• Dropping an impurity into a Chern insulator: A polaron view on topological matter 

      Camacho-Guardián, Arturo; Goldman, Nathan; Massignan, Pietro Alberto; Bruun, Georg M. (American Physical Society (APS), 2019-02-05)
      Article
      Accés obert
      We investigate the properties of an impurity particle interacting with a Fermi gas in a Cherninsulating state. The interaction leads to the formation of an exotic polaron, which consists of a coherent superposition of the ...
    • Mediated interactions between Fermi polarons and the role of impurity quantum statistics 

      Baroni, Cosetta; Huang, Bo; Fritsche, Isabella; Dobler, Erich; Anich, Gregor; Kirilov, Emil; Grimm, Rudolf; Bastarrachea Magnani, Miguel Angel; Massignan, Pietro Alberto; Bruun, Georg M. (Springer, 2023-10-26)
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      Accés obert
      The notion of quasi-particles is essential for understanding the behaviour of complex many-body systems. A prototypical example of a quasi-particle is a polaron, formed by an impurity strongly interacting with a surrounding ...
    • Mobile impurity in a Bose-Einstein condensate and the orthogonality catastrophe 

      Guenther, Nils Eric; Schmidt, Richard; Bruun, Georg M.; Gurarie, Victor; Massignan, Pietro Alberto (American Physical Society, 2021-01-01)
      Article
      Accés obert
      We analyze the properties of an impurity in a dilute Bose-Einstein condensate (BEC). First the quasiparticle residue of a static impurity in an ideal BEC is shown to vanish with increasing particle number as a stretched ...
    • Polarons, dressed molecules and itinerant ferromagnetism in ultracold Fermi gases 

      Massignan, Pietro Alberto; Zaccanti, Matteo; Bruun, Georg M. (Institute of Physics (IOP), 2014-02-19)
      Article
      Accés obert
      In this review, we discuss the properties of a few impurity atomsimmersed in a gas of ultracold fermions, the so-called Fermi polaron problem. On one side, this many-body system is appealing because it can be described ...
    • Stability and breakdown of Fermi polarons in a strongly interacting Fermi-Bose mixture 

      Fritsche, Isabella; Baroni, Cosetta; Dobler, Erich; Kirilov, Emil; Huang, Bo; Grimm, Rudolf; Bruun, Georg M.; Massignan, Pietro Alberto (American Physical Society, 2021-05-01)
      Article
      Accés obert
      We investigate the properties of a strongly interacting imbalanced mixture of bosonic 41K impurities immersed in a Fermi sea of ultracold 6 Li atoms. This enables us to explore the Fermi polaron scenario for large impurity ...
    • Strong-coupling ansatz for the one-dimensional Fermi gas in a harmonic potential 

      Levinsen, Jesper; Massignan, Pietro; Bruun, Georg M.; Parish, Meera M. (Science, 2015-07-24)
      Article
      Accés obert
      A major challenge in modern physics is to accurately describe strongly interacting quantum many-body systems. One-dimensional systems provide fundamental insights because they are often amenable to exact methods. However, ...
    • Topological transport of mobile impurities 

      Pimenov, Dimitri; Camacho-Guardián, Arturo; Goldman, Nathan; Massignan, Pietro Alberto; Bruun, Georg M.; Goldstein, Moshe (American Physical Society (APS), 2021-06-15)
      Article
      Accés obert
      We study the Hall response of topologically trivial mobile impurities (Fermi polarons) interacting weakly with majority fermions forming a Chern-insulator background. This setting involves a rich interplay between the ...