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Kim LY, Park S, Lee CY, Schöllkopf W, Zhao BS. Enhanced elastic scattering of He 2 and He 3 from solids by multiple-edge diffraction. Phys Chem Chem Phys 2022; 24:21593-21600. [PMID: 35971780 DOI: 10.1039/d2cp02641d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on a method of enhanced elastic and coherent reflection of 4He2 and 4He3 from a micro-structured solid surface under grazing incidence conditions. The van der Waals bound ground-state helium clusters exhibit fundamental quantum effects: 4He2, characterized by a single ro-vibrational bound state of 10-7 eV dissociation energy, is known to be a quantum halo state; and 4He3 is the only electronic ground-state triatomic system possessing an Efimov state in addition to the ro-vibrational ground state. Classical methods to select and manipulate these clusters by interaction with a solid surface fail due to their exceedingly fragile bonds. Quantum reflection under grazing incidence conditions was demonstrated as a viable tool for elastic scattering from a solid surface but suffers from small reflection probabilities for typical conditions. Here we demonstrate that multiple-edge diffraction enables enhanced elastic scattering of the clusters from a solid. A dual-period reflection grating, where the strips consist of micro-structured edge arrays, shows an up to ten fold increased reflection probability as compared to its conventional counterpart where the strips are plane patches enabling quantum reflection of the clusters. The observed diffraction patterns of the clusters provide evidence of the coherent and elastic nature of scattering by multiple-edge diffraction.
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Affiliation(s)
- Lee Yeong Kim
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea.
| | - Sanghwan Park
- Department of Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
| | - Chang Young Lee
- Department of Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
| | - Wieland Schöllkopf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Bum Suk Zhao
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea. .,Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
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2
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Naidon P, Endo S. Efimov physics: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:056001. [PMID: 28350544 DOI: 10.1088/1361-6633/aa50e8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This article reviews theoretical and experimental advances in Efimov physics, an array of quantum few-body and many-body phenomena arising for particles interacting via short-range resonant interactions, that is based on the appearance of a scale-invariant three-body attraction theoretically discovered by Vitaly Efimov in 1970. This three-body effect was originally proposed to explain the binding of nuclei such as the triton and the Hoyle state of carbon-12, and later considered as a simple explanation for the existence of some halo nuclei. It was subsequently evidenced in trapped ultra-cold atomic clouds and in diffracted molecular beams of gaseous helium. These experiments revealed that the previously undetermined three-body parameter introduced in the Efimov theory to stabilise the three-body attraction typically scales with the range of atomic interactions. The few- and many-body consequences of the Efimov attraction have been since investigated theoretically, and are expected to be observed in a broader spectrum of physical systems.
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Abstract
Femtosecond laser pulses help to take a snapshot of the huge elusive Efimov state
[Also see Report by
Kunitski
et al.
