@article {1697,
title = {Photoassociation of spin polarized Chromium},
journal = {Physical Review A},
volume = {93},
year = {2016},
month = {2016/02/29},
pages = {021406},
abstract = {We report the homonuclear photoassociation (PA) of ultracold 52Cr atoms in an optical dipole trap. This constitutes the first measurement of PA in an element with total electron spin S~>1. Although Cr, with its 7S3 ground and 7P4,3,2 excited states, is expected to have a complicated PA spectrum we show that a spin polarized cloud exhibits a remarkably simple PA spectrum when circularly polarized light is applied. Over a scan range of 20 GHz below the 7P3 asymptote we observe two distinct vibrational series each following a LeRoy-Bernstein law for a C3/R3 potential with excellent agreement. We determine the C3 coefficients of the Hund{\textquoteright}s case c) relativistic adiabatic potentials to be -1.83{\textpm}0.02 a.u. and -1.46{\textpm}0.01a.u.. Theoretical non-rotating Movre-Pichler calculations enable a first assignment of the series to Ω=6u and 5g potential energy curves. In a different set of experiments we disturb the selection rules by a transverse magnetic field which leads to additional PA series.},
doi = {10.1103/PhysRevA.93.021406},
url = {http://arxiv.org/abs/1512.04378},
author = {Jahn R{\"u}hrig and Tobias B{\"a}uerle and Paul S. Julienne and Eite Tiesinga and Tilman Pfau}
}
@article {1294,
title = {Resonant control of polar molecules in an optical lattice},
journal = {Physical Review A},
volume = {85},
year = {2012},
month = {2012/2/8},
abstract = { We study the resonant control of two nonreactive polar molecules in an
optical lattice site, focussing on the example of RbCs. Collisional control can
be achieved by tuning bound states of the intermolecular dipolar potential, by
varying the applied electric field or trap frequency. We consider a wide range
of electric fields and trapping geometries, showing that a three-dimensional
optical lattice allows for significantly wider avoided crossings than free
space or quasi-two dimensional geometries. Furthermore, we find that dipolar
confinement induced resonances can be created with reasonable trapping
frequencies and electric fields, and have widths that will enable useful
control in forthcoming experiments.
},
doi = {10.1103/PhysRevA.85.022703},
url = {http://arxiv.org/abs/1111.0227v1},
author = {Thomas M. Hanna and Eite Tiesinga and William F. Mitchell and Paul S. Julienne}
}
@article {1301,
title = {Spatial separation in a thermal mixture of ultracold $^{174}$Yb and $^{87}$Rb atoms
},
journal = {Physical Review A},
volume = {83},
year = {2011},
month = {2011/4/21},
abstract = { We report on the observation of unusually strong interactions in a thermal
mixture of ultracold atoms which cause a significant modification of the
spatial distribution. A mixture of $^{87}$Rb and $^{174}$Yb with a temperature
of a few $\mu$K is prepared in a hybrid trap consisting of a bichromatic
optical potential superimposed on a magnetic trap. For suitable trap parameters
and temperatures, a spatial separation of the two species is observed. We infer
that the separation is driven by a large interaction strength between
$^{174}$Yb and $^{87}$Rb accompanied by a large three-body recombination rate.
Based on this assumption we have developed a diffusion model which reproduces
our observations.
},
doi = {10.1103/PhysRevA.83.040702},
url = {http://arxiv.org/abs/1104.1722v1},
author = {Florian Baumer and Frank M{\"u}nchow and Axel G{\"o}rlitz and Stephen E. Maxwell and Paul S. Julienne and Eite Tiesinga}
}
@article {1286,
title = {Creation and manipulation of Feshbach resonances with radio-frequency radiation
},
journal = {New Journal of Physics},
volume = {12},
year = {2010},
month = {2010/08/12},
pages = {083031},
abstract = { We present a simple technique for studying collisions of ultracold atoms in
the presence of a magnetic field and radio-frequency radiation (rf). Resonant
control of scattering properties can be achieved by using rf to couple a
colliding pair of atoms to a bound state. We show, using the example of 6Li,
that in some ranges of rf frequency and magnetic field this can be done without
giving rise to losses. We also show that halo molecules of large spatial extent
require much less rf power than deeply bound states. Another way to exert
resonant control is with a set of rf-coupled bound states, linked to the
colliding pair through the molecular interactions that give rise to
magnetically tunable Feshbach resonances. This was recently demonstrated for
87Rb [Kaufman et al., Phys. Rev. A 80:050701(R), 2009]. We examine the
underlying atomic and molecular physics which made this possible. Lastly, we
consider the control that may be exerted over atomic collisions by placing
atoms in superpositions of Zeeman states, and suggest that it could be useful
where small changes in scattering length are required. We suggest other species
for which rf and magnetic field control could together provide a useful tuning
mechanism.
