  We study the generation and evolution of entanglement between two qubits
coupled through one-dimensional waveguide modes. By using a complete quantum
electrodynamical formalism we go beyond the Markovian approximation. The
diagonalization of the hamiltonian is carried out, and a set of quasi-localized
eigenstates is found. We show that when the qubit-waveguide coupling is
increased, the Markov approximation is not anymore valid, and the generation of
entanglement is worsened.
