@article{ErdmengerHoyosO'Bannonetal.2017,
  author    = {Erdmenger, Johanna and Hoyos, Carlos and O'Bannon, Andy and Papadimitriou, Ioannis and Probst, Jonas and Wu, Jackson M.S.},
  title     = {Two-point functions in a holographic Kondo model},
  series = {Journal of High Energy Physics},
  volume    = {3},
  journal   = {Journal of High Energy Physics},
  number    = {39},
  doi       = {10.1007/JHEP03(2017)039},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171139},
  year      = {2017},
  abstract  = {We develop the formalism of holographic renormalization to compute two-point functions in a holographic Kondo model. The model describes a (0 + 1)-dimensional impurity spin of a gauged SU(N ) interacting with a (1 + 1)-dimensional, large-N , strongly-coupled Conformal Field Theory (CFT). We describe the impurity using Abrikosov pseudo-fermions, and define an SU(N )-invariant scalar operator O built from a pseudo-fermion and a CFT fermion. At large N the Kondo interaction is of the form O\(^{†}\)O, which is marginally relevant, and generates a Renormalization Group (RG) flow at the impurity. A second-order mean-field phase transition occurs in which O condenses below a critical temperature, leading to the Kondo effect, including screening of the impurity. Via holography, the phase transition is dual to holographic superconductivity in (1 + 1)-dimensional Anti-de Sitter space. At all temperatures, spectral functions of O exhibit a Fano resonance, characteristic of a continuum of states interacting with an isolated resonance. In contrast to Fano resonances observed for example in quantum dots, our continuum and resonance arise from a (0 + 1)-dimensional UV fixed point and RG flow, respectively. In the low-temperature phase, the resonance comes from a pole in the Green's function of the form -i〈O〉\(^{2}\), which is characteristic of a Kondo resonance.},
  language  = {en}
}