Few-Body Systems

, Volume 51, Issue 2, pp 153–180

Efimov Physics from the Functional Renormalization Group


    • Institut für Theoretische Physik
    • Physics DepartmentTheory Unit, CERN
  • Sergej Moroz
    • Institut für Theoretische Physik
  • Richard Schmidt
    • Physik DepartmentTechnische Universität München

DOI: 10.1007/s00601-011-0231-z

Cite this article as:
Floerchinger, S., Moroz, S. & Schmidt, R. Few-Body Syst (2011) 51: 153. doi:10.1007/s00601-011-0231-z


Few-body physics related to the Efimov effect is discussed using the functional renormalization group method. After a short review of renormalization in its modern formulation we apply this formalism to the description of scattering and bound states in few-body systems of identical bosons and distinguishable fermions with two and three components. The Efimov effect leads to a limit cycle in the renormalization group flow. Recently measured three-body loss rates in an ultracold Fermi gas of 6Li atoms are explained within this framework. We also discuss briefly the relation to the many-body physics of the BCS–BEC crossover for two-component fermions and the formation of a trion phase for the case of three species.

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© Springer-Verlag 2011