  A continuous-time quantum walk on a graph $X$ is represented by the complex
matrix $\exp (-\mathrm{i} t A)$, where $A$ is the adjacency matrix of $X$ and
$t$ is a non-negative time. If the graph models a network of interacting
qubits, transfer of state among such qubits throughout time can be formalized
as the action of the continuous-time quantum walk operator in the
characteristic vectors of the vertices.
  Here we are concerned with the problem of determining which graphs admit a
perfect transfer of state. More specifically, we will study graphs whose
adjacency matrix is a sum of tensor products of $01$-matrices, focusing on the
case where a graph is the tensor product of two other graphs. As a result, we
will construct many new examples of perfect state transfer.