},
doi = {10.1088/1367-2630/12/8/083031},
url = {http://arxiv.org/abs/1004.0636v1},
author = {Thomas M. Hanna and Eite Tiesinga and Paul S. Julienne}
}
@article {1293,
title = {Collisional cooling of ultra-cold atom ensembles using Feshbach resonances
},
journal = {Physical Review A},
volume = {80},
year = {2009},
month = {2009/9/8},
abstract = { We propose a new type of cooling mechanism for ultra-cold fermionic atom
ensembles, which capitalizes on the energy dependence of inelastic collisions
in the presence of a Feshbach resonance. We first discuss the case of a single
magnetic resonance, and find that the final temperature and the cooling rate is
limited by the width of the resonance. A concrete example, based on a p-wave
resonance of $^{40}$K, is given. We then improve upon this setup by using both
a very sharp optical or radio-frequency induced resonance and a very broad
magnetic resonance and show that one can improve upon temperatures reached with
current technologies.
},
doi = {10.1103/PhysRevA.80.030702},
url = {http://arxiv.org/abs/0903.2568v1},
author = {L. Mathey and Eite Tiesinga and Paul S. Julienne and Charles W. Clark}
}
@article {1280,
title = {Multi-channel modelling of the formation of vibrationally cold polar KRb molecules
},
journal = {New Journal of Physics},
volume = {11},
year = {2009},
month = {2009/05/14},
pages = {055043},
abstract = { We describe the theoretical advances that influenced the experimental
creation of vibrationally and translationally cold polar $^{40}$K$^{87}$Rb
molecules \cite{nphys08,science08}. Cold molecules were created from
very-weakly bound molecules formed by magnetic field sweeps near a Feshbach
resonance in collisions of ultra-cold $^{40}$K and $^{87}$Rb atoms. Our
analysis include the multi-channel bound-state calculations of the hyperfine
and Zeeman mixed X$^1\Sigma^+$ and a$^3\Sigma^+$ vibrational levels. We find
excellent agreement with the hyperfine structure observed in experimental data.
In addition, we studied the spin-orbit mixing in the intermediate state of the
Raman transition. This allowed us to investigate its effect on the
vibrationally-averaged transition dipole moment to the lowest ro-vibrational
level of the X$^1\Sigma^+$ state. Finally, we obtained an estimate of the
polarizability of the initial and final ro-vibrational states of the Raman
transition near frequencies relevant for optical trapping of the molecules.
},
doi = {10.1088/1367-2630/11/5/055043},
url = {http://arxiv.org/abs/0901.1486v1},
author = {Svetlana Kotochigova and Eite Tiesinga and Paul S. Julienne}
}
@article {1285,
title = {Prediction of Feshbach resonances from three input parameters},
journal = {Physical Review A},
volume = {79},
year = {2009},
month = {2009/4/30},
abstract = { We have developed a model of Feshbach resonances in gases of ultracold alkali
metal atoms using the ideas of multichannel quantum defect theory. Our model
requires just three parameters describing the interactions - the singlet and
triplet scattering lengths, and the long range van der Waals coefficient - in
addition to known atomic properties. Without using any further details of the
interactions, our approach can accurately predict the locations of resonances.
It can also be used to find the singlet and triplet scattering lengths from
measured resonance data. We apply our technique to $^{6}$Li--$^{40}$K and
$^{40}$K--$^{87}$Rb scattering, obtaining good agreement with experimental
results, and with the more computationally intensive coupled channels
technique.
