  Up to date, the life time of experimentally demonstrated entangled states has
been limited, due to their fragility under decoherence and dissipation.
Therefore, they are created under strict isolation conditions. In contrast, new
approaches harness the coupling of the system to the environment, which drives
the system into the desired state. Following these ideas, we present a robust
method for generating steady state entanglement between two distant atomic
ensembles. The proposed scheme relies on the interaction of the two atomic
systems with the common vacuum modes of the electromagnetic field which act as
an engineered environment. We develop the theoretical framework for two level
systems including dipole-dipole interactions and complement these results by
considering the implementation in multi-level ground states.
