  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.
