Three-body recombination at finite energy within an optical model

We consider three-body recombination into deep dimers in a mass-imbalanced two-component atomic gas. We use an optical model where a phenomenological imaginary potential is added to the lowest adiabatic hyper-spherical potential. The consequent imaginary part of the energy eigenvalue corresponds to the decay rate or recombination probability of the three-body system. The method is formulated in details and the relevant qualitative features are discussed as functions of scattering lengths and masses. We use zero-range model in analyses of recent recombination data. The dominating scattering length is usually related to the non-equal two-body systems. We account for temperature smearing which tends to wipe out the higher-lying Efimov peaks. The range and the strength of the imaginary potential determine positions and shapes of the Efimov peaks as well as the absolute value of the recombination rate. The Efimov scaling between recombination peaks is calculated and shown to depend on both scattering lengths. Recombination is predicted to be largest for heavy-heavy-light systems. Universal properties of the optical parameters are indicated. We compare to available experiments and find in general very satisfactory agreement.

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“…ijk (E) with a temperature distribution. The normalised Boltzmann distribution for 3 particles is given by [31]…”

Section: Recombination Coefficients and Finite Temperaturementioning

confidence: 99%

Three-body recombination of two-component cold atomic gases into deep dimers in an optical model

Mathias

Jensen

Fedorov

et al. 2015

J. Phys. B: At. Mol. Opt. Phys.

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“…We also note that the finite-range potential implies that we do not need to provide a three-body cut-off at short-range of the order the van der Waals length [54][55][56][57][58][59][60][61][62][63][64][65].…”

Section: Formulation Of Problemmentioning

confidence: 99%

Window for Efimov physics for few-body systems with finite-range interactions

Rasmussen¹,

Jensen²,

Fedorov³

2017

J. Phys. B: At. Mol. Opt. Phys.

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We investigate the two lowest-lying weakly bound states of N ≤ 8 bosons as functions of the strength of two-body Gaussian interactions. We observe the limit for validity of Efimov physics. We calculate energies and second radial moments as functions of scattering length. For identical bosons we find that two (N − 1)-body states appear before the N -body ground states become bound. This pattern ceases to exist for N ≥ 7 where the size of the ground state becomes smaller than the range of the two-body potential. All mean-square-radii for N ≥ 4 remain finite at the threshold of zero binding, where they vary as (N − 1) p with p = −3/2, −3 for ground and excited states, respectively. Decreasing the mass of one particle we find stronger binding and smaller radii. The identical particles form a symmetric system, while the lighter particle is further away in the ground states. In the excited states we find the identical bosons either surrounded or surrounding the light particle for few or many bosons, respectively. We demonstrate that the first excited states for all strengths resemble two-body halos of one particle weakly bound to a dense N -body system for N = 3, 4. This structure ceases to exist for N ≥ 5.

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“…Our assumption will be that this peak is moved as the Fermi sea modifies the binding energy of the three-body state and thus the threshold value. A more precise way would be to include a (small) imaginary part in the three-body parameter or in the real-space three-body potential to simulate the loss [26,40]. This can typically produce both a peak position and shape.…”

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confidence: 99%

Efimov three-body states on top of a Fermi sea

Nygaard¹,

Zinner²

2014

New J. Phys.

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The stabilization of Cooper pairs of bound electrons in the background of a Fermi sea is the origin of superconductivity and the paradigmatic example of the striking influence of many-body physics on few-body properties. In the quantum-mechanical three-body problem the famous Efimov effect yields unexpected scaling relations among a tower of universal states. These seemingly unrelated problems can now be studied in the same setup thanks to the success of ultracold atomic gas experiments. In light of the tremendous effect of a background Fermi sea on two-body properties, a natural question is whether a background can modify or even destroy the Efimov effect. Here we demonstrate how the generic problem of three interacting particles changes when one particle is embedded in a background Fermi sea, and show that Efimov scaling persists. It is found in a scaling that relates the three-body physics to the background density of fermionic particles.Keywords: few-body physics, Efimov effect, Fermi sea, many-body effects, cold atomsThe discovery by Vitaly Efimov of an anomaly in the spectrum of three equal mass particles when a two-body bound state is at zero energy [1] has excited theorists and experimentalists alike in the past four decades. While much effort was put into detecting these universal bound

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Three-body recombination at finite energy within an optical model

Cited by 13 publications

References 43 publications

Three-body recombination of two-component cold atomic gases into deep dimers in an optical model

Three-body recombination of two-component cold atomic gases into deep dimers in an optical model

Window for Efimov physics for few-body systems with finite-range interactions

Efimov three-body states on top of a Fermi sea

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