Seminarium Optyczne

One of the most remarkable manifestations of many-body physics is the collective emergence of quantum effects in the macroscopic world. The existence of phenomena such as superfluidity, superconductivity, giant magnetoresistance, or Bose–Einstein condensation relies directly on the macroscopic amplification of quantum properties, which are driven by mutual interactions and quantum statistics when the number of particles becomes sufficiently large. In order to better understand how this quantum collectivism emerges, it is worth considering strongly correlated quantum systems containing a small number of particles and searching for various precursors of macroscopic correlations. This approach has become particularly attractive in recent years due to the development of extremely precise experimental techniques that allow for the preparation and control of systems containing a small number of strongly interacting ultracold atoms. In my talk, I will first provide a brief review of recent progress in theoretical and experimental studies of mesoscopic ultracold systems, focusing primarily on two-component fermionic mixtures. In particular, I will explain how precursors of conventional Bardeen–Cooper–Schrieffer (BCS) and unconventional Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) pairing can be identified in mesoscopic systems. Next, I will present the first results for the simplest three-component fermionic mixtures, highlighting the existence of a surprising structural transition in the many-body ground state that has no counterpart in two-component systems.