  In the framework of cavity QED, we propose a practical scheme to purify
dynamically a bipartite entangled state using short chains of atoms coupled to
high-finesse optical cavities. In contrast to conventional entanglement
purification protocols, we avoid CNOT gates, thus reducing complicated pulse
sequences and superfluous qubit operations. Our interaction scheme works in a
deterministic way, and together with entanglement distribution and swapping,
opens a route towards efficient quantum repeaters for long-distance quantum
communication.