]
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Kunitski M, Zeller S, Voigtsberger J, Kalinin A, Schmidt LPH, Schöffler M, Czasch A, Schöllkopf W, Grisenti RE, Jahnke T, Blume D, Dörner R. Observation of the Efimov state of the helium trimer. Science 2015; 348:551-5. [DOI: 10.1126/science.aaa5601] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Maksim Kunitski
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Stefan Zeller
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Jörg Voigtsberger
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Anton Kalinin
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Lothar Ph. H. Schmidt
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Markus Schöffler
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Achim Czasch
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Wieland Schöllkopf
- Department of Molecular Physics, Fritz-Haber-Institut, Faradayweg 4-6, 14195 Berlin, Germany
| | - Robert E. Grisenti
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
- GSI Helmholtz Centre for Heavy Ion Research, Planckstraße 1, 64291 Darmstadt, Germany
| | - Till Jahnke
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
| | - Dörte Blume
- Department of Physics and Astronomy, Washington State University, Pullman, WA 99164-2814, USA
| | - Reinhard Dörner
- Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany
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Voigtsberger J, Zeller S, Becht J, Neumann N, Sturm F, Kim HK, Waitz M, Trinter F, Kunitski M, Kalinin A, Wu J, Schöllkopf W, Bressanini D, Czasch A, Williams JB, Ullmann-Pfleger K, Schmidt LPH, Schöffler MS, Grisenti RE, Jahnke T, Dörner R. Imaging the structure of the trimer systems 4He3 and 3He4He2. Nat Commun 2014; 5:5765. [DOI: 10.1038/ncomms6765] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/05/2014] [Indexed: 12/20/2022] Open
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Abstract
Despite their apparent simplicity, the properties of the two helium trimers, (4)He3 and (3)He(4)He2, are still not completely understood. In particular, the existence of a bound state of the asymmetric trimer (3)He(4)He2 was established many years ago, using different theoretical approaches, and later it was experimentally detected. However its structural properties have not been thoroughly investigated so far, probably because an accurate theoretical description of this very weakly bound system is computationally quite demanding. In this work we give for the first time an accurate and complete theoretical description of the geometrical structure of this fragile system using quantum Monte Carlo techniques employing the TTY potential and compare its properties with those of (4)He2 and (4)He3. We compute average values of distances and angles, along with the angle-angle distribution function: a two-dimensional probability distribution well suited to discuss the shape of a trimer. Our analysis shows that the lighter isotope is very diffuse and can be found at large distances from the other two atoms, but also close to the center of mass of the system in nearly linear configurations. For this system the concept of "equilibrium structure" is meaningless and all kinds of three-atom configurations must be taken into account in its description.
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Affiliation(s)
- Dario Bressanini
- Dipartimento di Scienza e Alta Tecnologia, Università dell'Insubria , Via Lucini 3, 22100 Como Italy
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7
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Efremov MA, Plimak L, Ivanov MY, Schleich WP. Three-body bound states in atomic mixtures with resonant p-wave interaction. PHYSICAL REVIEW LETTERS 2013; 111:113201. [PMID: 24074084 DOI: 10.1103/physrevlett.111.113201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Indexed: 06/02/2023]
Abstract
We employ the Born-Oppenheimer approximation to find the effective potential in a three-body system consisting of a light particle and two heavy ones when the heavy-light short-range interaction potential has a resonance corresponding to a nonzero orbital angular momentum. In the case of an exact resonance in the p-wave scattering amplitude, the effective potential is attractive and long range; namely, it decreases as the third power of the interatomic distance. Moreover, we show that the range and power of the potential, as well as the number of bound states, are determined by the mass ratio of the particles and the parameters of the heavy-light short-range potential.
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Affiliation(s)
- Maxim A Efremov
- Institut für Quantenphysik and Center for Integrated Quantum Science and Technology (IQST), Universität Ulm, D-89081 Ulm, Germany and A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, 119991 Moscow, Russia
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8
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Zhao BS, Zhang W, Schöllkopf W. Non-destructive quantum reflection of helium dimers and trimers from a plane ruled grating. Mol Phys 2013. [DOI: 10.1080/00268976.2013.787150] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Bum Suk Zhao
- a School of Nano-Bioscience and Chemical Engineering , Ulsan National Institute of Science and Technology (UNIST) , Ulsan , 689-798 , Korea
| | - Weiqing Zhang
- b Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6 , Berlin , 14195 , Germany
| | - Wieland Schöllkopf
- b Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6 , Berlin , 14195 , Germany
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9
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Affiliation(s)
- J. Peter Toennies
- a Max-Planck-Institut für Dynamik und Selbstorganisation , Göttingen , Germany
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10
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Cencek W, Przybytek M, Komasa J, Mehl JB, Jeziorski B, Szalewicz K. Effects of adiabatic, relativistic, and quantum electrodynamics interactions on the pair potential and thermophysical properties of helium. J Chem Phys 2012; 136:224303. [DOI: 10.1063/1.4712218] [Citation(s) in RCA: 209] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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11
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García-Vela A, Cabanillas-Vidosa I, Ferrero JC, Pino GA. The role of orbiting resonances in the vibrational relaxation of I(2)(B,v' = 21) by collisions with He at very low energies: a theoretical and experimental study. Phys Chem Chem Phys 2012; 14:5570-80. [PMID: 22434127 DOI: 10.1039/c2cp24061k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The low-energy collisions of I(2)(B,v' = 21) with He involving collision-induced vibrational relaxation of I(2) are investigated both experimentally and by means of wave packet simulations. The theoretical cross sections exhibit a structure of peaks originated by orbiting resonances of the I(2)(B,v' = 21) - He van der Waals complex formed in the I(2) + He collisions. Such a structure has similar characteristics as the structure of peaks found in the experimental cross sections. In fact, four of the five peaks of the measured cross sections appear at positions nearly coincident with those of four of the peaks found in the theoretical cross sections. Thus this result confirms the experimental finding that enhancement of I(2) vibrational relaxation is caused by the population of I(2)(B,v' = 21) - He orbiting resonances populated upon the low-energy collisions. The possibility of using this mechanism in the vibrational cooling of diatomic molecules is discussed.
