caa a22 4500 445867256 CHVBK 20180317145501.0 cr unu---uuuuu 170323e20111101xx s 000 0 eng 10.1140/epjd/e2011-20084-5 doi (NATIONALLICENCE)springer-10.1140/epjd/e2011-20084-5 Repulsive polarons and itinerant ferromagnetism in strongly polarized Fermi gases [Elektronische Daten] [P. Massignan, G. Bruun] 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 furthermore calculate the lifetime of the repulsive polaron. The stability conditions for the formation of fully spin polarized (ferromagnetic) domains are then examined for a binary mixture of atoms with a general mass ratio. Our results indicate that mass imbalance lowers the critical interaction strength for phase-separation, but that very short quasiparticle decay times will complicate the experimental observation of itinerant ferromagnetism. Finally, we present the spectral function of the impurity for various coupling strengths and momenta. EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2011 Massignan P. ICFO-Institut de Ciencies Fotoniques, 08860, Castelldefels (Barcelona), Spain aut Bruun G. Department of Physics and Astronomy, University of Aarhus, 8000, Aarhus C, Denmark aut The European Physical Journal D Springer-Verlag 65/1-2(2011-11-01), 83-89 1434-6060 65:1-2<83 2011 65 10053 https://doi.org/10.1140/epjd/e2011-20084-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1140/epjd/e2011-20084-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Massignan P. ICFO-Institut de Ciencies Fotoniques, 08860, Castelldefels (Barcelona), Spain aut NATIONALLICENCE 700 1- Bruun G. Department of Physics and Astronomy, University of Aarhus, 8000, Aarhus C, Denmark aut NATIONALLICENCE 773 0- The European Physical Journal D Springer-Verlag 65/1-2(2011-11-01), 83-89 1434-6060 65:1-2<83 2011 65 10053 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer