Impurity with a resonance in the vicinity of the Fermi energy

  title={Impurity with a resonance in the vicinity of the Fermi energy},
  author={Mikhail M. Maslov and Mikhail Lemeshko and Artem G. Volosniev},
  journal={Physical Review Research},
We study an impurity with a resonance level whose position coincides with the Fermi energy of the surrounding Fermi gas. An impurity causes a rapid variation of the scattering phase shift for fermions at the Fermi surface, introducing a new characteristic length scale into the problem. We investigate manifestations of this length scale in the self-energy of the impurity and in the density of the bath. Our calculations reveal a model-independent deformation of the density of the Fermi gas, which… 

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