SAMOP 2023 – scientific programme

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A: Fachverband Atomphysik

A 14: Ultra-cold Atoms, Ions and BEC II (joint session A/Q)

A 14.6: Talk

Wednesday, March 8, 2023, 12:30–12:45, F303

Induced interaction between ionic polarons in condensates — •Luis Ardila — Institut für Theoretische Physik, Leibniz Universität Hannover, Germany

In this talk, we will discuss ionic polarons and their induced interaction created as a result of charged particles interacting with a Bose-Einstein condensate. Here we show that even in a comparatively simple setup consisting of charged impurities in a weakly interacting bosonic medium with tunable atom-ion scattering length, the competition of length scales gives rise to a highly correlated mesoscopic state. Using quantum Monte Carlo simulations, we unravel its vastly different polaronic properties compared to neutral quantum impurities. Moreover, we identify a transition between the regime amenable to conventional perturbative treatment in the limit of weak atom-ion interactions and a many-body bound state with vanishing quasi-particle residue composed of hundreds of atoms. Contrary to the case of neutral impurities, ionic polarons can bound many excitations and bosons from the condensate, forming many-body bound-states and changing the ground-state properties of the polaron radically. Also, transport properties are accessible by using external electric fields. Finally, we investigate the specific case of two ions that mediate interactions via the bosonic bath. This interaction can be sizable with respect to the Coulomb interaction, giving rise to notable effects which may have direct consequences in the platform employed for future quantum technologies.