  Open quantum systems are subject to interaction with their surrounding
environment. In many applications, at low temperatures, quantum environments
fall into two universality classes of models: Caldeira-Leggett oscillator bath
models and Prokof'ev-Stamp spin bath models. The two classes are commonly
recognized to be distinct and to have strikingly different effects on principal
systems, except at weak coupling limits. However, I show here, in contrast,
that oscillator bath models can simulate the effect of spin bath models in
strong coupling limit of the spin bath. I choose parameters of the oscillator
bath models such that they produce incoherent relaxation, just as in the spin
bath models, with relaxation rates for a two-state system (a qubit) equivalent
to those of the spin bath models in the strong coupling limit.
