of 20 nK, indicating that atomic coherence was transferred directly to the molecules. An autocorrelating interference technique was used to observe the quadratic spatial dependence of the phase of an expanding molecular cloud. Finally, atoms initially prepared in two momentum states were observed to cross pair with one another, forming molecules in a third momentum state. This process is analogous to sum-frequency generation in optics.
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Affiliation(s)
- J R Abo-Shaeer
- Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, MIT, Cambridge, Massachusetts 02139, USA.
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32
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Cvitas MT, Soldán P, Hutson JM, Honvault P, Launay JM. Ultracold Li + Li2 collisions: bosonic and fermionic cases. PHYSICAL REVIEW LETTERS 2005; 94:033201. [PMID: 15698261 DOI: 10.1103/physrevlett.94.033201] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Indexed: 05/24/2023]
Abstract
We have carried out quantum dynamical calculations of vibrational quenching in Li + Li(2) collisions for both bosonic (7)Li and fermionic (6)Li. These are the first ever such calculations involving fermionic atoms. We find that for the low initial vibrational states considered here (v < or = 3), the quenching rates are not suppressed for fermionic atoms. This contrasts with the situation found experimentally for molecules formed via Feshbach resonances in very high vibrational states.
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Affiliation(s)
- Marko T Cvitas
- Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK
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33
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Thompson ST, Hodby E, Wieman CE. Spontaneous dissociation of 85Rb Feshbach molecules. PHYSICAL REVIEW LETTERS 2005; 94:020401. [PMID: 15698150 DOI: 10.1103/physrevlett.94.020401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Indexed: 05/24/2023]
Abstract
The spontaneous dissociation of 85Rb dimers in the highest lying vibrational level has been observed in the vicinity of the Feshbach resonance that was used to produce them. The molecular lifetime shows a strong dependence on magnetic field, varying by 3 orders of magnitude between 155.5 G and 162.2 G. Our measurements are in good agreement with theoretical predictions in which molecular dissociation is driven by inelastic spin relaxation. Molecule lifetimes of tens of milliseconds can be achieved within approximately a 1 G wide region directly above the Feshbach resonance.
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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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34
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Chwedeńczuk J, Góral K, Köhler T, Julienne PS. Molecular production in two component atomic fermi gases. PHYSICAL REVIEW LETTERS 2004; 93:260403. [PMID: 15697957 DOI: 10.1103/physrevlett.93.260403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Indexed: 05/24/2023]
Abstract
We provide a practical approach to the molecular production via linear downward sweeps of Feshbach resonances in degenerate Fermi gases containing incoherent mixtures of two atomic spin states. We show that the efficiency of the association of atoms is determined just by the Landau-Zener parameter in addition to the density of the gas. Our approach of pairwise summation of the microscopic binary transition probabilities leads to an intuitive explanation for the observed saturation of the molecular production and recovers all atomic loss curves of Regal et al. [Nature (London) 427, 47 (2003))]] as well as Strecker et al. [Phys. Rev. Lett. 91, 080406 (2003))]] without adjustable parameters.
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Affiliation(s)
- Jan Chwedeńczuk
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
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