  Consider an infinite collection of qubits arranged in a line, such that every
pair of nearest neighbors is entangled: an "entangled chain." In this paper we
consider entangled chains with translational invariance and ask how large one
can make the nearest neighbor entanglement. We find that it is possible to
achieve an entanglement of formation equal to 0.285 ebits between each pair of
nearest neighbors, and that this is the best one can do under certain
assumptions about the state of the chain.
