FIG. 4.

(a) Expectation value of the spin in the middle of the chain under time evolution with Hamiltonian (3), starting from initial configurations with two pairs of domain walls: 00 · · · 011…100 · · · 011…100 · · · 0. The dashed lines mark the diagonal ensemble average values: ${\langle {\sigma }_{13}^z\rangle }_{\text{diag}}={\sum }_n\langle n\left|{\sigma }_{13}^z\right|n\rangle {\left|c_n\right|}^2$, where |n⟩ denotes the eigenstate of the Hamiltonian and c_n = $\langle n\mid {\psi }_0\rangle$ is the overlap between the initial state and each eigenstate. (b) Scaling of the saturation timescale t_* as a function of d_DW.