Repulsive polarons and itinerant ferromagnetism in strongly polarized Fermi gases

  title={Repulsive polarons and itinerant ferromagnetism in strongly polarized Fermi gases},
  author={Pietro Massignan and Georg M. Bruun},
  journal={The European Physical Journal D},
Abstract We analyze the properties of a single impurity immersed in a Fermi sea. At positive energy and scattering lengths, we show that the system possesses a well-defined but metastable excitation, the repulsive polaron, and we calculate its energy, quasiparticle residue and effective mass. From a thermodynamic argument we obtain the number of particles in the dressing cloud, illustrating the repulsive character of the polaron. Identifying the important 2- and 3-body decay channels, we… Expand

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