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Affiliation(s)
- Alberto García-Vela
- Instituto de Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain.
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12
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Blume D. Few-body physics with ultracold atomic and molecular systems in traps. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:046401. [PMID: 22790507 DOI: 10.1088/0034-4885/75/4/046401] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Few-body physics has played a prominent role in atomic, molecular and nuclear physics since the early days of quantum mechanics. It is now possible-thanks to tremendous progress in cooling, trapping and manipulating ultracold samples-to experimentally study few-body phenomena in trapped atomic and molecular systems with unprecedented control. This review summarizes recent studies of few-body phenomena in trapped atomic and molecular gases, with an emphasis on small trapped systems. We start by introducing the free-space scattering properties and then investigate what happens when two particles, bosons or fermions, are placed in an external confinement. Next, various three-body systems are treated analytically in limiting cases. Our current understanding of larger two-component Fermi systems and Bose systems is reviewed, and connections with the corresponding bulk systems are established. Lastly, future prospects and challenges are discussed. Throughout this review, commonalities with other systems such as nuclei or quantum dots are highlighted.
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Affiliation(s)
- D Blume
- Department of Physics and Astronomy, Washington State University, Pullman, WA 99164-2814, USA
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13
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Bressanini D, Morosi G. What is the shape of the helium trimer? A comparison with the neon and argon trimers. J Phys Chem A 2011; 115:10880-7. [PMID: 21894924 DOI: 10.1021/jp206612j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite its apparent simplicity and extensive theoretical investigations, the issue of what is the shape of the helium trimer is still debated in the literature. After reviewing previous conflicting interpretations of computational studies, we introduce the angle-angle distribution function as a tool to discuss in a simple way the shape of any trimer. We compute this function along with many different geometrical distributions using variational and diffusion Monte Carlo methods. We compare them with the corresponding ones for the neon and argon trimers. Our analysis shows that while Ne(3) and Ar(3) fluctuate around an equilibrium structure that is an equilateral triangle, (4)He(3) shows an extremely broad angle-angle distribution function, and all kinds of three-atom configurations must be taken into account in its description. Classifying (4)He(3) as either equilateral or linear or any other particular shape, as was done in the past, is not sensible, because in this case the intuitive notion of equilibrium structure is ill defined. Our results could help the interpretation of future experiments aimed at measuring the geometrical properties of the helium trimer.
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Affiliation(s)
- Dario Bressanini
- Dipartimento di Scienze Chimiche e Ambientali, Universita' dell'Insubria, Via Lucini 3, 22100 Como, Italy.
