Pascal Naidon

Probing Interactions Between Ultracold Fermions

At ultracold temperatures, the Pauli exclusion principle suppresses collisions between identical fermions. This has motivated the development of atomic clocks with fermionic isotopes. However, by probing an optical clock transition with thousands of lattice-confined, ultracold fermionic strontium atoms, we observed density-dependent collisional frequency shifts. These collision effects were measured systematically and are supported by a theoretical description attributing them to inhomogeneities in the probe excitation process that render the atoms distinguishable. This work also yields insights for zeroing the clock density shift.

Two-color photoassociation spectroscopy of ytterbium atoms and the precise determinations of s-wave scattering lengths

By performing high-resolution two-color photoassociation spectroscopy, we have successfully determined the binding energies of several of the last bound states of the homonuclear dimers of six different isotopes of ytterbium. These spectroscopic data are in excellent agreement with theoretical calculations based on a simple model potential, which very precisely predicts the

Nonuniversal Efimov atom-dimer resonances in a three-component mixture of 6Li.

s

Efimov Physics: a review

-wave scattering lengths of all 28 pairs of the seven stable isotopes. The

Microscopic Origin and Universality Classes of the Efimov Three-Body Parameter

s

Universality and the three-body parameter of4He trimers

-wave scattering lengths for collision of two atoms of the same isotopic species are 13.33(18) nm for

Independent Control of Scattering Lengths in Multicomponent Quantum Gases

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Pair dynamics in the formation of molecules in a Bose-Einstein condensate

, 3.38(11) nm for

The Efimov effect in lithium 6

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Effective-range description of a Bose gas under strong one- or two-dimensional confinement

,