Repulsive Fermi and Bose Polarons in Quantum Gases

Year: 2022

Authors: Scazza F., Zaccanti M., Massignan P., Parish M.M., Levinsen J.

Autors Affiliation: Department of Physics, University of Trieste, 34127 Trieste, Italy; Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche (CNR-INO), 50019 Sesto Fiorentino, Italy; European Laboratory for Nonlinear Spectroscopy (LENS), University of Florence, 50019 Sesto Fiorentino, Italy; Departament de Fnsica, Universitat Politicnica de Catalunya, Campus Nord B4-B5, 08034 Barcelona, Spain; School of Physics and Astronomy, Monash University, Victoria 3800, Australia; ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria 3800, Australia

Abstract: Polaron quasiparticles are formed when a mobile impurity is coupled to the elementary excitations of a many-particle background. In the field of ultracold atoms, the study of the associated impurity problem has attracted a growing interest over the last fifteen years. Polaron quasiparticle properties are essential to our understanding of a variety of paradigmatic quantum many-body systems realized in ultracold atomic gases and in the solid state, from imbalanced Bose-Fermi and Fermi-Fermi mixtures to fermionic Hubbard models. In this topical review, we focus on the so-called repulsive polaron branch, which emerges as an excited many-body state in systems with underlying attractive interactions such as ultracold atomic mixtures, and is characterized by an effective repulsion between the impurity and the surrounding medium. We give a brief account of the current theoretical and experimental understanding of repulsive polaron properties, for impurities embedded in both fermionic and bosonic media, and we highlight open issues deserving future investigations.

Journal/Review: ATOMS

Volume: 10 (2)      Pages from: 55-1  to: 55-30

More Information: F.S. acknowledges funding from the European Research Council (ERC) under the European Union´s Horizon 2020 research and innovation programme (Grant Agreement no. 949438). M.Z. acknowledges funding from the ERC through grant no. 637738 PoLiChroM and from the Italian MIUR through the FARE grant no. R168HMHFYM. P.M. was supported by grant PID2020-113565GB-C21 funded by MCIN/AEI/10.13039/501100011033, by EU FEDER Quantumcat, by the National Science Foundation under Grant No. NSF PHY-1748958, and by the ICREA Academia program. J.L. and M.M.P. acknowledge support from the Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies (CE170100039). J.L. and M.M.P. are also supported through the Australian Research Council Future Fellowships FT160100244 and FT200100619, respectively, and J.L. furthermore acknowledges support from the Australian Research Council Discovery Project DP210101652.
KeyWords: Fermi polarons; Bose polarons; repulsive interactions; metastable quasiparticles; quasiparticle lifetime; mediated interactions; repulsive Fermi gas; ultracold atomic mixtures
DOI: 10.3390/atoms10020055