Erlangen 2022 – scientific programme

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A: Fachverband Atomphysik

A 31: Ultra-cold atoms, ions and BEC IV (joint session A/Q)

A 31.2: Talk

Friday, March 18, 2022, 11:00–11:15, A-H1

Ionic Polarons in a Bose-Einstein condensate — •Luis Ardila — Institut für Theoretische Physik, Leibniz Universität Hannover, Germany

The versatility and control of ultracold quantum gases opened up a plethora of theoretical predictions on polaronic physics using ultra-cold quantum gases, resulting in several experimental realizations. In his talk, we will discuss ionic polarons 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 a charged impurity 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. Recent experiments on ionic impurities in quantum gases are promising platforms to study ionic polarons. Our work paves the way to understand how ions coupled a quantum gas which may be important for future applications in quantum technologies.