Observation of Atom-Surface Interaction Using Ultracold Atoms

David M. Harber

Mukund Vengalattore, Wilbert Rooijakkers, Richard Conroy +1 more

Christian Stehle, Claus Zimmermann, Sebastian Slama

Erik G. C. P. van Loon, Mikhail I. Katsnelson, Lauriane Chomaz +1 more

Anisotropic dipole-dipole interactions between ultracold dipolar fermions break the symmetry of the Fermi surface and thereby deform it. Here we demonstrate that such a Fermi surface deformation induces a topological phase transition---the so-called Lifshitz transition---in the regime accessible to present-day experiments. We describe the impact of the Lifshitz transition on observable quantities such as the Fermi surface topology, the density-density correlation function, and the excitation spectrum of the system. The Lifshitz transition in ultracold atoms can be controlled by tuning the dipole orientation and, in contrast to the transition studied in crystalline solids, is completely interaction driven.

Michael E. Holmes

David A. Smith, Simon Aigner, Sebastian Hofferberth +7 more

Imaging ultracold atomic gases close to surfaces is an important tool for the detailed analysis of experiments carried out using atom chips. We describe the critical factors that need be considered, especially when the imaging beam is purposely reflected from the surface. In particular we present methods to measure the atom-surface distance, which is a prerequisite for magnetic field imaging and studies of atom surface-interactions.