},
doi = {10.1103/PhysRevA.79.040701},
url = {http://arxiv.org/abs/0903.0884v2},
author = {Thomas M. Hanna and Eite Tiesinga and Paul S. Julienne}
}
@article {1283,
title = {Avoided crossings between bound states of ultracold Cesium dimers},
journal = {Physical Review A},
volume = {78},
year = {2008},
month = {2008/11/5},
abstract = { We present an efficient new computational method for calculating the binding
energies of the bound states of ultracold alkali-metal dimers in the presence
of magnetic fields. The method is based on propagation of coupled differential
equations and does not use a basis set for the interatomic distance coordinate.
It is much more efficient than the previous method based on a radial basis set
and allows many more spin channels to be included. This is particularly
important in the vicinity of avoided crossings between bound states. We
characterize a number of different avoided crossings in Cs_2 and compare our
converged calculations with experimental results. Small but significant
discrepancies are observed in both crossing strengths and level positions,
especially for levels with l symmetry (rotational angular momentum L=8). The
discrepancies should allow the development of improved potential models in the
future.
},
doi = {10.1103/PhysRevA.78.052703},
url = {http://arxiv.org/abs/0806.2583v1},
author = {Jeremy M. Hutson and Eite Tiesinga and Paul S. Julienne}
}
@article {1276,
title = {Two-body transients in coupled atomic-molecular BECs},
journal = {Physical Review Letters},
volume = {100},
year = {2008},
month = {2008/3/3},
abstract = { We discuss the dynamics of an atomic Bose-Einstein condensate when pairs of
atoms are converted into molecules by single-color photoassociation. Three main
regimes are found and it is shown that they can be understood on the basis of
time-dependent two-body theory. In particular, the so-called rogue dissociation
regime [Phys. Rev. Lett., 88, 090403 (2002)], which has a density-dependent
limit on the photoassociation rate, is identified with a transient regime of
the two-atom dynamics exhibiting universal properties. Finally, we illustrate
how these regimes could be explored by photoassociating condensates of
alkaline-earth atoms.
},
doi = {10.1103/PhysRevLett.100.093001},
url = {http://arxiv.org/abs/0707.2963v2},
author = {Pascal Naidon and Eite Tiesinga and Paul S. Julienne}
}
@article {1277,
title = {Coherent, adiabatic and dissociation regimes in coupled atomic-molecular Bose-Einstein condensates
},
year = {2007},
month = {2007/11/02},
abstract = { We discuss the dynamics of a Bose-Einstein condensate of atoms which is
suddenly coupled to a condensate of molecules by an optical or magnetic
Feshbach resonance. Three limiting regimes are found and can be understood from
the transient dynamics occuring for each pair of atoms. This transient dynamics
can be summarised into a time-dependent shift and broadening of the molecular
state. A simple Gross-Pitaevskii picture including this shift and broadening is
proposed to describe the system in the three regimes. Finally, we suggest how
to explore these regimes experimentally.
},
url = {http://arxiv.org/abs/0711.0397v2},
author = {Pascal Naidon and Eite Tiesinga and Paul S. Julienne}
}
@article {1291,
title = {Effective-range description of a Bose gas under strong one- or two-dimensional confinement
},
journal = {New Journal of Physics},
volume = {9},
year = {2007},
month = {2007/01/29},
pages = {19 - 19},
abstract = { We point out that theories describing s-wave collisions of bosonic atoms
confined in one- or two-dimensional geometries can be extended to much tighter
confinements than previously thought. This is achieved by replacing the
scattering length by an energy-dependent scattering length which was already
introduced for the calculation of energy levels under 3D confinement. This
replacement accurately predicts the position of confinement-induced resonances
in strongly confined geometries.
},
doi = {10.1088/1367-2630/9/1/019},
url = {http://arxiv.org/abs/physics/0607140v2},
author = {Pascal Naidon and Eite Tiesinga and William F. Mitchell and Paul S. Julienne}
}
@article {1290,
title = {Multichannel quantum-defect theory for slow atomic collisions},
journal = {Physical Review A},
volume = {72},
year = {2005},
month = {2005/10/28},
abstract = { We present a multichannel quantum-defect theory for slow atomic collisions
that takes advantages of the analytic solutions for the long-range potential,
and both the energy and the angular-momentum insensitivities of the short-range
parameters. The theory provides an accurate and complete account of scattering
processes, including shape and Feshbach resonances, in terms of a few
parameters such as the singlet and the triplet scattering lengths. As an
example, results for $^{23}$Na-$^{23}$Na scattering are presented and compared
close-coupling calculations.
},
doi = {10.1103/PhysRevA.72.042719},
url = {http://arxiv.org/abs/physics/0508060v1},
author = {Bo Gao and Eite Tiesinga and Carl J. Williams and Paul S. Julienne}
}
@article {1275,
title = {Spontaneous dissociation of long-range Feshbach molecules},
journal = {Physical Review Letters},
volume = {94},
year = {2005},
month = {2005/1/18},
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 $^{85}$Rb 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
$^{85}$Rb$_2$.
},
doi = {10.1103/PhysRevLett.94.020402},
url = {http://arxiv.org/abs/cond-mat/0408387v2},
author = {Thorsten Koehler and Eite Tiesinga and Paul S. Julienne}
}
@article {1288,
title = {Adiabatic association of ultracold molecules via magnetic field tunable interactions
},
journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
volume = {37},
year = {2004},
month = {2004/09/14},
pages = {3457 - 3500},
abstract = { We consider in detail the situation of applying a time dependent external
magnetic field to a 87Rb atomic Bose-Einstein condensate held in a harmonic
trap, in order to adiabatically sweep the interatomic interactions across a
Feshbach resonance to produce diatomic molecules. To this end, we introduce a
minimal two-body Hamiltonian depending on just five measurable parameters of a
Feshbach resonance, which accurately determines all low energy binary
scattering observables, in particular, the molecular conversion efficiency of
just two atoms. Based on this description of the microscopic collision
phenomena, we use the many-body theory of T. Koehler and K. Burnett [Phys. Rev.
A 65, 033601 (2002)] to study the efficiency of the association of molecules in
a 87Rb Bose-Einstein condensate during a linear passage of the magnetic field
strength across the 100 mT Feshbach resonance. We explore different,
experimentally accessible, parameter regimes, and compare the predictions of
Landau-Zener, configuration interaction, and two level mean field calculations
with those of the microscopic many-body approach. Our comparative studies
reveal a remarkable insensitivity of the molecular conversion efficiency with
respect to both the details of the microscopic binary collision physics and the
coherent nature of the Bose-Einstein condensed gas, provided that the magnetic
field strength is varied linearly. We provide the reasons for this universality
of the molecular production achieved by linear ramps of the magnetic field
strength, and identify the Landau-Zener coefficient determined by F.H. Mies et
al. [Phys. Rev. A 61, 022721 (2000)] as the main parameter that controls the
efficiency.
},
doi = {10.1088/0953-4075/37/17/006},
url = {http://arxiv.org/abs/cond-mat/0312178v5},
author = {Krzysztof Goral and Thorsten Koehler and Simon A. Gardiner and Eite Tiesinga and Paul S. Julienne}
}
@article {1289,
title = {Ultracold collision properties of metastable alkaline-earth atoms},
journal = {Physical Review Letters},
volume = {90},
year = {2003},
month = {2003/2/13},
abstract = { Ultra-cold collisions of spin-polarized 24Mg,40Ca, and 88Sr in the metastable
3P2 excited state are investigated. We calculate the long-range interaction
potentials and estimate the scattering length and the collisional loss rate as
a function of magnetic field. The estimates are based on molecular potentials
between 3P2 alkaline-earth atoms obtained from ab initio atomic and molecular
structure calculations. The scattering lengths show resonance behavior due to
the appearance of a molecular bound state in a purely long-range interaction
potential and are positive for magnetic fields below 50 mT. A loss-rate model
shows that losses should be smallest near zero magnetic field and for fields
slightly larger than the resonance field, where the scattering length is also
positive.
},
doi = {10.1103/PhysRevLett.90.063002},
url = {http://arxiv.org/abs/physics/0210076v1},
author = {Andrei Derevianko and Sergey G. Porsev and Svetlana Kotochigova and Eite Tiesinga and Paul S. Julienne}
}