Seminarium Optyczne

In 2016, the Tilman Pfau's group from Stuttgart measured an unexpected phenomenon, the formation of quantum droplets out of ultracold gas. This happened in the regime of interaction when matter should explode as a supernova. It has been shown that the unexpected stability is due to quantum correlations and three-body effects, that determine the macroscopic properties of this new phase.Our theoretical research focuses on studying quasi-one-dimensional system. The interplay between the attractive dipolar and repulsive van der Waals interactions may lead also to quantum self-bound states, as pointed out in [1]. First we’ve showed that the droplet form for any interaction regime,including fermionied system [2], and then we pointed out novel many-body effects and nonlinear phenomena. Within a dipolar quantum droplet, one may generate a dark solitary wave with a steerable width, theoretically infinitely broad [3]. Intriguingly, a one-dimensional dipolar droplet, when subjected to a change in van der Waals interaction strength from repulsive to attractive, exhibits unexpected many-body behaviour. Instead of collapsing (which, intuitively, would be the expected scenario given all forces are attractive) or increasing stability (as known due to the super Tonks-Girardeau effect), the droplet evaporates [4]. I would like to elucidate the origin of such droplets and their unexpected features.[1] D. Edler, C. Mishra, F. Wachtler, R. Nath, S. Sinha, L. Santos, Phys. Rev. Lett. 119, 050403 (2017)[2] R. Ołdziejewski, W. Gorecki, K. Pawłowski, K. Rzazewski, Phys. Rev. Lett. 124, 090401 (2020)[3] J. Kopycinski, M. Łebek, W. Górecki, K. Pawłowski, Phys. Rev. Lett. 130, 043401 (2023)[4] M. Marciniak, M. Łebek, J. Kopycinski, W. Górecki, R. Ołdziejewski, K. Pawłowski, Phys. Rev. A 108, 043304 (2023)"