title: Hidden Caldeira-Leggett dissipation in a Bose-Fermi Kondo model.
abstract: We show that the Bose-Fermi Kondo model (BFKM), which may find applicability both to certain dissipative mesoscopic qubit devices and to heavy-fermion systems described by the Kondo lattice model, can be mapped exactly onto the Caldeira-Leggett model. This mapping requires an ohmic bosonic bath and an Ising-type coupling between the latter and the impurity spin. This allows us to conclude unambiguously that there is an emergent Kosterlitz-Thouless quantum phase transition in the BFKM with an ohmic bosonic bath. By applying a bosonic numerical renormalization group approach, we thoroughly probe physical quantities close to the quantum phase transition.
authors.affiliation: Département de Physique and RQMP, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.
authors.forename: Mei-Rong
authors.initials: MR
authors.lastname: Li
authors.forename: Karyn
authors.initials: K
authors.lastname: Le Hur
authors.forename: Walter
authors.initials: W
authors.lastname: Hofstetter