The dynamics of an ensemble of identically prepared two-qubit systems is
investigated which is subjected to the iteratively applied measurements and
conditional selection of a typical entanglement purification protocol. It is
shown that the resulting measurement-induced non-linear dynamics of the
two-qubit state exhibits strong sensitivity to initial conditions and also true
chaos. For a special class of initially prepared two-qubit states two types of
islands characterize the asymptotic limit. They correspond to a separable and a
maximally entangled two-qubit state, respectively, and their boundaries form
fractal-like structures. In the presence of incoherent noise an additional
stable asymptotic cycle appears.Comment: 5 pages, 3 figure
