Symmetry-protected equivalence of the Affleck--Kennedy--Lieb--Tasaki state and cluster state
= Symmetry-protected equivalence of the Affleck--Kennedy--Lieb--Tasaki state and cluster state
{c}
After suitable blocking, the AKLT and one-dimensional <cluster states> realize the same nontrivial $\mathbb Z_2\times\mathbb Z_2$ <symmetry-protected topological phase>. Their virtual symmetries carry the same nontrivial projective class and produce protected edge degrees of freedom.