A groundbreaking study published in Physical Review Letters unveils a new class of polarons arising from the interaction between charged impurities and degenerate Fermi gases.  Polarons are fundamental for understanding quantum many-body systems across various energy scales. In particular, polarons arising from atom—ion hybrid systems are potential candidates for unlocking uncharted regimes in solid-state systems, providing deeper insight into quantum effects in materials, for instance, excitons — polarons arising in van Der Waals heterostructures characterized by their unique electronic and optical properties.  In this work, the authors investigate the quasiparticle properties using ab initio quantum Monte Carlo methods, known as the best-suited method to study strong interactions and strong correlations. The study's novelty is that quasiparticle properties are heavily affected by the large density deformations caused by the attractive potential and the Fermi exclusion principle. This breakthrough aligns with experimental advances in realizing impurity atoms within quantum  degenerate gases paving the way for a new generation of experiments at the crossroads of quantum gases and atom-ion cold systems where these charged polaron can be observed.

The study was conducted and coordinated by Luis A. Peña Ardila from the university of Trieste. The work presented is the result of an international collaboration between the University of Trieste, Universidade Federal de Goiás, and Universidade Estadual de Campinas in Brazil.

Pessoa, Renato, S. A. Vitiello, and L. A. Peña Ardila. "Fermi Polaron in Atom-Ion Hybrid Systems." Physical Review Letters 133   233002 (2024). https://doi.org/10.1103/PhysRevLett.133.233002.