Speaker's Brief Introduction：Prof. Dr. Henning Moritz, currently holding a W2 professorship at the University of Hamburg, is an accomplished physicist specializing in optical quantum technologies. With a diploma from the University of Heidelberg and a Ph.D. from ETH Zürich, he has made significant contributions to the field. Throughout his career, he has held various leadership roles, including director of the Institute for Laser Physics and membership in the Board of Directors of the Bundesexzellenzcluster AIM. Prof. Moritz is dedicated to fostering young talent, overseeing numerous students and postdocs, and has received recognition for his teaching and research, including an ERC Starting Grant and multiple teaching awards. His research focus includes the excitation spectrum and superfluidity in ultracold Fermi gases, as evidenced by his seminal publications in leading scientific journals.
Abstract: Understanding the origins of unconventional superconductivity has been a major focus of condensed matter physics and experiments have found the highest critical temperatures in layered 2D materials. However, to what extent the remarkable stability is affected by their reduced dimensionality is still an open question. Here, I will discuss fermionic superfluidity in ultracold atoms, in particular in 2D systems and how dimensionality affects the stability.
I will introduce fermionic superfluidity in ultracold atoms, where Cooper pairs forms. Their pair size can be continuously tuned from the Bardeen-Cooper-Schrieffer (BCS) regime of loosely bound pairs to the BEC regime of very tightly bound pairs. After introducing the critical velocity vc and the pairing gap Δ, I will explain how to determine them using Bragg spectroscopy. I will discuss our results comparing superfluidity in 2D and 3D. We find that the superfluid gap follows the same universal function of the interaction strength regardless of dimensionality. Finally, I will show how we have created vortices in these systems.