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Title: Efimov physics in cold atoms

Abstract

Atoms with a large scattering length have universal low-energy properties that do not depend on the details of their structure or their interactions at short distances. In the 2-atom sector, the universal properties are familiar and depend only on the scattering length. In the 3-atom sector for identical bosons, the universal properties include the existence of a sequence of shallow triatomic molecules called Efimov trimers and log-periodic dependence of scattering observables on the energy and the scattering length. In this review, we summarize the universal results that are currently known. We also summarize the experimental information that is currently available with an emphasis on 3-atom loss processes.

Authors:
 [1];  [2]
  1. Department of Physics, Ohio State University, Columbus, OH 43210 (United States). E-mail: braaten@mps.ohio-state.edu
  2. Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn, 53115 Bonn (Germany). E-mail: hammer@itkp.uni-bonn.de
Publication Date:
OSTI Identifier:
20845988
Resource Type:
Journal Article
Resource Relation:
Journal Name: Annals of Physics (New York); Journal Volume: 322; Journal Issue: 1; Other Information: DOI: 10.1016/j.aop.2006.10.011; PII: S0003-4916(06)00238-7; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMS; BOSONS; INTERACTIONS; MOLECULES; PERIODICITY; SCATTERING; SCATTERING LENGTHS

Citation Formats

Braaten, Eric, and Hammer, H.-W. Efimov physics in cold atoms. United States: N. p., 2007. Web. doi:10.1016/j.aop.2006.10.011.
Braaten, Eric, & Hammer, H.-W. Efimov physics in cold atoms. United States. doi:10.1016/j.aop.2006.10.011.
Braaten, Eric, and Hammer, H.-W. Mon . "Efimov physics in cold atoms". United States. doi:10.1016/j.aop.2006.10.011.
@article{osti_20845988,
title = {Efimov physics in cold atoms},
author = {Braaten, Eric and Hammer, H.-W.},
abstractNote = {Atoms with a large scattering length have universal low-energy properties that do not depend on the details of their structure or their interactions at short distances. In the 2-atom sector, the universal properties are familiar and depend only on the scattering length. In the 3-atom sector for identical bosons, the universal properties include the existence of a sequence of shallow triatomic molecules called Efimov trimers and log-periodic dependence of scattering observables on the energy and the scattering length. In this review, we summarize the universal results that are currently known. We also summarize the experimental information that is currently available with an emphasis on 3-atom loss processes.},
doi = {10.1016/j.aop.2006.10.011},
journal = {Annals of Physics (New York)},
number = 1,
volume = 322,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • A new narrow three-atom loss resonance associated with an Efimov trimer crossing the three-atom threshold has recently been discovered in a many-body system of ultracold {sup 6}Li atoms in the three lowest hyperfine spin states at a magnetic field near 895 G. O'Hara and coworkers have used measurements of the three-body recombination rate in this region to determine the complex three-body parameter associated with Efimov physics. Using this parameter as the input, we calculate the universal predictions for the spectrum of Efimov states and for the three-body recombination rate in the universal region above 600 G where all three scatteringmore » lengths are large. We predict an atom-dimer loss resonance at 672+-2 G associated with an Efimov trimer disappearing through an atom-dimer threshold. We also predict an interference minimum in the three-body recombination rate at 759+-1 G where the three-spin mixture may be sufficiently stable to allow experimental study of the many-body system.« less
  • {sup 6}Li atoms in the three lowest hyperfine states display universal properties when the S-wave scattering length between each pair of states is large. Recent experiments reported four pronounced features arising from Efimov physics in the atom-dimer relaxation rate, namely two resonances and two local minima. We use the universal effective-field theory to calculate the atom-dimer relaxation rate at zero temperature. Our results describe the four features qualitatively and imply there is a hidden local minimum. In the vicinity of the resonance at 685 G, we perform a finite temperature calculation which improves the agreement of theory and experiment. Wemore » conclude that finite temperature effects cannot be neglected in the analysis of the experimental data.« less
  • We consider a system of three identical bosons near a Feshbach resonance in the universal regime with large scattering length usually described by model-independent zero-range potentials. We employ the adiabatic hyperspherical approximation and derive the rigorous large-distance equation for the adiabatic potential for finite-range interactions. The effective range correction to the zero-range approximation must be supplemented by a new term of the same order. The nonadiabatic term can be decisive. Efimov physics is always confined to the range between effective range and scattering length. The analytical results agree with numerical calculations for realistic potentials.
  • We explore the manifestation of Efimov physics through the collision energy dependence of the three-body scattering observables and propose that it can be measured by observing atom loss in collisions of Bose-Einstein condensates. Our study shows that log-periodic Efimov features in the scattering observables extend beyond the usual threshold regime to nonzero collision energies and result from two interfering pathways. Further, these oscillations have a one-to-one connection with the scattering length oscillations at zero energy and thus to Efimov states themselves.
  • Bosonic atom-trimer scattering is studied in the unitary limit using momentum-space equations for four-particle transition operators. The impact of the Efimov effect on the atom-trimer scattering observables is explored, and a number of universal relations is established. Positions and widths of tetramer resonances are determined. The trimer relaxation rate constant is calculated.