Topic: collective interactions

Coupling cold atoms to a lossy optical cavity creates collective interactions and can drive self-organized phases. This seminar treats lattice bosons and fermions with a many-body adiabatic-elimination approach that retains the cavity's open-system character and global coupling. It examines the importance of fluctuations, emergent approximate symmetries and a form of bistability arising from excited states, within a broader landscape of proposed topological and glass-like phases.

An ultracold Fermi gas inside an optical resonator acquires collective interactions through virtual photons. The seminar describes observations of charge-density ordering with spatial and temporal resolution, then considers coupling photons to pairs in a superfluid and initial evidence for pair-density ordering. It concludes with prospects for programmable cavity-mediated interactions and simulation of strongly correlated systems, including the SYK model.