Bonn 2025 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 16: Ultra-cold atoms, ions and BEC I (joint session A/Q)

Q 16.7: Talk

Monday, March 10, 2025, 18:45–19:00, KlHS Mathe

Bose and Fermi Polarons in Atom - Ion Hybrid Systems — •Luis Ardila — Dipartimento di Fisica,Università di Trieste, Strada Costiera 11, I-34151 Trieste, Italy

Charged quasiparticles dressed by the low excitations of an electron gas constitute one of the fundamental pillars for understanding quantum many-body effects in some materials. Quantum simulation of quasiparticles arising from atom-ion hybrid systems may shed light on solid-state uncharted regimes. Here, we will discuss ionic polarons created as a result of charged dopants interacting with a Bose-Einstein condensate and a polarized Fermi gas. Here, we show that even in a comparatively simple setup consisting of charged impurities in a weakly interacting bosonic medium and an ideal Fermi gas with tunable atom-ion scattering length, the competition of length scales gives rise to a highly correlated mesoscopic state in the bosonic case; in contrast, a molecular state appears in the Fermi case. We unravel their vastly different polaronic properties compared to neutral quantum impurities using quantum Monte Carlo simulations. Contrary to the case of neutral impurities, ionic polarons can bind many excitations, forming a nontrivial interplay between few and many-body physics, radically changing the ground-state properties of the polaron.

Keywords: Polaron; Atom; Ion; Fermi gas; Bose Einstein condensate