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14
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Das TK, Chakrabarti B, Canuto S. Use of correlated potential harmonic basis functions for the description of the 4He trimer and small clusters. J Chem Phys 2011; 134:164106. [PMID: 21528949 DOI: 10.1063/1.3583365] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A correlated many-body basis function is used to describe the (4)He trimer and small helium clusters ((4)He(N)) with N = 4-9. A realistic helium dimer potential is adopted. The ground state results of the (4)He dimer and trimer are in close agreement with earlier findings. But no evidence is found for the existence of Efimov state in the trimer for the actual (4)He-(4)He interaction. However, decreasing the potential strength we calculate several excited states of the trimer which exhibit Efimov character. We also solve for excited state energies of these clusters which are in good agreement with Monte Carlo hyperspherical description.
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Affiliation(s)
- Tapan Kumar Das
- Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009, India
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15
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Ulrich B, Vredenborg A, Malakzadeh A, Schmidt LPH, Havermeier T, Meckel M, Cole K, Smolarski M, Chang Z, Jahnke T, Dörner R. Imaging of the Structure of the Argon and Neon Dimer, Trimer, and Tetramer. J Phys Chem A 2011; 115:6936-41. [DOI: 10.1021/jp1121245] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- B. Ulrich
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - A. Vredenborg
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - A. Malakzadeh
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - L. Ph. H. Schmidt
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - T. Havermeier
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - M. Meckel
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - K. Cole
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - M. Smolarski
- Department Physik, ETH Zürich, Wolfgang-Pauli-Strasse 16, 8093 Zürich, Switzerland
| | - Z. Chang
- Physics Department, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506, United States
| | - T. Jahnke
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
| | - R. Dörner
- Institut für Kernphysik, Goethe Universität, Max-von-Laue-Strasse 1, 60486 Frankfurt, Germany
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16
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Brahms N, Tscherbul TV, Zhang P, Kłos J, Forrey RC, Au YS, Sadeghpour HR, Dalgarno A, Doyle JM, Walker TG. Formation and dynamics of van der Waals molecules in buffer-gas traps. Phys Chem Chem Phys 2011; 13:19125-41. [DOI: 10.1039/c1cp21317b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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18
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Brahms N, Tscherbul TV, Zhang P, Kłos J, Sadeghpour HR, Dalgarno A, Doyle JM, Walker TG. Formation of van der Waals molecules in buffer-gas-cooled magnetic traps [corrected]. PHYSICAL REVIEW LETTERS 2010; 105:033001. [PMID: 20867761 DOI: 10.1103/physrevlett.105.033001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 05/29/2010] [Indexed: 05/29/2023]
Abstract
We predict that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10(12) cm(-3). We explore the spin relaxation of these molecules in buffer-gas-loaded magnetic traps and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T(-6) thermal dependence of the spin-change rate of silver (Ag) trapped in dense (3)He is accounted for by the formation and spin change of Ag(3)He van der Waals molecules, thus providing indirect evidence for molecular formation in a buffer-gas trap.
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Affiliation(s)
- N Brahms
- Department of Physics, University of California, Berkeley, California 97420, USA
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19
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Chandler DW. Cold and ultracold molecules: Spotlight on orbiting resonances. J Chem Phys 2010; 132:110901. [DOI: 10.1063/1.3357286] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Ferlaino F, Grimm R. Forty years of Efimov physics: How a bizarre prediction turned into a hot topic. PHYSICS 2010. [DOI: 10.1103/physics.3.9] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Williams JR, Hazlett EL, Huckans JH, Stites RW, Zhang Y, O'Hara KM. Evidence for an excited-state Efimov trimer in a three-component Fermi gas. PHYSICAL REVIEW LETTERS 2009; 103:130404. [PMID: 19905496 DOI: 10.1103/physrevlett.103.130404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Indexed: 05/28/2023]
Abstract
We observe enhanced three-body recombination in a three-component ;{6}Li Fermi gas attributable to an excited Efimov trimer state intersecting the three-atom scattering threshold near 895 G. From measurements of the recombination rate we determine the Efimov parameters kappa_{*} and eta_{*} for the universal region above 600 G which includes three overlapping Feshbach resonances. The value of kappa_{*} also predicts the locations of loss features previously observed near 130 and 500 G [T. B. Ottenstein, Phys. Rev. Lett. 101, 203202 (2008)10.1103/PhysRevLett.101.203202; J. H. Huckans, Phys. Rev. Lett. 102, 165302 (2009)10.1103/PhysRevLett.102.165302] suggesting they are associated with a ground-state Efimov trimer near threshold. We also report on the realization of a degenerate three-component Fermi gas with approximate SU(3) symmetry.
