Entangling atoms and ions in dissipative environments

Quantum information processing rests on our ability to manipulate quantum s uperpositions through coherent unitary transformations, and to establish en tanglement between constituent quantum components of the processor. The qua ntum information processor (a linear ion trap, or a cavity confining the ra diation field for example) exists in a dissipative environment. We discuss ways in which entanglement can be established within such dissipative envir onments. We can even make use of a strong interaction of the system with it s environment to produce entanglement in a controlled way.