  We study bipartite entanglement in a general one-particle state, and find
that the linear entropy, quantifying the bipartite entanglement, is directly
connected to the paricitpation ratio, charaterizing the state localization. The
more extended the state is, the more entangled the state. We apply the general
formalism to investigate ground-state and dynamical properties of entanglement
in the one-dimensional Harper model.
