Kondo physics and dissipation: A numerical renormalization-group approach to Bose-Fermi Kondo models

摘要: We extend the numerical renormalization-group method to treat Bose-Fermi Kondo models BFKMs describing a local moment coupled both conduction band and dissipative bosonic bath representing, e.g., lattice or spin collective excitations of environment. apply Ising-symmetry BFKM with structureless spectral function s . The is valid for all exponents temperatures T. For 0s 1, range interest in context heavy-fermion quantum criticality, an interacting critical point, characterized by hyperscaling /T scaling, describes continuous phase transition between Kondo-screened localized phases. Ohmic dissipation =1, where model relevant certain mesoscopic qubit devices, found be Kosterlitz-Thouless-like. In regimes impurity corresponding Anderson shows clearly collapse resonance at transition. Connection made other recent results spin-boson model.