36 research outputs found
The Efimov effect in lithium 6
We analyse the recent experiments investigating the low-energy physics of
three lithium 6 atoms in different internal states with resonant two-body
scattering lengths. All observed features are qualitatively consistent with the
expected Efimov effect, i.e. the effective universal three-body attraction that
arises for large values of the scattering lengths. However, we find that a
quantitative description at negative energy requires non-universal two- and
three-body corrections due to presently unknown behaviour at short distance. An
attempt to implement these corrections is made through energy-dependent
parameters fitted to the experimental data.Comment: 12 pages, 8 figures. Same as published version. Contains additions
detailing the derivation of some formulae;
http://dx.doi.org/10.1016/j.crhy.2010.12.00
Universal geometry of two-neutron halos and Borromean Efimov states close to dissociation
The geometry of Borromean three-body halos, such as two-neutron halo nuclei
or triatomic molecules close to dissociation, is investigated using a
three-body model. This model enables to analytically derive the universal
geometric properties found recently within an effective-field theory for halos
made of a core and two resonantly-interacting particles [Phys. Rev. Lett., 128,
212501 (2022)]. It is shown that these properties not only apply to the ground
three-body state, but also to all the excited (Efimov) states where the
core-particle interaction is resonant. Furthermore, a universal geometry
persists away from the resonant regime between the two particles, for any state
close to the three-body threshold. This "halo universality" is different from
the Efimov universality which is only approximate for the ground state. It is
explained by the separability of the hyper-radius and hyper-angles close to the
three-body dissociation threshold.Comment: 7 pages + appendix, 7 figure
Optical Feshbach resonances of Alkaline-Earth atoms in a 1D or 2D optical lattice
Motivated by a recent experiment by Zelevinsky et al. [Phys. Rev. Lett. 96,
203201], we present the theory for photoassociation and optical Feshbach
resonances of atoms confined in a tight one-dimensional (1D) or two-dimensional
(2D) optical lattice. In the case of an alkaline-earth intercombination
resonance, the narrow natural width of the line makes it possible to observe
clear manifestations of the dimensionality, as well as some sensitivity to the
scattering length of the atoms. Among possible applications, a 2D lattice may
be used to increase the spectroscopic resolution by about one order of
magnitude. Furthermore, a 1D lattice induces a shift which provides a new way
of determining the strength of a resonance by spectroscopic measurements.Comment: 12 pages, 4 figures. Typos were corrected and a connection was made
to the fermionization of boson