  Two, non-interacting two-level atoms immersed in a common bath can become
mutually entangled when evolving with a Markovian, completely positive
dynamics. For an environment made of external quantum fields, this phenomenon
can be studied in detail: one finds that entanglement production can be
controlled by varying the bath temperature and the distance between the atoms.
Remarkably, in certain circumstances, the quantum correlations can persist in
the asymptotic long-time regime.
