Emergence of chaotic scattering in ultracold Er and Dy

ERBIUM NEWS:

Now in PRX! We show that for ultracold magnetic lanthanide atoms (Er and Dy) chaotic scattering emerges due to a combination of anisotropic interaction potentials and Zeeman coupling under an external magnetic field. The scattering is studied in a collaborative experimental and theoretical effort, involving our group, the Stuttgart Dy Group led by T. Pfau and the theory colleagues S. Kotochigova and E. Tiesinga in the USA.  [more]

Anisotropic Relaxation Dynamics in a Dipolar Fermi Gas Driven Out of Equilibrium

ERBIUM NEWS

We report on the observation of a large anisotropy in the rethermalization dynamics of an ultracold dipolar Fermi gas driven out of equilibrium. Our system consists of an ultracold sample of strongly magnetic Er167 fermions, spin polarized in the lowest Zeeman sublevel. In this system, elastic collisions arise purely from universal dipolar scattering. Based on cross-dimensional rethermalization experiments, we observe a strong anisotropy of the scattering, which manifests itself in a large angular dependence of the thermal relaxation dynamics. Our result is in good agreement with recent theoretical predictions. Furthermore, we measure the rethermalization rate as a function of temperature for different angles and find that the suppression of collisions by Pauli blocking is not influenced by the dipole orientation.[more]