Dynamics of interacting fermions under spin-orbit coupling in an optical lattice clock

Prof. Ana Maria Rey
2017-12-20 (周三) 10:00

The Pauli exclusion principle forbids identical fermions from interacting via s-wave collisions. However, in the presence of spin-orbit coupling (SOC), identical fermions can experience effective interactions which can give rise to exotic topological and pairing behaviors, many of which have yet to be observed in condensed matter systems. Spin-orbit coupled alkaline-earth gases offer a promising pathway for quantum simulation of SOC physics given their long-lived electronic clock states which significantly reduce spontaneous emission and heating, as has been demonstrated in recent experiment. However, these first experiments were carried out in the dilute regime where single-particle physics dominates. Here I will report recent progress in the one dimensional optical lattice clock at JILA to enter the regime where interactions compete with single-particle effects. Using clock spectroscopy, we observed the precession of the collective magnetization and the emergence of spin-locking effects arising from an interplay between p-wave and SOC-induced exchange interactions. I will show that a collective XXZ spin model, which describes a broad class of condensed matter systems ranging from superconductors to quantum magnets, captures the many-body dynamics. This work opens a path towards the observation of richer exotic behaviors, such as, topological superfluids, and will aid in the design of next-generation of optical lattice clocks by offering a route for avoiding the observed large density shifts caused by SOC-induced exchange interactions.