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Affiliation(s)
- J R Williams
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802-6300, USA
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22
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Abstract
Cool molecules: The cooling of molecules to sub-Kelvin temperatures promises to have a great impact in chemistry and physics. Recently, the first experimental realizations of samples of deeply bound molecules that are approaching the ultracold regime were reported. In this contribution, these interesting results are briefly discussed.
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Affiliation(s)
- David W Chandler
- Combustion Research Facility, Sandia National Laboratory, Livermore CA 94550, USA.
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24
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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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25
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Chaiken J, Goodisman J, Kornilov O, Peter Toennies J. Application of scaling and kinetic equations to helium cluster size distributions: Homogeneous nucleation of a nearly ideal gas. J Chem Phys 2006; 125:074305. [PMID: 16942337 DOI: 10.1063/1.2218837] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A previously published model of homogeneous nucleation [Villarica et al., J. Chem. Phys. 98, 4610 (1993)] based on the Smoluchowski [Phys. Z. 17, 557 (1916)] equations is used to simulate the experimentally measured size distributions of 4He clusters produced in free jet expansions. The model includes only binary collisions and does not consider evaporative effects, so that binary reactive collisions are rate limiting for formation of all cluster sizes despite the need for stabilization of nascent clusters. The model represents these data very well, accounting in some cases for nearly four orders of magnitude in variation in abundance over cluster sizes ranging up to nearly 100 atoms. The success of the model may be due to particularities of 4He clusters, i.e., their very low coalescence exothermicity, and to the low temperature of 6.7 K at which the data were collected.
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Affiliation(s)
- J Chaiken
- Department of Chemistry, Syracuse University, Syracuse, New York 13244-4100, USA.
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26
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Kraemer T, Mark M, Waldburger P, Danzl JG, Chin C, Engeser B, Lange AD, Pilch K, Jaakkola A, Nägerl HC, Grimm R. Evidence for Efimov quantum states in an ultracold gas of caesium atoms. Nature 2006; 440:315-8. [PMID: 16541068 DOI: 10.1038/nature04626] [Citation(s) in RCA: 827] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 02/02/2006] [Indexed: 11/09/2022]
Abstract
Systems of three interacting particles are notorious for their complex physical behaviour. A landmark theoretical result in few-body quantum physics is Efimov's prediction of a universal set of bound trimer states appearing for three identical bosons with a resonant two-body interaction. Counterintuitively, these states even exist in the absence of a corresponding two-body bound state. Since the formulation of Efimov's problem in the context of nuclear physics 35 years ago, it has attracted great interest in many areas of physics. However, the observation of Efimov quantum states has remained an elusive goal. Here we report the observation of an Efimov resonance in an ultracold gas of caesium atoms. The resonance occurs in the range of large negative two-body scattering lengths, arising from the coupling of three free atoms to an Efimov trimer. Experimentally, we observe its signature as a giant three-body recombination loss when the strength of the two-body interaction is varied. We also detect a minimum in the recombination loss for positive scattering lengths, indicating destructive interference of decay pathways. Our results confirm central theoretical predictions of Efimov physics and represent a starting point with which to explore the universal properties of resonantly interacting few-body systems. While Feshbach resonances have provided the key to control quantum-mechanical interactions on the two-body level, Efimov resonances connect ultracold matter to the world of few-body quantum phenomena.
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Affiliation(s)
- T Kraemer
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
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